I can’t wait to get off work and see my baby


Male seed beetles (Callosobruchus maculatus) have long spikes covering their penises [photo]. These spikes are thought to have evolved in response to female promiscuity, as a way of increasing the male’s chances of fertilizing a female’s eggs. Females, in response to the spikes, have evolved every man’s worst nightmare: spikes inside her vagina.

This is what evolutionary biologists call sexual conflict.

Males and females of a species have a common goal: to pass on their genes to the next generation. Sometimes, however, males and females have conflicting best strategies for getting that done. (…)

The penis of the male seed beetle punctures the female’s reproductive tract and, eventually, all those injuries will kill her. Females even have to kick the male constantly during mating to lessen the severity of the injuries–but she still won’t be deterred from hooking up again.

Why would male beetles want to harm females like this? (…)

While we’re on the topic of sharp penises that harm females, I thought I would throw in a little bed-bug action as well. Bed-bugs mate using what is known as “traumatic insemination.” Males bypass the female genitals entirely and pierce them in a specialized location on their bellies. They then ejaculate into the female sperm storage organ directly.

{ Molecular Love | Continue reading }