The praying mantis is sometimes considered a symbol of ultimate female empowerment. After mating, it has been observed that the female would immediately proceed to kill the male she just mated with and eat his corpse, head first.
However, one thing that is less known is that this act – known as sexual cannibalism – occurs almost exclusively in captivity. This is because in the wild, a male runs off quickly after mating to avoid a grim fate. The female, with a massive appetite after the tiring act of copulation, looks for a source of nutrients to upkeep her pregnancy. As in a captive environment the male cannot run far and the female cannot hunt easily, she opts to eat the male as this is more beneficial for her. Furthermore, as mantises have very sharp vision, it is highly likely that the observing scientists (giant, towering figures dressed in white) will intimidate the female mantis. The anxiety caused by the observation would thus make the female act more violently.
The theory that lab intervention caused sexual cannibalism was proven when mantises stopped cannibalising after being fed ad libitum (until they were full). In fact, the female would carefully observe the courtship dance of the male and decide whether he is worthy of mating. This courtship dance also has the effect of switching the female’s priorities from feeding to mating.
It has also been suggested that females may choose to eat the males they do not deem worthy (before mating), or that the males are sacrificing themselves to improve the chance of fertilisation. This is supported by evidence of decapitated male mantises copulating more vigorously and mounting the female for much longer periods.
In other words, male submissiveness can be a factor in reproductive success.