Scientists observed spiders sailing across the water like ships, explaining how they cover great distances in order to widely colonize.
Published in the journal BMC Evolutionary Biology, the new study detailed how spiders use their limbs to catch the wind and propel them across a body of water. The spiders also used their silk as an anchor.
However, study lead author Morito Hayashi, of London's Natural History Museum, said in a press release the strategy - called "ballooning" - is risky.
"Even Darwin took note of flying spiders that kept dropping on the Beagle miles away from the sea shore. 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 behavior to be maintained?" he said. "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 the uncontrolled spider flights."
Their legs acting as sails, the spiders allow the wind to carry them through the air, making them vulnerable to sinking if wind conditions stop being favorable and the arachnid is stuck in the open water. But the study also suggests spiders can use their silk to latch on to a floating object, acting as a lifeline.
"Being able to cope with water effectively 'joins the dots' as far as the spider is concerned," study co-author Sara Goodacre, of the University of Nottingham, said in the release. "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."
