For the first time, researchers have caught female moorland hawkers playing one of the oldest tricks in the book. While out in the Swiss Alps, biologist Rassim Khelifa from the University of Zurich witnessed how a female simply crash-dived to the ground while a male pursued her. The female stayed motionless on the ground until the poor male suitor left, then took off once she was confident the male had lost interest.

A moorland hawker dragonfly. Credit: Wikimedia Commons.

‘Hey, gorgeous!’

‘I’m just gonna drop dead now’

Khelifa has been studying dragonflies for more than ten years but never came across this odd behavior. But when he and colleagues took a systematic look, they found 27 out of 31 surveyed female moorland hawkers (Aeshna juncea) played the same trick plummeting to the ground and playing dead to avoid suitors. The ruse didn’t work all the time, as only 21 of the ploys were actually successful, as reported in the journal Ecology.

For these female hawkers, it’s not just about forgoing sex when they don’t want it — it’s about the survivors of their offspring. A single sexual encounter with a male is enough to fertilize all of a female hawker’s eggs and copulating again would destroy them. Unlike other species dragonflies, after the male copulates with the female, he makes a run for it never to return. Males from other dragonfly species typically tag along with the female to protect her against rival suitors.

This explains why the female hawkers basically need to play dead as a last resort to avoid male coercion. That’s when hiding in the dense grass near ponds doesn’t work.

Though rare, this isn’t the first instance of an animal feigning death to avoid suitors. According to New Scientist, two species of robber fly, a type of mantis, a species of spider all do it too. What they all have in common is they all lay eggs, which is why Khelifa wants to investigate how widespread this behavior really is.