praying mantis
A female praying mantis cannibalising the male during sex. Oliver Koemmerling

Female praying mantises lure males to their deaths by tricking them into thinking they are offering sex, scientists have discovered.

Experts at Australia's Macquarie University looked at how starving females deceptively signal to males in order to lure them in then eat them.

The study, published in the Proceedings of the Royal Society B, examined sexual deception in the cannibalistic mating system.

Normally, praying mantises mate by the male searching for the female, guided by airborne sex pheromones that provide cues.

"The Femme Fatale hypothesis suggests that female mantids may be selected to exploit conspecific males as prey if they benefit nutritionally from cannibalism," the authors wrote. "Females use the resources gained from male consumption to significantly increase their body condition and reproductive output."

Researchers studied praying mantis behaviour in large field enclosures. Females were placed in one of four feeding conditions – very poor, poor, medium and good. Males could choose from all groups.

They found males were more attracted to starving females than better fed ones despite the risk of being eaten without mating.

Lead researcher Kate Barry said: "This is the first evidence in support of the Femme Fatale hypothesis, which posits that female mantids in poor condition might dishonestly entice males in order to eat them rather than mate with them."

Authors suggest this is due to signals given off by the starving females: "We presume this attraction is due to an increase in the quality or quantity of pheromone emissions, which makes sense because very hungry females gain both survival and reproductive benefits from attracting and consuming a male," Barry added.

"There are many examples in the animal kingdom of males exploiting females to secure paternity, however in this instance, female praying mantids have turned the tables."