Santa Barbara Museum of Natural History

Can you identify the spider that makes these beautiful bubble/balloon webs? I have never seen such interesting webs in Santa Barbara/Goleta area, only back at a family cabin in the Los Padres NF.

I am sending both photos in hopes that your curators can help me identify the creator and provide me with resources for finding out more about this magnificent artisan with 8 legs.

Gail, Santa Barbara, CA - September 29, 2020

Curator Response

Hi Gail,

Happy Spider Month! ::::)

This picture with the "bubble/balloon webs" is such an odd and fascinating picture. Thanks for sharing it! Well, this is definitely a cobweb spider (as opposed to an orb weaver). The egg sacs to me look like sacs laid by a hungry spider or one at the end of her life, as they have few eggs for the sac size/silk amount. Steatoda triangulosa lays these fried egg-like sacs, so that may be the species. I'm not very familiar with S. triangulosa, but maybe it's a newcomer to the area or becoming more abundant. However, there's something strange about your picture: there appears to be a large spider inside the supportive silk of the egg sac. This is unusual in my experience, so I would only say with confidence that this is probably a spider in the Steatoda genus. Steatoda nobilis common in our area. Here's a picture of a nobilis female with her egg sac, but you can see the bubble or fried-egg effect is not as prominent in this case: https://www.researchgate.net/figure/Captive-mature-female-Steatoda-nobilis-guarding-her-egg-sac-suspended-in-a-brooding_fig4_319881734

Thanks again for sharing. Keep appreciating spiders,

Collections Associate Jen Maupin, Ph.D., and Naturalist Dylan Otte