You turn on the light and a medium-sized, brown-colored spider runs back under your sink cabinet. It moved just fast enough that you did not get a good look at it. Was it a dangerous spider, like a Brown Recluse, or was it just an ordinary spider? What should you do?
The truth is, brown spiders of the genus Loxosceles (also called “fiddle-backed” spiders) are fairly wide spread in the U.S. Seven species of these sometimes bite humans, but the bites of only two of them have been reported to cause human deaths. Because of that, the Brown Recluse Spider, Loxosceles reclusa Gertsch & Mulaik, the more common, gets blamed for nearly any spider bite which causes any symptom beyond immediate local pain or fang marks.
Just because you saw a brown-colored spider, near the time and place when a human suffered a surface wound, that certainly does not automatically mean it was a Brown Recluse bite. Even a Doctor cannot, from only seeing a wound, tell that it was caused by any particular kind of spider (or even that it was caused by a spider). Precise additional tests would have to be done to help find that out.
Real Brown Recluse bites occur most often when a human rolls over on, or puts their hand down near (or on the leg of), a spider and the spider bites defensively. All spiders-male and female-are venomous. That’s how they subdue their prey. They have voluntary control of whether any, and how much, venom is injected in any bite. Symptoms then depend on the nature and amount of venom injected, and on the host’s individual reaction to that specific venom.
Brown Recluse Spiders are wandering hunters, which sometimes ‘trail’ a strand on webbing. They do not use webbing to capture prey, as do Black Widows, House Spiders, and half of the other 3,000 species of spiders in the U.S. Females of the species do spin a small amount of irregular, loose webbing in a remote corner as a “retreat,” and also spin a loose egg sac, in which they lay 30 to 300 eggs. These take nearly a year to develop from egg to adult. These spiders typically live outside around rocks, old tires, utility boxes, wood piles, or under loose bark of logs or trees. Inside, they prefer undisturbed areas in or under boxes, shelving, furniture (especially large upholstered items which provide ample covered areas), closets, crevices under or beside doors or window frames, under loose cedar “shake” shingles (or siding), or in wall voids, undisturbed crawl spaces, or attics. They usually run into any available hiding place when disturbed.
As always, it is very important to get an accurate identification of exactly what spider is involved before starting any control effort. Sticky traps can be a great surveillance and control tool for Brown Recluse Spiders.
Spider control often requires the advice and assistance of a trained and state-certified pest management professional. This is especially true for Brown Recluse Spiders. Their populations can build up very large numbers throughout a structure before they are first noticed. Large, wide-spread populations of Brown Recluse Spiders may require several months to be brought under control by even an experience pest manager. If you know, or suspect, you may have a spider problem, contact us. Our trained professionals can help identify the pests, determine the extent or infestation, and recommend a prompt, effective control program. We use an Integrated Pest Management (IPM) strategy, emphasizing non-chemical methods, and only when necessary progressing to use specifically targeted placement of the minimum effective amount of the least toxic materials which will do the job.