Females in Charge

Insects in Brazil go beyond simple behavioral sex-role reversal. In these animals, the females use an erectile organ to penetrate the male’s genital chamber.

Written byJef Akst
| 2 min read

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A male (bottom) and female Neotrogla matingYOSHIZAWA ET AL., CURRENT BIOLOGY (2014)Like most sex-role reversed organisms, populations of insects called Neotrogla have aggressive, promiscuous females and males who tend to be choosier about whom they mate with. But unlike other species that follow such a reversed pattern of sex-specific behaviors, these tiny winged insects seemed to have also swapped genitalia.

In a study published last week (April 17) in Current Biology, researchers described the female Neotrogla’s “elaborate penis-like organ,” which they call the “gynosome.” The organ is used “as an intromittent organ [that] anchors the female to the male [during copulation],” the researchers wrote, which can sometimes last for days and often results in the transfer of “a large and potentially nutritious ejaculate” from the male. The authors thus speculate that the “genital evolution in Neotrogla is probably driven by reversed sexual selection with females competing for seminal gifts. Nothing similar is known among sex-role reversed animals.”

Neotrogla were first described in 2010, after ecologist Rodrigo Ferreira from the Federal University of Lavras in Brazil spotted them in the country’s caves and entomologist Charles Lienhard ...

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  • Jef (an unusual nickname for Jennifer) got her master’s degree from Indiana University in April 2009 studying the mating behavior of seahorses. After four years of diving off the Gulf Coast of Tampa and performing behavioral experiments at the Tennessee Aquarium in Chattanooga, she left research to pursue a career in science writing. As The Scientist's managing editor, Jef edited features and oversaw the production of the TS Digest and quarterly print magazine. In 2022, her feature on uterus transplantation earned first place in the trade category of the Awards for Excellence in Health Care Journalism. She is a member of the National Association of Science Writers.

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