Are There Brown Recluse Spiders in California?

Pest experts at the University of California at Davis and UC-Riverside have reassuring news for California residents, and gardeners in particular: Brown recluse spiders (Loxosceles reclusa) are rare to nonexistent in California. The state has its share of venomous spiders, and some belong to genus Loxosceles, but Californians don't have to worry about the necrotic venom of the brown recluse as much as do people in south-central states, such as Arkansas, Oklahoma and Missouri, where the spider is common.

Two other species of recluse spiders are more common in California. The first is the desert recluse (Loxosceles deserta), which inhabits the arid southeastern part of the state. The second is a non-native species Loxosceles laeta, or the Chilean recluse, which has inhabited a limited part of Los Angeles County since the mid-20th century. In addition, another recluse species -- the Mediterranean recluse (Loxosceles rufescens) -- is sometimes found in commercial goods shipped from overseas. These species aren't necessarily brown, and in the case of the Chilean recluse, its venom may be even more toxic than that of the brown recluse.

Brown recluse spiders are sometimes called fiddleback spiders because of the fiddlelike marking just behind the eyes, but not all recluse spiders -- in particular the desert recluse -- have it. It's the eyes themselves that distinguish the Loxosceles species; whereas most spiders have eight, recluse spiders have only six eyes, arranged in three pairs. Two other California species -- spitting spiders (Scytodes spp.) and woodlouse spiders, (Dysdera crocata) -- have six eyes, but their body markings differentiate them from recluses. Chances are you will never get close enough to count the eyes, but if you should get bitten and manage to catch the perpetrator, this information can help your doctor treat the bite appropriately.

Recluse spider venom has a component that causes skin necrosis, but instances of this condition are often mistakenly ascribed to recluse spiders, and in some cases the actual cause is more dangerous. For example, Staphylococcus aureus (MSRA) infections, which can cause death in a few days, are often misdiagnosed as recluse bites. Among the other causes of necrotic wounds Californians should consider before a recluse bite are:

A _Staphylococcus aureu_s bacterial infection

mites, fleas, ticks or other insect parasites

diabetic ulcer

infected herpes

shingles

Lyme disease

If you have a naturalistic landscape and live in a California desert area, your surroundings may attract some desert recluse spiders. Recluse bites are usually painless when inflicted and usually result in little more than redness, soreness and eventually hardness around the bitten area. More serious symptoms develop in only 10 percent of bite cases, and in the other 90 percent, a simple first aid RICE strategy is all that's needed:

Rest

Ice

Compression

Elevation

Antibiotics are ineffective against spider venom. If necrosis develops, the area around the bite will turn purplish within four days of the bite. If that doesn't happen, the wound should heal completely in about eight weeks.