Brown Recluse Spider

Brown Recluse (Loxosceles reclusa)

The brown recluse is prominent in the south and lower Midwest. Its bite, though toxic to humans, seldom causes the serious flesh-rotting symptoms we often hear about. Could it have hitched a ride inside a moving box to the PNW? This could be possible. 

Habitat

Brown recluse spiders often live outdoors where they are typically found around rocks, utility boxes and woodpiles. Indoors, brown recluses can be found in any undisturbed area, such as inside boxes, among papers, in seldom-used apparel and shoes, under furniture or in crevices of window moldings. Closets, attics, crawl spaces and basements are the most common brown recluse spider hiding spots. These spiders spin irregular webs, which are not used for catching prey but rather as a retreat.

Food

 Brown recluse spiders are nocturnal and eat other small bugs like cockroaches and crickets. 

Biology

Brown recluse spiders start to emerge from their winter harborages around April–May and then go into seclusion again around October. In comparison to many other spiders of similar size, Loxosceles spiders live around 3-5 years. Brown recluse spiders can survive longer without food than other house spiders. Resistance to starvation is one aspect that can lead to the ability of a recluse spider to be transported outside of its indigenous range and live. However, it also means that in controlling the prey population inside a home, resistance to starvation can contribute to and complicate management issues. Brown recluse spiders are not very fecund. They produce an average of 50 eggs per egg sac and produce an average of 2.7 egg sacs in a lifetime. They have a characteristic dark brown violin marking on their back and only have 6 eyes.

Threat

Like the black widow spider, the brown recluse spider bites in defense and does not bite humans instinctively. However, both female and male brown recluse spiders can bite and inject venom. The brown recluse’s bite is usually not felt, but results in a stinging sensation followed by intense pain as long as six to eight hours later. A small blister usually develops at the bite location that can turn into an open ulcer. Restlessness, fever and difficulty sleeping are common symptoms of a brown recluse spider bite. Bite victims may also develop systemic reactions that can be life-threatening if medical attention is delayed or unavailable.

Prevention

To avoid these spiders, do not store clothing on the floor. Store clothing and shoes inside plastic containers.