January 25th, 2009


More Urban Species: Striped Wolf Spider

Striped wolf spider Gladicosa sp. (probably)

Wolf Spiders are generally fairly large spiders that don't spin webs to trap their prey. They are familiar to many people in the southern United States as household animals, usually an unwelcome appearance. Of course, like all but about three types of spiders in North America, wolf spiders do not have a harmful bite. But this individual had a leg span of an inch and a half or so (3cm) and was the largest spider I'd seen in quite some time. I can understand why a wolf spider in one's home might inspire nervousness.

At first I was sure that this was an Agelena spider, strayed from his web. The pattern on the body is about right, and some Agelenas are fairly large. But when I examined the pattern of eyes in the second photo, and compared it in my spider book, it was not a match. Instead the relatively large forward facing eyes, in two rows of four, identify it as a Lycosid. The closest match using other field marks, notably the stripes and the orange-tan color, is the Genus Gladicosa, or striped wolf spider, a group relatively recently reclassified from the type Genus Lycosa.

Striped wolf spiders are nocturnal beasts that roam through leaf litter in oak forests looking for insect prey. Just outside the door where these photos were taken, is the great artificial oak forest of Franklin Park in Boston, covered with a thick blanket of snow. This spider probably found paltry hunting out there, and moved toward the building, with it's year-round warmth and year round source of delicious crickets, cockroaches, woodlice, and earwigs. When I found him (his large palps and skinny abdomen suggest he is a male) he had fallen on hard times. He was sluggish, and after some handling began to curl his legs toward his underside in the classic spider death pose. Hopefully his offspring are out there in the warmth of decomposing leaves, snug in an egg-case the female is carrying.