Trading energy for safety, bees extend legs to stay stable in wind

June 2, 2009
Bee

New research shows some bees brace themselves against wind and turbulence by extending their sturdy hind legs while flying. But this approach comes at a steep cost, increasing aerodynamic drag and the power required for flight by roughly 30 percent, and cutting into the bees' flight performance.

The findings are detailed in the .

"Wind is a universal part of life for all flying animals," says Stacey Combes, assistant professor of organismic and in Harvard University's Faculty of Arts and Sciences. "Yet we know remarkably little about how animals navigate windy conditions and unpredictable airflows, since most studies of animal flight have taken place in simplified environments, such as in still air or perfect laminar flows. Our work shows clearly that the effect of environmental turbulence on flight stability is an important and previously unrecognized determinant of flight performance."

Together with Robert Dudley of the University of California, Berkeley, and the Smithsonian Tropical Research Institute, Combes studied 10 species of wild orchid bees that fly at high speeds for tens of kilometers each day seeking food and other resources. Males of these species are especially motivated to collect aromatic scents in pouches on their oversized hind legs, which are then used in mating displays that attract females.

Because male orchid bees are so strongly attracted by scents, they will readily traverse severe conditions, such as those created when Combes and Dudley set up powerful air jets in the bees' Panamanian jungle habitats. Using high-speed video, the scientists measured the bees' maximum flight speed as they were buffeted by varying levels of environmental turbulence. In every case, the bees displayed a side-to-side rolling motion at high flight speeds, negotiating the turbulence by extending their rear legs while in flight.

"This increases the bees' moment of inertia and reduces rolling," Combes says, "much like a spinning ice skater who extends her arms to slow down."

This rolling increased with flight speed until the bees were rolled to one side or the other roughly 80 percent of the time, at which point the bees would become unstable and either crash to the ground or be blown from the airstream. Bees were able to reach higher speeds when flying in lower levels of turbulence, altered through the use of different types of screens to deflect air flow in the air jet.

While Combes and Dudley only studied 10 species of euglossine bees, Combes says that this stabilizing behavior is likely to be seen across Hymenoptera, the order of insects that includes , wasps, ants, and sawflies, and that turbulent airflow may decrease the flight performance of many other flying insects as well.

Source: Harvard University (news : web)

Explore further: Study: City bees better than rural bees

Related Stories

Study: City bees better than rural bees

January 17, 2006

A French beekeepers' association says it has determined bees reared in cities are healthier and more productive than bees raised in rural areas.

Halictid bees' social behavior studied

March 13, 2006

Cornell University scientists say the social behavior of many species of sweat bees evolved simultaneously during a period of global warming.

The cost of long tongues

April 16, 2007

Orchid bees use their extraordinarily long tongues to drink nectar from the deep, tropical flowers only they can access. Researchers have long suspected that this kind of exclusive access came with a mechanical cost.

Recommended for you

Which insects are the best pollinators?

September 3, 2015

Bees top the charts for pollination success according to one of the first studies of insect functionality within pollination networks, published today by researchers at the University of Bristol and the University of St Andrews.

Scientists discover key clues in turtle evolution

September 2, 2015

A research team led by NYIT scientist Gaberiel Bever has determined that a 260-million year-old fossil species found in South Africa's Karoo Basin provides a long awaited glimpse into the murky origins of turtles.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.