Do female mantids really eat the males head after mating?
This was one of the first things I learned about praying mantids as a kid and no doubt what the praying mantis is most known for. Although not always the case, this actually holds some merit.
Most mantis species are cannibalistic. A praying mantis will eat or try to eat just about any insect it can grab a hold of and is not strong enough to fight back, and another mantis is no exception. However, when mating, females are less likely to attack a male. Studies have shown that males are eaten less during mating in the wild than in captivity.
I have kept dozens of different species of mantis. There have been times when a female mantis would eat just about every male that came near her. There have also been times when a male would mate with several different females before dying of old age. Depending on the species and how long I leave the male in the cage, I would say about half of my males get eaten by females before, after, or during mating. Most of the time it is because the male was left in the enclosure long enough after mating that the female saw him as food. In the wild, that number is FAR less.
After mating, most males jump off of the female and usually make a run for it. In the wild, they would have no problems escaping without harm as they are usually much faster than the females and most of them can fly. The females are usually too heavy to give chase, and most of the time aren't even interested. In captivity of course, the male jumps off, runs around, and usually ends up running directly into the female.
Does this mean that females really don't bite the heads off males? No way. I have seen them do it with my own eyes, watching in horror as they made a meal of their mates often times while mating! When the male is attached, the females can only eat so much of him without bending their bodies too much. That usually involves just the head and a portion of the upper body. A male mantis can continue to mate even with his head bitten off. I have even witnessed a male get his head bitten off before making its way onto the back of the female and copulating.
So, in conclusion, I would have to say this myth is somewhat true. Just not in the way the media/movies make it out to be.