3 out of 10 chance of losing your head.
Now that’s romantic.
Guys?
I see your point. However, the OP said the head loss was a prerequisite for mantis sex. Obviously that’s not the case.
A little further on at the link I posted, it said the key was to avoid hungry females. If the males couldp just figure out whether she’s eaten recently or not, they could increase their odds dramatically.