Why this insect fakes death to avoid sex

Acting dead allows the moorland hawker dragonfly to reproduce with the mate she chooses.

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 genitals, which are near the end of her body, connect with the male’s genitals, 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.

Before she can do that, other males may show up seeking sex. Evolution predisposes her to resist: She has limited eggs, her reproductive tract can be damaged by repeated copulations, she’s already been inseminated by the mate she chose, and the dragonfly penis is structured so that it removes any sperm present before making a new deposit. So to avoid further sex, she may fall down dead—or more precisely, she may fake death, dropping from the air and lying motionless in the ground cover.

At the University of Zurich, Khelifa conducted a study of the females’ death feigning and found that usually “their strategy works.” Most males buzzed the crash site briefly, he says, then flew off to look for other conquests. Once the males left, the lifeless-looking females stirred and went on their way.

Read This Next

An icy world is in meltdown, amid penguin population shifts
This sacred valley could become the next national monument
This 50-year project is tracking the Cascades' melting glaciers

Go Further

Subscriber Exclusive Content

Why are people so dang obsessed with Mars?

How viruses shape our world

The era of greyhound racing in the U.S. is coming to an end

See how people have imagined life on Mars through history

See how NASA’s new Mars rover will explore the red planet

Why are people so dang obsessed with Mars?

How viruses shape our world

The era of greyhound racing in the U.S. is coming to an end

See how people have imagined life on Mars through history

See how NASA’s new Mars rover will explore the red planet

Why are people so dang obsessed with Mars?

How viruses shape our world

The era of greyhound racing in the U.S. is coming to an end

See how people have imagined life on Mars through history

See how NASA’s new Mars rover will explore the red planet