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Jumping Spider Guards Egg Sac

6-5-14 jumping spider2  077Spiders protect their eggs by wrapping them up in a sac they make out of silk. Some species (such as garden, or black-and-yellow argiope, spiders) then die, leaving their egg sac to withstand the elements, as well as potential parasites and predators, on their own. As you would guess, these sacs are usually fairly impenetrable. In other species, female spiders survive long enough to guard their eggs until they hatch, or even until the young spiderlings disperse, and these sacs are usually far less tough. In the species where the female protects her eggs, some females carry their egg sacs with them at all times (wolf spiders, nursery web spiders) while others (jumping spiders) simply remain with the sac. Their excellent eyesight and impressive ability to leap many times their body length gives jumping spiders an advantage over any potential predators. (Photo – jumping spider with egg sac)

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9 responses

  1. I don’t think that’s a jumping spider; the eyes are too small and the legs are too long. Maybe a crab spider? Xysticus?

    June 5, 2014 at 1:24 pm

  2. Kathie Fiveash

    I love the way your posts turn into educational conversations! Thank you Mary and Peter!

    June 5, 2014 at 3:05 pm

  3. You are all so generous in forgiving my mistakes!!!

    June 5, 2014 at 4:17 pm

  4. Ruth Sylvester

    ” these sacs are usually fairly impenetrable”
    How do the baby spiders get out, when the time comes? Do they have the arachnidean equivalent of an egg tooth?

    June 5, 2014 at 5:28 pm

  5. What an excellent question! I know that some of the spiders that stay with their egg sac help tear it open when the young spiders are ready to exit. For instance, the wolf spider rotates the egg sac with her legs and palps and cuts the seam of the egg sac with her chelicerae (mouthparts). As far as those egg sacs without parental oversight, I have never run across anything that told me exactly how the spiderlings make their exit holes, but my guess is that their chelicerae are involved.

    June 5, 2014 at 7:33 pm

  6. star

    I recently came upon a jumping spider egg sac and she was with them. I tried to relocate them because they were in a dangerous spot and she didn’t stay with the eggs when I relocated them. I felt bad so I put them in a little jar and now that they warmed up they’re starting to hatch. If I put them back outside do you think they will live through winter? and if they will not survive winter what kind of enclosure can I build for them where they will not get out until it’s warm enough to put them outside.?

    February 12, 2015 at 4:36 pm

    • I’m afraid that the young spiders won’t survive anywhere – even inside, unless you start breeding fruit flies or some very tiny insects…you could try putting them in a small glass tank but I don’t know what you would find – maybe double cheesecloth? to put on the top of it, and then some old banana skins, etc. to attract fruit flies, but I’m not too optimistic, I’m afraid. Spiderlings that overwinter outside need the protection of the silk egg sac, and need to not warm up as there isn’t anything except each other for them to eat…good luck!

      February 12, 2015 at 5:49 pm

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