If you spend time outside, especially in the morning, you've probably seen spider webs in your grass or shrubs. These unique webs are built by grass spiders, also identified as funnel web spiders, which closely resemble wolf spiders. Wolf spiders, however, don't build webs. Grass spiders greatly depend on their webs for food and protection.
Webs in grass and bushes are made by tiny brown or grey grass spiders. Females typically measure 10 to 20mm, while males measure 9 to 18mm long. These spiders have light and dark stripes near the head. Their spinerettes, or web silk organs, are slightly less than an inch long.
Grass spiders will also build their webs in other low places such as around steps, home foundations and in forest debris such as leaves and sticks. Their webs are easy to find when dew settles on them in the morning. Their webs are designed with a funnel shape, and a narrow tunnel is built through the web that the spider hides in. When the spider feels vibrations, it runs to the entrance to see if bugs fell into its web. Since the webs aren't sticky, the spiders rely on their speed to catch unassuming prey.
Unlike other spiders, grass spiders are not harmful to humans, although they will bite when they are threatened. Following a bite from a grass spider, you may experience redness, itching and swelling. Grass spiders build their webs for shelter and to catch food, rarely creeping into your home.
There are several ways to control the number of grass spiders on your property. Remove all yard debris to deter them from building webs and keep up with yard maintenance. Regularly mow your lawn to keep the grass short. Trim shrubs and take down any nests you find. Refrain from using outdoor lighting to prevent bugs from flying near your home, which attracts preying spiders.
- The University of Minnesota; Common Spiders in and Around Homes; Jeffrey Hahn, et al.; 1997
- Penn State College of Agricultural Sciences; Grass Spiders; Steve Jacobs; 2006
- University of Kentucky Department of Entomology; Funnel Weavers and Grass Spiders; Blake Newton; June 2007
- Spiderz Rule: Funnel Weaver/Grass Spiders