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Leaf-curling Sac Spiders Guarding Eggs

While all spiders spin silk, not all spiders make webs with their silk.  Some spiders actively hunt prey instead of passively catching it in a web, including Leaf-curling Sac Spiders. They utilize their silk to form a protective brooding chamber for their eggs by stitching the underside of a leaf together.  Within this shelter the mother spider first constructs an egg sac from strong silk that is tough enough to protect her developing offspring from the elements. She then deposits her eggs inside it, fertilizing them as they emerge. A single egg sac may contain just a few eggs, or several hundred, depending on the species. The mother spider remains within the shelter protecting her eggs until they hatch. Look for these spider shelters on the under side of grape leaves.

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3 responses

  1. Alice

    That’s an interesting sequence: first making the egg sac, then laying the eggs & then fertilizing them. Grape lives are so pliable and resilient, I wonder if that’s why they are chosen. I’ve relocated many (harvester?) spiders from just after the doorway to the basement, all holding egg sacs.

    June 24, 2022 at 8:14 am

  2. Such a good mama.

    June 24, 2022 at 11:33 am

  3. I’ve seen these web sacks on grape leaves from my vines, but I’ve never seen the actual spider.

    June 26, 2022 at 9:06 am

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