Pollination

Pollination

Overview
Pollination is the process
Process (science)
In science, a process is every sequence of changes of a real object/body which is observable using the scientific method. Therefore, all sciences analyze and model processes....

 by which pollen
Pollen
Pollen is a fine to coarse powder containing the microgametophytes of seed plants, which produce the male gametes . Pollen grains have a hard coat that protects the sperm cells during the process of their movement from the stamens to the pistil of flowering plants or from the male cone to the...

 is transferred in plants, thereby enabling fertilisation
Fertilisation
Fertilisation is the fusion of gametes to produce a new organism. In animals, the process involves the fusion of an ovum with a sperm, which eventually leads to the development of an embryo...

 and sexual reproduction
Sexual reproduction
Sexual reproduction is the creation of a new organism by combining the genetic material of two organisms. There are two main processes during sexual reproduction; they are: meiosis, involving the halving of the number of chromosomes; and fertilization, involving the fusion of two gametes and the...

. Pollen grains transport the male gamete
Gamete
A gamete is a cell that fuses with another cell during fertilization in organisms that reproduce sexually...

s (sperm
Sperm
The term sperm is derived from the Greek word sperma and refers to the male reproductive cells. In the types of sexual reproduction known as anisogamy and oogamy, there is a marked difference in the size of the gametes with the smaller one being termed the "male" or sperm cell...

) to where the female gamete(s) are contained within the carpel; in gymnosperms the pollen is directly applied to the ovule itself. The receptive part of the carpel is called a stigma in the flower
Flower
A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants . The biological function of a flower is to effect reproduction, usually by providing a mechanism for the union of sperm with eggs...

s of angiosperms. The receptive part of the gymnosperm
Gymnosperm
The gymnosperms are a group of seed-bearing plants that includes conifers, cycads, Ginkgo, and Gnetales. The term "gymnosperm" comes from the Greek word gymnospermos , meaning "naked seeds", after the unenclosed condition of their seeds...

 ovule is called the micropyle
Micropyle
A micropyle is small opening in the surface of an ovule, through which the pollen tube penetrates, often visible as a small pore in the ripe seed....

.
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Encyclopedia
Pollination is the process
Process (science)
In science, a process is every sequence of changes of a real object/body which is observable using the scientific method. Therefore, all sciences analyze and model processes....

 by which pollen
Pollen
Pollen is a fine to coarse powder containing the microgametophytes of seed plants, which produce the male gametes . Pollen grains have a hard coat that protects the sperm cells during the process of their movement from the stamens to the pistil of flowering plants or from the male cone to the...

 is transferred in plants, thereby enabling fertilisation
Fertilisation
Fertilisation is the fusion of gametes to produce a new organism. In animals, the process involves the fusion of an ovum with a sperm, which eventually leads to the development of an embryo...

 and sexual reproduction
Sexual reproduction
Sexual reproduction is the creation of a new organism by combining the genetic material of two organisms. There are two main processes during sexual reproduction; they are: meiosis, involving the halving of the number of chromosomes; and fertilization, involving the fusion of two gametes and the...

. Pollen grains transport the male gamete
Gamete
A gamete is a cell that fuses with another cell during fertilization in organisms that reproduce sexually...

s (sperm
Sperm
The term sperm is derived from the Greek word sperma and refers to the male reproductive cells. In the types of sexual reproduction known as anisogamy and oogamy, there is a marked difference in the size of the gametes with the smaller one being termed the "male" or sperm cell...

) to where the female gamete(s) are contained within the carpel; in gymnosperms the pollen is directly applied to the ovule itself. The receptive part of the carpel is called a stigma in the flower
Flower
A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants . The biological function of a flower is to effect reproduction, usually by providing a mechanism for the union of sperm with eggs...

s of angiosperms. The receptive part of the gymnosperm
Gymnosperm
The gymnosperms are a group of seed-bearing plants that includes conifers, cycads, Ginkgo, and Gnetales. The term "gymnosperm" comes from the Greek word gymnospermos , meaning "naked seeds", after the unenclosed condition of their seeds...

 ovule is called the micropyle
Micropyle
A micropyle is small opening in the surface of an ovule, through which the pollen tube penetrates, often visible as a small pore in the ripe seed....

. Pollination is a necessary step in the reproduction of flowering plants, resulting in the production of offspring that are genetically diverse.

The study of pollination brings together many disciplines, such as botany
Botany
Botany, plant science, or plant biology is a branch of biology that involves the scientific study of plant life. Traditionally, botany also included the study of fungi, algae and viruses...

, horticulture
Horticulture
Horticulture is the industry and science of plant cultivation including the process of preparing soil for the planting of seeds, tubers, or cuttings. Horticulturists work and conduct research in the disciplines of plant propagation and cultivation, crop production, plant breeding and genetic...

, entomology
Entomology
Entomology is the scientific study of insects, a branch of arthropodology...

, and ecology
Ecology
Ecology is the scientific study of the relations that living organisms have with respect to each other and their natural environment. Variables of interest to ecologists include the composition, distribution, amount , number, and changing states of organisms within and among ecosystems...

. The pollination process as an interaction between flower
Flower
A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants . The biological function of a flower is to effect reproduction, usually by providing a mechanism for the union of sperm with eggs...

 and vector
Pollinator
A pollinator is the biotic agent that moves pollen from the male anthers of a flower to the female stigma of a flower to accomplish fertilization or syngamy of the female gamete in the ovule of the flower by the male gamete from the pollen grain...

 was first addressed in the 18th century by Christian Konrad Sprengel
Christian Konrad Sprengel
Christian Konrad Sprengel was a German theologist, teacher and, most importantly, a naturalist. He is most famously known for his research into plant sexuality....

. It is important in horticulture and 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...

, because fruit
Fruit
In broad terms, a fruit is a structure of a plant that contains its seeds.The term has different meanings dependent on context. In non-technical usage, such as food preparation, fruit normally means the fleshy seed-associated structures of certain plants that are sweet and edible in the raw state,...

ing is dependent on fertilisation, which is the end result of pollination.

Abiotic



Abiotic pollination refers to situations where pollination is mediated without the involvement of other organisms. Only 10% of flower
Flower
A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants . The biological function of a flower is to effect reproduction, usually by providing a mechanism for the union of sperm with eggs...

ing plants are pollinated without 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...

 assistance. The most common form of abiotic pollination, anemophily
Anemophily
Anemophily or wind pollination is a form of pollination whereby pollen is distributed by wind. Anemophilous plants may be either gymnosperms or angiosperms ....

, is pollination by wind
Wind
Wind is the flow of gases on a large scale. On Earth, wind consists of the bulk movement of air. In outer space, solar wind is the movement of gases or charged particles from the sun through space, while planetary wind is the outgassing of light chemical elements from a planet's atmosphere into space...

. This form of pollination is predominant in grasses
Poaceae
The Poaceae is a large and nearly ubiquitous family of flowering plants. Members of this family are commonly called grasses, although the term "grass" is also applied to plants that are not in the Poaceae lineage, including the rushes and sedges...

, most conifers, and many deciduous trees. Hydrophily
Hydrophily
Hydrophily is a fairly uncommon form of pollination whereby pollen is distributed by the flow of waters, particularly in rivers and streams. Hydrophilous species fall into two categories: those that distribute their pollen to the surface of water, and those that distribute it beneath the...

 is pollination by water, and occurs in aquatic plants which release their pollen directly into the surrounding water. About 80% of all plant pollination is biotic. In gymnosperms, biotic pollination is generally incidental when it occurs, though some gymnosperms and their pollinators are mutually adapted for pollination. The best-known examples probably are members of the order Cycadales
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...

 and associated species of beetles. Most conifera are anemophilous
Anemophily
Anemophily or wind pollination is a form of pollination whereby pollen is distributed by wind. Anemophilous plants may be either gymnosperms or angiosperms ....

; they depend on wind pollination. Of the 20% of abiotically pollinated species, 98% are anemophilous and 2% hydrophilous
Hydrophily
Hydrophily is a fairly uncommon form of pollination whereby pollen is distributed by the flow of waters, particularly in rivers and streams. Hydrophilous species fall into two categories: those that distribute their pollen to the surface of water, and those that distribute it beneath the...

, being pollinated by water.

Biotic


More commonly, the process of pollination requires pollinator
Pollinator
A pollinator is the biotic agent that moves pollen from the male anthers of a flower to the female stigma of a flower to accomplish fertilization or syngamy of the female gamete in the ovule of the flower by the male gamete from the pollen grain...

s: organisms that carry or move the pollen grains from the anther
Stamen
The stamen is the pollen producing reproductive organ of a flower...

 to the receptive part of the carpel or pistil. This is biotic pollination. The various flower traits (and combinations thereof) that differentially attract one type of pollinator or another are known as pollination syndrome
Pollination syndrome
Pollination syndromes are suites of flower traits that have evolved in response to natural selection imposed by different pollen vectors, which can be abiotic or biotic, such as birds, bees, flies, and so forth. These traits include flower shape, size, colour, odour, reward type and amount, nectar...

s.

There are roughly 200,000 varieties of animal pollinators in the wild, most of which are 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. Entomophily
Entomophily
Entomophily is a form of pollination whereby pollen is distributed by insects. Several insect are reported to be responsible for the pollination of many plant species, particularly bees, Lepidoptera , wasps, flies, ants and beetles. Some plant species co-evolved with a particular pollinator, such...

, pollination by 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, often occurs on plants that have developed colored petals and a strong scent to attract insects such as, bees, wasps and occasionally ants (Hymenoptera
Hymenoptera
Hymenoptera is one of the largest orders of insects, comprising the sawflies, wasps, bees and ants. There are over 130,000 recognized species, with many more remaining to be described. The name refers to the heavy wings of the insects, and is derived from the Ancient Greek ὑμήν : membrane and...

), beetle
Beetle
Coleoptera is an order of insects commonly called beetles. The word "coleoptera" is from the Greek , koleos, "sheath"; and , pteron, "wing", thus "sheathed wing". Coleoptera contains more species than any other order, constituting almost 25% of all known life-forms...

s (Coleoptera), moths and butterflies (Lepidoptera
Lepidoptera
Lepidoptera is a large order of insects that includes moths and butterflies . It is one of the most widespread and widely recognizable insect orders in the world, encompassing moths and the three superfamilies of butterflies, skipper butterflies, and moth-butterflies...

), and flies (Diptera
Diptera
Diptera , or true flies, is the order of insects possessing only a single pair of wings on the mesothorax; the metathorax bears a pair of drumstick like structures called the halteres, the remnants of the hind wings. It is a large order, containing an estimated 240,000 species, although under half...

). In zoophily
Zoophily
Zoophily is a form of pollination whereby pollen is transferred by vertebrates, particularly by hummingbirds and other birds, and bats, but also by monkeys, marsupials, lemurs, bears, rabbits, deer, rodents, lizards and other animals...

, pollination is performed by vertebrates such as birds and bat
Bat
Bats are mammals of the order Chiroptera "hand" and pteron "wing") whose forelimbs form webbed wings, making them the only mammals naturally capable of true and sustained flight. By contrast, other mammals said to fly, such as flying squirrels, gliding possums, and colugos, glide rather than fly,...

s, particularly, hummingbird
Hummingbird
Hummingbirds are birds that comprise the family Trochilidae. They are among the smallest of birds, most species measuring in the 7.5–13 cm range. Indeed, the smallest extant bird species is a hummingbird, the 5-cm Bee Hummingbird. They can hover in mid-air by rapidly flapping their wings...

s, sunbird
Sunbird
The sunbirds and spiderhunters are a family, Nectariniidae, of very small passerine birds. There are 132 species in 15 genera. The family is distributed throughout Africa, southern Asia and just reaches northern Australia. Most sunbirds feed largely on nectar, but also take insects and spiders,...

s, spiderhunter
Spiderhunter
The spiderhunters are birds of the genus Arachnothera, part of the sunbird family Nectariniidae. The genus contains eleven species found in the forests of south and southeastern Asia. They are large representatives of the sunbird family, with drab plumage and long strongly curved bills...

s, honeyeater
Honeyeater
The honeyeaters are a large and diverse family of small to medium sized birds most common in Australia and New Guinea, but also found in New Zealand, the Pacific islands as far east as Samoa and Tonga, and the islands to the north and west of New Guinea known as Wallacea...

s, and fruit bat
Fruit Bat
Fruit Bat can refer to:* Megabats, a species of bat which eats fruit* Les "Fruitbat" Carter, guitarist of Carter the Unstoppable Sex Machine* Fruit Bats , an American band...

s. Plants adapted to using bats or moths as pollinators typically have white petals and a strong scent, while plants that use birds as pollinators tend to develop red petals and rarely develop a scent (few birds rely on a sense of smell to find plant-based food).

Insect pollinators such as honeybees (Apis mellifera), bumblebees (Bombus terrestris), and butterflies (Thymelicus flavus) have been observed to engage in flower constancy
Flower constancy
Flower constancy or pollinator constancy is defined as the tendency of individual pollinators to exclusively visit certain flower species or morphs within a species, bypassing other available flower species that could potentially be more rewarding...

, which means they are more likely to transfer pollen to other conspecific plants. This can be beneficial for the pollenisers, as flower constancy prevents the loss of pollen during interspecific flights and pollinators from clogging stigmas with pollen of other flower species.

Mechanics


Pollination can be accomplished by cross-pollination or by self-pollination :
  • Cross-pollination, also called allogamy
    Allogamy
    Allogamy is a term used in the field of biological reproduction describing the fertilization of an ovum from one individual with the spermatozoa of another. By contrast, autogamy is the term used for self-fertilization. In humans, the fertilization event is an instance of allogamy...

    occurs when pollen is delivered to a flower from a different plant. Plants adapted to outcross or cross-pollinate often have taller stamens than carpels or use other mechanisms to better ensure the spread of pollen to other plants' flowers.

  • Self-pollination occurs when pollen from one flower pollinates the same flower or other flowers of the same individual. It is thought to have evolved under conditions when pollinators were not reliable vectors for pollen transport, and is most often seen in short-lived annual species and plants that colonize new locations. Self pollination may include autogamy, where pollen moves to the female part of the same flower; or geitonogamy, when pollen is transferred to another flower on the same plant. Plants adapted to self-fertilize often have similar stamen and carpel lengths. Plants that can pollinate themselves and produce viable offspring are called self-fertile. Plants that cannot fertilize themselves are called self-sterile, a condition which mandates cross pollination for the production of offspring.
  • Cleistogamy
    Cleistogamy
    Cleistogamy or automatic self-pollination describes the trait of certain plants to propagate by using non-opening, self-pollinating flowers...

    : is self-pollination that occurs before the flower opens. The pollen is released from the anther within the flower or the pollen on the anther grows a tube down the style to the ovules. It is a type of sexual breeding, in contrast to asexual systems such as apomixis. Some cleistogamous flowers never open, in contrast to chasmogamous flowers that open and are then pollinated. Cleistogamous flowers by necessity are self-compatible or self-fertile plants. Many plants are self-incompatible, and these two conditions are end points on a continuum.

Pollination also requires consideration of pollenizer
Pollenizer
A pollenizer or polleniser, sometimes pollinizer or polliniser is a plant that provides pollen.In American English, the words pollenizer and pollinator are often confused: A pollinator is the biotic agent that moves the pollen, such as bees, moths, bats, and birds...

s. The terms "pollinator" and "pollenizer" are often confused: a pollinator is the agent that moves the pollen, whether it be bees, flies, bats, moths, or birds; a pollenizer is the plant that serves as the pollen source for other plants. Some plants are self-fertile
Self-incompatibility in plants
Self-incompatibility is a general name for several genetic mechanisms in angiosperms, which prevent self-fertilization and thus encourage outcrossing...

or self-compatible and can pollinate themselves (e.g., they act as their own pollenizer). Other plants have chemical or physical barriers to self-pollination
Self-pollination
Self-pollination is a form of pollination that can occur when a flower has both stamen and a carpel in which the cultivar or species is self fertile and the stamens and the sticky stigma of the carpel contact each other in order to accomplish pollination...

.

In agriculture and horticulture
Horticulture
Horticulture is the industry and science of plant cultivation including the process of preparing soil for the planting of seeds, tubers, or cuttings. Horticulturists work and conduct research in the disciplines of plant propagation and cultivation, crop production, plant breeding and genetic...

 pollination management, a good pollenizer is a plant that provides compatible, viable and plentiful pollen and blooms at the same time as the plant that is to be pollinated or has pollen that can be stored and used when needed to pollinate the desired flowers. Hybridization is effective pollination between flowers of different 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...

, or between different breeding lines or populations. see also Heterosis
Heterosis
Heterosis, or hybrid vigor, or outbreeding enhancement, is the improved or increased function of any biological quality in a hybrid offspring. The adjective derived from heterosis is heterotic....

.

Peach
Peach
The peach tree is a deciduous tree growing to tall and 6 in. in diameter, belonging to the subfamily Prunoideae of the family Rosaceae. It bears an edible juicy fruit called a peach...

es are considered self-fertile because a commercial crop can be produced without cross-pollination, though cross-pollination usually gives a better crop. Apples are considered self-incompatible, because a commercial crop must be cross-pollinated. Many commercial fruit tree varieties are grafted
Grafting
Grafting is a horticultural technique whereby tissues from one plant are inserted into those of another so that the two sets of vascular tissues may join together. This vascular joining is called inosculation...

 clone
Cloning
Cloning in biology is the process of producing similar populations of genetically identical individuals that occurs in nature when organisms such as bacteria, insects or plants reproduce asexually. Cloning in biotechnology refers to processes used to create copies of DNA fragments , cells , or...

s, genetically
Genetics
Genetics , a discipline of biology, is the science of genes, heredity, and variation in living organisms....

 identical. An orchard block of apples of one variety is genetically a single plant. Many growers now consider this a mistake. One means of correcting this mistake is to graft a limb of an appropriate pollenizer (generally a variety of crabapple
Crabapple
Crabapple is a term used for several species of Malus in the family Rosaceae, which are characterized by small sour fruit resembling familiar table apples . They are usually small trees or shrubs....

) every six trees or so.

Pollen vectors


Pollen vectors are animals, usually insects, that transport pollen
Pollen
Pollen is a fine to coarse powder containing the microgametophytes of seed plants, which produce the male gametes . Pollen grains have a hard coat that protects the sperm cells during the process of their movement from the stamens to the pistil of flowering plants or from the male cone to the...

 of plants when using the flowers for feeding, breeding or hiding. The pollen is found adhered to 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 body parts such as face, legs and mouthparts or to mammal
Mammal
Mammals are members of a class of air-breathing vertebrate animals characterised by the possession of endothermy, hair, three middle ear bones, and mammary glands functional in mothers with young...

's hairs, resulting or helping in the pollination of many plant species. An example are wasps, which can transport pollen and contribute for the pollination of several plant species, being potential or even efficient pollinators.

Evolution of plant/pollinator interactions


The first fossil record for abiotic pollination is from fern
Fern
A fern is any one of a group of about 12,000 species of plants belonging to the botanical group known as Pteridophyta. Unlike mosses, they have xylem and phloem . They have stems, leaves, and roots like other vascular plants...

-like plants in the late Carboniferous
Carboniferous
The Carboniferous is a geologic period and system that extends from the end of the Devonian Period, about 359.2 ± 2.5 Mya , to the beginning of the Permian Period, about 299.0 ± 0.8 Mya . The name is derived from the Latin word for coal, carbo. Carboniferous means "coal-bearing"...

 period. Gymnosperm
Gymnosperm
The gymnosperms are a group of seed-bearing plants that includes conifers, cycads, Ginkgo, and Gnetales. The term "gymnosperm" comes from the Greek word gymnospermos , meaning "naked seeds", after the unenclosed condition of their seeds...

s show evidence for biotic pollination as early as the 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...

 period. Many fossilized pollen grains show characteristics similar to the biotically dispersed pollen today. Furthermore, the gut contents, wing structures, and mouthpart morphologies of fossilized beetles and flies
Diptera
Diptera , or true flies, is the order of insects possessing only a single pair of wings on the mesothorax; the metathorax bears a pair of drumstick like structures called the halteres, the remnants of the hind wings. It is a large order, containing an estimated 240,000 species, although under half...

 suggest that they acted as early pollinators.
The association between beetles and angiosperms during the early 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...

 period led to parallel radiations of angiosperms and insects into the late Cretaceous. The evolution of
nectaries in late Cretaceous flowers signals the beginning of the mutualism between hymenoptera
Hymenoptera
Hymenoptera is one of the largest orders of insects, comprising the sawflies, wasps, bees and ants. There are over 130,000 recognized species, with many more remaining to be described. The name refers to the heavy wings of the insects, and is derived from the Ancient Greek ὑμήν : membrane and...

ns and angiosperms.

In agriculture



Pollination management
Pollination management
Pollination Management is the label for horticultural practices that accomplish or enhance pollination of a crop, to improve yield or quality, by understanding of the particular crop's pollination needs, and by knowledgeable management of pollenizers, pollinators, and pollination...

 is a branch of agriculture that seeks to protect and enhance present pollinators and often involves the culture and addition of pollinators in monoculture
Monoculture
Monoculture is the agricultural practice of producing or growing one single crop over a wide area. It is also known as a way of farming practice of growing large stands of a single species. It is widely used in modern industrial agriculture and its implementation has allowed for large harvests from...

 situations, such as commercial fruit orchard
Orchard
An orchard is an intentional planting of trees or shrubs that is maintained for food production. Orchards comprise fruit or nut-producing trees which are grown for commercial production. Orchards are also sometimes a feature of large gardens, where they serve an aesthetic as well as a productive...

s. The largest managed pollination event in the world is in California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...

n almond
Almond
The almond , is a species of tree native to the Middle East and South Asia. Almond is also the name of the edible and widely cultivated seed of this tree...

 orchards, where nearly half (about one million hives
Beehive (beekeeping)
A beehive is an enclosed structure in which some honey bee species of the subgenus Apis live and raise their young. Natural beehives are naturally occurring structures occupied by honeybee colonies, while domesticated honeybees live in man-made beehives, often in an apiary. These man-made...

) of the US 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...

s are trucked to the almond orchards each spring. New York
New York
New York is a state in the Northeastern region of the United States. It is the nation's third most populous state. New York is bordered by New Jersey and Pennsylvania to the south, and by Connecticut, Massachusetts and Vermont to the east...

's apple
Apple
The apple is the pomaceous fruit of the apple tree, species Malus domestica in the rose family . It is one of the most widely cultivated tree fruits, and the most widely known of the many members of genus Malus that are used by humans. Apple grow on small, deciduous trees that blossom in the spring...

 crop requires about 30,000 hives; Maine
Maine
Maine is a state in the New England region of the northeastern United States, bordered by the Atlantic Ocean to the east and south, New Hampshire to the west, and the Canadian provinces of Quebec to the northwest and New Brunswick to the northeast. Maine is both the northernmost and easternmost...

's blueberry
Blueberry
Blueberries are flowering plants of the genus Vaccinium with dark-blue berries and are perennial...

 crop uses about 50,000 hives each year.

Bees are also brought to commercial plantings of cucumber
Cucumber
The cucumber is a widely cultivated plant in the gourd family Cucurbitaceae, which includes squash, and in the same genus as the muskmelon. The plant is a creeping vine which bears cylindrical edible fruit when ripe. There are three main varieties of cucumber: "slicing", "pickling", and...

s, squash
Squash (fruit)
Squashes generally refer to four species of the genus Cucurbita, also called marrows depending on variety or the nationality of the speaker...

, melon
Melon
thumb|200px|Various types of melonsThis list of melons includes members of the plant family Cucurbitaceae with edible, fleshy fruit e.g. gourds or cucurbits. The word "melon" can refer to either the plant or specifically to the fruit...

s, strawberries
Strawberry
Fragaria is a genus of flowering plants in the rose family, Rosaceae, commonly known as strawberries for their edible fruits. Although it is commonly thought that strawberries get their name from straw being used as a mulch in cultivating the plants, the etymology of the word is uncertain. There...

, and many other crops. Honey bees are not the only managed pollinators: a few other 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...

 of bees are also raised as pollinators. The alfalfa leafcutter bee
Alfalfa leafcutter bee
Megachile rotundata, the alfalfa leafcutter bee or lucerne leafcutter bee is a European bee that has been introduced to other regions...

 is an important pollinator for alfalfa
Alfalfa
Alfalfa is a flowering plant in the pea family Fabaceae cultivated as an important forage crop in the US, Canada, Argentina, France, Australia, the Middle East, South Africa, and many other countries. It is known as lucerne in the UK, France, Australia, South Africa and New Zealand, and known as...

 seed
Seed
A seed is a small embryonic plant enclosed in a covering called the seed coat, usually with some stored food. It is the product of the ripened ovule of gymnosperm and angiosperm plants which occurs after fertilization and some growth within the mother plant...

 in western United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 and Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...

. Bumblebee
Bumblebee
A bumble bee is any member of the bee genus Bombus, in the family Apidae. There are over 250 known species, existing primarily in the Northern Hemisphere although they are common in New Zealand and in the Australian state of Tasmania.Bumble bees are social insects that are characterised by black...

s are increasingly raised and used extensively for greenhouse
Greenhouse
A greenhouse is a building in which plants are grown. These structures range in size from small sheds to very large buildings...

 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...

es and other crops.


The ecological
Ecology
Ecology is the scientific study of the relations that living organisms have with respect to each other and their natural environment. Variables of interest to ecologists include the composition, distribution, amount , number, and changing states of organisms within and among ecosystems...

 and financial importance of natural pollination by insects to agricultural
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...

 crops
Crop (agriculture)
A crop is a non-animal species or variety that is grown to be harvested as food, livestock fodder, fuel or for any other economic purpose. Major world crops include maize , wheat, rice, soybeans, hay, potatoes and cotton. While the term "crop" most commonly refers to plants, it can also include...

, improving their quality and quantity, becomes more and more appreciated and has given rise to new financial opportunities. The vicinity of a forest
Forest
A forest, also referred to as a wood or the woods, is an area with a high density of trees. As with cities, depending where you are in the world, what is considered a forest may vary significantly in size and have various classification according to how and what of the forest is composed...

 or wild grassland
Grassland
Grasslands are areas where the vegetation is dominated by grasses and other herbaceous plants . However, sedge and rush families can also be found. Grasslands occur naturally on all continents except Antarctica...

s with native pollinators near agricultural crops, such as apples, almonds or coffee
Coffee
Coffee is a brewed beverage with a dark,init brooo acidic flavor prepared from the roasted seeds of the coffee plant, colloquially called coffee beans. The beans are found in coffee cherries, which grow on trees cultivated in over 70 countries, primarily in equatorial Latin America, Southeast Asia,...

 can improve their yield by about 20%. The benefits of native pollinators may result in forest owners demanding payment for their contribution in the improved crop results - a simple example of the economic value of ecological services.

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 native insect pollination saves the United States agricultural
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...

 economy nearly an estimated $3.1 billion annually through natural crop production; pollination produces some $40 billion worth of products annually in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 alone.

Pollination of food crops has become an environmental issue
Environmental movement
The environmental movement, a term that includes the conservation and green politics, is a diverse scientific, social, and political movement for addressing environmental issues....

, due to two trends. The trend to monoculture
Monoculture
Monoculture is the agricultural practice of producing or growing one single crop over a wide area. It is also known as a way of farming practice of growing large stands of a single species. It is widely used in modern industrial agriculture and its implementation has allowed for large harvests from...

 means that greater concentrations of pollinators are needed at bloom time than ever before, yet the area is forage
Forage (honeybee)
For bees, their forage or food supply consists of nectar and pollen from blooming plants within flight range. The forage sources for honey bees are an important consideration for beekeepers. In order to determine where to locate hives for maximum honey production and brood one must consider the...

 poor or even deadly to bees for the rest of the season. The other trend is the decline of pollinator populations
Pollinator decline
The term pollinator decline refers to the reduction in abundance of pollinators in many ecosystems worldwide during the end of the twentieth century....

, due to 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...

 misuse and overuse, new diseases and parasites of bees, clearcut logging, decline of beekeeping, suburb
Suburb
The word suburb mostly refers to a residential area, either existing as part of a city or as a separate residential community within commuting distance of a city . Some suburbs have a degree of administrative autonomy, and most have lower population density than inner city neighborhoods...

an development, removal of hedges and other habitat
Habitat (ecology)
A habitat is an ecological or environmental area that is inhabited by a particular species of animal, plant or other type of organism...

 from farm
Farm
A farm is an area of land, or, for aquaculture, lake, river or sea, including various structures, devoted primarily to the practice of producing and managing food , fibres and, increasingly, fuel. It is the basic production facility in food production. Farms may be owned and operated by a single...

s, and public concern about bees. Widespread aerial spraying
Agricultural aircraft
An agricultural aircraft is an aircraft that has been built or converted for agricultural use - usually aerial application of pesticides or fertilizer ; in these roles they are referred to as "crop dusters" or "top dressers"...

 for mosquito
Mosquito
Mosquitoes are members of a family of nematocerid flies: the Culicidae . The word Mosquito is from the Spanish and Portuguese for little fly...

es due to West Nile fears is causing an acceleration of the loss of pollinators.

The US solution to the pollinator shortage, so far, has been for commercial beekeepers to become pollination contractor
Independent contractor
An independent contractor is a natural person, business, or corporation that provides goods or services to another entity under terms specified in a contract or within a verbal agreement. Unlike an employee, an independent contractor does not work regularly for an employer but works as and when...

s and to migrate. Just as the combine harvester
Combine harvester
The combine harvester, or simply combine, is a machine that harvests grain crops. The name derives from the fact that it combines three separate operations, reaping, threshing, and winnowing, into a single process. Among the crops harvested with a combine are wheat, oats, rye, barley, corn ,...

s follow the wheat
Wheat
Wheat is a cereal grain, originally from the Levant region of the Near East, but now cultivated worldwide. In 2007 world production of wheat was 607 million tons, making it the third most-produced cereal after maize and rice...

 harvest
Harvest
Harvest is the process of gathering mature crops from the fields. Reaping is the cutting of grain or pulse for harvest, typically using a scythe, sickle, or reaper...

 from Texas
Texas
Texas is the second largest U.S. state by both area and population, and the largest state by area in the contiguous United States.The name, based on the Caddo word "Tejas" meaning "friends" or "allies", was applied by the Spanish to the Caddo themselves and to the region of their settlement in...

 to Manitoba
Manitoba
Manitoba is a Canadian prairie province with an area of . The province has over 110,000 lakes and has a largely continental climate because of its flat topography. Agriculture, mostly concentrated in the fertile southern and western parts of the province, is vital to the province's economy; other...

, beekeepers follow the bloom from south to north, to provide pollination for many different crops.

Environmental impacts


Loss of pollinators, also known as Pollinator decline
Pollinator decline
The term pollinator decline refers to the reduction in abundance of pollinators in many ecosystems worldwide during the end of the twentieth century....

 (of which colony collapse disorder
Colony Collapse Disorder
Colony collapse disorder is a phenomenon in which worker bees from a beehive or European honey bee colony abruptly disappear. While such disappearances have occurred throughout the history of apiculture, the term colony collapse disorder was first applied to a drastic rise in the number of...

 is perhaps the most well known) has been noticed in recent years. Observed losses would have significant economic impacts. Possible explanations for pollinator decline include habitat destruction
Habitat destruction
Habitat destruction is the process in which natural habitat is rendered functionally unable to support the species present. In this process, the organisms that previously used the site are displaced or destroyed, reducing biodiversity. Habitat destruction by human activity mainly for the purpose of...

, 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...

, parasitism
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...

/diseases, and others.

See also


  • Cheating (biology)
    Cheating (biology)
    Cheating is a metaphor commonly used in behavioral ecology to describe organisms that receive a benefit at the cost of others. Cheating is common in many mutualistic and altruistic relationships. Natural selection favors cheating, but there are mechanisms to regulate cheating.- Theoretical Models...

  • Fruit tree pollination
    Fruit tree pollination
    -Apple:Most Apples are self incompatible and must be cross pollinated. A few are described as "self-fertile" and are capable of self-pollination although they tend to carry larger crops when pollinated. A relatively small number of species are "Triploid", meaning that they provide no viable pollen...

  • Hand pollination
    Hand pollination
    Hand pollination is a technique used when natural, or open pollination is insufficient or undesirable. The most common techniques are for crops such as cucurbits, which may exhibit poor pollination by fruit abortion, fruit deformity or poor maturation...

  • Self-pollination
    Self-pollination
    Self-pollination is a form of pollination that can occur when a flower has both stamen and a carpel in which the cultivar or species is self fertile and the stamens and the sticky stigma of the carpel contact each other in order to accomplish pollination...

  • Domestication
    Domestication
    Domestication or taming is the process whereby a population of animals or plants, through a process of selection, becomes accustomed to human provision and control. In the Convention on Biological Diversity a domesticated species is defined as a 'species in which the evolutionary process has been...

  • Pollination syndrome
    Pollination syndrome
    Pollination syndromes are suites of flower traits that have evolved in response to natural selection imposed by different pollen vectors, which can be abiotic or biotic, such as birds, bees, flies, and so forth. These traits include flower shape, size, colour, odour, reward type and amount, nectar...

  • Canadian Pollination Initiative
    Canadian Pollination Initiative
    The Canadian Pollination Initiative is a one of nine new Strategic Networks announced in September 2009 and supported by the Natural Sciences and Engineering Research Council of Canada . NSERC-CANPOLIN has funding for five years to address a perceived decline in pollinators in both agricultural...

  • Hermann Müller (botanist)
    Hermann Müller (botanist)
    Heinrich Ludwig Hermann Müller , German botanist who provided important evidence for Darwin's theory of evolution. He was the author in 1873 of Die Befruchtung der Blumen durch Insekten, a book translated at the suggestion of Darwin in 1883 as The fertilisation of flowers...

  • Paul Knuth (botanist)
    Paul Knuth
    Paul Erich Otto Wilhelm Knuth was a 19th century German botanist and pollination ecologist....


External links