Joro Spider

Known as joro-gumo in Japan, the joro spider (Nephila clavata) can be seen in gardens, parks and wooded areas during mid-autumn. With a large body (up to 2 inches in length, excluding the legs), yellow and bluish-grey abdomen, bright red near the tip of the abdomen on the reverse side and yellow and black striped legs, the female joro spider is easy to identify. Often one or two males, at one third to one fourth the size of the female, can be found lurking around the edges of the web waiting for a chance to mate.

The joro spider is an orb (or golden orb) spider. The large web, often a yard in diameter, is built in three layers (a central orb plus one in front and one in back) with web threads radiating irregularly out from the front and back of the web. This three layer construction is not typical of orb spiders.

The female joro spider lays her eggs on tree trunks, buildings, other structures or even on the underside of a leaf. The eggs are attached and held in place by special silk threads. After lying dormant over the winter, the eggs hatch late the following spring. Adults die off in the winter.

Once prey is caught, the joro spider immediately bites her victim with a potent venom. If bit by a joro spider, a human will usually experience pain, redness and blistering that disappears within twenty four hours. The venom is potent, but not strong enough to harm a human except in rare occasions when there is an allergic reaction.

These joro spiders were photographed at Manno Lake on the Island of Shikoku. The joro-gumo web was in a cemetery in Sakaide.

Also called banana spiders, I was fascinated by these truly beautiful arachnids.

Gallery | This entry was posted in Arachnids and tagged , , , , , , . Bookmark the permalink.

5 Responses to Joro Spider

  1. usermattw says:

    The body alone is up to two inches? Beautiful, yes, but yikes! 🙂

  2. Pingback: Addendum: Joro Spider | The Nature Niche

  3. Lin Erickson says:

    I agree…they are BEAUTIFUL !!!

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