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I saw this on the wall while going upstairs one night, and noticed it doing what looked like an odd dance. Its whole ody would be vibrating up and down very rapidly,its legs stationary. Occasionally it would stop, then continue again. Very odd!

I also have a video of it on youtube somewhere.

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Here's that video:

YouTube Video

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Hi Larry

Reminds me of what some spiders (weavers) do when bothered, why they do it I do not know.

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Some rodents make strong noise in their holes when distrurbed, perhaps to make their enemies scared. Enemies eat them anyway. But once some are saved with this, it works.

This limo either displays some spider movements or tries to attract someone in one or another way.

But, if absolutely frankly and honestly, - I do not know.

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yes, this in in defense, saw this behaviour many times in the same sp. on leaves usually when they were disturbed

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I, too, don't know .... but another possibility occurred to me: could muscular action be a means of thermoregulation?

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I think its to confound predators - given the choice between eating a still fly and a vibrating one, the still one is easier!

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but a vibrating one would be easier to spot. But if it already has been spotted (by the photographer) it is perhaps difficult for the predator to focus? Or perhaps attracting the opposite sex for mating? For short: I don't know, just guessing.

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That depends on your eyesight - the vibrations are usually very fast and may be so fast that the predator cannot focus on the body of the cranefly. In which case it may not be able to "see" it. There has to be some protective advantage to rapid vibrating, otherwise why should so many spiders and flies do it?

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maybe they are just laughing about us and think "did you see that ridiculous hair? and those white socks."

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don't think it has to do something with predators. Those two was doing same, just after landing there, before allowing me to take photo:
http://agrozoo.ne...&l2=en