Natures wonders: spiders spin fibers to fly distances (Introduction)

by David Turell @, Thursday, June 14, 2018, 21:06 (11 days ago) @ David Turell

The fibers are difficult to see but this study has it all worked out:

https://www.newscientist.com/article/2171701-spiders-can-fly-because-they-make-near-inv...

"We’ve finally seen how even relatively large spiders manage to take to the air. Rather than just spinning out just one or two silk fibres to catch the wind, as was thought, they make “paragliders” from dozens of thin fibres.

“'The fibres are very hard to observe with our naked eyes,” says aerodynamic engineer Moonsung Cho of the Technical University of Berlin, Germany. “This is why, until now, we have not been able to explain the flight of ‘ballooning’ spiders.”

"Many kinds of spiders “balloon” with the help of silk fibres that act like paragliders, travelling hundreds of kilometres with the winds. They have been found as high as 4.5 kilometres and are often among the first animals to reach new islands. Some species can also glide or windsurf.

"There’s been no mystery about the ballooning of baby spiderlings, which often take to the air soon after hatching to avoid being eaten by their siblings. But it has been hard to explain how larger spiders fly.

***

"They found that the arachnids are advanced aviators. Before taking off, they anchor themselves to the platform with a safety line. They then raise themselves “on tiptoe” and lift a leg to test the wind.

***

'If the take-off goes well and they climb rapidly, the spiders immediately cut the dragline anchoring them to the platform. But in slow take-offs they sometimes keep the safety line until it is 5 metres long. This means the spiders must keep spinning out the safety line as they take off, as silk cannot stretch this much.

"What Cho cannot yet explain is how, with so many fibres being spun out at the same time, the spiders prevent them becoming entangled. It might be that they are electrostatically charged after all, so the fibres repel each other."

Comment: Another amazing adaptation. Did they learn this by experimentation?


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