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Study

Female Penis, Male Vagina, and Their Correlated Evolution in a Cave Insect

Highlights

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Females of the cave insect genus Neotrogla take an elaborate penis-like organ

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The female penis acts as an intromittent organ and anchors the female to the male

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Correlated evolution is detected between the female penis and male ballocks

Summary

Sex-specific elaborations are common in animals and have attracted the attending of many biologists, including Darwin [ane]. It is accepted that sexual selection promotes the development of sex-specific elaborations. Due to the faster replenishment rate of gametes, males generally take higher potential reproductive and optimal mating rates than females. Therefore, sexual choice acts strongly on males [two], leading to the rapid evolution and diversification of male genitalia [three]. Male genitalia are sometimes used as devices for coercive holding of females equally a upshot of sexual conflict over mating [iv, 5]. In contrast, female person genitalia are usually simple. Here we report the reversal of intromittent organs in the insect genus Neotrogla (Psocodea: Prionoglarididae) from Brazilian caves. Females accept a highly elaborate, penis-like structure, the gynosome, while males lack an intromittent organ. The gynosome has species-specific elaborations, such every bit numerous spines that fit species-specific pouches in the simple male person genital chamber. During prolonged copulation (∼40–lxx hr), a big and potentially nutritious ejaculate is transferred from the male via the gynosome. The correlated genital evolution in Neotrogla is probably driven past reversed sexual selection with females competing for seminal gifts. Nothing similar is known amongst sex-role reversed animals.

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