This is specific to one dragonfly type, the moorland hawkers, but other species may partake in the process as well.
While collecting larvae samples in the Swiss Alps, Rassim Khelifa from the University of Zurich, witnessed the behavior for the first time in the moorland hawker dragonfly (Aeshna juncea).
He watched a female crash-dive to the ground while being pursued by a male. She lay motionless on her back, and as soon as her suitor flew away and the coast was clear, she took off.
Khelifa has been studying dragonflies for over a decade and said he was surprised to see this phenomenon.
At the University of Zurich, Khelifa conducted a study of the females’ death feigning and discovered that this strategy is usually successful.
He observed 27 out of 31 female dragonflies fall from the sky crashing to the ground and pretending to be dead in an attempt to persuade the harassing males to move on, and 21 of these ploys ended with a success.
Khelifa explained that the moorland hawkers do not stay with their male mates once the act is done and their eggs are fertilized, so they are left more vulnerable to harassment.
Yet, he is interested in finding out whether the behavior is unique to species that lay eggs alone or whether it is more widespread.
According to National Geographic,
“The mating ritual of the moorland hawker dragonfly—common around the ponds and wetlands of Europe, Asia, and North America—begins with what biologist Rassim Khelifa calls “an acrobatic aerial copulation.”
While in flight, the female Aeshna juncea contorts so that her lady parts, which are near the end of her body, connect with the male’ parts, which are near his thorax. Thus joined in a lopsided-heart shape, they land and complete the sex act, whereupon the female will head off to lay her eggs.”
However, other males can seek sex before she can do it. However, as she has limited eggs, she has been inseminated by the chosen mate, and her reproductive tract can be damaged by repeated copulations, she rejects them.
Therefore, to avoid further sex, she may fall down dead and fake death, dropping from the air and lying motionless in the ground cover.
Pretending to be in an immobile state as a way to discourage or ambush a predator is known as tonic immobility, death feigning, or thanatosis, and it has been seen in a wide variety of vertebrates and invertebrates.
