Researchers Use Motion-Capture Technology to Study Dragonfly Hunting Techniques

Posted on December 12, 2014

Researchers have used motion-capture technology to study the hunting techniques of the dragonfly. The study was conducted by researchers at the Howard Hughes Medical Institute's Janelia Research Campus. The researchers found that once prey has been spotted it only talks about half a second for a dragonfly to swoop in and snatch it.

The researchers found that a dragonfly's movement is guided by internal models of its own body and the anticipated movement of its prey. Study leader Anthony Leonardo and his colleagues recorded dragonflies' movements with a high-speed video camera as they chased after a fruit fly or artificial prey (a bead maneuvered by a pulley system). The scientists focused on following the orientation of the dragonfly's head and body. The dragonflies carried retroreflective markers for tracking as seen in the photograph above.

The researchers say scientists used to see prey capture by insects as a fairly straightforward system in which a predator's movement is guided solely by the position of its prey. Leonardo says in a statement that, "This is the way guided missiles work and how people catch footballs."

However, when the researchers analyzed the footage they recorded they saw that it was clear the dragonflies were not simply responding to the movements of the prey. Instead, they were making structured turns that adjusted the orientation of their bodies.

Leonardo says, "Those turns were driven by the dragonfly's internal representation of its body and the knowledge that it has to rotate its body and line it up to the prey's flight path in a particular way."

The researchers also say the dragonflies always aligned themselves to intercept prey from below so the prey could not see them coming. Each dragonfly also moved its head to keep the image of its prey centered on the eye. Leonardo says the dragonfly keeps the image of its prey fixed in the crosshairs of its eyes during the entire chase.

The dragonfly makes a perfect basket-like catch of the insect at the end in this video. Take a look:



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