Praying mantis cannibalism allows males to assign more of their biological material in female mantis’ eggs

Scientists have found that female mantises who eat their male sex partner after sex produce more eggs than those who do not. Sexual cannibalism in mantises allows the male to assign more of their biological material in female mantis’ eggs in order to make her more fertile.

The study from Macquarie University and the State University of New York, published in the journal Proceedings of the Royal Society B, found that the cannibalistic females after devouring their male sex partners used the additional food to produce an average of nearly 51 more eggs, writes Business Insider Australia.

An author of the paper, Kate Barry from Macquarie University, said that praying mantis sexual cannibalism allows the female mantis ensure a greater biological influence over a larger amount of eggs. After the female ate the male mantis, she had around 17.7 percent more of the male’s biological material in her reproductive tissues, which included ovaries and eggs. This was not the case for the females who did not cannibalise their male partners.

The study provides an answer to why sexual cannibalism evolved in praying mantis species. Further studies are required to understand why the males prefer to sacrifice themselves than live with their mate. It is important to know whether this is mating strategy of the mantis. Factors such as single mating event and mate availability may have an effect this weird phenomenon.

“There is an obvious cost – you are dead, you have lost all future mating possibilities. We measure costs and benefit in terms of offspring production,” co-author William Brown of the State University of New York at Fredonia told The Guardian.

Brown believes that sexual cannibalism in mantises marks the ultimate male investment. The study showed “that [the cost of the male] being killed by a female can be partially recouped if more offspring are produced with his body.” However, in the larger context, this may affect the willingness of the male mantises to take such a huge sacrifice.