Reproduction in the animal kingdom is at best often weird. Reproduction is subject to evolution just like all other biological systems, and the unique needs of each species can become…off-beat. Which raises the question of why, precisely, insects in Brazil have evolved so that the females have penises and the males vaginas. Also, they have sex for 40 to 70 hours.
Yes, you read that correctly. Here’s a relevant quote from the abstract in Current Biology:
Females have a highly elaborate, penis-like structure, the gynosome, while males lack an intromittent organ. The gynosome has species-specific elaborations, such as numerous spines that fit species-specific pouches in the simple male genital chamber. During prolonged copulation (∼40–70 hr), a large and potentially nutritious ejaculate is transferred from the male via the gynosome.
If you were wondering how they got the phrase “female penis” out of this, it’s actually down to the size of sexual reproduction cells, or gametes. Females have much larger gametes than males. Furthermore, it appears that the female draws ejaculate from the male, gets pregnant, lays eggs, the whole boat. Also, they can get abortions at ATMs.
As to why this evolved, the paper essentially boils down to “dunno.” It’s not even really clear how, precisely, the female draws out the sperm cells from the male. All we know is that in a cave in Brazil, female insects have penises, and also that this is probably going to inspire a terrible horror film approximately two years from now.
Via Current Biology