Insects' stealth tactic gains dogfight dominance.
It sounds like a trick better suited to military aircraft. Dragonflies can fly without appearing to move at all.
A male dragonfly (Hemianax papuensis) locked in a breakneck territorial dogfight with another adjusts his flight path so that to his rival he seems stationary. This impressive feat is called motion camouflage.
"It involves a lot of high-_G_ maneouvres - the flies are slipping and sliding in the air relative to one another," says Javaan Chahl, one of the study team at the Australian National University in Canberra1. "Human fighter pilots do this as well," he adds, to gain a favourable position without being seen.
The researchers used two tightly synchronized video cameras to track the duelling dragonflies. This stereo set-up, much like the human visual system, pinpoints objects precisely.
Now the team is looking forward to working out how dragonflies plot and execute such stealthy swoops. "We hope there's a simple rule that they follow," says Chahl. "But if it's a complex mechanism then that will be interesting too."
Mizutani, A., Chahl, J. S. & Srinivasan, M. V. Motion camouflage in dragonflies. Nature, 423, 604, (2003).