By Maya Palit
Can you think of ten movie scenes where the female could have used a trick or two to avoid a mad stalker? Maybe they should have been watching dragonflies. It turns out that female dragonflies might be using a shrewd strategyto put off potential mates that they’d rather not have around: they play dead, by diving suddenly to the ground and waiting motionless until the stalker male flies off.
Rassim Khelifa, a researcher from the University of Zurich, Switzerland, who has studied dragonflies for 10 years, recently observed moorland hawker dragonflies collecting larvae in the Swiss Alps, and watched most of the females crash-dive to the ground while being pursued by males and then lie completely still.
The New Scientist reports that “The female then lay motionless on her back. Her suitor soon flew away, and the female took off once the coast was clear.” Out of 27 females, about 21 pulled off the playing dead act. (This game, according to another researcher, is a risky business because it involves plunging at high speeds, and is probably only used when “harassment is intense”.)
According to the report, female moorland hawkers lay their eggs but these aren’t overseen by males. While one sexual experience with a male dragonfly could fertilise their eggs at one go, a second could potentially harm their reproductive tracts. So the females tend to lurk in the green near ponds as well, presumably to avoid being harassed.
While Khelifa finds out whether this move to ward off over-keen males happens only in species that lay eggs, the New Scientist reminds us of previous discoveries which show that other insects and animals use the faking death ruse too, including species of spiders, flies, and mantis.