It's the same old story. Boy meets girl. Boy and girl have sex.
Girl eats boy . . .
Well, it's actually quite natural . . . Ah, yes, the sex life of a praying mantis. While the male is having sex with the female, she will often turn around and bite his head off. You might wonder why the male even bothers. However, his genes will live on in a whole new generation, the embryos growing with nourishment from their father's body.