March 28th, 2006
spiders on the move
On Sunday, while hiking at Charleston Lake Provincial Park, I stopped to photograph mosses and lichens growing on an expanse of stone. As I knelt to shoot some macros, I found myself surrounded by marching spiders. At first, they weren’t particularly visible, but then one would race forward a few centimeters, then another would do so, then another. Occasionally, a few would move forward together. Their activity reminded me a bit of forward scouts in an advancing army. All seemed to be heading north to south across several meters of exposed stone.
I turned my camera to the spiders and tried to capture a few. Most were species of Wolf Spiders (Lycosidae) — medium brown in colour, with dark brown bands on either side of the carapace, and vague patterning on the abdomen — much like the spider on the left of the above image. While trying to photograph that Wolf Spider, it moved forward a half a meter or so, then came to an abrupt halt. I crept forward and lowered my camera lens, only to find that I now had two spiders on my LCD screen — the Wolf Spider, and next to it, a lovely dun-coloured Thanatus formicinus, also sometimes called a Diamond Spider, for the conspicuous marking on its abdomen. Although it looks rather like a Wolf Spider, it belongs to the Family (Philodromidae) – the Running Crab spiders.
The two spiders remained motionless for several seconds, their legs in close contact. Then, the Wolf Spider raced onwards, leaving the Running Crab Spider resting quietly on a patch of lichen. I shot a few more photos of it from different angles. Its colour blended so well with the surrounding micro-terrain of gray lichen and dried conifer needles, that I doubt I would have noticed it if not for the assistance of the Wolf Spider.
Tags: Wolf Spider, Lycosidae, Diamond Spider, Running Crab Spider, Thanatus formicinus, Philodromidae
March 28th, 2006 at 8:00 pm
Bev, any idea what these siders were doing? It seems remarkable for them to be so abundant and so close together, particularly when there was more than one species.
March 28th, 2006 at 10:12 pm
Pete – I’d say this was just fairly normal behaviour that one would see on a warm afternoon when snow is melting away in early spring. Last Sunday, the snow was all but gone in the forests where we were hiking, and those kinds of conditions seem to bring out the ground hunting spiders such as the Wolf Spiders (Lycosidae) and the Ground Spiders (Gnaphosidae) – and also, by the looks of things, some Running Crab Spiders such at the Thanatus in the photo. Many species overwinter as adults, so it doesn’t take too much to get them all running about on a warm spring day. They weren’t all that close together as in the photo either. They were more spread out, but would occasionally run towards each other — perhaps thinking the other might be potential prey. This afternoon, I was out for a walk in one of the fields here at the farm and there were large numbers of Gnaphosidae and probably some other species of spiders, running about in the long, tangled pasture grasses. Again, possibly hunting, but maybe just sort of “waking up” and moving about as it was such a warm, sunny afternoon (about 10C) and the snow has really been melting down this last couple of days.