Why do praying mantis eat each others heads?

This is one of those animal habits that people think is totally weird. The female mantis is going to need food to make all those eggs. The male is not going to live much longer after he reproduces. Therefore, it makes sense for the female to eat the male and have extra energy to start making eggs. If you feed the female good before mateing her she might not eat the male It seem that this behavior is mostly observed in laboratory settings, when the mantis is starving. It doesnt happen all the time. Mantises rarely turn cannibalistoc in the wild. It's most done in captivity.