Research published Friday in the open access academic journal BMC Evolutionary Biology reveals how spiders are able to travel across vast distances, and why they are able to quickly colonize new areas.
Academic researchers found spiders, using a technique called “ballooning,” can journey up to 30km a day in their quests to find new habitats and resources.
It was always thought the travelling strategies of spiders were risky as they had little control over where they travelled.
Dr. Morito Hayashi from London's Natural History Museum, London, lead author of the report, said: "Even Darwin took note of flying spiders that kept dropping on the ship, the Beagle, miles away from the seashore. But given that spiders are terrestrial, and that they do not have control over where they will travel when ballooning, how could evolution allow such a risky behavior to be maintained?"
"We've now found that spiders actively adopt postures that allow them to use the wind direction to control their journey on water. They even drop silk and stop on the water surface when they want. This ability compensates for the risks of landing on water after uncontrolled spider flights."
Researchers collected 325 adult spiders from small islands in nature reserves in the Nottinghamshire area of Britain.
The observed many of the spider species adopted elaborate postures, such as lifting up a pair of legs, to seemingly take advantage of the wind current whilst on the water surface. This allowed them to "sail" in turbulent, still, fresh, and salt water conditions.
By releasing their silk on water, the sailing spiders also seemed to act like ships dropping their anchors to slow down or stop their movement.
"This suggests that the silk may sometimes work as a dragline for the water-trapped spider to attach to floating objects or to the shore," Hayashi said.
The research team also found that the spiders that adopted "ballooning" behavior for airborne dispersal were also the most eager and able "sailors."
By Ruchi Singh
reporter
Park Sae-jin
swatchsjp@ajunews.com
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