How dragonflies use ultrafast wing movements to flip over in flight

By Corryn Wetzel

Dragonflies use a combination of visual clues and control of their wing pitch to perform acrobatics.

Researchers weren't sure how the four-winged insects were able to right themselves from an upside-down position. Almost eight years ago, Jane Wang, who studies the physics of living organisms at Cornell University in New York, noticed the intriguing behavior. When she dropped the insect, it flipped itself faster than she could see.

Wang and her colleagues designed a series of experiments to find out how the insects managed it. They painted the wings and bodies of seven dragonflies. After releasing the insects upside down, they recorded their movement with a high-speed video camera. They slowed down the footage to get a better look at the wing angles and used a computer to create a three-dimensional model of the dragonflies.

The simulation showed Wang that the dragonflies were flipping their wings at different angles in just 200 milliseconds.

Dragonflies have to create a difference between the left and the right wings to beat their wings.

There were some that went left and some that rolled to the right. The insects used the same wing angle to flip in the air.

The experiment didn't answer how they knew they were upside down. Wang suspected they might be using visual input from their large, multi-lens eyes, or from light-sensitive organs called ocelli on top of their head.

The team blocked the eyes and ocelli of the insects with black paint. They couldn't right themselves, sometimes they didn't flap their wings at all.

According to the researchers, visual signals must help the insects orient themselves in space. Wang thinks the technique isn't the only one used by dragonflies.

She says that almost all flying insects have this ability. I think the modern ones have the same ability if they have already evolved it.

There is a journal reference called Science.

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