Lepidoptera genitalia

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Male genitalia of Lepidoptera Male genitalia Lepidoptera.jpg
Male genitalia of Lepidoptera
Female genitalia of Lepidoptera Female genitalia Lepidoptera.jpg
Female genitalia of Lepidoptera

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. [1] 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. [2] [3]

Contents

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. [4]

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: [1]

Male

Genitalia in male and female of any particular Lepidopteran species are adapted to fit each other like a lock (female) and key (male). [4] In males, the ninth abdominal segment is divided into a dorsal 'tegumen' and ventral 'vinculum'. [5] They form a ring-like structure for the attachment of genital parts and a pair of lateral clasping organs (claspers, valvae (singular valva), or 'harpes'). The male has a median tubular organ (called aedeagus or phallus) which is extended through an eversible sheath (or 'vesica') to inseminate the female. [3] The males have paired sperm ducts in all Lepidopterans; however, the paired testes are separate in basal taxa and fused in advanced forms. [3]

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. [6]

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 to form a common duct (called the 'oviductus communis') which leads to the vagina. [3] [5]

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 (the 'ductus bursae') into a special seminal receptacle (the '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. [3] [5]

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. [2] The females of some moths have a scent-emitting organ located at the tip of the abdomen. [4]

See also

Related Research Articles

<span class="mw-page-title-main">Lepidoptera</span> Order of insects including moths and butterflies

Lepidoptera or lepidopterans is an order of winged insects that includes butterflies and moths. About 180,000 species of the Lepidoptera have been described, representing 10% of the total described species of living organisms, making it the second largest insect order with 126 families and 46 superfamilies. and one of the most widespread and widely recognizable insect orders in the world.

<span class="mw-page-title-main">Damselfly</span> Suborder of insects

Damselflies are flying insects of the suborder Zygoptera in the order Odonata. They are similar to dragonflies but are smaller and have slimmer bodies. Most species fold the wings along the body when at rest, unlike dragonflies which hold the wings flat and away from the body. Damselflies have existed since the Jurassic, and are found on every continent except Antarctica.

<span class="mw-page-title-main">Aedeagus</span> Reproductive organ of male arthropods

An aedeagus is a reproductive organ of male arthropods through which they secrete sperm from the testes during copulation with a female. It can be thought of as the insect equivalent of a mammal's penis, though the comparison is fairly loose given the greater complexity of insect reproduction. The term is derived from Ancient Greek αἰδοῖα and ἀγός. It is pronounced or.

<span class="mw-page-title-main">Gonopod</span> Specialized reproductive appendages in arthropods

Gonopods are specialized appendages of various arthropods used in reproduction or egg-laying. In males, they facilitate the transfer of sperm from male to female during mating, and thus are a type of intromittent organ. In crustaceans and millipedes, gonopods are modified walking or swimming legs. Gonopods may be highly decorated with elaborate structures which may play roles in sperm competition, and can be used to differentiate and identify closely related species. Gonopods generally occur in one or more pairs, as opposed to the single (un-paired) reproductive organs such as the aedeagus of insects or the penis of harvestmen.

The Exoporia are a group of primitive Lepidoptera comprising the superfamilies Mnesarchaeoidea and Hepialoidea. They are a natural group or clade. Exoporia is the sister group of the lepidopteran infraorder Heteroneura. They are characterised by their unique female reproductive system which has an external groove between the ostium bursae and the ovipore by which the sperm is transferred to the egg rather than having the mating and egg-laying parts of the abdomen with a common opening (cloaca) as in other nonditrysian moths, or with separate openings linked internally by a "ductus seminalis" as in the Ditrysia. See Kristensen for other exoporian characteristics.

<i>Sympetrum danae</i> Species of dragonfly

Sympetrum danae, the black darter or black meadowhawk, is a dragonfly found in northern Europe, Asia, and North America. At about 30 mm (1.2 in) long, it is Britain's smallest resident dragonfly. It is a very active late summer insect typical of heathland and moorland bog pools.

<span class="mw-page-title-main">Traumatic insemination</span> Mating practice in invertebrates

Traumatic insemination, also known as hypodermic insemination, is the mating practice in some species of invertebrates in which the male pierces the female's abdomen with his aedeagus and injects his sperm through the wound into her abdominal cavity (hemocoel). The sperm diffuses through the female's hemolymph, reaching the ovaries and resulting in fertilization.

<i>Luehdorfia japonica</i> Species of butterfly

The Japanese luehdorfia is a species of butterfly in the subfamily Parnassiinae of Papilionidae. It is found only in Japan. It was discovered by Yasushi Nawa in Japan's Gifu Prefecture in 1883. It is also known as the Gifu butterfly

<span class="mw-page-title-main">Mating plug</span> Gelatinous secretion used in the mating of some species

A mating plug, also known as a copulation plug, sperm plug, vaginal plug, or sphragis, is a gelatinous secretion used in the mating of some species. It is deposited by a male into a female genital tract, such as the vagina, and later hardens into a plug or glues the tract together. While females can expel the plugs afterwards, the male's sperm still gets a time advantage in getting to the egg, which is often the deciding factor in fertilization.

<span class="mw-page-title-main">Reproductive system of gastropods</span>

The reproductive system of gastropods varies greatly from one group to another within this very large and diverse taxonomic class of animals. Their reproductive strategies also vary greatly, see mating of gastropods.

<span class="mw-page-title-main">External morphology of Lepidoptera</span> External features of butterflies and moths

The external morphology of Lepidoptera is the physiological structure of the bodies of insects belonging to the order Lepidoptera, also known as butterflies and moths. Lepidoptera are distinguished from other orders by the presence of scales on the external parts of the body and appendages, especially the wings. Butterflies and moths vary in size from microlepidoptera only a few millimetres long, to a wingspan of many inches such as the Atlas moth. Comprising over 160,000 described species, the Lepidoptera possess variations of the basic body structure which has evolved to gain advantages in adaptation and distribution.

An intromittent organ is any external organ of a male organism that is specialized to deliver sperm during copulation. Intromittent organs are found most often in terrestrial species, as most non-mammalian aquatic species fertilize their eggs externally, although there are exceptions. For many species in the animal kingdom, the male intromittent organ is a hallmark characteristic of internal fertilization.

<span class="mw-page-title-main">Female sperm storage</span>

Female sperm storage is a biological process and often a type of sexual selection in which sperm cells transferred to a female during mating are temporarily retained within a specific part of the reproductive tract before the oocyte, or egg, is fertilized. This process takes place in some species of animals, but not in humans. The site of storage is variable among different animal taxa and ranges from structures that appear to function solely for sperm retention, such as insect spermatheca and bird sperm storage tubules, to more general regions of the reproductive tract enriched with receptors to which sperm associate before fertilization, such as the caudal portion of the cow oviduct containing sperm-associating annexins. Female sperm storage is an integral stage in the reproductive process for many animals with internal fertilization. It has several documented biological functions including:

Sexual antagonistic co-evolution is the relationship between males and females where sexual morphology changes over time to counteract the opposite's sex traits to achieve the maximum reproductive success. This has been compared to an arms race between sexes. In many cases, male mating behavior is detrimental to the female's fitness. For example, when insects reproduce by means of traumatic insemination, it is very disadvantageous to the female's health. During mating, males will try to inseminate as many females as possible, however, the more times a female's abdomen is punctured, the less likely she is to survive. Females that possess traits to avoid multiple matings will be more likely to survive, resulting in a change in morphology. In males, genitalia is relatively simple and more likely to vary among generations compared to female genitalia. This results in a new trait that females have to avoid in order to survive.

<i>Dryomyza anilis</i> Species of fly

Dryomyza anilis is a common fly from the family Dryomyzidae. The fly is found through various areas in the Northern hemisphere and has brown and orange coloration with distinctive large red eyes. The life span of the fly is not known, but laboratory-reared males can live 28–178 days. D. anilis has recently been placed back in the genus Dryomyza, of which it is the type species. Dryomyzidae were previously part of Sciomyzidae but are now considered a separate family with two subfamilies.

Sexual coercion among animals is the use of violence, threats, harassment, and other tactics to help them forcefully copulate. Such behavior has been compared to sexual assault, including rape, among humans.

Most insects reproduce oviparously, i.e. by laying eggs. The eggs are produced by the female in a pair of ovaries. Sperm, produced by the male in one testicle or more commonly two, is transmitted to the female during mating by means of external genitalia. The sperm is stored within the female in one or more spermathecae. At the time of fertilization, the eggs travel along oviducts to be fertilized by the sperm and are then expelled from the body ("laid"), in most cases via an ovipositor.

Chionea scita is a species of crane fly in the family Limoniidae. C. scita is known as a type of snow crane fly because it is commonly seen walking on piles of snow during the winter months. These flies are also often observed in caves and heavily wooded areas. C. scita flies are small, hairy, wingless, and somewhat spider-like in appearance, unlike other flies.

<i>Philodromus cespitum</i> Species of spider

Philodromus cespitum is a species of running crab spider in the family Philodromidae. It is found in North America, Europe, North Africa, and parts of the Middle East and Asia. P. cespitum is a foliage-dweller, and is the most abundant species found in European fruit orchards. It acts as a biological control by preying on orchard pests. P. cespitum is a diurnal ambush hunter and preys on aphids, insects, and occasionally competitor spider species. Males court females by tapping on the females’ bodies with their forelegs. They then insert a genital plug into the female during copulation. Unlike in many other spider species, subsequent males can mate with plugged females by removing part of the plug prior to copulation. Males discriminate among females based on virginity and plug size, and can determine these factors using the females’ draglines and plug samples.

<i>Larinia jeskovi</i> Species of arachnid

Larinia jeskovi is a species of the family of orb weaver spiders and a part of the genus Larinia. It is distributed throughout the Americas, Africa, Australia, Europe, and Asia and commonly found in wet climes such as marshes, bogs, and rainforests. Larinia jeskovi have yellow bodies with stripes and range from 5.13 to 8.70 millimeters in body length. They build their webs on plants with a small height above small bodies of waters or wetlands. After sunset and before sunrise are the typical times they hunt and build their web. Males usually occupy a female's web instead of making their own. The mating behavior is noteworthy as male spiders often mutilate external female genitalia to reduce sperm competition while female spiders resort to sexual cannibalism to counter such mechanisms. The males also follow an elaborate courtship ritual to attract the female. The bite of Larinia jeskovi is not known to be of harm to humans.

References

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  2. 1 2 Heppner, J.B. (2008). "Butterflies and moths". In Capinera, John L. (ed.). Encyclopedia of Entomology. Gale virtual reference library. Vol. 4 (2 ed.). Springer Reference. p. 4345. ISBN   978-1-4020-6242-1 . Retrieved 14 November 2010.
  3. 1 2 3 4 5 "Lepidopteran". Encyclopædia Britannica Online. Encyclopædia Britannica, London. Retrieved 16 November 2010.
  4. 1 2 3 Hoskins, Adrian. "Butterfly Anatomy Head (& other pages)". www.learnaboutbutterflies.com. Retrieved 15 Nov 2010.
  5. 1 2 3 Scoble (1995). Section Adult abdomen, (pp 98 to 102).
  6. Evans, W.H. (1932). Identification of Indian Butterflies (Free full text download (first edition)) (2 ed.). Mumbai: Bombay Natural History Society. pp. 454 (with 32 plates). Retrieved 14 November 2010.. Section Introduction, (pp 1 to 35).