London, July 3 (IANS) When it comes to special super powers, the comic hero Spiderman has a rival — the spider. New research in Britain shows the common spider can travel vast distances across water like a ship. They even use their legs as sails and their silk as anchors.
Research published on 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 30 km a day in their quest to find new habitats and resources, Xinhua news agency reported.
It was always thought the travelling strategies of spiders were risky as they had little control over where they travelled.
“Even Darwin took note of flying spiders that kept dropping on the ship, the Beagle, miles away from the sea shore,” Morito Hayashi from London’s Natural History Museum, London, lead author of the report, said.
“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 risky behaviour to be maintained?” he asked.
“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.
They 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,” added Hayashi.
The research team also found that the spiders that adopted “ballooning” behaviour for airborne dispersal were also the most eager and able “sailors”.
Co-author Sara Goodacre from Britain’s University of Nottingham, added: “Being able to cope with water effectively ‘joins the dots’ as far as the spider is concerned. It can move from one land mass to another, and potentially across huge spatial scales through the air. If landing on water poses no problem, then in a week or two they could be a long way away from where they started.”