As you may know, in the wild, when praying mantises breed the female mantis will more often than not rip off the head of its male counterpart and consume it. On the ark, the mantises are equipped with significantly more intelligence, enough for the males to realize that making a move on a female will probably lead to its end. Because of this, male mantises completely avoid all sexual intercourse. Unfortunately, this leaves every single mantis very horny. So to solve this problem, all a survivor must do is sneak up behind said mantis and shove a huge, long, thick horn straight up its ass. The wave of pleasure it feels will instantly make it your loyal slave forever. Although a big rhino horn is big enough to tame them, the sheer size of a huge death worm horn will satisfy them significantly more. And that is why you tame mantises with horns

Well that’s my theory anyway