Lepidoptera genitalia

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.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: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 dorsal '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.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.Citheronia regalis with claspers closed.Citheronia regalis with claspers open.Female Apollo with sphragis or mating plug.Close up of the hardened Parnassius sphragis extruding 2 to 3 mm behind the abdomen.