June 14, 2011

Bees Fooled Into Revealing Flight Secrets

Bees use their eyes to tell them how best to streamline their bodies for rapid flight, a world first study shows.

Scientists at The Vision Centre have fooled the honeybee into revealing its flying secrets by tethering the creature and running background images past its eyes. This tricks the bee into thinking it is "Ëœflying' and it moves its body into a posture for rapid flight "“ even though both it and the air are still.

The research indicates that vision is an important sense that helps bees adopt the best position for flying. The experiments show that in the absence of wind, the bees still activate a streamline response by looking at their environment.

"We created a simulated scene, by running images rapidly past its eyes so the bee thinks that it's flying forward down a tunnel," says Dr Tien Luu from The Vision Centre and the University of Queensland. "We saw that the bee raised its abdomen during flight, lifting it higher as the speed of the background images increases. When the speed of the background images decreases, the bee's abdomen would droop and stay at 90 degrees to their upper body.

"While previous research has demonstrated that insects lift their abdomens during flight, we have found that that visual stimulus alone is powerful enough to provoke the streamlining response."

This finding suggests that flying insects sense their airspeed by using their visual system to calculate their forward speed by scanning the motion of the background environment.

"Bees fly at a high speed, which is typically 35 Kilometers per hour, yet they seldom collide with obstacles or crash land," Dr Luu says. "This is because their eyes have lots of photoreceptors "“ vision cells "“ which focus on objects as they fly past, and so detect motion very clearly.

"When their eyes signal that they can fly faster, they streamline their bodies to reduce the aerodynamic drag that would otherwise be caused by the abdomen."

She says that having a close up view of how honeybees fly has always been a tough task.

"We can't observe bees closely in the field because they live in hives, making it hard to mark and identify them," she says. "It also isn't easy to trick them into flying in a simulated setting. Bees, being smart creatures, can quickly sense a fake environment - and refuse to keep flapping their wings.

"The research could be useful in designing control systems for aircraft that rely on vision to control aircraft attitude "“ for example, control of the flare-out that is performed just prior to touchdown during landing, when the image of the ground appears to be moving very rapidly."

The group's paper "Honeybee flight: A novel "Ëœstreamlining' response" by Tien Luu, Allen Cheung, David Ball and Mandyam V. Srinivasan appears in the latest issue of the Journal of Experimental Biology.

The Vision Centre is funded by the Australian Research Council as the ARC Centre of Excellence in Vision Science.


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