Female dragonflies use an extreme tactic to get rid of unwanted suitors: they drop out the sky and then pretend to be dead."You can't harass me! I'm dead!"
Rassim Khelifa from the University of Zurich, Switzerland, witnessed the behaviour for the first time in the moorland hawker dragonfly (Aeshna juncea). While collecting their larvae in the Swiss Alps, he watched a female crash-dive to the ground while being pursued by a male.
The female then lay motionless on her back. Her suitor soon flew away, and the female took off once the coast was clear.
"I was surprised," says Khelifa, who had never previously seen this in 10 years of studying dragonflies.
Female moorland hawkers are vulnerable to harassment when they lay their eggs since, unlike some other dragonflies, they aren't guarded by their male mates. A single sexual encounter with another male is enough to fertilise all eggs and copulating again could damage their reproductive tract.
...He observed 27 out of 31 females plummeting and playing dead to avoid males, with 21 of these ploys successful. Plunging at high speed is risky though, and according to Adolfo Cordero-Rivera at the University of Vigo in Spain, it may be a strategy that they use only in areas with lots of dragonflies. "Females may only behave in this way if male harassment is intense," he says.
Few animals have been caught feigning death to trick suitors. The behaviour has been seen in a species of spider (the males use it to improve their chances of mating), two species of robber fly, and a type of mantis.
Playing dead to avoid predators, however, is more common and has been observed in dragonflies. "It's likely that females expanded its use to overcome male coercion," says Khelifa.
Being a lady dragonfly sounds like a rough gig! Imagine having to pretend to be dead just to avoid "intense male harassment" and "male coercion." I can only assume the lady dragonflies had to resort to this strategy after decades of pretending to read a book and traversing their territory with earbuds firmly in place failed to deter the determined males.
This reminds me of another of my favorite science stories, which is also definitely not a metaphor:
In his book A Primate's Memoir, Sapolsky studied the activities and lifestyle of the Forest Troop to explore the relationship between stress and disease. In typical baboon fashion, the males behaved badly, angling either to assume or maintain dominance with higher ranking males or engaging in bloody battles with lower ranking males, which often tried to overthrow the top baboon by striking tentative alliances with fellow underlings.Not a metaphor and definitely not a cautionary tale warning that a steady diet of poisoned garbage may eventually oblige the lady baboons to take over.
Females were often harassed and attacked. Internecine feuds were routine.
Through a heartbreaking twist of fate, the most aggressive males in the Forest Troop were wiped out. The males, which had taken to foraging in an open garbage pit adjacent to a tourist lodge, had contracted bovine tuberculosis, and most died between 1983 and 1986. Their deaths drastically changed the gender composition of the troop, more than doubling the ratio of females to males, and by 1986 troop behavior had changed considerably as well; males were significantly less aggressive.
After the deaths, Sapolsky stopped observing the Forest Troop until 1993. Surprisingly, even though no adult males from the 1983–1986 period remained in the Forest Troop in 1993 (males migrate after puberty), the new males exhibited the less aggressive behavior of their predecessors.
[H/T to Trudy.]
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