Something about the name burrowing wolf spider just doesn’t sound right, right? We know wolf spiders as creatures that actively pursue their prey – like their namesake – reflected in the name of the family – Lycosidae (wolf). They wander about our world without a home. But what is a wolf spider doing living underground?
Although we do not know exactly what drove them to adopt this way of life, members of the aptly named genus Geolycosa do just that – stay put in a burrow that they dig into the earth. They feed largely at night, perched at the entrance of their burrows, waiting for passing prey to come within reach. This way of life has led to a slight adjustment to parts of their bodies, but apart from that, they are still wolf spiders.
I first encountered these interesting spiders while in college in north Mississippi, coming across a group of their holes on open ground in a forest. Being a student of spiders at the time, I and a friend had heard of them and hoped to see one by enticing the critter out of its burrow, using a piece of pine straw. Sure enough, the occupant rushed out, launching both of us backward on the ground. Round one to the spider!
Unlike the nomad existence of most of their relatives, burrowing spiders dig vertical holes in the ground that they line with silk, to keep the soil in place. Burrows can be several inches deep with a horizontal chamber at the bottom. Many species further use silk and bits of straw or grass to create a turret around the opening. This likely also helps keep debris from entering the hole.
Short of having to abandon a hole because of disturbance, these spiders spend their entire lives in their burrows, enlarging them as they grow. Their two front pairs of legs are larger than the rear pair, aiding in the process of digging. Mature males do abandon their burrows to seek out and mate with females, within the opening of her burrow.
Apart from living a sessile life, these wolf spiders follow the same life practices of their close relatives, spinning a circular egg sac that is attached to the female’s spinnerets and hosting the newly hatched spiderlings on her back for a bit. The females are good mothers. There are at least 18 recognized species of Geolycosa across North America, with additional species likely.
Although unique to wolf spiders as a group, living in the ground is not unique to Geolycosa. A few other species of large wolf spiders are reported to occasionally dig a shallow burrow. Trap door spiders belong to an older group of spiders and are much better known as building elaborate silk-lined burrows, with doors that close and shut, making them much harder to find.
For burrowing wolf spiders, their distinctive turrets make them more obvious, and yet a challenge to find. The openings and turrets are best viewed from directly above and not from the sides. I find them in suspected open ground by looking straight down near my feet as I walk along. The turrets distinguish them from other holes dug by wasps and other ground-dwelling insects.
So, there you have it. Another critter to look out for as you wander about in nature, looking down at your feet as you go.
Hope to see you in our great outdoors!