In early March I heard a radio story about a scientist doing amazing research on dragonflies.
Scientist Frances Chance was featured on the Ted Radio Hour speaking about how she was trying to understand how the insects are able to react so quickly. Dragonflies hunt other flying insects, so their reactions have to be very fast.
“In the wild, dragonflies capture approximately 95% of the prey they choose to go after,” Chance said.
This ability to capture prey as it moves is called interception. I usually think of interception as something related to football. An interception is when the defender catches a pass intended for a receiver. For dragonflies it is kind of the same, trying to figure out where the insect is going to be next.
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“When dragonflies are hunting, they do more than just fly straight at the prey,” Chance explained. “They fly in such a way that they will intercept it. They aim for where the prey is going to be.”
Dragonflies do this amazing task with a brain that has 1 million neurons. In comparison, you and I have about 86 billion neurons. Neurons are nerve cells, the basic building blocks of our brains. Signals sent through neurons from our brain to our muscles are what help us move. They are what help football players catch and intercept passes.
Dragonflies also make their flight changes very quickly, in about 50 milliseconds, Chance said. That’s half the time it takes to blink your eye.
There are a lot of other interesting facts about dragonflies. They have huge eyes that enable them to see to the front, back and all sides. Their front and rear wings are shaped differently. (The helicopter-like machines in the newest “Dune” movies look like big dragonflies.)
Young dragonflies spend the first part of their life underwater as nymphs. While underwater they have crab-like claws that help them catch food. For breathing underwater, they have gills in their rectum — the same tube they poop through. Water is drawn in through their poop chute, and then pumped out. Shooting water out their butt can also help dragonfly nymphs move quickly in the water like a mini jet boat.
So the next time you see an insect, Chance suggested we consider how even their tiny brains are very remarkable and specialized.
— Brett French, french@billingsgazette.com