So a while back I was thinking about the praying mantis and how the female eats the male during and shortly after copulation and I was curious as to whether or not this always happened. I wondered if it was a necessary part of the mating process or if it was simply something they did. And if it was a necessary part, what made it necessary?
Well, I looked up some information and discovered something interesting. Copulation Canibalism is not necessary for the praying mantis, but it is simply the nearest source of nutrition for the female's prospective children. Sometimes the male gets away, if he is quick enough. Sometimes the female starts eating him during reproduction. Sometimes it is after.
But the MOST interesting things I found were about other such critters. There is one that in order to ensure that no other male will follow after them they break off their penis. This holds their sperm inside and prevents another male from mating with that female. Most of them just ate their mates for nutritional value post-copulation.