Field studies were conducted about 67 km northeast of Iquitos, Peru, and on Barro Colorado Island, Republic of Panama.
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Stephen P. Yanoviak, an associate biology professor at the University of Louisville, and colleagues examined spiders in the genus Selenops called “flatties”, an extremely flat kind of spider that typically measures two inches in diameter.
The researchers began the study 10 years ago when they started to drop off different creatures from the tree branches to study the gliding behavior. 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.
“The remaining 7% of study spiders either landed on the ground or on understory vegetation following apparently undirected parachuting”.
Study suggested that those spiders were well-adapted to skydiving. The researchers discovered the selenopid spiders, some gliding spider species, while stressing out those only spiders, bristletails, and ants make use of a directed aerial descent. Their aerial performance was also restricted by the body mass and wings load. “These include cockroaches, mantids, katydids, stick insects and true bugs”, Yanoviak said.
“My guess is that many animals living in the trees are good at aerial gliding, from snakes and lizards to ants and now spiders”.
It seems though that when Selenops spiders are threatened by a predator, they prefer not to jump off of the tree and glide.
Spiders with the ability to glide have been studied for the first time.
Researcher Stephen Yanoviak of the University of Louisville in Kentucky says ‘We really did not expect to see gliding behavior in spiders. The team dusted these test subjects with fluorescent powder, then dropped them from up to 80 feet high and recorded their falls. It’s believed that “flatties” have aptly evolved and gained gliding abilities to avoid the ground-dwelling predators that might be waiting for them at the bottom of the tree. While the results were able to identify the mechanisms used by the insects to “fly”, the authors acknowledged that further investigations are warranted to establish the role of visual cues, leg positioning and spines in the overall aerodynamic capabilities of the spiders.
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Reported in the Journal of the Royal Society Interface, this is the first evidence of spiders being able to control their aerial descent.
