The female of this species can grow a 'penis' to penetrate males

In a Brazilian cave live insects that have an unusual way of reproducing. Like most other species, they have to copulate in order to reproduce, but here it is not the males who lead the dance or perform the act of penetration.

Role reversal

In nature, the pattern of reproduction is usually quite simple: the male penetrates the female and inserts his semen into her with a penis, or an ersatz penis (we'll let you see what a duck's reproductive organ looks like).

But, as we would be bored if all species obeyed this rule, there are exceptions! In the Neotrogla, for example, it is the females that penetrate the males! This species of tiny, flea-like insects was discovered in a cellar in Brazil. And the females have an erectile organ called a gynosome that they use to penetrate the males and pump out their sperm. The way this organ works has just been studied by researchers.

A rarity of nature

The females of this species are not the only ones to have a gynosome: this organ has also been observed in the female of another South African insect. So how can the development of such an organ be explained? The dryness and darkness of the cellar in which the Neotrogla lives would be the cause. As our colleagues in the New York Times explain:

virile mates are hard to come by in dark caves, so the female bugs must hold their living sperm banks tight. The gynosome’s prickly spines lock the penislike structure inside the male, keeping him snug during bouts of copulation that can last up to 70 hours. The gynosome’s grip is so secure that attempting to separate a pair of mating Neotrogla will tear the male in half.

Does this sound sordid to you? Did you know that the duck's pseudopenis is shaped like a corkscrew, in part to enable it to remove sperm from its rivals? In nature, sex is a deadly competition, and everyone wants to win... And no, don't try to find out what a duck's reproductive organ looks like, you have been warned.

This article was translated from Gentside FR.

Sources used:

Royal Society: Acquisition of novel muscles enabled protruding and retracting mechanisms of female penis in sex-role reversed cave insects

New York Times: The Muscles That Power a Female Insect’s Penislike Organ