The Choreography of Dragonflies
Dragonflies have interesting common names like the wandering glider or globe skimmer. Why? Because they migrate further than any other in their class. Dragonflies have been found all over the world, traveling to every continent except Antarctica. They also know choreography, really.
Meal on the Go
You have probably seen dragonflies flitting around over a lake or even a swimming pool. They are attracted to water and prefer wetlands in nature settings. At the nymph stage of their lives, you can find them underwater where females like to lay their eggs. You will see them from spring to autumn when it’s hot and sunny outside.
They have staying power, too. They have been around longer than dinosaurs, or about 300 million years. Archeologists and botanists have found fossils of dragonflies with a wingspan of about two and a half feet!
And they are choosy. The clubtail species only hang around very clean, unpolluted waters, such as flowing rivers. They like their meals on the fly (no pun intended), snatching snatch dinner flying through the air. They bunch their legs together and form a kind of basket to scoop up prey. In different types and angles of light, they have the ability to reflect multiple colors, creating quite a distraction for their prey.
As for dinner, these predators are apt to eat insects, such as bees, butterflies or even other dragonflies. It’s not all eat and fly because they are also prey. Spiders, praying mantis and bats, frogs or small fish eat dragonflies.
Aside from their great wing pairs with little pockets to catch the wind, a long sinewy body and wonderful scooping legs, they also have big bug eyes, the best in the insect world. Not only do they have top-notch vision, but their eyes can look up, down, right, left—and all at the same time with a 360-degree span. Dragonflies have something called compound eyes—ommtidia, a cluster of photoreceptor cells that are equal to thousands of eye facets! Under a transparent cornea, each ommatidium sends one picture image to its brain; it is more like sensory input and that allows them to zero in on prey. They can see colors in ultraviolet light unlike humans who cannot.
In fact, researchers at the University of Adelaide in Australia are studying the way insects see and track their prey. They hope to apply this information to a new robot under development.
The Choreography of Flight
Snap! One half-second is all it takes the dragonfly to snatch an insect out of the air.
At Howard Hughes Medical Institute, scientists have used motion-capture sequence to track the details of a dragonfly’s movement. The brain of the dragonfly creates this complex behavior and that proves to be important ideas for future research.
The watchers claim that what the dragonfly does is every bit as complicated as the most talented ballet dancer; there is sophisticated internal information processing going on there.
Getting a body to move through space involves many mechanisms. Up until now, researchers have thought this was straightforward and the dragonfly simply reacted to the position of its prey. It is much more complicated, like a guided missile performance or catching footballs.
A team of researchers spent several years figuring out how to track a dragonfly’s body movements. They found if they placed reflective markers on different points of the dragonfly body, under high-speed video, the light reflected, providing markers of each type of movement. Kind of like a body cam for an insect, if you will.
- Structured turns
- Oriented their bodies from internal knowledge
- Lined themselves up with the prey’s flight path
- Got the jump on the insect from below
Anthony Leonardo, who led the study, says that each dragonfly moved its head to keep the image of its prey centered on the eye, despite the rotation of its own body.
The dragonfly’s movements are choreography so fine-tuned that their prey is kept in the crosshairs, using an elegant combination of control and reaction.
Some dragonflies bite. To hold them, take them gently out of a net by folding all four of its wings over its back. This doesn’t hurt them, allows you a better look and stops it from nip pinching.