Some flies have special hind wings so that they can take off faster and are harder to hit.
Many flies can be notoriously difficult to catch. You can avoid incoming hazards by taking off from a standing position in a split second.
They primarily use vision to escape danger, but Alexandra Yarger of Case Western Reserve University in Ohio and her team have come up with a new mechanism that may help them escape.
All fly species have shortened hind wings, so-called halter. These do not generate any useful lift, but are used as sense organs for balance, to stabilize the insect in flight.
A group of flies known as calyptratae, which includes house flies and blowflies, move these wings rhythmically when standing.
“We know they are the only group that does this,” says Yarger. “It’s still a mystery why they do it.”
Yarger and her team tested whether this behavior affected their starts. Using high-speed cameras to film the flights of over 20 species of flies, they found that Calpytrate flies took off around five times faster than other flies. The team then removed the holsters and found that both the speed and stability of launches decreased in Calyptratae species.
Yarger suggests that this slower motion increases the amount of sensory information these flies receive, but what they can perceive and how it’s processed remains unclear.
“We believe there is a way from holsters to legs that makes them take off faster,” says Yarger. “It doesn’t go through a central nervous system, it’s almost like a reflex,” she says.
With a quick start, this group of flies can better avoid damage.
“This is one of the reasons they are so successful that they can escape very quickly,” says team member Jessica Fox. “The transition from takeoff to flight is challenging, and using holsters to help both is clearly very beneficial,” she says.