Re: Do orb-weaver spiders eat butterflies?

Hi James,

Thanks for sending us a question. I am a fan of spiders, and it was nice having a good excuse to learn more about them. As you already know, orb weaver spiders build what we think of as a typical wheel-shaped spider's web. They use these webs to capture prey. The webs are usually spun in openings (spaces between trees, fence posts, etc.) and positioned to catch flying insects.

Most orb weavers catch small insects such as flies or gnats, but the larger ones can capture butterflies and moths. Butterflies can sometimes avoid being permanently trapped in orb weaver webs because their wings are covered with tiny scales that slough off and stick to the web, allowing the butterfly to escape. At the bottom of this web page there's a photo of an orb weaver spider dining on a butterfly that didn't manage to get away.

I wasn't able to find any information on whether monarch butterflies, specifically, are captured by orb weavers, but my guess is that they can be. I did find a lot of very cool pictures and information on orb weavers at these web sites:

http:// www.amonline.net.au/factsheets/orb_weaving_spiders.htm
http://animaldiversity.ummz.umich.edu/accounts/argiope/ a._aurantia$narrative.html
http:// www.arachnology.org/Arachnology/Pages/Orbweb.html. This page is a collection of links to other pages about spiders.

I hope this answers your question!

Allison J. Gong
MAD Scientist