stealth dragonflies

Male dragonflies appear to be extraordinarily wily when in pursuit of rivals in their territories: they can fly in such a way that they appear completely motionless to their foes, a technique known as motion camouflage. Akiko Mizutani of Australian National University in Canberra and her colleagues used stereo cameras to precisely capture dragonfly flight maneuvers in three dimensions and then reconstructed dragonfly-eye views of pursuers. Their results, published in the June 5 Nature, show that a male dragonfly can adjust its position relative to a rival so perfectly that its image always appears on the same spot on the rival’s retina. This fools the rival into thinking his pursuer isn’t moving, and can help the pursuer perform sneak attacks. The researchers admit they’re not sure how the dragonflies do the trick, which requires highly accurate flight control and positional sensing.

This news brief appeared in the Random Data column of the Boston Globe’s Health/Science section on 6/17/2003.