New Flying Spiders Found

By R. Siva Kumar - 19 Aug '15 13:12PM

Some insects can soar through the air even without silk, and just dive through nearby tree trunks, scientists have discovered, according to natgeo.

These spiders are flying arachnids. They are able to steer through the air with their outstretched forelegs, says a study published in August 19, in the Journal of the Royal Society Interface.

How can spiders, which are not flying beings fly, wonder scientists. "We really did not expect to see gliding behavior in spiders," says study leader Stephen Yanoviak, a tropical arthropod ecologist at the University of Louisville in Kentucky.

"There are no winged spiders. Spiders don't fly."

So this is a novel evolution for spiders to dwell on tree trunks, which are safer than the forest floor, in which they may be eaten, say scientists.

Yanoviak and his colleagues have been searching for gliding insects for a long time. To test them, they just drop some creatures from a height. Their tests have led to ant species that can "hang glide," or make "controlled aerial descents, as do immature praying mantises and grasshoppers."

While most spiders did not seem to fly, the scientists tried huge arachnids known as "flatties," that dwell in the American tropics. These could be as large as "a soup can lid" and could also be nimbler than cats.

They might be so quick and hidden that they cannot be seen unless they move. "The best skydivers could swerve to a landing after falling only 13 feet (4 meters) or so.," says natgeo.

"You'll see the spider steering as it goes through the tree," Yanoviak says. "If it wants to turn left, it changes the angle of the right front leg. And if it wants to turn right, it does the same with the left front leg."

It is the flatness that is making them glide. Sarah Crews, an independent evolutionary biologist, also an expert on flatties, says she's "convinced" by the findings, which show spiders are just as capable of gliding as insects---but do the job differently.

"These results are indeed surprising for a spider," says Marie Herberstein, a behavioral ecologist at Australia's Macquarie University and editor of the book Spider Behavior. "Spiders generally rely on dragline silk ... as a safety line should they fall," she says.

Adds study leader Yanoviak, "It's awesome to see them do it. They're so good at it."