Beetle

Beetle

Overview
Coleoptera is an order of insect
Insect
Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...

s commonly called beetles. The word "coleoptera" is from the Greek
Ancient Greek
Ancient Greek is the stage of the Greek language in the periods spanning the times c. 9th–6th centuries BC, , c. 5th–4th centuries BC , and the c. 3rd century BC – 6th century AD of ancient Greece and the ancient world; being predated in the 2nd millennium BC by Mycenaean Greek...

 , koleos, "sheath"; and , pteron, "wing", thus "sheathed wing". Coleoptera contains more species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 than any other order, constituting almost 25% of all known life-forms. About 40% of all described insect species are beetles (about 400,000 species), and new species are discovered frequently.
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Encyclopedia
Coleoptera is an order of insect
Insect
Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...

s commonly called beetles. The word "coleoptera" is from the Greek
Ancient Greek
Ancient Greek is the stage of the Greek language in the periods spanning the times c. 9th–6th centuries BC, , c. 5th–4th centuries BC , and the c. 3rd century BC – 6th century AD of ancient Greece and the ancient world; being predated in the 2nd millennium BC by Mycenaean Greek...

 , koleos, "sheath"; and , pteron, "wing", thus "sheathed wing". Coleoptera contains more species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 than any other order, constituting almost 25% of all known life-forms. About 40% of all described insect species are beetles (about 400,000 species), and new species are discovered frequently. Some estimates put the total number of species, described and undescribed, at as high as 100 million, but 1 million is a more accepted figure. The largest taxonomic family, the Curculionidae
Curculionidae
Curculionidae is the family of the "true" weevils . It was formerly recognized in 1998 as the largest of any animal family, with over 40,000 species described worldwide at that time...

 (the weevils or snout beetles), also belongs to this order.

The diversity of beetles is very wide-ranging. They are found in almost all types of habitats, but are not known to occur in the sea or in the polar region
Polar region
Earth's polar regions are the areas of the globe surrounding the poles also known as frigid zones. The North Pole and South Pole being the centers, these regions are dominated by the polar ice caps, resting respectively on the Arctic Ocean and the continent of Antarctica...

s. They interact with their ecosystem
Ecosystem
An ecosystem is a biological environment consisting of all the organisms living in a particular area, as well as all the nonliving , physical components of the environment with which the organisms interact, such as air, soil, water and sunlight....

s in several ways. They often feed on plants and fungi
Fungus
A fungus is a member of a large group of eukaryotic organisms that includes microorganisms such as yeasts and molds , as well as the more familiar mushrooms. These organisms are classified as a kingdom, Fungi, which is separate from plants, animals, and bacteria...

, break down animal and plant debris, and eat other invertebrate
Invertebrate
An invertebrate is an animal without a backbone. The group includes 97% of all animal species – all animals except those in the chordate subphylum Vertebrata .Invertebrates form a paraphyletic group...

s. Some species are prey of various animals including birds and mammals. Certain species are agricultural pests, such as the Colorado potato beetle
Colorado potato beetle
The Colorado potato beetle , also known as the Colorado beetle, the ten-striped spearman, the ten-lined potato beetle or the potato bug, is an important pest of potato crops. It is approximately 10 mm long, with a bright yellow/orange body and five bold brown stripes along the length of each...

 Leptinotarsa decemlineata, the boll weevil
Boll weevil
The boll weevil is a beetle measuring an average length of six millimeters, which feeds on cotton buds and flowers. Thought to be native to Central America, it migrated into the United States from Mexico in the late 19th century and had infested all U.S. cotton-growing areas by the 1920s,...

 Anthonomus grandis, the red flour beetle
Red flour beetle
The red flour beetle is a tenebrionid beetle. It is a worldwide stored product pest.Red flour beetles attack stored grain products causing loss and damage...

 Tribolium castaneum, and the mungbean or cowpea beetle Callosobruchus maculatus, while other species of beetles are important controls of agricultural pests. For example, beetles in the family Coccinellidae
Coccinellidae
Coccinellidae is a family of beetles, known variously as ladybirds , or ladybugs . Scientists increasingly prefer the names ladybird beetles or lady beetles as these insects are not true bugs...

 ("ladybirds" or "ladybugs") consume aphid
Aphid
Aphids, also known as plant lice and in Britain and the Commonwealth as greenflies, blackflies or whiteflies, are small sap sucking insects, and members of the superfamily Aphidoidea. Aphids are among the most destructive insect pests on cultivated plants in temperate regions...

s, scale insect
Scale insect
The scale insects are small insects of the order Hemiptera, generally classified as the superfamily Coccoidea. There are about 8,000 species of scale insects.-Ecology:...

s, thrips
Thrips
Thrips are tiny, slender insects with fringed wings . Other common names for thrips include thunderflies, thunderbugs, storm flies, thunderblights, and corn lice...

, and other plant-sucking insects that damage crops.

Species in the order Coleoptera are generally characterized by a particularly hard exoskeleton
Exoskeleton
An exoskeleton is the external skeleton that supports and protects an animal's body, in contrast to the internal skeleton of, for example, a human. In popular usage, some of the larger kinds of exoskeletons are known as "shells". Examples of exoskeleton animals include insects such as grasshoppers...

 and hard forewings (elytra
Elytron
An elytron is a modified, hardened forewing of certain insect orders, notably beetles and a few of the true bugs ; in most true bugs, the forewings are instead called hemelytra, as only the basal half is thickened while the apex is membranous...

, singular elytron). These elytra distinguish beetles from most other insect species, except for a few species of Hemiptera
Hemiptera
Hemiptera is an order of insects most often known as the true bugs , comprising around 50,000–80,000 species of cicadas, aphids, planthoppers, leafhoppers, shield bugs, and others...

. The beetle's exoskeleton is made up of numerous plates called sclerite
Sclerite
A sclerite is a hardened body part. The term is used in various branches of biology for various structures including hardened portions of sponges, but it is most commonly used for the hardened portions of arthropod exoskeletons....

s, separated by thin sutures. This design creates the armored defenses of the beetle while maintaining flexibility. The general anatomy
Anatomy
Anatomy is a branch of biology and medicine that is the consideration of the structure of living things. It is a general term that includes human anatomy, animal anatomy , and plant anatomy...

 of a beetle is quite uniform, although specific organs and appendage
Appendage
In invertebrate biology, an appendage is an external body part, or natural prolongation, that protrudes from an organism's body . It is a general term that covers any of the homologous body parts that may extend from a body segment...

s may vary greatly in appearance and function between the many families in the order. Like all insects, beetles' bodies are divided into three sections: the head, the thorax, and the abdomen. Coleopteran internal morphology is similar to other insects, although there are several examples of novelty. Such examples include species of water beetle
Water beetle
A water beetle is a beetle adapted to living in water. Water beetles rise to the water surface and take atmospheric air into their tracheal systems. There are approximately 2000 species of water beetles. The rest marine species tend to live in the intertidal zone...

 who use air bubbles in order to dive under the water, and can remain submerged thanks to passive diffusion allowing oxygen to transfer from the water into the bubble.

Beetles are endopterygotes
Endopterygota
The Endopterygota, also known as Holometabola, are insects of the subclass Pterygota which go through distinctive larval, pupal, and adult stages. They undergo a radical metamorphosis, with the larval and adult stages differing considerably in their structure and behaviour...

, which means that they undergo complete metamorphosis, a biological process
Biological process
A biological process is a process of a living organism. Biological processes are made up of any number of chemical reactions or other events that results in a transformation....

 by which an animal
Animal
Animals are a major group of multicellular, eukaryotic organisms of the kingdom Animalia or Metazoa. Their body plan eventually becomes fixed as they develop, although some undergo a process of metamorphosis later on in their life. Most animals are motile, meaning they can move spontaneously and...

 physically develops
Developmental biology
Developmental biology is the study of the process by which organisms grow and develop. Modern developmental biology studies the genetic control of cell growth, differentiation and "morphogenesis", which is the process that gives rise to tissues, organs and anatomy.- Related fields of study...

 after birth
Birth
Birth is the act or process of bearing or bringing forth offspring. The offspring is brought forth from the mother. The time of human birth is defined as the time at which the fetus comes out of the mother's womb into the world...

 or hatching, undergoing a series of conspicuous and relatively abrupt change in the its body
Body
With regard to living things, a body is the physical body of an individual. "Body" often is used in connection with appearance, health issues and death...

 structure. Coleopteran species have an extremely intricate behavior when mating, using such methods as pheromones for communication to locate potential mates. Males may fight for females using very elongated mandibles, causing a strong divergence between males and females in sexual dimorphism
Sexual dimorphism
Sexual dimorphism is a phenotypic difference between males and females of the same species. Examples of such differences include differences in morphology, ornamentation, and behavior.-Examples:-Ornamentation / coloration:...

.

Etymology


Coleoptera comes from the Greek
Ancient Greek
Ancient Greek is the stage of the Greek language in the periods spanning the times c. 9th–6th centuries BC, , c. 5th–4th centuries BC , and the c. 3rd century BC – 6th century AD of ancient Greece and the ancient world; being predated in the 2nd millennium BC by Mycenaean Greek...

 koleopteros, literally "sheath-wing", from koleos meaning "sheath", and pteron, meaning "wing". The name was given to the group by Aristotle
Aristotle
Aristotle was a Greek philosopher and polymath, a student of Plato and teacher of Alexander the Great. His writings cover many subjects, including physics, metaphysics, poetry, theater, music, logic, rhetoric, linguistics, politics, government, ethics, biology, and zoology...

 for their elytra, hardened shield-like forewings. The English name "beetle" comes from the Old English word bitela, literally meaning small biter, deriving from the word bitel, which means biting. In addition to names including the word "beetle", individual species of Coleoptera have a variety of common names, including fireflies
Firefly
Lampyridae is a family of insects in the beetle order Coleoptera. They are winged beetles, and commonly called fireflies or lightning bugs for their conspicuous crepuscular use of bioluminescence to attract mates or prey. Fireflies produce a "cold light", with no infrared or ultraviolet frequencies...

, June bugs
Phyllophaga (genus)
Phyllophaga is a very large genus of New World scarab beetles in the subfamily Melolonthinae. Common names for this genus and many other related genera in the subfamily Melolonthinae are May beetles, June bugs, and June beetles. They range in size from and are blackish or reddish-brown in colour,...

, ladybugs
Coccinellidae
Coccinellidae is a family of beetles, known variously as ladybirds , or ladybugs . Scientists increasingly prefer the names ladybird beetles or lady beetles as these insects are not true bugs...

 and weevil
Weevil
A weevil is any beetle from the Curculionoidea superfamily. They are usually small, less than , and herbivorous. There are over 60,000 species in several families, mostly in the family Curculionidae...

s.

Distribution and diversity


Beetles are one of the largest orders of insects, with 350,000–400,000 species in four suborders (Adephaga
Adephaga
Adephaga , with more than 40,000 recorded species in 10 families, is a suborder of highly specialized beetles and the second largest suborder of the order Coleoptera. Members of this suborder are adephagans, a term which notably include ground beetles, tiger beetles, predacious diving beetles, and...

, Archostemata
Archostemata
Archostemata is the smallest suborder of beetles, consisting of fewer than fifty known species organized into five families. Archostemata is an ancient lineage with a number of primitive characteristics. They are similar in morphology to the first beetles, which appear in the fossil record...

, Myxophaga
Myxophaga
Myxophaga is the second smallest suborder of Coleoptera after Archostemata, consisting of approximately 65 species of small to minute beetles in four families...

, and Polyphaga
Polyphaga
Polyphaga is the largest and most diverse suborder of beetles; the name is derived from two two Greek words: poly-, meaning 'many', and phagein, meaning 'to eat', so the suborder is called the “eaters of many things”...

), making up about 40% of all insect species described. Even though classification at the family level is a bit unstable, there are about 500 recognized families and subfamilies. One of the first proposed estimates of the total number of beetle species on the planet, based on field data rather than on catalog numbers. The technique used for his original estimate, possibly as many as 12,000,000 species, was criticized, and was later revised, with estimates of 850,000–4,000,000 species proposed. Some 70–95% of all beetle species, depending on the estimate, remain undescribed. The beetle fauna is not equally well known in all parts of the world. For example, the known beetle diversity of Australia is estimated at 23,000 species in 3265 genera and 121 families. This is slightly lower than reported for North America, a land mass of similar size with 25,160 species in 3526 genera and 129 families. While other predictions show there could be as many as 28,000 species in North America, including those currently undescribed, a realistic estimate of the little-studied Australian beetle fauna's true diversity could vary from 80,000 to 100,000.

Patterns of beetle diversity can be used to illustrate factors that have led to the success of the group as a whole. Based on estimates for all 165 families, more than 358,000 species of beetles have been described and are considered valid. Most species (about 62%) are in six extremely diverse families, each with at least 20,000 described species: Curculionidae
Curculionidae
Curculionidae is the family of the "true" weevils . It was formerly recognized in 1998 as the largest of any animal family, with over 40,000 species described worldwide at that time...

, Staphylinidae, Chrysomelidae, Carabidae, Scarabaeidae
Scarabaeidae
The family Scarabaeidae as currently defined consists of over 30,000 species of beetles worldwide. The species in this large family are often called scarabs or scarab beetles. The classification of this family is fairly unstable, with numerous competing theories, and new proposals appearing quite...

, and Cerambycidae. The smaller families account for 22% of the total species - 127 families with fewer than 1000 described species and 29 families with 1000–6000 described species. So, the success of beetles as a whole is driven not only by several extremely diverse lineages, but also by a high number of moderately successful lineages. The patterns seen today indicate that beetles went through a massive adaptive radiation early in their evolutionary history, with many of the resulting lineages flourishing through hundreds of millions of years to the present. The adaptive radiation of angiosperms helped drive the diversification of beetles, as four of the six megadiverse families of beetles are primarily angiosperm-feeders:Curculionidae
Curculionidae
Curculionidae is the family of the "true" weevils . It was formerly recognized in 1998 as the largest of any animal family, with over 40,000 species described worldwide at that time...

, Chrysomelidae, Scarabaeidae
Scarabaeidae
The family Scarabaeidae as currently defined consists of over 30,000 species of beetles worldwide. The species in this large family are often called scarabs or scarab beetles. The classification of this family is fairly unstable, with numerous competing theories, and new proposals appearing quite...

, and Cerambycidae. However, even without the phytophagous groups, lineages of predators, scavengers, and fungivores are tremendously successful. Coleoptera are found in nearly all natural habitats, including freshwater and marine habitats, everywhere there is vegetative foliage, from trees and their bark to flowers, leaves, and underground near roots- even inside plants in galls, in every plant tissue including dead or decaying ones.

External morphology


Beetles are generally characterized by a particularly hard exoskeleton
Exoskeleton
An exoskeleton is the external skeleton that supports and protects an animal's body, in contrast to the internal skeleton of, for example, a human. In popular usage, some of the larger kinds of exoskeletons are known as "shells". Examples of exoskeleton animals include insects such as grasshoppers...

 and hard forewings (elytra
Elytron
An elytron is a modified, hardened forewing of certain insect orders, notably beetles and a few of the true bugs ; in most true bugs, the forewings are instead called hemelytra, as only the basal half is thickened while the apex is membranous...

). The beetle's exoskeleton is made up of numerous plates called sclerite
Sclerite
A sclerite is a hardened body part. The term is used in various branches of biology for various structures including hardened portions of sponges, but it is most commonly used for the hardened portions of arthropod exoskeletons....

s, separated by thin sutures. This design provides armored defenses while maintaining flexibility. The general anatomy
Anatomy
Anatomy is a branch of biology and medicine that is the consideration of the structure of living things. It is a general term that includes human anatomy, animal anatomy , and plant anatomy...

 of a beetle is quite uniform, although specific organs and appendage
Appendage
In invertebrate biology, an appendage is an external body part, or natural prolongation, that protrudes from an organism's body . It is a general term that covers any of the homologous body parts that may extend from a body segment...

s may vary greatly in appearance and function between the many families in the order. Like all insects, beetles' bodies are divided into three sections: the head, the thorax, and the abdomen.

Head


The head, having mouthparts projecting forward or sometimes downturned, is usually heavily sclerotized and varies in size. The eyes are compound and may display remarkable adaptability, as in the case of whirligig beetle
Whirligig beetle
The whirligig beetles are a family of water beetles that normally live on the surface of the water. They get their common name from their habit of swimming rapidly in circles when alarmed, and are also notable for their which can see both above and below water.They are also known for their...

s (family Gyrinidae), where they are split to allow a view both above and below the waterline. Other species also have divided eyes – some longhorn beetle
Longhorn beetle
The longhorn beetles are a cosmopolitan family of beetles, typically characterized by extremely long antennae, which are often as long as or longer than the beetle's body...

s (family Cerambycidae) and weevils – while many have eyes that are notched to some degree. A few beetle genera also possess ocelli
Ocellus
A simple eye refers to a type of eye design or optical arrangement that contains a single lens which detect light. A "simple eye" is so-called in distinction from a multi-lensed "compound eye", and is not necessarily at all simple in the usual sense of the word...

, which are small, simple eyes usually situated farther back on the head (on the vertex
Vertex (anatomy)
In arthropod and vertebrate anatomy, the vertex refers to the upper surface of the head.In humans, the vertex is formed by four bones of the skull: the frontal bone, the two parietal bones, and the occipital bone...

).

Beetles' antennae
Antenna (biology)
Antennae in biology have historically been paired appendages used for sensing in arthropods. More recently, the term has also been applied to cilium structures present in most cell types of eukaryotes....

 are primarily organs of smell, but may also be used to feel out a beetle's environment physically. They may also be used in some families during mating, or among a few beetles for defence. Antennae vary greatly in form within the Coleoptera, but are often similar within any given family. In some cases, males and females of the same species will have different antennal forms. Antennae may be clavate (flabellate and lamellate are sub-forms of clavate, or clubbed antennae), filiform, geniculate, moniliform, pectinate, or serrate.

Beetles have mouthparts
Insect mouthparts
Insects exhibit a range of mouthparts, adapted to particular modes of feeding. The earliest insects had chewing mouthparts...

 similar to those of grasshopper
Grasshopper
The grasshopper is an insect of the suborder Caelifera in the order Orthoptera. To distinguish it from bush crickets or katydids, it is sometimes referred to as the short-horned grasshopper...

s. Of these parts, the most commonly known are probably the mandibles
Mandible (insect)
Insect mandibles are a pair of appendages near the insect’s mouth, and the most anterior of the three pairs of oral appendages . Their function is typically to grasp, crush, or cut the insect’s food, or to defend against predators or rivals...

, which appear as large pincers on the front of some beetles. The mandibles are a pair of hard, often tooth-like structures that move horizontally to grasp, crush, or cut food or enemies (see defence, below). Two pairs of finger-like appendage
Appendage
In invertebrate biology, an appendage is an external body part, or natural prolongation, that protrudes from an organism's body . It is a general term that covers any of the homologous body parts that may extend from a body segment...

s are found around the mouth in most beetles, serving to move food into the mouth. These are the maxillary and labial palpi. In many species the mandibles are sexually dimorphic, with the males' enlarged enormously compared with those of females of the same species.

Thorax


The thorax is segmented
Segmentation (biology)
Segmentation in biology refers to either a type of gastrointestinal motility or the division of some animal and plant body plans into a series of repetitive segments. This article will focus on the segmentation of animal body plans, specifically using the examples of the phyla Arthropoda,...

 into the two discernible parts, the pro- and pterathorax. The pterathorax is the fused meso- and metathorax, which are commonly separate in other insect species, although flexibly articulate from the prothorax. When viewed from below, the thorax is that part from which all three pairs of legs and both pairs of wings arise. The abdomen is everything posterior to the thorax. When viewed from above, most beetles appear to have three clear sections, but this is deceptive: on the beetle's upper surface, the middle "section" is a hard plate called the pronotum, which is only the front part of the thorax; the back part of the thorax is concealed by the beetle's wings
Insect wing
Insects are the only group of invertebrates known to have evolved flight. Insects possess some remarkable flight characteristics and abilities, still far superior to attempts by humans to replicate their capabilities. Even our understanding of the aerodynamics of flexible, flapping wings and how...

. This further segmentation is usually best seen on the abdomen.


Extremities


The multi-segmented legs
Arthropod leg
The arthropod leg is a form of jointed appendage of arthropods, usually used for walking. Many of the terms used for arthropod leg segments are of Latin origin, and may be confused with terms for bones: coxa , trochanter , femur, tibia, tarsus, ischium, metatarsus, carpus, dactylus ,...

 end in two to five small segments called tarsi. Like many other insect orders beetles bear claws, usually one pair, on the end of the last tarsal segment of each leg. While most beetles use their legs for walking, legs may be variously modified and adapted for other uses. Among aquatic families – Dytiscidae
Dytiscidae
Dytiscidae – based on the Greek dytikos , "able to dive" – are the predaceous diving beetles, a family of water beetles. They are about 25 mm long on average, though there is much variation between species. Dytiscus latissimus, the largest, can grow up to 45 mm long...

, Haliplidae, many species of Hydrophilidae and others – the legs, most notably the last pair, are modified for swimming and often bear rows of long hairs to aid this purpose. Other beetles have fossorial
Fossorial
A fossorial organism is one that is adapted to digging and life underground such as the badger, the naked mole rat, and the mole salamanders Ambystomatidae...

 legs that are widened and often spined for digging. Species with such adaptations are found among the scarabs, ground beetles, and clown beetle
Clown beetle
Histeridae is a family of beetles commonly known as Clown beetles or Hister beetles. This very diverse group of beetles contains 3,900 species found worldwide. They can be easily identified by their shortened elytra that leaves two of the seven tergites exposed, and their elbowed antennae with...

s (family Histeridae). The hind legs of some beetles, such as flea beetle
Flea beetle
Flea beetles is a general name applied to the small, jumping beetles of the leaf beetle family . They make up the tribe Alticini, which is a part of the subfamily Galerucinae, though they were historically classified as a subfamily in their own right...

s (within Chrysomelidae) and flea weevils (within Curculionidae), are enlarged and designed for jumping.

Wings


The elytra are connected to the pterathorax, so named because it is where the wings are connected (pteron meaning "wing" in Greek). The elytra are not used for flight
Insect flight
Insects are the only group of invertebrates known to have evolved flight. Insects possess some remarkable flight characteristics and abilities, still far superior to attempts by humans to replicate their capabilities. Even our understanding of the aerodynamics of flexible, flapping wings and how...

, but tend to cover the hind part of the body and protect the second pair of wings
Insect wing
Insects are the only group of invertebrates known to have evolved flight. Insects possess some remarkable flight characteristics and abilities, still far superior to attempts by humans to replicate their capabilities. Even our understanding of the aerodynamics of flexible, flapping wings and how...

 (alae). They must be raised in order to move the hind flight wings. A beetle's flight wings are crossed with veins and are folded after landing, often along these veins, and stored below the elytra. In some beetles, the ability to fly has been lost. These include some ground beetle
Ground beetle
Ground beetles are a large, cosmopolitan family of beetles, Carabidae, with more than 40,000 species worldwide, approximately 2,000 of which are found in North America and 2,700 in Europe.-Description and ecology:...

s (family Carabidae) and some "true weevils" (family Curculionidae
Curculionidae
Curculionidae is the family of the "true" weevils . It was formerly recognized in 1998 as the largest of any animal family, with over 40,000 species described worldwide at that time...

), but also desert- and cave-dwelling species of other families. Many have the two elytra fused together, forming a solid shield over the abdomen. In a few families, both the ability to fly and the elytra have been lost, with the best known example being the glow-worms
Glowworm
Glowworm, or glow worm, is the common name for various groups of insect larvae and adult larviform females that glow through bioluminescence. They may sometimes resemble worms, but all are insects .-Classification:Major families are:* Lampyridae , found around the world...

 of the family Phengodidae
Phengodidae
The beetle family Phengodidae is known also as glowworm beetles, whose larvae are known as glowworms. The females and larvae have bioluminescent organs. They occur throughout the New World from extreme southern Canada to Chile...

, in which the females are larviform
Larviform female
Larviform female is biological phenomenon occurring in some species, where the females in the adult stage of metamorphosis resemble the larvae to various degrees. Typically, the female is wingless and generally larger than the male...

 throughout their lives.

Abdomen


The abdomen
Abdomen
In vertebrates such as mammals the abdomen constitutes the part of the body between the thorax and pelvis. The region enclosed by the abdomen is termed the abdominal cavity...

 is the section behind the metathorax, made up of a series of rings, each with a hole for breathing and respiration, called a spiracle; composing three different segmented sclerites: the tergum, pleura, and the sternum. The tergum in almost all species is membranous, or usually soft and concealed by the wings and elytra when not in flight. The pleura (singular: pleuron) are usually small or hidden in some species, with each pleuron having a single spiracle. The sternum is the most widely visible part of the abdomen, being a more or less scelortized segment. The abdomen itself does not have any appendages, however some species (for example,, Mordellidae
Mordellidae
Mordellidae is a family of beetles commonly known as tumbling flower beetles for the typical irregular movements they make when escaping predators, or as pintail beetles due to their abdominal tip which aids them in performing these tumbling movements...

) have articulating sternal lobes.

Internal morphology



Digestive system


The digestive system of beetles is primarily based on plants which they for the most part feed upon, with mostly the anterior midgut
Midgut
The midgut is the portion of the embryo from which most of the intestines develop. After it bends around the superior mesenteric artery, it is called the "midgut loop"...

 performing digestion, although in predatory species (for example Carabidae) most digestion occurs in the crop by means of midgut enzymes. In Elateridae species, the predatory larvae defecate enzymes on their prey, with digestion being extraorally. The alimentary canal basically consists of a short narrow pharynx
Pharynx
The human pharynx is the part of the throat situated immediately posterior to the mouth and nasal cavity, and anterior to the esophagus and larynx. The human pharynx is conventionally divided into three sections: the nasopharynx , the oropharynx , and the laryngopharynx...

, a widened expansion, the crop
Crop
Crop may refer to:* Crop, a plant grown and harvested for agricultural use* Crop , part of the alimentary tract of some animals* Crop , a modified whip used in horseback riding or disciplining humans...

 and a poorly developed gizzard
Gizzard
The gizzard, also referred to as the ventriculus, gastric mill, and gigerium, is an organ found in the digestive tract of some animals, including birds, reptiles, earthworms and some fish. This specialized stomach constructed of thick, muscular walls is used for grinding up food; often rocks are...

. After there is a midgut, that varies in dimensions between species, with a large amount of cecum
Cecum
The cecum or caecum is a pouch, connecting the ileum with the ascending colon of the large intestine. It is separated from the ileum by the ileocecal valve or Bauhin's valve, and is considered to be the beginning of the large intestine. It is also separated from the colon by the cecocolic...

, with a hindgut, with varying lengths. There are typically four to six Malpighian tubules.

Nervous system


The nervous system
Nervous system
The nervous system is an organ system containing a network of specialized cells called neurons that coordinate the actions of an animal and transmit signals between different parts of its body. In most animals the nervous system consists of two parts, central and peripheral. The central nervous...

 in beetles contains all the types found in insects, varying between different species. With three thoracic and seven or eight abdominal ganglia can be distinguished to that in which all the thoracic and abdominal ganglia are fused to form a composite structure.

Respiratory system


Oxygen
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...

 is obtained via a tracheal system
Invertebrate trachea
The invertebrate trachea refers to the open respiratory system composed of spiracles, tracheae, and tracheoles that terrestrial arthropods have to transport metabolic gases to and from tissues....

. Air enters a series of tubes along the body through openings called spiracle
Spiracle
Spiracles are openings on the surface of some animals that usually lead to respiratory systems.-Vertebrates:The spiracle is a small hole behind each eye that opens to the mouth in some fishes. In the primitive jawless fish the first gill opening immediately behind the mouth is essentially similar...

s, and is then taken into increasingly finer fibers. This bubble may be held under the elytra or it may be trapped against the body using specialized hairs. The bubble usually covers one or more spiracles so the insect can breathe air from the bubble while submerged. An air bubble provides an insect with only a short-term supply of oxygen, but thanks to its unique physical properties, oxygen will diffuse into the bubble and displacing the nitrogen, called passive diffusion, however the volume of the bubble eventually diminishes and the beetle will have to return to the surface.

Circulatory system


Pumping movements of the body force the air through the system. Beetles have hemolymph
Hemolymph
Hemolymph, or haemolymph, is a fluid in the circulatory system of some arthropods and is analogous to the fluids and cells making up both blood and interstitial fluid in vertebrates such as birds and mammals...

 instead of blood
Blood
Blood is a specialized bodily fluid in animals that delivers necessary substances such as nutrients and oxygen to the cells and transports metabolic waste products away from those same cells....

 like other insect species, the open circulatory system of the beetle is driven by a tube-like heart attached to the top inside of the thorax. Some species of diving beetle
Dytiscidae
Dytiscidae – based on the Greek dytikos , "able to dive" – are the predaceous diving beetles, a family of water beetles. They are about 25 mm long on average, though there is much variation between species. Dytiscus latissimus, the largest, can grow up to 45 mm long...

s (Dytiscidae) carry a bubble of air with them whenever they dive beneath the water surface.

Specialized organs


Different glands specialize for different pheromones produced for finding mates. Pheromones from species of Rutelinea are produced from epithelial cell
Epithelium
Epithelium is one of the four basic types of animal tissue, along with connective tissue, muscle tissue and nervous tissue. Epithelial tissues line the cavities and surfaces of structures throughout the body, and also form many glands. Functions of epithelial cells include secretion, selective...

s lining the inner surface of the apical abdominal segments or amino acid based pheromones of Melolonthinae
Melolonthinae
Melolonthinae is a subfamily of the scarab beetles . It is a very diverse group; distributed over most of the world, it contains many familiar species. Some authors include the scarab subfamilies Euchirinae and Pachypodinae as tribes in the Melolonthinae.Unlike some of their relatives, their...

 from eversible glands on the abdominal apex. Other species produce different types of pheromones. Dermestids produce ester
Ester
Esters are chemical compounds derived by reacting an oxoacid with a hydroxyl compound such as an alcohol or phenol. Esters are usually derived from an inorganic acid or organic acid in which at least one -OH group is replaced by an -O-alkyl group, and most commonly from carboxylic acids and...

s, and species of Elateridae produce fatty-acid-derived aldehyde
Aldehyde
An aldehyde is an organic compound containing a formyl group. This functional group, with the structure R-CHO, consists of a carbonyl center bonded to hydrogen and an R group....

s and acetate
Acetate
An acetate is a derivative of acetic acid. This term includes salts and esters, as well as the anion found in solution. Most of the approximately 5 billion kilograms of acetic acid produced annually in industry are used in the production of acetates, which usually take the form of polymers. In...

s. For means of finding a mate also, fireflies (Lampyridae) utilized modified fat body cells with transparent surfaces backed with reflective uric acid crystals to biosynthetically produce light, or bioluminescence
Bioluminescence
Bioluminescence is the production and emission of light by a living organism. Its name is a hybrid word, originating from the Greek bios for "living" and the Latin lumen "light". Bioluminescence is a naturally occurring form of chemiluminescence where energy is released by a chemical reaction in...

. The light produce is highly efficient, as it is produced by oxidation of luciferin
Firefly luciferin
Firefly luciferin is the luciferin, or light-emitting compound, found in many firefly species. It is the substrate of luciferase , which is responsible for the characteristic yellow light emission from many firefly species...

 by the enzymes luciferase
Luciferase
Luciferase is a generic term for the class of oxidative enzymes used in bioluminescence and is distinct from a photoprotein. One famous example is the firefly luciferase from the firefly Photinus pyralis. "Firefly luciferase" as a laboratory reagent usually refers to P...

 in the presence of ATP
Adenosine triphosphate
Adenosine-5'-triphosphate is a multifunctional nucleoside triphosphate used in cells as a coenzyme. It is often called the "molecular unit of currency" of intracellular energy transfer. ATP transports chemical energy within cells for metabolism...

 (adenosine triphospate) and oxygen, producing oxyluciferin, carbon dioxide, and light.

A notable number of species have developed special glands that produce chemicals for deterring predators (see Defense and predation). The Ground beetle
Ground beetle
Ground beetles are a large, cosmopolitan family of beetles, Carabidae, with more than 40,000 species worldwide, approximately 2,000 of which are found in North America and 2,700 in Europe.-Description and ecology:...

's (of Carabidae) defensive glands, located at the posterior, produce a variety of hydrocarbon
Hydrocarbon
In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons from which one hydrogen atom has been removed are functional groups, called hydrocarbyls....

s, aldehyde
Aldehyde
An aldehyde is an organic compound containing a formyl group. This functional group, with the structure R-CHO, consists of a carbonyl center bonded to hydrogen and an R group....

s, phenol
Phenol
Phenol, also known as carbolic acid, phenic acid, is an organic compound with the chemical formula C6H5OH. It is a white crystalline solid. The molecule consists of a phenyl , bonded to a hydroxyl group. It is produced on a large scale as a precursor to many materials and useful compounds...

s, quinone
Quinone
A quinone is a class of organic compounds that are formally "derived from aromatic compounds [such as benzene or naphthalene] by conversion of an even number of –CH= groups into –C– groups with any necessary rearrangement of double bonds," resulting in "a fully conjugated cyclic dione structure."...

s, ester
Ester
Esters are chemical compounds derived by reacting an oxoacid with a hydroxyl compound such as an alcohol or phenol. Esters are usually derived from an inorganic acid or organic acid in which at least one -OH group is replaced by an -O-alkyl group, and most commonly from carboxylic acids and...

s, and acid
Acid
An acid is a substance which reacts with a base. Commonly, acids can be identified as tasting sour, reacting with metals such as calcium, and bases like sodium carbonate. Aqueous acids have a pH of less than 7, where an acid of lower pH is typically stronger, and turn blue litmus paper red...

s released from an opening at the end of the abdomen. African carabid beetles (for example, Anthia
Anthia
Anthia is a genus of the ground beetle family, the Carabidae. Species of Anthia can spray a jet of formic acid up to , which if not treated, can cause blindness in cats and chickens....

and Thermophilum - Thermophilum generally included within Anthia
Anthia
Anthia is a genus of the ground beetle family, the Carabidae. Species of Anthia can spray a jet of formic acid up to , which if not treated, can cause blindness in cats and chickens....

) employ the same chemicals as ants: formic acid
Formic acid
Formic acid is the simplest carboxylic acid. Its chemical formula is HCOOH or HCO2H. It is an important intermediate in chemical synthesis and occurs naturally, most notably in the venom of bee and ant stings. In fact, its name comes from the Latin word for ant, formica, referring to its early...

. Bombardier beetle
Bombardier beetle
Bombardier beetles are ground beetles in the tribes Brachinini, Paussini, Ozaenini, or Metriini—more than 500 species altogether—which are most notable for the defense mechanism that gives them their name: When disturbed, the beetle ejects a noxious chemical spray in a rapid burst of pulses from...

s have well-developed, like other carabid beetles, pygidial glands that empty from the lateral edges of the intersegment membranes between the seventh and eighth abdominal segments. The gland is made of two containing chambers. The first holds hydroquinone
Hydroquinone
Hydroquinone, also benzene-1,4-diol or quinol, is an aromatic organic compound that is a type of phenol, having the chemical formula C6H42. Its chemical structure, shown in the table at right, has two hydroxyl groups bonded to a benzene ring in a para position. It is a white granular solid...

s and hydrogen peroxide
Hydrogen peroxide
Hydrogen peroxide is the simplest peroxide and an oxidizer. Hydrogen peroxide is a clear liquid, slightly more viscous than water. In dilute solution, it appears colorless. With its oxidizing properties, hydrogen peroxide is often used as a bleach or cleaning agent...

, with the second holding just hydrogen peroxide plus catalase
Catalase
Catalase is a common enzyme found in nearly all living organisms that are exposed to oxygen, where it catalyzes the decomposition of hydrogen peroxide to water and oxygen...

s. These chemicals mix and result in an explosive ejection, forming temperatures of around 100 °C (212 °F), with the breakdown of hydroquinone to H2 + O2 + quinone, with the O2 propelling the excretion.

Tympanal organ
Tympanal organ
A tympanal organ is a hearing organ in insects, consisting of a membrane stretched across a frame backed by an air sac and associated sensory neurons...

s or hearing organs, which is a membrane (tympanum) stretched across a frame backed by an air sac and associated sensory neurons, are described in two families. Several species of the genus Cicindela
Cicindela
Cicindela are generally brightly colored and metallic beetles, often with some sort of patterning of ivory or cream-colored markings. They are most abundant and diverse in habitats with sandy soil , and very often near bodies of water, even if seasonally transient; along river, sea and lake shores,...

(Cicindelidae) have ears on the dorsal surface of the first abdominal segment beneath the wing; two tribes in the subfamily Dynastinae (Scarabaeidae
Scarabaeidae
The family Scarabaeidae as currently defined consists of over 30,000 species of beetles worldwide. The species in this large family are often called scarabs or scarab beetles. The classification of this family is fairly unstable, with numerous competing theories, and new proposals appearing quite...

) have ears just beneath the pronotal shield or neck membrane. The ears of both families are to ultrasonic frequencies, with strong evidence that they function to detect the presence of bats via there ultrasonic echolocation. Even though beetles constitute a large order and live in a variety of niche
Ecological niche
In ecology, a niche is a term describing the relational position of a species or population in its ecosystem to each other; e.g. a dolphin could potentially be in another ecological niche from one that travels in a different pod if the members of these pods utilize significantly different food...

s, examples of hearing is surprisingly lacking in species, though it is likely that most are just undiscovered.

Reproduction and development


Beetles are members of Endopterygota
Endopterygota
The Endopterygota, also known as Holometabola, are insects of the subclass Pterygota which go through distinctive larval, pupal, and adult stages. They undergo a radical metamorphosis, with the larval and adult stages differing considerably in their structure and behaviour...

, which means like most other insects under complete metamorphosis, which consists of four main stages: the egg
Egg (biology)
An egg is an organic vessel in which an embryo first begins to develop. In most birds, reptiles, insects, molluscs, fish, and monotremes, an egg is the zygote, resulting from fertilization of the ovum, which is expelled from the body and permitted to develop outside the body until the developing...

, the larva
Larva
A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle...

, the pupa
Pupa
A pupa is the life stage of some insects undergoing transformation. The pupal stage is found only in holometabolous insects, those that undergo a complete metamorphosis, going through four life stages; embryo, larva, pupa and imago...

, and the imago
Imago
In biology, the imago is the last stage of development of an insect, after the last ecdysis of an incomplete metamorphosis, or after emergence from the pupa where the metamorphosis is complete...

 or adult. The larvae are commonly called grubs
Larva
A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle...

 and the pupa are called cocoons.

Mating



Beetles may display extremely intricate behavior when mating. Pheromone communication is likely to be important in the location of a mate.
Different species use different chemicals for their pheromones. Some scarab beetles (for example,, Rutelinae) utilize pheromones derived from fatty acid synthesis
Fatty acid synthesis
Fatty acid synthesis is the creation of fatty acids from acetyl-CoA and malonyl-CoA precursors through action of enzymes called fatty acid synthases...

, while other scarab beetles use amino acid
Amino acid
Amino acids are molecules containing an amine group, a carboxylic acid group and a side-chain that varies between different amino acids. The key elements of an amino acid are carbon, hydrogen, oxygen, and nitrogen...

s and terpenoid compounds (for example,, Melolonthinae
Melolonthinae
Melolonthinae is a subfamily of the scarab beetles . It is a very diverse group; distributed over most of the world, it contains many familiar species. Some authors include the scarab subfamilies Euchirinae and Pachypodinae as tribes in the Melolonthinae.Unlike some of their relatives, their...

). Another way species of Coleoptera find mates is the use of biosynthesized light, or bioluminescence
Bioluminescence
Bioluminescence is the production and emission of light by a living organism. Its name is a hybrid word, originating from the Greek bios for "living" and the Latin lumen "light". Bioluminescence is a naturally occurring form of chemiluminescence where energy is released by a chemical reaction in...

. This special form of a mating call is confined to fireflies
Firefly
Lampyridae is a family of insects in the beetle order Coleoptera. They are winged beetles, and commonly called fireflies or lightning bugs for their conspicuous crepuscular use of bioluminescence to attract mates or prey. Fireflies produce a "cold light", with no infrared or ultraviolet frequencies...

 (Lampyridae) by the use of abdominal light producing organs. The males and females engage in complex dialogue before mating, identifying different species by differences in duration, flight patterns, composition, and intensity.

Before mating male and females may engage in various forms of behavior. Males and females may stridulate, or vibrate the object they are on. In some species (for example,, Meloidae) the male climbs onto the dorsum of the female and stroke his antennae on her head, palps and antennae. In the genus Eupompha of said family, the males draws the antennae along the longitudinal vertex on the male. They may not mate at all if they do not perform the precopulatory ritual.

Conflict can play a part in the mating rituals of species such as burying beetle
Burying beetle
Burying beetles or sexton beetles are the best-known members of the family Silphidae . Burying beetles are true to their name. Most of these beetles are black with red markings on the elytra . They bury the carcasses of small vertebrates such as birds and rodents as a food source for their larvae...

s (genus Nicrophorus) where conflicts between males and females rage until only one of each is left, thus ensuring reproduction by the strongest and fittest. Many male beetles are territorial and will fiercely defend their small patch of territory from intruding males. In such species, the males may often have horns on the head and/or thorax, making their overall body lengths greater than those of the females, unlike most insects. Pairing is generally short but in some cases will last for several hours. During pairing sperm cell
Spermatozoon
A spermatozoon is a motile sperm cell, or moving form of the haploid cell that is the male gamete. A spermatozoon joins an ovum to form a zygote...

s are transferred to the female to fertilize the egg.

Life cycle



Egg


A single female may lay from several dozen to several thousand eggs during her lifetime. Eggs are usually laid according to the substrate the larva
Larva
A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle...

 will feed on upon hatching. Among others, they can be laid loose in the substrate (for example, flour beetle), laid in clumps on leaves (for example, Colorado potato beetle
Colorado potato beetle
The Colorado potato beetle , also known as the Colorado beetle, the ten-striped spearman, the ten-lined potato beetle or the potato bug, is an important pest of potato crops. It is approximately 10 mm long, with a bright yellow/orange body and five bold brown stripes along the length of each...

), or individually attached (for example, mungbean beetle and other seed borers) or buried in the medium (for example, carrot weevil).

Parental care varies between species, ranging from the simple laying of eggs under a leaf to certain scarab beetles
Scarabaeidae
The family Scarabaeidae as currently defined consists of over 30,000 species of beetles worldwide. The species in this large family are often called scarabs or scarab beetles. The classification of this family is fairly unstable, with numerous competing theories, and new proposals appearing quite...

, which construct underground structures complete with a supply of dung to house and feed their young. Other beetles are leaf roller
Attelabidae
The Attelabidae or leaf-rolling weevils are a widespread family of weevils. There are more than 2000 species. They are included within the primitive weevils, because of their straight antennae, which are inserted near the base of the rostrum...

s, biting sections of leaves to cause them to curl inwards, then laying their eggs, thus protected, inside.

Larva



The larva
Larva
A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle...

 is usually the principal feeding stage of the beetle life cycle
Biological life cycle
A life cycle is a period involving all different generations of a species succeeding each other through means of reproduction, whether through asexual reproduction or sexual reproduction...

. Larvae tend to feed voraciously once they emerge from their eggs. Some feed externally on plants, such as those of certain leaf beetles, while others feed within their food sources. Examples of internal feeders are most Buprestidae and longhorn beetles. The larvae of many beetle families are predatory like the adults (ground beetles, ladybirds, rove beetles). The larval period varies between species but can be as long as several years. The larva are highly varied amongst species, with a well-developed and sclerotized head and have distinguishable thoracic and abdominal segments (usually the tenth, though sometimes the eight or ninth).

Beetle larvae can be differentiated from other insect larvae by their hardened, often darkened head, the presence of chewing mouthparts, and spiracle
Spiracle
Spiracles are openings on the surface of some animals that usually lead to respiratory systems.-Vertebrates:The spiracle is a small hole behind each eye that opens to the mouth in some fishes. In the primitive jawless fish the first gill opening immediately behind the mouth is essentially similar...

s along the sides of the body. Like adult beetles, the larvae are varied in appearance, particularly between beetle families. Beetles whose larvae are somewhat flattened and are highly mobile are the ground beetles, some rove beetles, and others; their larvae are described as campodeiform. Some beetle larvae resemble hardened worms with dark head capsules and minute legs. These are elateriform larvae, and are found in the click beetle
Click beetle
The family Elateridae is commonly called click beetles , elaters, snapping beetles, spring beetles or "skipjacks". They are a cosmopolitan beetle family characterized by the unusual click mechanism they possess...

 (Elateridae) and darkling beetle
Darkling beetle
Darkling beetles are a family of beetles found worldwide, estimated at more than 20,000 species. Many of the beetles have black elytra, leading to their common name...

 (Tenebrionidae) families. Some elateriform larvae of click beetles are known as wireworms
Click beetle
The family Elateridae is commonly called click beetles , elaters, snapping beetles, spring beetles or "skipjacks". They are a cosmopolitan beetle family characterized by the unusual click mechanism they possess...

. Beetles in the families of the Scarabaeoidea
Scarabaeoidea
Scarabaeoidea is a superfamily of beetles, the only subgroup of the infraorder Scarabaeiformia. Around 35,000 species are placed in this superfamily and some 200 new species are described each year...

 have short, thick larvae described as scarabaeiform, but more commonly known as grubs.

All beetle larvae go through several instar
Instar
An instar is a developmental stage of arthropods, such as insects, between each molt , until sexual maturity is reached. Arthropods must shed the exoskeleton in order to grow or assume a new form. Differences between instars can often be seen in altered body proportions, colors, patterns, or...

s, which are the developmental stages between each moult
Ecdysis
Ecdysis is the moulting of the cuticula in many invertebrates. This process of moulting is the defining feature of the clade Ecdysozoa, comprising the arthropods, nematodes, velvet worms, horsehair worms, rotifers, tardigrades and Cephalorhyncha...

. In many species the larvae simply increase in size with each successive instar as more food is consumed. In some cases, however, more dramatic changes occur. Among certain beetle families or genera, particularly those that exhibit parasitic lifestyles, the first instar (the planidium
Planidium
A planidium is a specialized type of first-instar insect larva, seen in groups that are parasitoids; they are generally flattened, highly sclerotized, have legs, are quite mobile, and sometimes have eyes...

) is highly mobile in order to search out a host, while the following instars are more sedentary and remain on or within their host. This is known as hypermetamorphosis
Hypermetamorphosis
Hypermetamorphosis is a kind of complete insect metamorphosis in which the different larval instars represent two or more different forms of larva. As the larva molts its morphology can change from that of a campodeiform to scarabaeiform or to vermiform...

; examples include the blister beetle
Blister beetle
Blister beetles are beetles of the family Meloidae, so called for their defensive secretion of a blistering agent, cantharidin. There are approximately 7,500 known species worldwide. Many are conspicuous and some aposematically colored, announcing their toxicity to would-be...

s (family Meloidae) and some rove beetles, particularly those of the genus Aleochara
Aleochara
Rove beetles of the genus Aleochara are among the only insect parasites in the beetle family Staphylinidae. Most of the Aleochara are more rightly called parasitoids because their larvae use a single host, which is killed during the beetle's maturation. Adult Aleochara are predators...

.

Pupa


As with all endopterygotes, beetle larvae pupate, and from this pupa
Pupa
A pupa is the life stage of some insects undergoing transformation. The pupal stage is found only in holometabolous insects, those that undergo a complete metamorphosis, going through four life stages; embryo, larva, pupa and imago...

 emerges a fully formed, sexually mature adult beetle, or imago
Imago
In biology, the imago is the last stage of development of an insect, after the last ecdysis of an incomplete metamorphosis, or after emergence from the pupa where the metamorphosis is complete...

. Adults have an extremely variable lifespan, from weeks to years, depending on the species. In some species the pupa may go through all four forms during its development, called hypermetamorphosis (for example,, Meloidae). Pupae always have no mandibles, or adecticous. In most, the appendages are not attached to the pupae, or they are exarate; with most being obtect in form.

Locomotion



Aquatic beetles use several techniques for retaining air beneath the water's surface. Beetles of the family Dytiscidae hold air between the abdomen and the elytra when diving. Hydrophilidae have hairs on their under surface that retain a layer of air against their bodies. Adult crawling water beetles use both their elytra and their hind coxa
Arthropod leg
The arthropod leg is a form of jointed appendage of arthropods, usually used for walking. Many of the terms used for arthropod leg segments are of Latin origin, and may be confused with terms for bones: coxa , trochanter , femur, tibia, tarsus, ischium, metatarsus, carpus, dactylus ,...

e (the basal segment of the back legs) in air retention, while whirligig beetle
Whirligig beetle
The whirligig beetles are a family of water beetles that normally live on the surface of the water. They get their common name from their habit of swimming rapidly in circles when alarmed, and are also notable for their which can see both above and below water.They are also known for their...

s simply carry an air bubble down with them whenever they dive.

The elytra allows beetles and weevils to both fly and move through confined spaces. Doings so by folding the delicate wings under the elytra while not flying, and folding their wings out just before take off. The unfolding and folding of the wings is operated by muscles attached to the wing base; as long as the tension on the radial and cubital veins remains, the wings remain straight. In day-flying species (for example, Buprestidae, Scarabaeidae
Scarabaeidae
The family Scarabaeidae as currently defined consists of over 30,000 species of beetles worldwide. The species in this large family are often called scarabs or scarab beetles. The classification of this family is fairly unstable, with numerous competing theories, and new proposals appearing quite...

), flight does not include large amounts of lifting of the elytra, having the metathorac wings extended under the lateral elytra margins.

Communication


Beetles have a variety of ways to communicate. Some of which include a sophisticated chemical language through the use of pheromone
Pheromone
A pheromone is a secreted or excreted chemical factor that triggers a social response in members of the same species. Pheromones are chemicals capable of acting outside the body of the secreting individual to impact the behavior of the receiving individual...

s. From the host tree, the mountain pine beetle
Mountain pine beetle
The mountain pine beetle Dendroctonus ponderosae, is a species of bark beetle native to the forests of western North America from Mexico to central British Columbia. It has a hard black exoskeleton, and measures about 5 millimeters, about the size of a grain of rice.Mountain pine beetles inhabit...

 have many forms of communication. They can emit both an aggregative pheromone and an anti-aggregative pheramone. The aggregative pheromone attracts other beetles to the tree, and the anti-aggregative pheromone neutralizes the aggregative pheromone. This helps to avoid the harmful effects of having too many beetles on one tree competing for resources. The mountain pine beetle can also stridulate to communicate, or rub body parts together to create sound, having a “scraper” on their abdomen that they rub against a grooved surface on the underside of their left wing cover to create a sound that is not audible to humans. Once the female beetles have arrived on a suitable pine tree host, they begin to stridulate and produce aggregative pheromones to attract other unmated males and females. New females arrive and do the same as they land and bore into the tree. As the males arrive, they enter the galleries that the females have tunneled, and begin to stridulate to let the females know they have arrived, and to also warn others that the female in that gallery is taken. At this point, the female stops producing aggregative pheromones and starts producing anti-aggregative pheromone to deter more beetles from coming.

Since species of Coleoptera use environmental stimuli to communicate, they are affected by the climate. Microclimate
Microclimate
A microclimate is a local atmospheric zone where the climate differs from the surrounding area. The term may refer to areas as small as a few square feet or as large as many square miles...

s, such as wind or temperature, can disturb the use of pheromones; wind would blow the pheromones while they ravel through the air. Stridulating can be interrupted when the stimulus is vibrated by something else.

Parental care



Among insect, parental care is very uncommon, only found in a few species. Some beetles also display this unique social behavior. One theory states why there is parental care is that it is necessary for the survival of the larvae, protecting them from adverse environmental conditions and predators. One species, a rover beetle (Bledius spectabilis) displays both causes for parental care: physical and biotic environmental factors. Said species lives in salt marsh
Salt marsh
A salt marsh is an environment in the upper coastal intertidal zone between land and salt water or brackish water, it is dominated by dense stands of halophytic plants such as herbs, grasses, or low shrubs. These plants are terrestrial in origin and are essential to the stability of the salt marsh...

es, so the eggs and/or larvae are endangered by the rising tide
Tide
Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the moon and the sun and the rotation of the Earth....

. The maternal beetle will patrol the eggs and larva and apply the appropriate burrowing behavior to keep them from flooding and from asphyxiating. Another advantage is that the mother protects the eggs and larvae from the predatory carabid beetles species Dicheirotrichus gustavi and from the parasitoid
Parasitism
Parasitism is a type of symbiotic relationship between organisms of different species where one organism, the parasite, benefits at the expense of the other, the host. Traditionally parasite referred to organisms with lifestages that needed more than one host . These are now called macroparasites...

 wasp species Barycnemis blediator. Up to 15% of larvae are killed by this parasitoid wasp, being only protected by maternal beetles in their dens.

Some species of dung beetle
Dung beetle
Dung beetles are beetles that feed partly or exclusively on feces. All of these species belong to the superfamily Scarabaeoidea; most of them to the subfamilies Scarabaeinae and Aphodiinae of the family Scarabaeidae. This beetle can also be referred to as the scarab beetle. As most species of...

 also display a form of parental care. Dung beetles collect animal feces, or "dung", from which their name is derived, and roll it into a ball, sometimes being up to 50 times their own weight; albeit sometimes it is also used to store food. Usually it is the male that rolls the ball, with the female hitch-hiking or simply following behind. In some cases the male and the female roll together. When a spot with soft soil is found, they stop and bury the dung ball. They will then mate
Mating
In biology, mating is the pairing of opposite-sex or hermaphroditic organisms for copulation. In social animals, it also includes the raising of their offspring. Copulation is the union of the sex organs of two sexually reproducing animals for insemination and subsequent internal fertilization...

 underground. After the mating, both or one of them will prepare the brooding ball. When the ball is finished, the female lays eggs inside it, a form of mass provisioning
Mass provisioning
Mass provisioning is a term used in entomology to refer to a form of parental behavior in which an adult stocks all of the food for each offspring in a small chamber prior to laying the egg...

. Some species do not leave after this stage, but remain to safeguard their offspring.

Feeding


Besides being abundant and varied, beetles are able to exploit the wide diversity of food sources available in their many habitats. Some are omnivores, eating both plants and animals. Other beetles are highly specialized in their diet. Many species of leaf beetles, longhorn beetles, and weevils are very host-specific, feeding on only a single species of plant. Ground beetle
Ground beetle
Ground beetles are a large, cosmopolitan family of beetles, Carabidae, with more than 40,000 species worldwide, approximately 2,000 of which are found in North America and 2,700 in Europe.-Description and ecology:...

s and rove beetle
Rove beetle
The rove beetles are a large family of beetles, primarily distinguished by their short elytra that leave more than half of their abdomens exposed. With over 46,000 species in thousands of genera, the group is the second largest family of beetles after the Curculionidae...

s (family Staphylinidae), among others, are primarily carnivorous and will catch and consume many other arthropod
Arthropod
An arthropod is an invertebrate animal having an exoskeleton , a segmented body, and jointed appendages. Arthropods are members of the phylum Arthropoda , and include the insects, arachnids, crustaceans, and others...

s and small prey, such as earthworms and snails. While most predatory beetles are generalists, a few species have more specific prey requirements or preferences.

Decaying organic matter is a primary diet for many species. This can range from dung
Feces
Feces, faeces, or fæces is a waste product from an animal's digestive tract expelled through the anus or cloaca during defecation.-Etymology:...

, which is consumed by coprophagous species (such as certain scarab beetle
Dung beetle
Dung beetles are beetles that feed partly or exclusively on feces. All of these species belong to the superfamily Scarabaeoidea; most of them to the subfamilies Scarabaeinae and Aphodiinae of the family Scarabaeidae. This beetle can also be referred to as the scarab beetle. As most species of...

s of the family Scarabaeidae), to dead animals, which are eaten by necrophagous species (such as the carrion beetle
Carrion beetle
Silphidae is a family of beetles that are known commonly as carrion or burying beetles. There are two subfamilies: Silphinae and Nicrophorinae. Both families feed on decaying organic matter such as dead animals. The families differ in which uses parental care and which types of carcasses they prefer...

s of the family Silphidae). Some of the beetles found within dung
Feces
Feces, faeces, or fæces is a waste product from an animal's digestive tract expelled through the anus or cloaca during defecation.-Etymology:...

 and carrion are in fact predatory. These include the clown beetle
Clown beetle
Histeridae is a family of beetles commonly known as Clown beetles or Hister beetles. This very diverse group of beetles contains 3,900 species found worldwide. They can be easily identified by their shortened elytra that leaves two of the seven tergites exposed, and their elbowed antennae with...

s, preying on the larvae of coprophagous and necrophagous insects.

Defense and predation


Beetles and their larvae have a variety of strategies to avoid being attacked by predators or parasitoid
Parasitoid
A parasitoid is an organism that spends a significant portion of its life history attached to or within a single host organism in a relationship that is in essence parasitic; unlike a true parasite, however, it ultimately sterilises or kills, and sometimes consumes, the host...

s. These include camouflage
Camouflage
Camouflage is a method of concealment that allows an otherwise visible animal, military vehicle, or other object to remain unnoticed, by blending with its environment. Examples include a leopard's spotted coat, the battledress of a modern soldier and a leaf-mimic butterfly...

, mimicry, toxicity, and active defense. Camouflage
Camouflage
Camouflage is a method of concealment that allows an otherwise visible animal, military vehicle, or other object to remain unnoticed, by blending with its environment. Examples include a leopard's spotted coat, the battledress of a modern soldier and a leaf-mimic butterfly...

 involves the use of coloration or shape to blend into the surrounding environment. This sort of protective coloration is common and widespread among beetle families, especially those that feed on wood or vegetation, such as many of the leaf beetle
Leaf beetle
Beetles in the family Chrysomelidae are commonly known as leaf beetles. This is a family of over 35,000 species in more than 2,500 genera, one of the largest and most commonly encountered of all beetle families....

s (family Chrysomelidae) or weevil
Weevil
A weevil is any beetle from the Curculionoidea superfamily. They are usually small, less than , and herbivorous. There are over 60,000 species in several families, mostly in the family Curculionidae...

s. In some of these species, sculpturing or various colored scales or hairs cause the beetle to resemble bird dung or other inedible objects. Many of those that live in sandy environments blend in with the coloration of the substrate. For example, the Giant African longhorn beetle (Petrognatha gigas) which resembles the moss and bark of the tree from which it feeds on.

Another defense that often uses color or shape to deceive potential enemies is mimicry. A number of longhorn beetle
Longhorn beetle
The longhorn beetles are a cosmopolitan family of beetles, typically characterized by extremely long antennae, which are often as long as or longer than the beetle's body...

s (family Cerambycidae) bear a striking resemblance to wasp
Wasp
The term wasp is typically defined as any insect of the order Hymenoptera and suborder Apocrita that is neither a bee nor an ant. Almost every pest insect species has at least one wasp species that preys upon it or parasitizes it, making wasps critically important in natural control of their...

s, which helps them avoid predation even though the beetles are in fact harmless. This defense can be found to a lesser extent in other beetle families, such as the scarab beetles. Beetles may combine their color mimicry with behavioral mimicry, acting like the wasps they already closely resemble. Many beetle species, including ladybirds
Coccinellidae
Coccinellidae is a family of beetles, known variously as ladybirds , or ladybugs . Scientists increasingly prefer the names ladybird beetles or lady beetles as these insects are not true bugs...

, blister beetle
Blister beetle
Blister beetles are beetles of the family Meloidae, so called for their defensive secretion of a blistering agent, cantharidin. There are approximately 7,500 known species worldwide. Many are conspicuous and some aposematically colored, announcing their toxicity to would-be...

s, and lycid beetles
Lycidae
Lycidae is a family in the beetle order Coleoptera, members of which are commonly called net-winged beetles.Beetles of this family are elongated and usually found on flowers or stems. The adults of some species are nectarivores while some may have short-lived adult lives during which they may not...

 can secrete distasteful or toxic substances to make them unpalatable or even poisonous. These same species often exhibit aposematism
Aposematism
Aposematism , perhaps most commonly known in the context of warning colouration, describes a family of antipredator adaptations where a warning signal is associated with the unprofitability of a prey item to potential predators...

, where bright or contrasting color patterns warn away potential predators, and there are, not surprisingly, a great many beetles and other insects that mimic these chemically protected species.
Chemical defense is another important defense found amongst species of Coleoptera, usually being advertised by bright colors. Others may utilize behaviors that would be done when releasing noxious chemicals (for example,, Tenebrionidae). Chemical defense may serve purposes other than just protection from vertebrates, such as protection from a wide range of microbes, and repellents. Some species release chemicals in the form of a spray with surprising accuracy, such as ground beetle
Ground beetle
Ground beetles are a large, cosmopolitan family of beetles, Carabidae, with more than 40,000 species worldwide, approximately 2,000 of which are found in North America and 2,700 in Europe.-Description and ecology:...

s (Carabidae), may spray chemicals from their abdomen to repel predators. Some species take advantage of the plants from which they feed, and sequester the chemicals from the plant that would protect it and incorporate into their own defense. African carabid beetles (for example,, Anthia and Thermophilum) employ the same chemicals used by ants, while Bombardier beetle
Bombardier beetle
Bombardier beetles are ground beetles in the tribes Brachinini, Paussini, Ozaenini, or Metriini—more than 500 species altogether—which are most notable for the defense mechanism that gives them their name: When disturbed, the beetle ejects a noxious chemical spray in a rapid burst of pulses from...

s have a their own unique separate gland, spraying potential predators from far distances.

Large ground beetle
Ground beetle
Ground beetles are a large, cosmopolitan family of beetles, Carabidae, with more than 40,000 species worldwide, approximately 2,000 of which are found in North America and 2,700 in Europe.-Description and ecology:...

s and longhorn beetles may defend themselves using strong mandibles
Mandible (insect)
Insect mandibles are a pair of appendages near the insect’s mouth, and the most anterior of the three pairs of oral appendages . Their function is typically to grasp, crush, or cut the insect’s food, or to defend against predators or rivals...

 and/or spines or horns to forcibly persuade a predator to seek out easier prey. Many species have large protrusions from their thorax and head such as the Rhinoceros beetle
Rhinoceros beetle
The Rhinoceros Beetles or Rhino Beetles are a subfamily of the scarab beetle family . Other common names – some for particular groups of rhino beetles – are for example Hercules beetles, unicorn beetles or horn beetles...

, which can be used to defended themselves from predators. Many species of weevil that feed out in the open on leaves of plants react to attack by employing a "drop-off reflex". Even further, some will combine it with thanatosis, which they will close up their legs, antennae, mandibles, etc. and use their cryptic coloration to blend in with the background. Species with varied coloration do not do this as they can not camaflouge.

Parasitism


There are over 1000 known species of beetles to be either parasitic, predatory, or commensals in the nests of ants. Most beetle larvae can be considered parasites, as they feed on the plants and live inside the bark of trees and plants. Though there are a few species that are ectoparasitic to mammals, such as Platypsyllus castoris, which is affects beavers (Castor
Beaver
The beaver is a primarily nocturnal, large, semi-aquatic rodent. Castor includes two extant species, North American Beaver and Eurasian Beaver . Beavers are known for building dams, canals, and lodges . They are the second-largest rodent in the world...

 spp.). This beaver beetle parasite is a parasite as both an adult and a larva, with the appropriate modifications. They are wingless and eyeless with a striking dorso-ventral flattening. Additionally, P. castoris, has a remarkably modified antennal club, with antennomeres 3-11 shortened, globularly compacted, and partly enclosed in a scoop shaped antennomere 2, as is also found in Gyrinidae and Dryopidae.

other parasites include those who are parasitoids of other invertebrates, such as the small hive beetle
Small hive beetle
The small hive beetle is a beekeeping pest.Endemic to sub-Saharan Africa, the small hive beetle, Aethina tumida was first discovered in the United States in 1996 and has now spread to many U.S. states including, Georgia, South Carolina, North Carolina, Pennsylvania, Ohio, Illinois, Minnesota,...

 (Aethina tumida) infecting Honey bee
Honey bee
Honey bees are a subset of bees in the genus Apis, primarily distinguished by the production and storage of honey and the construction of perennial, colonial nests out of wax. Honey bees are the only extant members of the tribe Apini, all in the genus Apis...

 hives. The larvae tunnel through comb towards stored honey or pollen, damaging or destroying cappings and comb in the process. Larvae defecate in honey and the honey becomes discolored from the feces, which causes fermentation and a frothiness in the honey; the honey develops a characteristic odor of decaying oranges. Damage and fermentation cause honey to run out of combs, destroing large portions in hives and sometimes the extracting rooms. Heavy infestations cause bees to abscond; some beekeepers have reported the rapid collapse of even strong colonies.

Pollination


Beetle-pollinated flowers are usually large, greenish or off-white in color and heavily scented. Scents may be spicy, fruity, or similar to decaying organic material. Most beetle-pollinated flowers are flattened or dish shaped, with pollen easily accessible, although they may include traps to keep the beetle longer. The plant's ovaries are usually well protected from the biting mouthparts of their pollinators. Beetles may be particularly important in some parts of the world such as semi-arid areas of southern Africa
Southern Africa
Southern Africa is the southernmost region of the African continent, variably defined by geography or geopolitics. Within the region are numerous territories, including the Republic of South Africa ; nowadays, the simpler term South Africa is generally reserved for the country in English.-UN...

 and southern California
Southern California
Southern California is a megaregion, or megapolitan area, in the southern area of the U.S. state of California. Large urban areas include Greater Los Angeles and Greater San Diego. The urban area stretches along the coast from Ventura through the Southland and Inland Empire to San Diego...

 and the montane grasslands of KwaZulu-Natal
KwaZulu-Natal
KwaZulu-Natal is a province of South Africa. Prior to 1994, the territory now known as KwaZulu-Natal was made up of the province of Natal and the homeland of KwaZulu....

 in South Africa
South Africa
The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...

.

Mutualism


Amongst most orders of insects, mutualism is not common, however there are some examples in species of Coleoptera. Such as the Ambrosia beetle
Ambrosia beetle
Ambrosia beetles are beetles of the weevil subfamilies Scolytinae and Platypodinae , which live in nutritional symbiosis with ambrosia fungi and probably with bacteria...

, the Ambrosia fungus, and probably bacteria. The beetles excavate tunnels in dead trees in which they cultivate fungal gardens, their sole source of nutrition. After landing on a suitable tree, an ambrosia beetle excavates a tunnel in which it releases spores of its fungal symbiont. The fungus penetrates the plant's xylem tissue, digests it, and concentrates the nutrients on and near the surface of the beetle gallery; so the weevils and the fungus both benefit. The beetles can not eat due to toxins, which uses its relationship with fungi to help overcome it's host tree defenses and to provide nutrition for their larvae.

The beetle-fungal mutualism is chemically mediated by a bacterially produced polyunsaturated peroxide. The molecule's selective toxicity toward the beetle's fungal antagonist, combined with the prevalence and localization of its bacterial source, indicates an insect-microbe association that is both mutualistic and coevolved. This unexpected finding in a well-studied system indicates that mutualistic associations between insects and antibiotic-producing bacteria are more common than currently recognized and that identifying their small-molecule mediators can provide a powerful search strategy for therapeutically useful antimicrobial compounds.

Commensalism


Pseudoscorpion
Pseudoscorpion
A pseudoscorpion, , is an arachnid belonging to the order Pseudoscorpionida, also known as Pseudoscorpiones or Chelonethida....

s are small arachnids with a flat, pear-shaped body and pincers that resemble those of scorpion
Scorpion
Scorpions are predatory arthropod animals of the order Scorpiones within the class Arachnida. They have eight legs and are easily recognized by the pair of grasping claws and the narrow, segmented tail, often carried in a characteristic forward curve over the back, ending with a venomous stinger...

s (only distant relatives), usually ranging from 2 to 8 mm (0.078740157480315 to 0.31496062992126 ) in length. Their small size allows them to hitch rides under the elytra of a giant harlequin beetle to be dispersed over wide areas while simultaneously being protected from predators. They may also find mating partners as other individuals join them on the beetle. This would be a form of parasitism if the beetle was harmed in the process, however the beetle is, presumably, unaffected by the presence of the hitchhikers.

Phylogeny and systematics



Fossil record


A 2007 study based on DNA
DNA
Deoxyribonucleic acid is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms . The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in...

 of living beetles and maps of likely beetle evolution indicated that beetles may have originated during the Lower Permian
Permian
The PermianThe term "Permian" was introduced into geology in 1841 by Sir Sir R. I. Murchison, president of the Geological Society of London, who identified typical strata in extensive Russian explorations undertaken with Edouard de Verneuil; Murchison asserted in 1841 that he named his "Permian...

, up to 299 million years ago. In 2009, a fossil beetle was described from the Pennsylvanian
Pennsylvanian
The Pennsylvanian is, in the ICS geologic timescale, the younger of two subperiods of the Carboniferous Period. It lasted from roughly . As with most other geochronologic units, the rock beds that define the Pennsylvanian are well identified, but the exact date of the start and end are uncertain...

 of Mazon Creek
Mazon Creek fossils
The Mazon Creek fossil beds are a conservation found near Morris, in Grundy County, Illinois. The fossil beds are located in ironstone concretions, formed approximately in the mid-Pennsylvanian epoch of the Carboniferous period...

, Illinois, pushing the origin of the beetles to an earlier date, . Fossils from this time have been found in Asia and Europe, for instance in the red slate fossil beds of Niedermoschel near Mainz, Germany. Further fossils have been found in Obora, Czechia and Tshekarda in the Ural mountains, Russia. However, there are only a few fossils from North America before the middle Permian, although both Asia and North America had been united to Euramerica
Euramerica
Euramerica was a minor supercontinent created in the Devonian as the result of a collision between the Laurentian, Baltica, and Avalonia cratons .300 million years ago in the Late Carboniferous tropical rainforests lay over the equator of Euramerica...

. The first discoveries from North America were made in the Wellington formation of Oklahoma and were published in 2005 and 2008.

As a consequence of the Permian–Triassic extinction event, there is only little fossil record of insects including beetles from the Lower Triassic. However, there are a few exceptions, like in Eastern Europe: at the Babiy Kamen site in the Kuznetsk Basin numerous beetle fossils were discovered, even entire specimen of the infraorders Archostemata
Archostemata
Archostemata is the smallest suborder of beetles, consisting of fewer than fifty known species organized into five families. Archostemata is an ancient lineage with a number of primitive characteristics. They are similar in morphology to the first beetles, which appear in the fossil record...

 (e.g. Ademosynidae, Schizocoleidae), Adephaga
Adephaga
Adephaga , with more than 40,000 recorded species in 10 families, is a suborder of highly specialized beetles and the second largest suborder of the order Coleoptera. Members of this suborder are adephagans, a term which notably include ground beetles, tiger beetles, predacious diving beetles, and...

 (e.., Triaplidae, Trachypachidae) and Polyphaga
Polyphaga
Polyphaga is the largest and most diverse suborder of beetles; the name is derived from two two Greek words: poly-, meaning 'many', and phagein, meaning 'to eat', so the suborder is called the “eaters of many things”...

 ( e.g. Hydrophilidae, Byrrhidae, Elateroidea) and in nearly a perfectly preserved condition. However, species from the families Cupedidae and Schizophoroidae are not present at this site, whereas they dominate at other fossil sites from the Lower Triassic. Further records are known from Khey-Yaga, Russia in the Korotaikha Basin. There are many important sites from the Jurassic, with more than 150 important sites with beetle fossils, the majority being situated in Eastern Europe and North Asia. In North America and especially in South America and Africa the number of sites from that time period is smaller and the sites have not been exhaustively investigated yet. Outstanding fossil sites include Solnhofen
Solnhofen
Solnhofen is a municipality in the district of Weißenburg-Gunzenhausen in the region of Franconia in the Land of Bavaria in Germany. It lies within the Altmühl valley....

 in Upper Bavaria, Germany, Karatau in South Kazakhstan
Kazakhstan
Kazakhstan , officially the Republic of Kazakhstan, is a transcontinental country in Central Asia and Eastern Europe. Ranked as the ninth largest country in the world, it is also the world's largest landlocked country; its territory of is greater than Western Europe...

, the Yixian formation in Liaoning
Liaoning
' is a province of the People's Republic of China, located in the northeast of the country. Its one-character abbreviation is "辽" , a name taken from the Liao River that flows through the province. "Níng" means "peace"...

, North China, as well as the Jiulongshan formation and further fossil sites in Mongolia
Mongolia
Mongolia is a landlocked country in East and Central Asia. It is bordered by Russia to the north and China to the south, east and west. Although Mongolia does not share a border with Kazakhstan, its western-most point is only from Kazakhstan's eastern tip. Ulan Bator, the capital and largest...

. In North America there are only a few sites with fossil records of insects from the Jurassic, namely the shell limestone deposits in the Hartford basin, the Deerfield basin and the Newark basin.

There is a large number of important fossil sites worldwide containing beetles from the Cretaceous. Most of them are located in Europe and Asia and belong to the temperate climate zone during the Cretaceous. A few of the fossil sites mentioned in the chapter Jurassic also shed some light on the early cretaceous beetle fauna (for example, the Yixian formation in Liaoning, North China). Further important sites from the Lower Cretaceous include the Crato Fossil Beds in the Araripe basin in the Ceará
Ceará
Ceará is one of the 27 states of Brazil, located in the northeastern part of the country, on the Atlantic coast. It is currently the 8th largest Brazilian State by population and the 17th by area. It is also one of the main touristic destinations in Brazil. The state capital is the city of...

, North Brazil as well as overlying Santana formation, with the latter was situated near the paleoequator, or the position of the earth's equator in the geologic past as defined for a specific geologic period. In Spain
Spain
Spain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...

 there are important sites near Montsec
Serra del Montsec
The Serra del Montsec is a mountain system of the Pre-Pyrenees.-Description:The Serra del Montsec consists of a series of calcareous mountain ranges. Runs from east to west, it is about 40 km long and 186.96 square kilometres in area...

 and Las Hoyas
Las Hoyas
Las Hoyas is a Cretaceous Konservat-Lagerstätten located near the city of Cuenca, Spain.It is dated as Barremian , and is mostly known from its exquisitely preserved dinosaurs, especially enantiornithines.- Taphonomy :...

. In Australia the Koonwarra fossil beds of the Korumburra group, South Gippsland
South Gippsland
South Gippsland, a region of Gippsland in Victoria, Australia, is a well-watered region consisting of low, rolling hills descending to the coast in the south and the Latrobe Valley in the north. Low granite hills continue into Wilsons Promontory, the southernmost point of Victoria and mainland...

, Victoria is noteworthy. Important fossil sites from the Upper Cretaceous are Kzyl-Dzhar in South Kazakhstan
Kazakhstan
Kazakhstan , officially the Republic of Kazakhstan, is a transcontinental country in Central Asia and Eastern Europe. Ranked as the ninth largest country in the world, it is also the world's largest landlocked country; its territory of is greater than Western Europe...

 and Arkagala in Russia.

Evolution


The oldest known insect that resembles species of Coleoptera date back to the Lower Permian
Permian
The PermianThe term "Permian" was introduced into geology in 1841 by Sir Sir R. I. Murchison, president of the Geological Society of London, who identified typical strata in extensive Russian explorations undertaken with Edouard de Verneuil; Murchison asserted in 1841 that he named his "Permian...

 (270 mya), though they instead have 13-segmented antenna
Antenna (biology)
Antennae in biology have historically been paired appendages used for sensing in arthropods. More recently, the term has also been applied to cilium structures present in most cell types of eukaryotes....

e, elytra with more fully developed venation and more irregular longitudinal ribbing, and an abdomen and ovipositor
Ovipositor
The ovipositor is an organ used by some animals for oviposition, i.e., the laying of eggs. It consists of a maximum of three pairs of appendages formed to transmit the egg, to prepare a place for it, and to place it properly...

 extending beyond the apex of the elytra. The oldest true beetle, that is having features that include 11-segmented antennae, regular longitudinal ribbing on the elytra, and having genitalia that are internal. At the end of the Permian, the biggest mass extinction in the history history took place, collectively called the Permian–Triassic extinction event: 30% of all insect species became extinct, however, it is the only mass extinction of insects in Earth's history until today.

Due to the P-Tr extinction, there is only little fossil record of insects including beetles from the Lower Triassic
Triassic
The Triassic is a geologic period and system that extends from about 250 to 200 Mya . As the first period of the Mesozoic Era, the Triassic follows the Permian and is followed by the Jurassic. Both the start and end of the Triassic are marked by major extinction events...

 . Around this time, during the Late Triassic, mycetophagous, or fungus feeding species (e.g. Cupedidae) appear in the fossil record. In the stages of the Upper Triassic representatives of the algophagous, or algae feeding species (e.g. Triaplidae and Hydrophilidae) begin to appear, as well as predatory water beetles. The first primitive weevils appear (e.g. Obrienidae), as well as the first representatives of the rove beetles (e.g. Staphylinidae), which show no marked difference in physique compared to recent species.

During the Jurassic there was a dramatic increase in the known diversity of family-level Coleoptera. This includes the development and growth of carnivorous and herbivorous species. Species of the superfamily Chrysomeloidea
Chrysomeloidea
Chrysomeloidea is an enormous superfamily of beetles. There are tens of thousands of species, mostly in the families Cerambycidae and Chrysomelidae, the leaf beetles.-Overview:...

 are believed to have developed around the same time, which include a wide array of plant host ranging from cycad
Cycad
Cycads are seed plants typically characterized by a stout and woody trunk with a crown of large, hard and stiff, evergreen leaves. They usually have pinnate leaves. The individual plants are either all male or all female . Cycads vary in size from having a trunk that is only a few centimeters...

s and conifer
Pinophyta
The conifers, division Pinophyta, also known as division Coniferophyta or Coniferae, are one of 13 or 14 division level taxa within the Kingdom Plantae. Pinophytes are gymnosperms. They are cone-bearing seed plants with vascular tissue; all extant conifers are woody plants, the great majority being...

s, to angiosperms. Close to the Upper Jurassic, the portion of the Cupedidae decreased, however at the same time the diversity of the early plant eating, or phytophagous species increased. Most of the recent phytophagous species of Coleoptera feed on flowering plants or angiosperms. It is believed that the increase in diversity of the angiosperms also influenced the diversity of the phytophagous species, which doubled during the Middle Jurassic. However, recently doubts have been raised since the increase of the number of beetle families during the Cretaceous does not correlate with the increase of the number of angiosperm species. Also around the same time, numerous primitive weevils (e.g. Curculionoidea) and click beetles (e.g. Elateroidea
Elateroidea
Elateroidea is a large superfamily of beetles. It contains the familiar click beetles, fireflies, and soldier beetles, and their relatives.Certain clusters of families within the superfamily are more strongly related to one another; for example, the Elateridae has close ties to Anischiidae,...

) appeared. Also first jewel beetles (e.g. Buprestidae) are present, however, they were rather rare until the Cretaceous. The first scarab beetles would appear around this time, however they were not coprophagous, or feeding upon fecal matter
Feces
Feces, faeces, or fæces is a waste product from an animal's digestive tract expelled through the anus or cloaca during defecation.-Etymology:...

, presumably feeding upon the rotting wood with the help of fungus, and early example of a mutualistic relationship (see the Mutualism section ).

The Cretaceous
Cretaceous
The Cretaceous , derived from the Latin "creta" , usually abbreviated K for its German translation Kreide , is a geologic period and system from circa to million years ago. In the geologic timescale, the Cretaceous follows the Jurassic period and is followed by the Paleogene period of the...

 witness the initiation of the most recent round of southern landmass fragmentation, via the opening of the southern Atlantic ocean and the isolation of New Zealand, while the South America, Antarctica, and Australia grew more distant. During the Cretaceous the diversity of Cupedidae and Archostemata
Archostemata
Archostemata is the smallest suborder of beetles, consisting of fewer than fifty known species organized into five families. Archostemata is an ancient lineage with a number of primitive characteristics. They are similar in morphology to the first beetles, which appear in the fossil record...

 decreased considerably. Predatory ground beetle
Ground beetle
Ground beetles are a large, cosmopolitan family of beetles, Carabidae, with more than 40,000 species worldwide, approximately 2,000 of which are found in North America and 2,700 in Europe.-Description and ecology:...

s (Carabidae) and rove beetle
Rove beetle
The rove beetles are a large family of beetles, primarily distinguished by their short elytra that leave more than half of their abdomens exposed. With over 46,000 species in thousands of genera, the group is the second largest family of beetles after the Curculionidae...

s (Staphylinidae) began to distribute into different patterns: whereas the Carabidae predominantly occurred in the warm regions, the Staphylinidae and click beetle
Click beetle
The family Elateridae is commonly called click beetles , elaters, snapping beetles, spring beetles or "skipjacks". They are a cosmopolitan beetle family characterized by the unusual click mechanism they possess...

s (Elateridae) preferred many areas with temperate climate. Likewise, predatory species of Cleroidea
Cleroidea
Cleroidea is a small superfamily of beetles. Most of the members of the group are somewhat slender, often with fairly soft, flexible elytra, and typically hairy or scaly.It contains about 10,000 species in the families:* Acanthocnemidae Crowson 1964...

 and Cucujoidea
Cucujoidea
Cucujoidea is a superfamily of beetles. They include many fungus beetles, as well as ladybugs. Also included are a diversity of lineages of "bark beetles" unrelated to the "true" bark beetles , which are weevils ....

, hunted their prey under the bark of trees together with the jewel beetle
Jewel beetle
Buprestidae is a family of beetles, known as jewel beetles or metallic wood-boring beetles because of their glossy iridescent colors. The family is among the largest of the beetles, with some 15,000 species known in 450 genera...

s (Buprestidae). The jewel beetles diversity increased rapidly during the Cretaceous, as they were the primary consumers of wood, while longhorn beetle
Longhorn beetle
The longhorn beetles are a cosmopolitan family of beetles, typically characterized by extremely long antennae, which are often as long as or longer than the beetle's body...

s (Cerambycidae) were rather rare and their diversity increased only towards the end of the Upper Cretaceous. The first coprophagous beetles have been recorded from the Upper Cretaceous, and are believed to have lived on the excrement of herbivorous dinosaurs, however there is still a discussion, whether the beetles were always tied to mammals during its development. Also, the first species with an adaption of both larvae and adults to the aquatic lifestyle are found. Whirligig beetle
Whirligig beetle
The whirligig beetles are a family of water beetles that normally live on the surface of the water. They get their common name from their habit of swimming rapidly in circles when alarmed, and are also notable for their which can see both above and below water.They are also known for their...

s (Gyrinidae) were moderately diverse, although other early beetles (e.g. Dytiscidae
Dytiscidae
Dytiscidae – based on the Greek dytikos , "able to dive" – are the predaceous diving beetles, a family of water beetles. They are about 25 mm long on average, though there is much variation between species. Dytiscus latissimus, the largest, can grow up to 45 mm long...

) were less, with the most widespread being the species of Coptoclavidae
Coptoclavidae
Coptoclavidae is an extinct family of beetles in the suborder Adephaga. The Coptoclavidae lived from the Jurassicto the Early Cretaceous....

, which preyed on aquatic fly larvae.

The time between the Paleogene
Paleogene
The Paleogene is a geologic period and system that began 65.5 ± 0.3 and ended 23.03 ± 0.05 million years ago and comprises the first part of the Cenozoic Era...

 and the Neogene
Neogene
The Neogene is a geologic period and system in the International Commission on Stratigraphy Geologic Timescale starting 23.03 ± 0.05 million years ago and ending 2.588 million years ago...

, or more recent history is where today's beetles developed. During this time, the continents began to situate themselves to where we see them today. Around the land bridge between South America and North America was formed, and this is when fauna exchange between Asia and North America started. Even though many recent genera and species already existed during the Miocene
Miocene
The Miocene is a geological epoch of the Neogene Period and extends from about . The Miocene was named by Sir Charles Lyell. Its name comes from the Greek words and and means "less recent" because it has 18% fewer modern sea invertebrates than the Pliocene. The Miocene follows the Oligocene...

, however, their distribution differed considerably from today's.

Phylogeny


The suborders diverged in the Permian and Triassic
Triassic
The Triassic is a geologic period and system that extends from about 250 to 200 Mya . As the first period of the Mesozoic Era, the Triassic follows the Permian and is followed by the Jurassic. Both the start and end of the Triassic are marked by major extinction events...

. Their phylogenetic
Phylogenetics
In biology, phylogenetics is the study of evolutionary relatedness among groups of organisms , which is discovered through molecular sequencing data and morphological data matrices...

 relationship is uncertain, with the most popular hypothesis being that Polyphaga
Polyphaga
Polyphaga is the largest and most diverse suborder of beetles; the name is derived from two two Greek words: poly-, meaning 'many', and phagein, meaning 'to eat', so the suborder is called the “eaters of many things”...

 and Myxophaga
Myxophaga
Myxophaga is the second smallest suborder of Coleoptera after Archostemata, consisting of approximately 65 species of small to minute beetles in four families...

 are most closely related, with Adephaga
Adephaga
Adephaga , with more than 40,000 recorded species in 10 families, is a suborder of highly specialized beetles and the second largest suborder of the order Coleoptera. Members of this suborder are adephagans, a term which notably include ground beetles, tiger beetles, predacious diving beetles, and...

 as the sister group to those two, and Archostemata
Archostemata
Archostemata is the smallest suborder of beetles, consisting of fewer than fifty known species organized into five families. Archostemata is an ancient lineage with a number of primitive characteristics. They are similar in morphology to the first beetles, which appear in the fossil record...

 as sister to the other three collectively. Although there are six other competing hypotheses, the other most widely discussed one is Myxophaga as the sister group of all remaining beetles rather than just of Polyphaga. Evidence for a close relationship of the two suborders, Polyphaga and Myxophaga, includes the shared reduction in the number of larval leg articles. The Adephaga is further considered as sister to Myxophaga and Polyphaga, based on their completely sclerotized elytra, reduced number of crossveins in the hind wings, and the folded (as opposed to rolled) hind wings of those three suborders.

Recent cladistic analysis of some of the structural characteristics supports the Polyphaga and Myxophaga hypothesis. The membership of the clade Coleoptera is not in dispute, with the exception of the twisted-wing parasites, Strepsiptera
Strepsiptera
The Strepsiptera are an order of insects with ten families making up about 600 species...

. These odd insects have been regarded as related to the beetle families Rhipiphoridae and Meloidae, with which they share first-instar larvae that are active, host-seeking triungulins and later-instar larvae that are endoparasites of other insects, or the sister group of beetles, or more distantly related to insects.

Taxonomy


There are about 450,000 species of beetles – representing about 40% of all known insects. Such a large number of species poses special problems for classification
Linnaean taxonomy
Linnaean taxonomy can mean either of two related concepts:# the particular form of biological classification set up by Carl Linnaeus, as set forth in his Systema Naturæ and subsequent works...

, with some families consisting of thousands of species and needing further division into subfamilies and tribes. This immense number of species allegedly led evolutionary biologist J. B. S. Haldane
J. B. S. Haldane
John Burdon Sanderson Haldane FRS , known as Jack , was a British-born geneticist and evolutionary biologist. A staunch Marxist, he was critical of Britain's role in the Suez Crisis, and chose to leave Oxford and moved to India and became an Indian citizen...

 to quip, when some theologians asked him what could be inferred about the mind of the Creator from the works of His Creation, that God displayed "an inordinate fondness for beetles".
  • Polyphaga
    Polyphaga
    Polyphaga is the largest and most diverse suborder of beetles; the name is derived from two two Greek words: poly-, meaning 'many', and phagein, meaning 'to eat', so the suborder is called the “eaters of many things”...

     is the largest suborder, containing more than 300,000 described species in more than 170 families, including rove beetle
    Rove beetle
    The rove beetles are a large family of beetles, primarily distinguished by their short elytra that leave more than half of their abdomens exposed. With over 46,000 species in thousands of genera, the group is the second largest family of beetles after the Curculionidae...

    s (Staphylinidae), scarab beetle
    Scarabaeidae
    The family Scarabaeidae as currently defined consists of over 30,000 species of beetles worldwide. The species in this large family are often called scarabs or scarab beetles. The classification of this family is fairly unstable, with numerous competing theories, and new proposals appearing quite...

    s (Scarabaeidae), blister beetle
    Blister beetle
    Blister beetles are beetles of the family Meloidae, so called for their defensive secretion of a blistering agent, cantharidin. There are approximately 7,500 known species worldwide. Many are conspicuous and some aposematically colored, announcing their toxicity to would-be...

    s (Meloidae), stag beetle
    Stag beetle
    Stag beetles are a group of about 1,200 species of beetle in the family Lucanidae, presently classified in four subfamilies Some species grow up to over 12 cm , but most are about 5 cm .-Overview:...

    s (Lucanidae) and true weevils
    Curculionidae
    Curculionidae is the family of the "true" weevils . It was formerly recognized in 1998 as the largest of any animal family, with over 40,000 species described worldwide at that time...

     (Curculionidae). These beetles can be identified by the cervical sclerite
    Sclerite
    A sclerite is a hardened body part. The term is used in various branches of biology for various structures including hardened portions of sponges, but it is most commonly used for the hardened portions of arthropod exoskeletons....

    s (hardened parts of the head used as points of attachment for muscles) absent in the other suborders.
  • Adephaga
    Adephaga
    Adephaga , with more than 40,000 recorded species in 10 families, is a suborder of highly specialized beetles and the second largest suborder of the order Coleoptera. Members of this suborder are adephagans, a term which notably include ground beetles, tiger beetles, predacious diving beetles, and...

     contains about 10 families of largely predatory beetles, includes ground beetle
    Ground beetle
    Ground beetles are a large, cosmopolitan family of beetles, Carabidae, with more than 40,000 species worldwide, approximately 2,000 of which are found in North America and 2,700 in Europe.-Description and ecology:...

    s (Carabidae), Dytiscidae
    Dytiscidae
    Dytiscidae – based on the Greek dytikos , "able to dive" – are the predaceous diving beetles, a family of water beetles. They are about 25 mm long on average, though there is much variation between species. Dytiscus latissimus, the largest, can grow up to 45 mm long...

     and whirligig beetle
    Whirligig beetle
    The whirligig beetles are a family of water beetles that normally live on the surface of the water. They get their common name from their habit of swimming rapidly in circles when alarmed, and are also notable for their which can see both above and below water.They are also known for their...

    s (Gyrinidae). In these beetles, the testes are tubular and the first abdominal sternum (a plate of the exoskeleton
    Exoskeleton
    An exoskeleton is the external skeleton that supports and protects an animal's body, in contrast to the internal skeleton of, for example, a human. In popular usage, some of the larger kinds of exoskeletons are known as "shells". Examples of exoskeleton animals include insects such as grasshoppers...

    ) is divided by the hind coxae
    Arthropod leg
    The arthropod leg is a form of jointed appendage of arthropods, usually used for walking. Many of the terms used for arthropod leg segments are of Latin origin, and may be confused with terms for bones: coxa , trochanter , femur, tibia, tarsus, ischium, metatarsus, carpus, dactylus ,...

     (the basal joints of the beetle's legs).
  • Archostemata
    Archostemata
    Archostemata is the smallest suborder of beetles, consisting of fewer than fifty known species organized into five families. Archostemata is an ancient lineage with a number of primitive characteristics. They are similar in morphology to the first beetles, which appear in the fossil record...

     contains four families of mainly wood-eating beetles, including reticulated beetle
    Reticulated beetle
    Cupedidae is a small family of beetles, notable for the square pattern of "windows" on their elytra , which gives the family their common name of reticulated beetles....

    s (Cupedidae) and the telephone-pole beetle
    Telephone-pole beetle
    The telephone-pole beetle, Micromalthus debilis, is a beetle native to the eastern United States, and the only species in the family Micromalthidae....

    .
  • Myxophaga
    Myxophaga
    Myxophaga is the second smallest suborder of Coleoptera after Archostemata, consisting of approximately 65 species of small to minute beetles in four families...

     contains about 100 described species in four families, mostly very small, including Hydroscaphidae and the genus Sphaerius.

As pests



About of beetle species are phytophagous in both the larval and adult stages, living in or on plants, wood, fungi, and a variety of stored products, including cereals, tobacco, and dried fruits. Because many of these plants are important for agriculture, forestry, and the household, the beetle can be considered a pest. Some of these species cause significant damage, such as the Boll weevil
Boll weevil
The boll weevil is a beetle measuring an average length of six millimeters, which feeds on cotton buds and flowers. Thought to be native to Central America, it migrated into the United States from Mexico in the late 19th century and had infested all U.S. cotton-growing areas by the 1920s,...

, which feeds on cotton
Cotton
Cotton is a soft, fluffy staple fiber that grows in a boll, or protective capsule, around the seeds of cotton plants of the genus Gossypium. The fiber is almost pure cellulose. The botanical purpose of cotton fiber is to aid in seed dispersal....

 buds and flowers. The Boll Weevil crossed the Rio Grande
Rio Grande
The Rio Grande is a river that flows from southwestern Colorado in the United States to the Gulf of Mexico. Along the way it forms part of the Mexico – United States border. Its length varies as its course changes...

 near Brownsville, Texas
Brownsville, Texas
Brownsville is a city in the southernmost tip of the state of Texas, in the United States. It is located on the northern bank of the Rio Grande, directly north and across the border from Matamoros, Tamaulipas, Mexico. Brownsville is the 16th largest city in the state of Texas with a population of...

 to enter the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 from Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...

 around 1892 and had reached southeastern Alabama
Alabama
Alabama is a state located in the southeastern region of the United States. It is bordered by Tennessee to the north, Georgia to the east, Florida and the Gulf of Mexico to the south, and Mississippi to the west. Alabama ranks 30th in total land area and ranks second in the size of its inland...

 by 1915. By the mid 1920s it had entered all cotton growing regions in the U.S., traveling 40 to- per year. It remains the most destructive cotton pest in North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

. Mississippi State University
Mississippi State University
The Mississippi State University of Agriculture and Applied Science commonly known as Mississippi State University is a land-grant university located in Oktibbeha County, Mississippi, United States, partially in the town of Starkville and partially in an unincorporated area...

 has estimated that since the boll weevil entered the United States it has cost U.S. cotton producers about $13 billion, and in recent times about $300 million per year. Many other species also have done extensive damage to plant populations, such as the bark beetle
Bark beetle
A bark beetle is one of approximately 220 genera with 6,000 species of beetles in the subfamily Scolytinae. Traditionally, this was considered a distinct family Scolytidae, but now it is understood that bark beetles are in fact very specialized members of the "true weevil" family...

 and elm Leaf beetle. The bark beetle and elm leaf beetle, among other species, have been known to nest in elm
Elm
Elms are deciduous and semi-deciduous trees comprising the genus Ulmus in the plant family Ulmaceae. The dozens of species are found in temperate and tropical-montane regions of North America and Eurasia, ranging southward into Indonesia. Elms are components of many kinds of natural forests...

 trees. Bark beetles in particular carry Dutch elm disease
Dutch elm disease
Dutch elm disease is a disease caused by a member of the sac fungi category, affecting elm trees which is spread by the elm bark beetle. Although believed to be originally native to Asia, the disease has been accidentally introduced into America and Europe, where it has devastated native...

 as they move from infected breeding sites to feed on healthy elm trees. The spread of Dutch elm disease by the beetle has led to the devastation of elm trees in many parts of the Northern Hemisphere
Northern Hemisphere
The Northern Hemisphere is the half of a planet that is north of its equator—the word hemisphere literally means “half sphere”. It is also that half of the celestial sphere north of the celestial equator...

, notably in Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...

 and North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

.


Situations in which a species has developed immunity to pesticides are worse, as in the case of the Colorado potato beetle
Colorado potato beetle
The Colorado potato beetle , also known as the Colorado beetle, the ten-striped spearman, the ten-lined potato beetle or the potato bug, is an important pest of potato crops. It is approximately 10 mm long, with a bright yellow/orange body and five bold brown stripes along the length of each...

, Leptinotarsa decemlineata, which is a notorious pest of potato
Potato
The potato is a starchy, tuberous crop from the perennial Solanum tuberosum of the Solanaceae family . The word potato may refer to the plant itself as well as the edible tuber. In the region of the Andes, there are some other closely related cultivated potato species...

 plants. Crops are destroyed and the beetle can only be treated by employing expensive pesticide
Pesticide
Pesticides are substances or mixture of substances intended for preventing, destroying, repelling or mitigating any pest.A pesticide may be a chemical unicycle, biological agent , antimicrobial, disinfectant or device used against any pest...

s, many of which it has begun to develop resistance
Pesticide resistance
Pesticide resistance is the adaptation of pest population targeted by a pesticide resulting in decreased susceptibility to that chemical. In other words, pests develop a resistance to a chemical through natural selection: the most resistant organisms are the ones to survive and pass on their...

 to. As well as potatoes, suitable hosts can be a number of plants from the potato family (Solanaceae
Solanaceae
Solanaceae are a family of flowering plants that include a number of important agricultural crops as well as many toxic plants. The name of the family comes from the Latin Solanum "the nightshade plant", but the further etymology of that word is unclear...

), such as nightshade, tomato
Tomato
The word "tomato" may refer to the plant or the edible, typically red, fruit which it bears. Originating in South America, the tomato was spread around the world following the Spanish colonization of the Americas, and its many varieties are now widely grown, often in greenhouses in cooler...

, eggplant and capsicum
Capsicum
Capsicum is a genus of flowering plants in the nightshade family, Solanaceae. Its species are native to the Americas where they have been cultivated for thousands of years, but they are now also cultivated worldwide, used as spices, vegetables, and medicines - and have become are a key element in...

. The Colorado potato beetle has developed resistance to all major insecticide classes, although not every population is resistant to every chemical.

Pests don't only affect agriculture, but can also even affect houses, such as the Death watch beetle
Death watch beetle
The death watch beetle, Xestobium rufovillosum, is a woodboring beetle. The adult beetle is long, while the xylophagous larvae are up to long....

. The death watch beetle, Xestobium rufovillosum, (family Anobiidae
Anobiidae
Anobiidae is a family of beetles. The larvae of a number of species tend to bore into wood, earning them the name "woodworm" or "wood borer". A few species are pests, causing damage to wooden furniture and house structures, notably the death watch beetle, Xestobium rufovillosum, and the common...

) is of considerable importance as a pest of older wooden buildings in Great Britain
Great Britain
Great Britain or Britain is an island situated to the northwest of Continental Europe. It is the ninth largest island in the world, and the largest European island, as well as the largest of the British Isles...

. It attacks hardwood
Hardwood
Hardwood is wood from angiosperm trees . It may also be used for those trees themselves: these are usually broad-leaved; in temperate and boreal latitudes they are mostly deciduous, but in tropics and subtropics mostly evergreen.Hardwood contrasts with softwood...

s such as oak
Oak
An oak is a tree or shrub in the genus Quercus , of which about 600 species exist. "Oak" may also appear in the names of species in related genera, notably Lithocarpus...

 and chestnut
Chestnut
Chestnut , some species called chinkapin or chinquapin, is a genus of eight or nine species of deciduous trees and shrubs in the beech family Fagaceae, native to temperate regions of the Northern Hemisphere. The name also refers to the edible nuts they produce.-Species:The chestnut belongs to the...

, always where some fungal decay has taken or is taking place. It is thought that the actual introduction of the pest into buildings takes place at the time of construction.

Other pest include the Coconut hispine beetle, Brontispa longissima
Brontispa longissima
Brontispa longissima is a leaf beetle that feeds on young leaves and damages seedlings and mature coconut palms...

, feeds on young leaves
Leaves
-History:Vocalist Arnar Gudjonsson was formerly the guitarist with Mower, and he was joined by Hallur Hallsson , Arnar Ólafsson , Bjarni Grímsson , and Andri Ásgrímsson . Late in 2001 they played with Emiliana Torrini and drew early praise from the New York Times...

 and damages seedlings and mature coconut
Coconut
The coconut palm, Cocos nucifera, is a member of the family Arecaceae . It is the only accepted species in the genus Cocos. The term coconut can refer to the entire coconut palm, the seed, or the fruit, which is not a botanical nut. The spelling cocoanut is an old-fashioned form of the word...

 palms. On September 27, 2007, Philippines
Philippines
The Philippines , officially known as the Republic of the Philippines , is a country in Southeast Asia in the western Pacific Ocean. To its north across the Luzon Strait lies Taiwan. West across the South China Sea sits Vietnam...

' Metro Manila
Metro Manila
Metropolitan Manila , the National Capital Region , or simply Metro Manila, is the metropolitan region encompassing the City of Manila and its surrounding areas in the Philippines...

 and 26 provinces were quarantined due to having been infested with this pest (to save the $800-million Philippine coconut
Coconut
The coconut palm, Cocos nucifera, is a member of the family Arecaceae . It is the only accepted species in the genus Cocos. The term coconut can refer to the entire coconut palm, the seed, or the fruit, which is not a botanical nut. The spelling cocoanut is an old-fashioned form of the word...

 industry
Industry
Industry refers to the production of an economic good or service within an economy.-Industrial sectors:There are four key industrial economic sectors: the primary sector, largely raw material extraction industries such as mining and farming; the secondary sector, involving refining, construction,...

). The mountain pine beetle
Mountain pine beetle
The mountain pine beetle Dendroctonus ponderosae, is a species of bark beetle native to the forests of western North America from Mexico to central British Columbia. It has a hard black exoskeleton, and measures about 5 millimeters, about the size of a grain of rice.Mountain pine beetles inhabit...

 normally attacks mature or weakened lodgepole pine
Lodgepole Pine
Lodgepole Pine, Pinus contorta, also known as Shore Pine, is a common tree in western North America. Like all pines, it is evergreen.-Subspecies:...

. It can be the most destructive insect pest of mature pine forests. The current infestation in British Columbia is the largest Canada has ever seen.

As beneficial



Beetles are not only pests, but can also be beneficial, usually by controlling the populations of pests. One of the best, and widely known, examples are the Ladybugs or ladybirds (family Coccinellidae
Coccinellidae
Coccinellidae is a family of beetles, known variously as ladybirds , or ladybugs . Scientists increasingly prefer the names ladybird beetles or lady beetles as these insects are not true bugs...

). Both the larvae and adults are found feeding on aphid
Aphid
Aphids, also known as plant lice and in Britain and the Commonwealth as greenflies, blackflies or whiteflies, are small sap sucking insects, and members of the superfamily Aphidoidea. Aphids are among the most destructive insect pests on cultivated plants in temperate regions...

 colonies. Other ladybugs feed on scale insect
Scale insect
The scale insects are small insects of the order Hemiptera, generally classified as the superfamily Coccoidea. There are about 8,000 species of scale insects.-Ecology:...

s and mealybug
Mealybug
Mealybugs are insects in the family Pseudococcidae, unarmored scale insects found in moist, warm climates. They are considered pests as they feed on plant juices of greenhouse plants, house plants and subtropical trees and also acts as a vector for several plant diseases.-Distribution:Mealybugs...

s. If normal food sources are scarce, they may feed on other things, such as small caterpillar
Caterpillar
Caterpillars are the larval form of members of the order Lepidoptera . They are mostly herbivorous in food habit, although some species are insectivorous. Caterpillars are voracious feeders and many of them are considered to be pests in agriculture...

s, young plant bugs, honeydew
Honeydew (secretion)
Honeydew is a sugar-rich sticky liquid, secreted by aphids and some scale insects as they feed on plant sap. When their mouthpart penetrates the phloem, the sugary, high-pressure liquid is forced out of the gut's terminal opening. Honeydew is particularly common as a secretion in the Hemipteran...

 and nectar. Ground beetle
Ground beetle
Ground beetles are a large, cosmopolitan family of beetles, Carabidae, with more than 40,000 species worldwide, approximately 2,000 of which are found in North America and 2,700 in Europe.-Description and ecology:...

s (family Carabidae) are common predators of many different insects and other arthropods, including fly eggs, caterpillars, wireworms and others.

Dung beetles (Coleoptera, Scarabidae) have been successfully used to reduce the populations of pestilent flies and parasitic worms that breed in cattle dung. The beetles make the dung unavailable to breeding pests by quickly rolling and burying it in the soil, with the added effect of improving soil fertility and nutrient cycling. The Australian Dung Beetle Project
Australian Dung Beetle Project
The Australian Dung Beetle Project , conceived and led by Dr. George Bornemissza, of the Commonwealth Scientific and Industrial Research Organisation , was an international scientific research and biological control project with the primary goal to introduce foreign species of dung beetle to...

 (1965–1985), led by Dr. George Bornemissza
George Bornemissza
George Francis Bornemissza is a Hungarian-born entomologist and ecologist. He studied science at the University of Budapest before obtaining his PhD in zoology at the University of Innsbruck in Austria in 1950. At the end of that year he emigrated to Australia...

 of the Commonwealth Scientific and Industrial Research Organization introduced species of dung beetle to Australia from South Africa and Europe and effectively reduced the bush fly (Musca vetustissima
Musca vetustissima
Musca vetustissima — commonly known as the Australian bush fly — is a species of fly found in Australia. It is the specific fly that has given rise to the expression "Aussie salute".- Description :...

) population by 90%.

Dung beetles play a remarkable role in agriculture
Agriculture
Agriculture is the cultivation of animals, plants, fungi and other life forms for food, fiber, and other products used to sustain life. Agriculture was the key implement in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that nurtured the...

. By burying and consuming dung, they improve nutrient recycling and soil structure. They also protect livestock, such as cattle
Cattle
Cattle are the most common type of large domesticated ungulates. They are a prominent modern member of the subfamily Bovinae, are the most widespread species of the genus Bos, and are most commonly classified collectively as Bos primigenius...

, by removing the dung which, if left, could provide habitat for pests
Pest (animal)
A pest is an animal which is detrimental to humans or human concerns. It is a loosely defined term, often overlapping with the related terms vermin, weeds, parasites and pathogens...

 such as flies
Fly
True flies are insects of the order Diptera . They possess a pair of wings on the mesothorax and a pair of halteres, derived from the hind wings, on the metathorax...

. Therefore, many countries have introduced
Biological pest control
Biological control of pests in agriculture is a method of controlling pests that relies on predation, parasitism, herbivory, or other natural mechanisms...

 the creature for the benefit of animal husbandry
Animal husbandry
Animal husbandry is the agricultural practice of breeding and raising livestock.- History :Animal husbandry has been practiced for thousands of years, since the first domestication of animals....

. In developing countries, the beetle is especially important as an adjunct for improving standards of hygiene. The American Institute of Biological Sciences
American Institute of Biological Sciences
The American Institute of Biological Sciences is a non-profit scientific association that is dedicated to advancing biological research and education.-Overview:...

 reports that dung beetles save the United States cattle industry an estimated US$
United States dollar
The United States dollar , also referred to as the American dollar, is the official currency of the United States of America. It is divided into 100 smaller units called cents or pennies....

380 million annually through burying above-ground livestock faeces.

Some beetles help in a professional setting, doing things that people can't; such as those of the family Dermestidae are often used in taxidermy
Taxidermy
Taxidermy is the act of mounting or reproducing dead animals for display or for other sources of study. Taxidermy can be done on all vertebrate species of animals, including mammals, birds, fish, reptiles, and amphibians...

 and preparation of scientific specimens to clean bones of remaining soft tissue. The beetle larvae to clean skulls because they do a thorough job of cleaning, and the beetle larvae do not leave the tool marks that taxidermists tools do. Another benefit is that with no traces of meat remaining, and no emulsified fats in the bones, the trophy will not develop the unpleasant dead odor. Using the beetle larvae means that all cartilage is removed along with the flesh, leaving the bones spotless.


As food


Insects are used as human food in 80% of the world's nations. Beetles are the most widely eaten insects. 344 species are known to be used as food. They are usually eaten in the larval stage. The mealworm
Mealworm
Mealworms are the larval form of the mealworm beetle, Tenebrio molitor, a species of darkling beetle. Like all holometabolic insects, they go through four life stages: egg, larva, pupa, and adult...

 is the most eaten beetle species. The larvae of the darkling beetle
Darkling beetle
Darkling beetles are a family of beetles found worldwide, estimated at more than 20,000 species. Many of the beetles have black elytra, leading to their common name...

 and the rhinoceros beetle
Rhinoceros beetle
The Rhinoceros Beetles or Rhino Beetles are a subfamily of the scarab beetle family . Other common names – some for particular groups of rhino beetles – are for example Hercules beetles, unicorn beetles or horn beetles...

 are also commonly eaten.


In art


Many beetles have beautiful and durable elytra that have been used as a material in arts, with Beetlewing
Beetlewing
Beetlewing, or beetlewing art, is an ancient craft technique using iridescent beetle wings practiced traditionally in Thailand, Myanmar, India, China and Japan.-Tradition:...

 the best example. Sometimes they're also incorporated into ritual objects for their religious significance. Whole beetles, either by themselves or encased in clear plastic, are also made into everything from cheap souvenirs such as key chains to expensive fine-art jewelry. In parts of Mexico, beetles of the genus Zopherus
Zopherus
Zopherus is a genus of beetles comprising 19 species. They live in North and Central America and are adapted to wood-boring. Some species are used as living brooches.-Distribution:...

 are made into living brooch
Brooch
A brooch ; also known in ancient times as a fibula; is a decorative jewelry item designed to be attached to garments. It is usually made of metal, often silver or gold but sometimes bronze or some other material...

es by attaching costume jewelry and golden chains. This is made possible by the incredibly hard elytra and sedentary habits of the genus.

In ancient culture




Beetles are prominent in ancient culture, however the most would probably be the dung beetle
Dung beetle
Dung beetles are beetles that feed partly or exclusively on feces. All of these species belong to the superfamily Scarabaeoidea; most of them to the subfamilies Scarabaeinae and Aphodiinae of the family Scarabaeidae. This beetle can also be referred to as the scarab beetle. As most species of...

 in Ancient Egypt
Ancient Egypt
Ancient Egypt was an ancient civilization of Northeastern Africa, concentrated along the lower reaches of the Nile River in what is now the modern country of Egypt. Egyptian civilization coalesced around 3150 BC with the political unification of Upper and Lower Egypt under the first pharaoh...

. Several species of the dung beetle, most notably the species Scarabaeus sacer
Scarabaeus sacer
Scarabaeus sacer is a species of dung beetle, found in coastal dunes and marshes around the Mediterranean Basin. It collects balls of dung which it rolls to an underground chamber to feed its offspring. This behaviour inspired the Ancient Egyptians to compare it to the sun god Khepri, and they...

(often referred to as the sacred scarab), enjoyed a sacred status among the ancient Egyptians. Popular interpretation in modern academia theorizes the hieroglyphic image of the beetle represents a triliteral phonetic
Egyptian language
Egyptian is the oldest known indigenous language of Egypt and a branch of the Afroasiatic language family. Written records of the Egyptian language have been dated from about 3400 BC, making it one of the oldest recorded languages known. Egyptian was spoken until the late 17th century AD in the...

 that Egyptologists transliterate as xpr or ḫpr and translate as "to come into being", "to become" or "to transform". The derivative term xprw or ḫpr(w) is variously translated as "form", "transformation", "happening", "mode of being" or "what has come into being", depending on the context. It may have existential, fictional, or ontologic significance.

The scarab was linked to Khepri
Khepri
This article is about the Egyptian god. For the type of robot, see Khepera mobile robot.In Egyptian mythology, Khepri is the name of a major god. Khepri is associated with the dung beetle , whose behavior of maintaining spherical balls of dung represents the forces which move the sun...

 ("he who has come into being"), the god of the rising sun
Sun
The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...

. The ancients believed that the dung beetle was only male in gender, and reproduced by depositing semen
Semen
Semen is an organic fluid, also known as seminal fluid, that may contain spermatozoa. It is secreted by the gonads and other sexual organs of male or hermaphroditic animals and can fertilize female ova...

 into a dung ball. The supposed self-creation of the beetle resembles that of Khepri, who creates himself out of nothing. Moreover, the dung ball rolled by a dung beetle resembles the sun. Plutarch
Plutarch
Plutarch then named, on his becoming a Roman citizen, Lucius Mestrius Plutarchus , c. 46 – 120 AD, was a Greek historian, biographer, essayist, and Middle Platonist known primarily for his Parallel Lives and Moralia...

 wrote: The ancient Egyptians believed that Khepri renewed the sun every day before rolling it above the horizon, then carried it through the other world after sunset, only to renew it, again, the next day. Some New Kingdom
New Kingdom
The New Kingdom of Egypt, also referred to as the Egyptian Empire is the period in ancient Egyptian history between the 16th century BC and the 11th century BC, covering the Eighteenth, Nineteenth, and Twentieth Dynasties of Egypt....

 royal tombs exhibit a threefold image of the sun god, with the beetle as symbol of the morning sun. The astronomical ceiling in the tomb of Ramses VI portrays the nightly "death" and "rebirth" of the sun as being swallowed by Nut
Nut (goddess)
In the Ennead of Egyptian mythology, Nut was the goddess of the sky.-Goddess of the sky:...

, goddess of the sky, and re-emerging from her womb as Khepri.

Excavations of ancient Egyptian sites have yielded images of the scarab in bone, ivory
Ivory
Ivory is a term for dentine, which constitutes the bulk of the teeth and tusks of animals, when used as a material for art or manufacturing. Ivory has been important since ancient times for making a range of items, from ivory carvings to false teeth, fans, dominoes, joint tubes, piano keys and...

, stone, Egyptian faience
Egyptian faience
Egyptian faience is a non-clay based ceramic displaying surface vitrification which creates a bright lustre of various blue-green colours. Having not been made from clay it is often not classed as pottery. It is called "Egyptian faience" to distinguish it from faience, the tin glazed pottery...

, and precious metals, dating from the Sixth Dynasty and up to the period of Roman rule. They are generally small, bored to allow stringing on a necklace, and the base bears a brief inscription or cartouche
Cartouche
In Egyptian hieroglyphs, a cartouche is an ellipse with a horizontal line at one end, indicating that the text enclosed is a royal name, coming into use during the beginning of the Fourth Dynasty under Pharaoh Sneferu, replacing the earlier serekh...

. Some have been used as seal
Impression seal
The impression seal is a common seal that leaves an impression, typically in clay and less often in wax. In antiquity they were common, largely because they served to authenticate legal documents, such as tax receipts, contracts, wills and decrees...

s. Pharaoh
Pharaoh
Pharaoh is a title used in many modern discussions of the ancient Egyptian rulers of all periods. The title originates in the term "pr-aa" which means "great house" and describes the royal palace...

s sometimes commissioned the manufacture of larger images with lengthy inscriptions, such as the commemorative scarab
The lion hunts of Amenhotep III during the first ten years of his reign
The Lion-Hunts of Amenhotep III During the First Ten Years of his Reign is one of a group of five historical and commemorative scarabs made during the reign of Amenhotep III. The set of five scarabs were presumably used to validate, and proclaim his choice of Tiye as his wife...

 of Queen Tiye
Tiye
Tiye was the daughter of Yuya and Tjuyu . She became the Great Royal Wife of the Egyptian pharaoh Amenhotep III....

. Massive sculptures of scarabs can be seen at Luxor Temple
Luxor Temple
Luxor Temple is a large Ancient Egyptian temple complex located on the east bank of the River Nile in the city today known as Luxor and was founded in 1400 BCE.,...

, at the Serapeum in Alexandria (see Serapis
Serapis
Serapis or Sarapis is a Graeco-Egyptian name of God. Serapis was devised during the 3rd century BC on the orders of Ptolemy I of Egypt as a means to unify the Greeks and Egyptians in his realm. The god was depicted as Greek in appearance, but with Egyptian trappings, and combined iconography...

) and elsewhere in Egypt.

The scarab was of prime significance in the funerary cult of ancient Egypt. Scarabs, generally, though not always, were cut from green stone, and placed on the chest of the deceased. Perhaps the most famous example of such "heart scarabs" is the yellow-green pectoral
Pectoral (Ancient Egypt)
The Pectorals of ancient Egypt were a form of jewellery, often represented as a brooch. This was mostly worn by richer people.One type, was the pectoral with a necklace, as a form of attachment, to be suspended from the neck, but to lay upon the breast...

 scarab found among the entombed provisions of Tutankhamen. It was carved from a large piece of Libyan desert glass
Libyan desert glass
Libyan desert glass , or great sand sea glass is a substance found in areas in the Libyan Desert. Fragments of desert glass can be found over large areas, up to tens of kilometers.- Geologic origin :...

. The purpose of the "heart scarab" was to ensure that the heart would not bear witness against the deceased at judgement in the Afterlife. Other possibilities are suggested by the "transformation spells" of the Coffin Texts, which affirm that the soul of the deceased may transform (xpr) into a human being, a god, or a bird and reappear in the world of the living.

In contrast to funerary contexts, some of ancient Egypt's neighbors adopted the scarab motif for seal
Scaraboid seal
The Scaraboid seal is a category of the impression seals of Egypt. It is also a category of Jewellery and amulets, though as a seal it is of minor size ....

s of varying types. The best-known of these being Judean LMLK seal
LMLK seal
LMLK seals were stamped on the handles of large storage jars mostly in and around Jerusalem during the reign of King Hezekiah based on several complete jars found in situ buried under a destruction layer caused by Sennacherib at Lachish...

s (8 of 21 designs contained scarab beetles), which were used exclusively to stamp impressions on storage jars during the reign of Hezekiah
Hezekiah
Hezekiah was the son of Ahaz and the 14th king of Judah. Edwin Thiele has concluded that his reign was between c. 715 and 686 BC. He is also one of the most prominent kings of Judah mentioned in the Hebrew Bible....

. The scarab remains an item of popular interest thanks to modern fascination with the art and beliefs of ancient Egypt. Scarab beads in semiprecious stones or glazed ceramics can be purchased at most bead shops, while at Luxor Temple a massive ancient scarab has been roped off to discourage visitors from rubbing the base of the statue "for luck".

In modern culture


Beetles still play a role in modern culture such as their use in insect fighting
Insect fighting
Insect fighting is an activity involving insects . It is practiced in areas in China, Japan, Vietnam, and Thailand. Insect fighting is a traditional Chinese pastime that dates back to the Tang Dynasty of 618-907 and had long been mainly practiced by aristocrats, senior officials and wealthy...

. Normally exploiting the large beetle's territorial behavior. Individuals may hoard many different type of insects for the fights. Some of the most popular are the Stag Beetle
Stag beetle
Stag beetles are a group of about 1,200 species of beetle in the family Lucanidae, presently classified in four subfamilies Some species grow up to over 12 cm , but most are about 5 cm .-Overview:...

, Rhinoceros Beetle
Rhinoceros beetle
The Rhinoceros Beetles or Rhino Beetles are a subfamily of the scarab beetle family . Other common names – some for particular groups of rhino beetles – are for example Hercules beetles, unicorn beetles or horn beetles...

, Kabutomushi
Japanese rhinoceros beetle
The Japanese rhinoceros beetle, Japanese horned beetle, or , Allomyrina dichotoma, is a species of rhinoceros beetle found in Japan, Korea, Taiwan and China...

, and Goliath Beetle
Goliathus
The Goliath beetles are among the largest insects on Earth, if measured in terms of size, bulk and weight. They are members of subfamily Cetoniinae, within the family Scarabaeidae. Goliath beetles can be found in many of Africa's tropical forests, where they feed primarily on tree sap and fruit...

, as their sheer size and jumping ability make them formidable opponents. They are trained by their owners to become stronger and more aggressive.

The study of beetles is called coleopterology (from Coleoptera, see above, and Greek
Ancient Greek
Ancient Greek is the stage of the Greek language in the periods spanning the times c. 9th–6th centuries BC, , c. 5th–4th centuries BC , and the c. 3rd century BC – 6th century AD of ancient Greece and the ancient world; being predated in the 2nd millennium BC by Mycenaean Greek...

 , -logia
-logy
-logy is a suffix in the English language, used with words originally adapted from Ancient Greek language ending in -λογία...

), and its practitioners are coleopterists. Coleopterists have formed organizations to facilitate the study of beetles. Among these is The Coleopterists Society, an international organization
International organization
An intergovernmental organization, sometimes rendered as an international governmental organization and both abbreviated as IGO, is an organization composed primarily of sovereign states , or of other intergovernmental organizations...

 based in the United States. Such organizations may have both professionals and amateurs interested in beetles as members. Research in this field is often published in peer-reviewed journals
Scientific journal
In academic publishing, a scientific journal is a periodical publication intended to further the progress of science, usually by reporting new research. There are thousands of scientific journals in publication, and many more have been published at various points in the past...

 specific to the field of coleopterology, though journals dealing with general entomology also publish many papers on various aspects of beetle biology. Some of the journals specific to beetle research are:
  • The Coleopterist
    The Coleopterist
    The Coleopterist is a UK-based journal for specialists in coleopterology .First published in March 1992, it is the successor to the Coleopterist's Newsletter, which originally appeared in 1980....

    (United Kingdom beetle fauna)
  • The Coleopterists Bulletin (published by The Coleopterists Society)
  • Elytron
    Elytron (journal)
    Elytron is a Spain-based journal for specialists in coleopterology .It was first published in 1987....

    (published by the European Association of Coleopterology)

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