Spider Sex Gets Even Weirder

A short article at New Scientist about the odd reproductive habits of spiders makes them seem more alien than ever. The gruesome habit of female spiders making a post-coital meal of their male suitors is well-known, but in certain species, the mommy-and-daddy dance is stranger still. While the males of some species try to avoid having their petit morte segue into plain old morte, other species, like the red back spider, actually somersault onto the female's fangs, thereby guaranteeing that, in stark contrast to humans, their first time remains the best panky of their lives. And then there is Argiope aurantia.

Male spiders possess two sexual organs called pedipalps, each of which inflates after inserting into one of a pair of genital openings in the female. In the 55 cases in which a male finished mating by inserting his second pedipalp, the researchers saw that the male immediately became unresponsive and assumed a death posture with legs folded under his body. The male spiders' hearts stopped beating after a few minutes. [apostropher: aside from double genitalia and the cardiac arrest, that still sounds uncomfortably familiar...]

There was no obvious sign that the female was responsible for this lethal effect. And any stealthy way of dealing out death was ruled out by the actions of one confused male that stuck his second pedipalp into a mealworm carcass trapped in the web. This cross-species necrophilia also instantly triggered the male's death, showing female Argiopes are not to blame.

The females do sometimes remove and devour their dead mates. But the researchers do not think the death program evolved to give her a post-sex snack, as the males are too tiny to provide much nutrition. Instead the researchers think the corpses act as a weird chastity belt that blocks the female genitals and discourages other suitors. If so, it appears to be effective. In 11 cases where competing males attempted to dislodge the dead mate, they only succeeded three times. And it was not for lack of trying, Foellmer told New Scientist: "The other males go berserk, bite into the legs and try to pull him off."

Which reminds me:
Why do female spiders bite the heads off their mates after sex?
To stop the snoring before it starts.