The female wasp is not the only one to sting.
Japanese scientists have indeed discovered the defense mechanism specific to male wasps: their penis.
The study was published Monday in the journal Current Biology.
These insects, unlike females, do not have a stinger, a formidable sting containing venom.
However, despite this handicap, they manage to escape their predators through behavior that has been misunderstood until now.
The hypothesis that certain male insects can sting with their genitals had been put forward by scientists, "but the proof was missing", explains Shinji Sugiura, of the University of Kobe, co-author of the study.
This specialist in anti-predator strategies in animals had a flea in his ear when one of his students, Misaki Tsujii, co-author of the study, was stung by a male mason wasp.
"I tried to get stung myself, and since I thought the males were harmless, I was very surprised to feel the pain of a sting", says Shinji Sugiura.
Two broad thorns
He suspects the two large spines distributed on either side of the insect's penis to have caused the pain.
Hypothesis that he decides to test in the laboratory, by offering wasps as a meal to two species of tree frogs.
“We observed many males who, at the time of the attack, pierced the mouth or other organs of the frogs with their genitals,” he describes.
One of the videos of the attacks shows an unlucky frog trying unsuccessfully to chew the insect, before using its front paw to vigorously spit out its prey.
In total, more than a third of the predators ended up spitting out the males after being stung.
The experiment was reproduced with wasps whose genitals had been removed: the frogs made short work of them.
The difference between the situations was "statistically significant", which suggests that this survival strategy in males played on the evolutionary history of the wasps, underlines Shinji Sugiura.
Apart from their reproductive role, the genitals of insects are still little studied.
However, previous research has shown how sphinx moths use their genitals to emit ultrasound against bats.
Shinji Sugiura has himself researched how certain beetles manage to escape once swallowed, by exiting through the anus of their predators.
The biologist now hopes to determine if other families of wasps have these same genital spikes as a defense system.
