Anyone who has tried to swat an insect can attest to how difficult it is to make contact with such elusive targets, but dragonflies, in spite of their tiny brains, have mastered the art. When humans attempt to intercept an object, our brains anticipate both how the object is moving as well as how our own bodies will behave as we move. It was previously unknown whether invertebrates possessed these predictive capacities, and most of their behaviors were thought to be completely reactionary. However, today researchers report in Nature that dragonflies do rely on predictive models to intercept prey. The researchers attached reflective markers to the dragonflies and then filmed them using high-speed cameras to determine how they tracked their prey: The dragonfly relies on approaching the target from below while matching its own body alignment with its prey’s. During the approach, the predator tracks the target with its head but maneuvers its body independently to maintain the proper alignment. These movements require that the insect successfully make predictions about the motion of its prey as well as its own body. If the dragonfly can match its prey’s body orientation, scoring a successful meal becomes as simple as closing the vertical gap and grabbing on as the target (a fruit fly in the video above) passes by. Whether other invertebrates are capable of this sort predictive neural modeling remains to be seen.
(Video credit: Anthony Leonardo, Janelia Research Campus, HHMI)