The Hidden World of Funnel Weavers

October 12, 2021

Walking through the Little Lake Valley grasslands every fall and winter, I notice many interesting funnel-like spider webs strung between the taller grasses and stalks of dead plants. Upon closer observation I notice they are a complex system of many silk threads coming together in a funnel with a hole at the bottom. When I touch the web material, I am surprised it is not sticky at all. Funnel-weavers or Grass spiders use their speed and agility to catch their prey, not a sticky web. Once they capture and sting whatever has fallen in, they drag their prey into the funnel of the web, as it is a smooth ride down.

There are about 300 different species of Grass spiders in North America. During spring and summer, Grass spiders are common around the home and in the landscape. Grass spiders are harmless to humans because their chelicerae (mouth parts) are too small to penetrate human skin. Grass spiders are also known as “Funnel-weavers” due to the type of web they weave for catching prey. Funnel-weaver spiders belong to the family Agelenidae. These spiders may not hurt humans, but they sure do create a lot of webs in the grass and on shrubs.

The female funnel-weavers build these beautiful webs and are larger than the males. Their long legs are distinctive and have feather-like setae on the body. Funnel-weaver spiders are similar to wolf spiders in appearance except for the black lines that run either side of a tan midline on their head. These black lines are not as bold and black as on a Wolf spider. Also, the abdomen on the Agelenidae has a series of light-colored chevrons on it which the Wolf spiders do not have. Probably the most important difference between the Grass spiders and the Wolf spiders is that the latter can bite you and has venom which the first one does not!

If you are interested in learning more about spiders, I recommend looking at the Field Guide to Spiders of California and the Pacific Coast States, text by R.J. Adams with illustrations (which are fantastic) by Tim D. Manolis. This is part of the California Natural History Guides.

Now, as I walk, my eyes are more attuned to finding the funnel webs and I begin seeing even more variety of spiders scurrying around the grass. With so many species of spiders living around us I wonder about the complex relationships that exist between them.