Lepidoptera genitalia
Encyclopedia
The study of the genitalia of Lepidoptera
is important for Lepidoptera taxonomy in addition to development
, anatomy
and natural history
. The genitalia are complex and provide the basis for species discrimination in most families and also in family identification. The genitalia are attached onto the tenth or most distal segment of the abdomen. Lepidoptera have some of the most complex genital structures in the insect groups with a wide variety of complex spines, setae, scales and tufts in males, claspers of different shapes and different modifications of the ductus bursae in females.
The arrangement of genitalia is important in the courtship and mating as they prevent cross-specific mating and hybridisation. The uniqueness of genitalia of a species led to the use of the morphological study of genitalia as one of the most important keys in taxonomic identification of taxa below family level. With the advent of DNA analysis, the study of genitalia has now become just one of the techniques used in taxonomy.
'tegumen' and ventral 'vinculum'. They form a ring-like structure for the attachment of genital parts and a pair of lateral clasping organs (claspers or 'harpe'). The male has a median tubular organ (called the aedeagus
) which is extended through an eversible sheath (or 'vesica') to inseminate the female. The males have paired sperm ducts in all Lepidopterans; however, the paired testes are separate in basal taxa and fused in advanced forms.
The males of many species of Papilionoidea
are furnished with secondary sexual characteristics. These consist of scent-producing organs, brushes, and brands or pouches of specialised scales. These presumably meet the function of convincing the female that she is mating with a male of the correct species.
When copulation takes place, the male butterfly or moth places a capsule of sperm (referred to as 'spermatophore') in a receptacle of the female (called the 'corpus bursae'). The sperm, when released from the capsule, swims directly into or via a small tube into a special seminal receptacle (called 'spermatheca'), where the sperm is stored until it is released into the vagina for fertilisation during egg laying, which may occur hours, days, or months after mating. The eggs pass through the ovipore
. The ovipore may be at the end of a modified 'ovipositor' or surrounded by a pair of broad setose anal papillae.
Butterflies of the Parnassinae (Family Papilionidae) and some Acraeini
(Family Nymphalidae
) add a post-copulatory plug, called the sphragis, to the abdomen of the female after copulation preventing her from mating again. The females of some moths have a scent-emitting organ located at the tip of the abdomen.
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...
is important for Lepidoptera taxonomy in addition to development
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...
, 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...
and natural history
Natural history
Natural history is the scientific research of plants or animals, leaning more towards observational rather than experimental methods of study, and encompasses more research published in magazines than in academic journals. Grouped among the natural sciences, natural history is the systematic study...
. The genitalia are complex and provide the basis for species discrimination in most families and also in family identification. The genitalia are attached onto the tenth or most distal segment of the abdomen. Lepidoptera have some of the most complex genital structures in the insect groups with a wide variety of complex spines, setae, scales and tufts in males, claspers of different shapes and different modifications of the ductus bursae in females.
The arrangement of genitalia is important in the courtship and mating as they prevent cross-specific mating and hybridisation. The uniqueness of genitalia of a species led to the use of the morphological study of genitalia as one of the most important keys in taxonomic identification of taxa below family level. With the advent of DNA analysis, the study of genitalia has now become just one of the techniques used in taxonomy.
Configurations
There are three basic configurations of genitalia in the majority of the Lepidoptera based on how the arrangement in females of openings for copulation, fertilisation and egg-laying has evolved:- ExoporiaExoporiaExoporia are a group of primitive Lepidoptera comprising the superfamilies Mnesarchaeoidea and Hepialoidea . Exoporia is a natural group or clade which is the sister group of the lepidopteran infraorder Heteroneura...
n : HepialidaeHepialidaeThe Hepialidae is a family of insects in the lepidopteran order. Moths of this family are often referred to as swift moths or ghost moths.-Taxonomy and systematics:...
and related families have an external groove that carries sperm from the copulatory opening (gonopore) to the (ovipore) and are termed Exoporian. - MonotrysiaMonotrysiaThe Monotrysia is a group of insects in the Lepidopteran order which is not currently considered to be a natural group or clade. The group contains only moths and most of these are small and are relatively understudied in many regions of the world...
n : Primitive groups have a single genital aperture near the end of the abdomen through which both copulation and egg laying occur. This character is used to designate the Monotrysia. - DitrysiaDitrysiaThe Ditrysia are a natural group or clade of insects in the Lepidopteran order containing both butterflies and moths. They are so named because the female has two distinct sexual openings: one for mating, and the other for laying eggs .About 98% of described species of Lepidoptera belong to Ditrysia...
n : The remaining groups have an internal duct that carry sperm and form the Ditrysia, with two distinct openings each for copulation and egg-laying.
Male
Genitalia in male and female of any particular Lepidopteran species are adapted to fit each other like a lock (female) and key (male). In males, the ninth abdominal segment is divided into a dorsalDorsum (biology)
In anatomy, the dorsum is the upper side of animals that typically run, fly, or swim in a horizontal position, and the back side of animals that walk upright. In vertebrates the dorsum contains the backbone. The term dorsal refers to anatomical structures that are either situated toward or grow...
'tegumen' and ventral 'vinculum'. They form a ring-like structure for the attachment of genital parts and a pair of lateral clasping organs (claspers or 'harpe'). The male has a median tubular organ (called the aedeagus
Aedeagus
An aedeagus is a reproductive organ of male insects through which they secrete sperm from the testes during copulation with a female insect...
) which is extended through an eversible sheath (or 'vesica') to inseminate the female. The males have paired sperm ducts in all Lepidopterans; however, the paired testes are separate in basal taxa and fused in advanced forms.
The males of many species of Papilionoidea
Papilionoidea
The superfamily Papilionoidea contains all the butterflies except for the skippers, which are classified in superfamily Hesperioidea, and the moth-like Hedyloidea....
are furnished with secondary sexual characteristics. These consist of scent-producing organs, brushes, and brands or pouches of specialised scales. These presumably meet the function of convincing the female that she is mating with a male of the correct species.
Female
While the layout of internal genital ducts and openings of the female genitalia depends upon the taxonomic group that insect belongs to, the internal female reproductive system of all Lepidopterans consists of paired ovaries and accessory glands which produce the yolks and shells of the eggs. Female insects have a system of receptacles and ducts in which sperm is received, transported and stored. The oviducts of the female join together to form a common duct (called the 'oviductus communis') which leads to the vagina.When copulation takes place, the male butterfly or moth places a capsule of sperm (referred to as 'spermatophore') in a receptacle of the female (called the 'corpus bursae'). The sperm, when released from the capsule, swims directly into or via a small tube into a special seminal receptacle (called 'spermatheca'), where the sperm is stored until it is released into the vagina for fertilisation during egg laying, which may occur hours, days, or months after mating. The eggs pass through the ovipore
Ovipore
An ovipore is a pore-like sexual organ of a female insect that gets inseminated by the spermatophores ejected by the aedeagus of a male insect during copulation. The spermatophores that pass through the ovipore are stored in most insect species in another organ called spermatheca....
. The ovipore may be at the end of a modified 'ovipositor' or surrounded by a pair of broad setose anal papillae.
Butterflies of the Parnassinae (Family Papilionidae) and some Acraeini
Acraeini
Acraeini is a tribe of butterflies of the subfamily Heliconiinae in the family Nymphalidae.-Genera:* Abananote Potts, 1943* Acraea – acraeas* Actinote* Altinote Potts, 1943* Bematistes* Cethosia – lacewings...
(Family Nymphalidae
Nymphalidae
The Nymphalidae is a family of about 5,000 species of butterflies which are distributed throughout most of the world. These are usually medium sized to large butterflies. Most species have a reduced pair of forelegs and many hold their colourful wings flat when resting. They are also called...
) add a post-copulatory plug, called the sphragis, to the abdomen of the female after copulation preventing her from mating again. The females of some moths have a scent-emitting organ located at the tip of the abdomen.