Research into how jumping spiders make their death-defying leaps recently won a place in the highlights section of prestigious science journal Nature published Aug. 15 for a team of Taiwan researchers.
The study led by biophysicist Chi Kai-jung of Taichung City-based National Chung Hsing University garnered a slew of international media coverage, including articles by the BBC and Wired magazine. It will also be published in the October 6 issue of the Journal of the Royal Society Interface.
Jumping spiders, or salticids, can jump up several dozen times their height to land atop their hapless victims. The arachnids do not spin webs, yet still extrude silk. The exact mechanism by which they made their precision pounces, however, was unclear until Chi and her team used stop motion photography and other techniques to study their predation.
Their research shows that the draglines the spiders trail behind them serve as a safety line and a steering mechanism, while helping slow descent to ensure a soft landing. They execute their jumps in under 0.15 seconds, faster than the human eye can process them, making the use of high speed photography a necessity to understand the biomechanics of their flight.
“Like other jumpers, they strive for stability and smooth landings,” the researcher said. “Instead of using inertia from swinging appendages or aerodynamic forces by flapping wings as in other organisms, salticids use a different mechanism for in-air stability by using dragline silk, which was previously believed to function solely as a safety line.”
The team spent more than a year observing the spiders, shooting high speed video at up to 1,000 frames per second. They compared the behavior of the spider Hasarius adansoni to other species which do not use dragline silk. The silkless spiders made clumsy and potentially dangerous landings and required quintuple the time to steady themselves during which their startled prey could escape. (SDH)
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