The nutrients are extra valuable in such a dry environment, creating a situation where females compete for males. I’m not sure why this would have driven the development of the gynosome- maybe the more females could insert themselves into the males the more successful they were.
Reference: Yoshizawa, K., Ferreira, R.L., Kamimura, Y. and Lienhard, C., 2014. Female penis, male vagina, and their correlated evolution in a cave insect. Current Biology, 24(9), pp.1006-1010.
This is a series of little illustrated factoids about animal reproduction, posted daily. I’d love to hear your suggestions/ feedback. I also post these on my insta.