If they have penises, then what makes them female? Well, they still give birth.
These strange female insects use elaborate erectile penis-like organs to penetrate and wrest the necessary sperm via their male’s vagina-like opening.
The discovery was announced this week in the journal Current Biology.
"There’s nothing that [this] can be compared to," study co-author Rodrigo Ferreira, a professor at the Federal University of Lavras in Brazil, told National Geographic. "This elaborate female penis is completely unique."
The four species are members of the Neotrogla genus, relatives of a group of insects commonly known as booklice or barklice.
During the unusual intertwining of these randy barklice, the females get more than just sperm -- in sapping the males of their reproductive fluids, females usurp little sacks of nutrients referred to as "nuptial gifts." In barren, dry caves, these nuptial gifts could be vital for survival, and help explain why the insects evolved to swap roles.
Nuptial gifts are so sought after, some females begin copulating before their developed enough to reproduce.
It's understandable why females would want a little bit of a nutritional pick-me-up after sex, copulation can last up to 70 hours. Such is the exhausting sex life of Neotrogla.
Neotrogla aren't the only species featuring males without penises, but scientists believe the four species offer the first example of truly reversed sexual roles, with choosy males and sexually-aggressive females. Scientists hope to study the Neotrogla in a more controlled environment for a better understanding of their behaviors -- to find out what turns them on, so to speak.