As you probably know, the female praying mantis will sometimes bite her mate's head off. It's not something that the insects make a habit of, exactly -- they probably only do it when a male is particularly aggressive, or when the female really needs a nutrient boost in order to successfully lay her eggs.
But when a lady is really hungry, she sometimes throws off fake fertility signals to get a guy into bed. And when that happens, he's pretty much always on the menu.
In a study published this week in Proceedings of the Royal Society B, researchers report that the false garden mantis -- the most common species of mantis in Australia -- will fake fertility to get a free meal.
Researcher Katherine Barry divided her females into four groups and fed each a different diet, ranging from poor to very good, Science News reports. She then hid them from sight, allowing males to pick mates by scent alone.
You'd expect the male mantids to go after the healthiest (in this case, best fed) females, and in general the males were more interested as a female's feedings went up. That's some sound biological signaling, because those females were the most fertile. But the males were most interested in the group of females who were basically starving to death.
It seems that a starving female will throw the last of her energy into producing the chemical signals associated with fertility. But while she's much more likely to eat the mates she lures in (90 percent of the hungry females did so) she's also less likely to actually let the male mate with her beforehand.
So by all appearances, the deception is quite intentional. After their meal, the females are much healthier and more fertile, meaning that their next paramours can reap the reproductive benefits of their femme fatale tactics.