Many in Arizona are concerned about brown recluse spiders, known for their distinctive appearance and medically significant bites. Understanding their distribution and characteristics can clarify misconceptions and provide accurate information.
Brown Recluse Geographic Range
The brown recluse spider (Loxosceles reclusa) is not native to Arizona and is rarely found there. Its natural range primarily encompasses the Midwest and South Central United States, including Nebraska, Iowa, Illinois, Indiana, Ohio, Kentucky, Tennessee, Missouri, Kansas, Oklahoma, Arkansas, Louisiana, Mississippi, Alabama, and parts of Texas and Georgia. Reports of brown recluse sightings in Arizona are almost always misidentifications. While individual brown recluses may be transported to Arizona, they do not establish breeding populations. Arizona’s warm, arid conditions are not conducive to their long-term survival and reproduction.
Recluse Spiders Native to Arizona
While the brown recluse is not typically found in Arizona, the state is home to native recluse species. The most common are the Arizona recluse (Loxosceles arizonica) and the desert recluse (Loxosceles deserta). These native species share physical similarities with the brown recluse, often leading to misidentification.
The Arizona recluse is abundant in southern Arizona, inhabiting outdoor environments such as under rocks and dead cacti. The desert recluse is prevalent across western Arizona, extending into southern California, Nevada, Utah, and New Mexico. This species prefers wild, arid areas, including packrat dens and natural vegetation, avoiding dense urban settings. Both species possess venom capable of causing necrotic lesions.
Distinguishing Features of Recluse Spiders
Identifying a recluse spider requires careful observation, as many other spiders can be mistaken for them. One often-cited characteristic is the “violin” or “fiddle” shaped marking on the spider’s cephalothorax. The base of this marking is broadest near the spider’s head, with the “neck” pointing towards the abdomen.
A more reliable identification feature for any recluse spider is their unique eye arrangement. Unlike most spiders that possess eight eyes, recluse spiders have only six eyes, arranged in three pairs. These three pairs of eyes are typically configured in a semicircle or U-shape across the front of the cephalothorax.
Additionally, recluse spiders have uniformly colored bodies and legs, without any distinct banding or complex patterns on their abdomen or legs. Their legs are covered in fine hairs rather than prominent spines.