Science Wednesday: Banded Garden Spider

by Katie Bowell, Curator of Cultural Interpretation

With the colder weather continuing, we won’t be seeing to many  spiders in the upcoming months (not outdoors, anyway. In your house is another matter entirely). For now, though, take a look at this lovely lady photographed outside museum associate Dave Dahm’s house:

This is a banded garden spider (Argiope trifasciata), and it’s the largest of the orb-weaving spiders in Colorado. You’re most likely to see banded garden spiders sitting in their beautiful, symmetrical orb webs in late summer and early fall, and if you do see one chances are very good it’s a female. Females are  silvery with dark and yellow striping, while males are much smaller and rarely seen.

Banded garden spiders catch flying insects in the webs, biting their prey to paralyze it and then wrapping it in silk.


As it continues to get even colder, the species will overwinter either as eggs in a large sack (up to 1000 eggs per sack!) or as tiny spiderlings hidden in foliage. The young spiders move around by “ballooning,” deploying threads of silk to be caught by the breeze. If this sounds familiar, you might remember the baby spiders doing something similar in Charlotte’s Web.

And in case you thought spiderlings were the only insects flying high above you, check out this story on The Billion-Bug Highway.

Are there any insects you’re still seeing out and about?

All images c/o Dave Dahms

7 Responses to “Science Wednesday: Banded Garden Spider”

  1. 1 Lesley November 17, 2010 at 9:53 am

    What a lovely spider!

    I’m still seeing boxelder bugs everywhere I turn!

  2. 2 Katie November 17, 2010 at 10:09 am

    Boxelder bugs will continue to be around until it gets really cold. Then they move into buildings to overwinter where it’s warm.

  3. 3 Lesley November 17, 2010 at 3:22 pm

    Must they move into MY building?!

  4. 4 Katie November 17, 2010 at 3:51 pm

    Yes. Yes, they must.

  5. 5 Jase Samber October 10, 2011 at 2:32 pm

    We have a female banded garden spider in a mesh cylinder, we found her in our backyard. She has been fun to watch as she has completed her egg sac one night as we slept. We were wondering when her eggs will hatch into baby spiders. She formed her sac about 5 days ago. We would appreciate any info you can give us, my six year old son is an avid spider lover! Thanks!

  6. 6 Treloar Bower October 10, 2011 at 4:03 pm

    Hi Jase!
    How fun to be enjoying a banded garden spider. It sounds as though she is living in the cylinder in your house?

    This species of spider lives for just one season. The female lays one or two egg sacs in the fall before she dies. The spiderlings overwinter as eggs and will hatch in the spring. It’s possible that keeping the egg sac warm in your home will cause the eggs to hatch sooner but you may not want that to happen, as a single egg sac can produce 1000 spiderlings! Also, the little spiderlings, if kept together in a container, will eat each other. Your best bet would be to return the egg sac to a safe place in your yard where you can keep an eye on it over the winter and into the spring. If you are lucky, you’ll see the spiderlings “ballooning” away on strands of their own silk come next spring. And maybe one will choose to stay in the same yard where his or her mother lived (yes, that’s a Charlotte’s Web reference).

  1. 1 The International Year of Biodiversity Wrap-Up « More to Explore Trackback on December 31, 2010 at 8:02 am
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November 2010

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