The kinky sex life of nephilid spiders

I didn’t tell you the whole story about our local Argiope. In fact, I cropped the photo I used by a lot — I left out that spider’s consort. Here’s the whole thing.

The female is on the right, that smaller, more gracile spider on the left is a male.

The thing about nephilid mating is that when the male gets lucky, one of the last things he does, once he gets his palp into the female epigyne, is to snap it off — that is, he voluntarily castrates himself and leaves the organ inside her. It acts as block to further mating by other males.

In addition, he builds a web very close to the female’s, and stations himself there to deter any males that might wander along and try courting her. That little guy in the left corner is a eunuch guard!

I know, that sounds creepy and stalkerish, and as I always tell people, the naturalistic fallacy is a fallacy, so don’t take this as an example. Maybe Dolomedes is a more attractive role model: the males don’t do the eunuch guardian thing at all, they just up and die on the spot as soon as they achieve copulation, and leave their lifeless corpse dangling from the female’s nether bits until it falls off. Carrying around the dead body of former partner’s is an excellent way to get other males to leave you alone.

I don’t recommend that for human women, either. It would work, though!