Female Dragonflies Fake Death to Avoid Sex

Ah, the little critters of nature. They don’t know that they’re ugly. Well, maybe some male dragonflies do, according to some bizarre new insect mating research. Rassim Khelifa from the University of Zurich was conducting field research of dragonflies in the Swiss Alps when he noticed some peculiar mating behavior that suggests female dragonflies have cunning ways of avoiding unwanted advances.

As he was observing mating behavior, Khelifa witnessed a dragonfly being chased by another when the pursuee suddenly fell to the ground upside down, seemingly dead. As its pursuer flew off, Khelifa went to examine the fallen dragonfly, which he noticed was female. After a few seconds, it flew away seemingly fine.

In his published case study of the behavior, Khelifa writes that he was stunned by what he witnessed:

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. The question arose: did she just trick that male? Did she fake death to avoid male harassment? If so, this would be the first record of sexual death feigning in odonates [(dragonflies)] and probably the fifth in the animal kingdom after a nuptial gift-giving spider, two species of robber fly, and a European mantis.

Khelifa was able to replicate sightings of the same behavior four more times by attempting to catch other females who were seen playing dead. All four flew away just fine after crashing 'dead' to the ground. So-called “sexual death feigning” is one of the rarest and most mysterious behaviors in nature, only witnessed in a few other insect species. Sure is a lot more interesting than the human equivalent, sexual sleep feigning, otherwise known as "marriage."

In the case of the dragonflies, Khelifa suspects the death feigning could be a way for females to protect already-fertilized eggs which could be damaged by the attempts of too-late would-be lovers. Whatever the reasons are, this study and others like it continue to show that animals (and animal researchers) never cease to surprise us with their bizarre behavior.