July 8, 2009

Study: Some insect wings bend in flight

A U.S. study shows not all insects have rigid wings, with some insects, such as moths, having wings that flex and deform during flight.

University of Washington researchers said most scientists who study the mechanics and aerodynamics of insect flight have assumed insect wings are relatively rigid as they flap.

But the researchers in the new study, led by biology Professor Thomas Daniel, used high-speed digital imaging to show some insects' wings flex and deform while in flight.

The evidence indicates that flexible wings are producing profoundly different air flows than stiff wings, and those flows appear to be more beneficial for generating lift, said doctoral student Andrew Mountcastle, lead author of the study.

The scientists used particle image velocimetry, a technique that determines flow velocities in fluids, to study how air flows over the wings of tobacco hawkmoths (Manduca sexta). The method combined laser light and high-speed digital video to model air flow.

Our results show that the flexible wings are doing a better job of generating lift-favorable momentum than are the stiff wings, Mountcastle said. 'They also are inducing airflow with greater overall velocity, which suggests the production of greater force for flight."

The research was reported in the May issue of the journal Experiments in Fluids.