Saturday, 26 April 2014 | MYT 1:50 PM

New Brazilian bugs: Females have a 'penis' for 70-hour mating romp

Four unique insects have been found deep inside Brazil's caves where the female has a 'penis' that she inserts into the male's 'vagina' during their 40 to 70-hour mating session. 

Scientists have discovered four insect species in Brazil that dwell in extremely dry caves, feed on bat guano, and possess what researchers call an ‘evolutionary novelty’. The female has an elaborate, penis-like organ while the male has a vagina-like opening into which a female inserts her 'penis' during mating, which can last 40 to 70 hours, the scientists reported in the journal Current Biology.

Researchers say these attributes make the four species of the insect genus Neotrogla unique in the world. “Evolution of novelties like a female penis is exceptionally rare. That’s why I was really surprised to see the structure,” says entomologist Kazunori Yoshizawa of Japan’s Hokkaido University. Yoshizawa says that although sex-role reversal has been documented in different types of animals, these insects are the sole example in which the “intromittent organ” – the penis – is reversed.

Neotrogla insects are small, betwen 2.7mm and 3.7mm in length. Superficially, they look like flies, with nothing particularly unusual about their appearance aside from their genital structures. Scientists are calling the female penis structure a gynosome. During mating, she inserts it into a male and receives sperm. Once inserted, part of the gynosome inflates and spines internally anchor the insects together.

During mating, Neotrogla females mount the males and penetrate his genital opening with her gynosome, a penis-like organ. The base of the gynosome inflates and they fuse for a session that can last 70 hours. 
A close-up of the gynosome, the female penis of the Neotrogla aurora insect species.

What happens when a Neotrogla female (right) penetrates a male (left). The bluish bulge on the bottom left is her gynosome that has inflated inside her mate, forming an anchor with which she holds on to him and sucks up his ejaculate.

Yoshizawa says Neotrogla females can hold their mates coercively using gynosome. “Because the female anchoring force is very strong, a male’s strong resistance may cause damage to his genitalia. Therefore, it is very likely that entire mating processes are controlled actively by females, whereas males are rather passive,” he says.

One of the reasons for this evolutionary quirk is attributed to the lack of food in the caves. Scientists have observed the Neotrogla female consume the seminal fluids produced by a male, which are highly nutritious – this also explains for the length of the copulation. Subsequently, the female preference for this trait in males led to the evolution of Neotrogla males without penises. 

A Brazilian researcher studying cave ecosystems initially came across the insects, first described in a 2010 paper. He then enlisted an insect expert to examine the previously unknown bugs. It was then that the unique attribute of the female Neotrogla was discovered, leading to the current study.

Yoshizawa cites other unusual examples of sex organs among animals, including female seahorses that use an organ to deposit eggs within a male’s brood pouch, and a kind of mite whose females have a long genital tube. There’s also the female spotted hyena that has an extended clitoris shaped like a penis and can achieve a bigger erection than her mates.

By the definition of female – an organism that produces egg cells that are larger than the sperm cells produced by males – “even with the penis-like intromittent organ, females of Neotrogla are still female,” Yoshizawa says. “Females of Neotrogla likely represent the most ‘macho’ females among animals discovered to date.” – Reuters

Tags / Keywords: Lifestyle , Lifestyle , Features , Science , Biology , Nature , Animal , Entomology , Brazil , cave , insect , macho , female , penis , sex role reversal , Neotrogla , Kazunori Yoshizawa


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