Dragonflies are known to fake their own death to avoid predation. However, a researcher from the University of Zurich observed that females of the Aeshna juncea species, also known as moorland hawkers, also fake their own death to avoid being sexually harassed by unwanted suitor.
This peculiar behavior of female dragonflies, described in a paper published in the journal Ecology, was observed by Rassim Khelifa from the University of Zurich while he was out in the Swiss Alps, collecting odonate eggs of dragonflies.
"I was surprised," said Khelifa, who witnessed the behavior for the first time despite studying dragonflies for 10 years, in a report from Tech Times. "Upside down is an atypical posture for a dragonfly ... I expected that the female could be unconscious or even dead after her crash landing, but she surprised me by flying away quickly as I approached."
To determine if the unusual behavior of female Aeshna juncea is common, Khelifa spent months following the dragonflies. Out of the 31 dragonflies observed, 27 crashed to the ground and played dead. Twenty-one of the risky plunge were successful in driving away unwanted suitors.
Khelifa observed that male moorland hawkers often patrol an area to wait for potential mates. The more male patrolling the area, the more likely the females to fake their own death.
Female dragonflies who did not crash-dived were coerced into having sexual intercourse. The researchers also found that the peculiar behavior of the female moorland hawkers is not always effective in driving away pesky suitors.
Unlike other dragonflies, Khelifa noted that male Aeshna juncea leave their females after mating. Due to this, the female dragonfly becomes vulnerable to other males while laying their eggs. A single sexual encounter with male is enough to fertilize the eggs of female Aeshna juncea, but mating one more time could damage the female's reproductive tract.
The female moorland hawkers is not the first animal to fake their dead to avoid being sexually harassed. The behavior has been previously observed in a species of spider, two species of robber fly and a type of mantis.