Friday Spider Blogging: Brown Recluse, Loxosceles reclusa

This is a Brown Recluse, Loxosceles reclusa (click the pic to enlarge). I took this picture after catching it on the glue trap underneath my bed last week. Geographically, I live in the center of the brown recluse's home range and have a house full of them. It doesn't take long to get one of these traps covered with these if placed in the right spot. A couple of weeks ago I was asleep in bed when I turned over and felt a funny tickle somewhere across my back and arm. It wasn't quite the same as the usual bed sheet corner rubbing across my skin that sometimes spooks me and gets me out of bed, so I jumped up and turned on my light. I raised the covers and looked around but didn't see anything, so I lifted up the pillow and hiding underneath was a brown recluse about the same size as the one pictured. With a quick slap of my hand it was all over. After that I put these traps behind furniture along nearly every baseboard in my house. Luckily I have never been bitten by one, because the bites can be pretty bad. I am not overly concerned about being bitten though because actual brown recluse bites are not nearly as common as most people think. As a family physician, I see at least one "spider bite" per day and usually more. In almost all cases, the patient has not seen an actual spider or any other biting animal. They just assume it had to be a spider bite. It almost always ends up being just a plain old "boil" or abscess. These tend to arise as a result of local invasion to the subcutaneous tissues, by Staphylococcus aureus following a break in the skin or through a hair follicle. The Dermatology Online Journal has a good article on Identifying and Misidentifying the Brown Recluse Spider. The key to correct identification is that the spider has both the violin pattern on its cephalothorax and rather than having eight eyes, the recluse spiders have 6 eyes arranged in pairs with one anterior pair and 2 lateral pairs.

Don't forget to check out Modulator's Friday Ark.