Blood flow through a spider’s leg




Here’s a phenomenon that is perplexing me, but perhaps the answer is simple. The legs of small spiders are so thin that you can often see the “blood” or hemolymph flowing through them with the Foldscope. Though this is visible even in low magnification, here I took a closer look with the high magnification lens. For the first time, though, I was able to capture the twitching of the leg coupled with footage of blood flow. What puzzles me is this: spiders use hydraulic pressure to extend their legs, which is why their legs curl up when they die (the pressure suddenly decreases). For blood to be flowing, there must be a pressure gradient as well. How does a spider simultaneously manage both blood flow and coordinated movement? This may be a simple question for someone familiar with a spider’s body plan… but this has also inspired me to undertake a more comprehensive study mapping blood flow and body movement in a single spider. More to come!


3 Comments Add yours

  1. Manu says:

    Fantastic @Tom. I love how steady your imaging is with the focus locking.. absolutely fantastic.

    On the pressure generated for hydraulics, I am still trying to wrap around my head on how to generate recirculating flows but still have a pressure that can be used for actuation.

    Time to “puncture” some spiders..


  2. Tom Hata says:

    Manu, you’ll have to get back to me once you puncture them. I wonder if you’d see a strong, immediate flow as the limb curls up.

  3. laksiyer says:

    It is amazing how much I have learnt since the foldscope. Here are some experiments on the spider’s leg that perhaps can be more easily done nowadays?

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