The elaboration of insects’ genitalia also has a more diabolical side. We may see two damselflies forming a heart shape with their bodies as they couple, abdomens elaborately curled as they perch on a stem, but if you could look inside them, you would see what appears to be a minuscule Swiss Army knife with its attachments unfolded. That would be the male’s penis. A female damselfly may mate with more than one partner, but from each male’s perspective, the more of her eggs he can keep from rivals and fertilize himself, the better. The spines and scoops on his penis serve to remove the prior male’s sperm so he can replace it with his own. Nature may be red in tooth and claw, but she is utterly ruthless when it comes to genitalia.
But back to mating position, and to the second reason scientists care about bug sex. Sexual position dictates whether males or females have control over the outcome of mating, which in turn has a host of repercussions on the evolution of other aspects of behavior. The side-by-side position of many bugs, including the family of which the fossil duo is a member, is common, but so is a female-on-top version. In the crickets I study, for example, once a female has been wooed by the song of a male, she has to clamber onto his back and orient herself just so. Once she is securely situated, the male reaches up with his nether regions and proffers a tiny aliquot of sperm, neatly contained in a vessel of chitin. The end of the vessel has a long stem that must be threaded skillfully into the reproductive opening of the female, after which the sperm drains into her body for several minutes. The process is incredibly painstaking, and requires the full cooperation of the female.