Femme Fattale: Why Cannibal Mantids are Sexy

We all know that some of the nastiest lady-bugs eat their mate right after coupling. It's a disturbing side of the invertebrate world that we humans have trouble wrapping our heads around. "If she's going to eat him after they mate, why would he go anywhere near her?" is one question commonly asked. Now new research shows that male bugs aren't necessarily stupid, they're just gullible.

The common mantis is one species that is infamous for its "man-eaters" - that is, female mantids that eat their smaller male partner's right after mating. However, contrary to popular belief, not every female is a man-eater. In fact, well-fed and healthy lady mantids will often just leave their mate alone after copulation, leaving the male to go and try his hand at siring more children elsewhere.

In a study recently published in the journal The Royal Society: Proceedings B, it was revealed that female mantids are most likely to eat their mate when they are underfed and in need of essential nutrients to mother a healthy brood.

That of course, led researcher Katherine Barry, at Sydney's Macquarie University, to wonder "if it simply undernourished females who will eat their mates, why don't male mantids simply steer clear of them?"

After all, entomologists have long known that it is males who select their mates in mantis populations, and not the other way around. Female mantids even release pheromones that indicate the state of their health, where males will always select the strongest of mates out of a healthy female population.

So why is it that males are willing to walk into mouths of starving females too? They clearly know better. (Scroll to read on...)

According to Barry, this may be a very clear example of "femme fatale," where males are somehow drawn to the most dangerous of the opposite sex - a phenomenon that the species as a whole can benefit from (IE- leading to more successful reproductions and healthy offspring.)

In a series of experiments, Barry found that males are drawn to the airborne sex pheromones of undernourished females even more than those of well-fed females. In fact, they appear to prefer signaling from a hungry female mantid over all else.

Barry suggests that this example of "femme fatale" may be the product of sexual deception, where uncharacteristically "dishonest" chemical cues are exclusively developed by starving insects to ensure a healthy brood.

However, more research will need to be conducted to determine how and when theis unique adaptation occurs.

For more great nature science stories and general news, please visit our sister site, Headlines and Global News (HNGN).