Comparative Morphology of Insect Genitalia

Wasp-Inspired Needle Insertion with Low Net Push Force

“…The dorsal valve is connected to the two ventral valves along its length by means of a tongue-and-groove mechanism that allows for relative movement of the valves in the direction of the ovipositor while preventing their separation. Abdominal musculature actuates the valves independently from each other [12,13]. The wasp penetrates the substrate by antagonistically moving the ventral valves while the dorsal valve acts as sliding support.…”

Evolution of genitalia: theories, evidence, and new directions

“…Almost any part of the male can be modified in this way, from the sucker-like ''bursa'' of male nematodes to the cephalothorax, the chelicerae and anterior legs of spiders, the antennae and telson in crustaceans, and the head, mandibles, antennae, pronotum, cerci, and wings of insects. As pointed out by Robson and Richards (1936), the mechanical function of many (though not all) of these structures is to grasp the female during copulation, the same function that is performed by a large fraction of the male genital structures that are species-specific in form (summaries in Eberhard 1985Eberhard , 2004aScudder 1971). The line between ''true'' genital claspers and non-genital claspers is, in the end, arbitrary (Chapman 1969;Darwin 1871;Eberhard 1985; see also Ghiselin 2009;Leonard and Cordoba-Aguilar 2009).…”

“…Although this theory can explain why genitalia are often species-specific in form and may be correct in particular cases, it has gradually lost favor as a general explanation for several reasons, and is probably in the process of being discarded definitively (Eberhard 1985;Shapiro and Porter 1989). Arguably the most important evidence against lock and key is that in many groups the supposed female locks simply do not exist (Eberhard 1985;Scudder 1971;Shapiro and Porter 1989). There also other serious problems, including an almost complete lack of the predicted pattern of character displacement in males in zones of sympatry of closely related species (McAlpine 1988;Ware and Opell 1989), and clear evidence of genital species-specificity in species (such as those of species endemic to caves and oceanic islands, and of parasites isolated from all close relatives in their different hosts) that have probably evolved in complete or nearly complete physical isolation from all close relatives, and should thus not have evolved species-specific genitalia (Eberhard 1985(Eberhard , 1996Hedin 1997;Shapiro and Porter 1989).…”

Geoffrey G.E. Scudder: zoologist, conservationist, educator

“…Also, in an important early paper (Scudder 1959), he described the heteropteran female genitalia and their role in classification. His 1971 paper in the Annual Review of Entomology (Scudder 1971a) is an admirable summary of the understanding at the time of the comparative morphology of insect genitalia.…”

“…De plus, dans une importante publication tôt dans sa carrière (Scudder 1959), il a décrit les pièces génitales femelles des Hétéroptères et leur rôle dans la classification. Son travail de 1971 dans la revue Annual Review of Entomology (Scudder 1971a) est une remarquable rétrospective de l'état des connaissances de l'époque sur la morphologie comparée des génitalias des insectes.…”