Large Spider

Asked October 6, 2018, 11:52 AM EDT

I found this spider this morning, he’s comparably larger than the other house spiders around here. What is it, and is it posinous?

Forsyth County North Carolina agelenopsis sp grass spider

1 Response

Thank you for your question. It can be very difficult to identify a spider based solely on a photograph, because you usually can't make out distinguishing characteristics necessary to make a positive identification. Things like the number and placement of eyes, for example, can be critical in determining an identity.

That being said, I believe your spider is in the genus Agelenopsis. They are known as the grass spiders or funnel-web spiders. They build broad webs in the grass, crevices of buildings, in low shrubbery and along the bottoms of fences with a funnel shape at one end, where the spider hides. The web is not sticky like the webs of other species. One of the characteristics of this genus is the fact that you can usually see the spider's spinnerets protruding from the rear of its abdomen, as you can see in your photograph.

The grass spider detects vibrations through the web if an insect crawls across it and runs out, bites the prey and paralyzes it with its venom. Like most spiders, members of this group are venomous, but their venom does not pose a significant health risk to humans. Occasionally, someone could be especially sensitive or allergic to this venom, in much the same way as a small percentage of people are allergic to bee stings.

Here's a link where you can learn more about this family of spiders:

https://ento.psu.edu/extension/factsheets/grass-spiders

If you are interested in learning more about spiders in the your area, here's an excellent and inexpensive field guide:

Gaddy, L.L. (2009). Spiders of the Carolinas. Duluth: Kollath + Stensaas Publishing.

I hope this answers your question, and thank you for contacting Ask an Expert.

Jim