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Laura, Lumi and Anda, juvenile Banana Spiders or Golden Silk Spiders (Nephila clavipes)
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Videos of Laura and her oscillatory responses to web motion and Lumi, cleaning, repairing and weaving

Vibrational behavior of juvenile Nephila clavipes (banana spider or golden silk spider)

Twice I have noticed that when I disturb the web, the web suddenly starts vibrating at perhap 5 - 10 Hz (speculation). The web then instantaneously stops vibrating. It occured to me that perhaps this is a defensive response. When the web is perturbed in a hostile manner (i.e. different from motion induced by wind etc) then the juvenile banana spider ( Naphils clavipes) will start pumping the center of the web, just as a child pumps a swing. The spider seems able to pump the web at its resonate frequency - initiating and terminating high frequency web motion by stopping the pumping.
Here are two short video segments demonstrating the vibrational response to disturbing the web. I must admit, that this response is not as dramatic as when I did by accident yesterday - but ...
  • Vibrational response (10 sec) 1Mb mpeg Initially I plucked one of the web supports. Then there was a brief delay and she initiated an rapid high frequency oscillatory lateral movement of her body. In addition, the locus of the lateral pulsation, shifts at a frequency of about 1/sec as she shifts her body to the left and then back to the right and then back again. Since is it difficult to actually see her, I suspect that she uses rapid movement to blur the image of a large threat (like me) - thus making it extremely difficult to know what to attack.

I have prepared 2 slow motion mpegs of the vibrational response. Laura appears to anchor all 8 legs and swing her thorax from side to side (laterally) at a very high rate - perhaps 10 - 20 Hz? In addition, the high speed lateral motion is packaged in approximately 1 second pulses where she appears to shift the locus of the vibration from left to right and back again - thus making it extremely difficult for an approaching threat to accurately locate her. The pulsing is difficult to see in the videos below - but can readily be seen in this one (mpeg compression from the camera) Has anyone seen this and is it a defensive response?

Jun 6, 2004: Videos of my sister, Lumi: web repairs and the vibration response

Jun 25, 2004: Videos of Lumi: rebuilding her web - the circumferential elements. Note that she is repairing only the bottom half. You will see that she weaves to the left and then to the right, but never continuously in a circle.

Reference links

I have located some references about defensive behavior. Vibrating the web is apparently well known.

Copyright 2004 C. Frank Starmer