Tuesday, November 5, 2019

Blowing in the Wind (and Electric Fields)

Image result for spider ballooningEnvironmental & Science Education
Nature of Science
Edward Hessler

Ballooning or kiting is a flight mechanism that spiderlings and adult spiders use to disperse. What a chancy event this is. A spider turns its abdomen skyward, releases since spider silk and the air then takes over, a kind of "Look Ma, no hands."

The young naturalist Charles Darwin reported on it while he was on the HMS Beagle. Writing for The Telegraph, Sarah Knapton includes a diary entry. "Baffled by the sight, Darwin wrote in his HMS Beagle diary: 'Inundated by ballooning spiders on a relatively, calm, clear day,' later noting that the spiders took off again with 'unaccountable speed'".

Both air currents and electricity have been suspected as triggers for this behavior. In their paper, "Electric Fields Elicit Ballooning in Spiders" published July 2018 in Current Biology, Erica Morley and Daniel Robert report on an experiment to "test the hypothesis that electric fields can be detected and are sufficient to stimulate ballooning."

Spoiler alert: they are. But please read on because you can see the experiment.

Their paper includes the standard summary plus highlights (a useful addition) PLUS a short video (~ 3 minutes +) of the research (scroll down to the bottom) which gives you an idea of what and how they did this investigation.

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