Sexual cannibalism in mantis is a very well known phenomenon. Female mantises bite off the male’s head after or during sex, therefore, is also known as fatale femme. However, the reason behind such sexual cannibalism remains debatable.
Female mantises use pheromones to attract males for mating, however, females most of the time ends up eating male mantis, even before the poor male gets a chance to mate. Researchers until now believed that well fed females attracts more males and in turn laid more eggs. Nevertheless, a new study rebuts this popular belief.
Deceiving males for snacking
Katherine Barry, an evolutionary biologist with Macquarie University in Australia, while studying found that starving female mantis attracts more males than well-fed females. Starving female mantis deceive males to snack on them rather than to make love with them.
Researcher Barry was of the view that starved females generally produce more pheromones in comparison to others. Such females produce pheromones that allure more males, which also means more food to feed on. To validate this view, she seized around 100 false garden female mantises (Pseudomantis albofimbriata) and kept them in mesh cages. The captured females were separated in four different cages. The levels of nourishment given to females in each cage varied from good, average, poor and very poor. Later in these cages, male mantises were introduced. After the introduction, Barry observed and noted the number of males attracted to each group of females.
Sex and death
Findings from the study indicated that females labeled as good allured more males that medium or poor labeled females. But interestingly, females categorized and fed poorly drew more males, almost twice than females categorized as good. This result clearly shows that males are more attracted towards hungry females. Such starving females are undesirable as they are more likely to lay very few eggs and thus very few newborns. So, very intelligently, such female releases more pheromones to allure more males, which are eventually eaten by females to get the much needed nourishment, which help them to lay more eggs thereafter.
Barry further explains that pheromone creation is not cheap for females in such poor physical state rather producing more pheromones can negatively affect survival and reproduction chances of the female mantises. But indulging in such deceiving act, females have more to gain than to lose. As feeding on even one single male can give them nourishment required for survival as well for fertility.
Overall, the approach used by the insect fatale femme is interesting however, I am curious to know what tactics the males, for safeguarding from the female counterpart, use. I hope the experts carry out their research soon, till then, let’s keep on guessing.
Source: BBC-Earth
