The brown recluse spider (Loxosceles reclusa) is frequently misidentified due to its reputation and similarities with other common spiders. Accurately distinguishing this species from its many look-alikes is important for understanding potential risks and reducing unnecessary alarm. This article details the specific characteristics of the brown recluse to aid in correct identification.
Distinctive Features of the Brown Recluse
The brown recluse spider has several unique physical characteristics. A prominent feature is the violin-shaped marking on its cephalothorax, the fused head and thorax. The “neck” of this violin shape points backward towards the abdomen. Its intensity and exact shape can vary, sometimes being faint or less distinct, especially in younger spiders.
A more reliable identifier is the brown recluse’s eye arrangement. Unlike most spiders with eight eyes, the brown recluse has only six eyes, arranged in three pairs in a semicircle. Its body is uniformly colored, from pale to medium brown, without stripes or patterns on its legs or abdomen. The legs are covered with fine hairs but lack conspicuous spines. Adult females have a body length between 10 to 15 millimeters, with a leg span that can exceed 25 millimeters.
Spiders Commonly Mistaken for Brown Recluses
Many other spiders are frequently misidentified as brown recluses due to their brown coloration or general shape. Wolf spiders are often confused with brown recluses due to their similar brown coloration. However, wolf spiders are larger and hairier, with eight eyes arranged in three rows, including two large eyes prominently positioned in the middle. Their legs often have noticeable stripes or banding.
Funnel weavers, including hobo spiders, are another group often mistaken for brown recluses. These spiders have eight eyes arranged in two straight rows. While hobo spiders are brown, they lack the distinct violin marking and may have faint chevron patterns on their abdomens. Their legs do not have conspicuous spines but are covered in fine hairs.
Cellar spiders, sometimes called “daddy long-legs,” can also be misidentified. Some cellar spiders have six eyes arranged in two groups, but their body shapes are much more slender with extremely long, thin legs. Sac spiders are pale yellow to tan and are confused with brown recluses due to similar body shape and size. However, sac spiders lack the violin marking and have eight eyes arranged in two rows. Their bites, while sometimes painful, are less severe than those of a brown recluse.
Geographic Range and Typical Habitats
The brown recluse spider is native to a specific geographic region within the United States, predominantly across the south-central and Midwestern states. Its native range includes:
- Kansas
- Oklahoma
- Texas
- Louisiana
- Arkansas
- Missouri
- Mississippi
- Alabama
- Parts of Georgia, Tennessee, Kentucky, Ohio, Indiana, Illinois, Iowa, and Nebraska
Encounters outside this established region are rare and usually attributed to accidental transport.
These spiders prefer secluded, undisturbed environments both indoors and outdoors. In natural settings, they inhabit areas under rocks, logs, woodpiles, and leaf litter. Indoors, brown recluses seek refuge in dark, quiet spaces like attics, basements, closets, and crawl spaces. They are often found in boxes, clothing, shoes, and behind furniture, with a particular affinity for cardboard.
Understanding Brown Recluse Bites
Understanding the potential impact of a brown recluse bite is important. A bite may not be immediately painful, with symptoms developing several hours later. Initial signs include redness, itching, and pain at the bite site.
The bite can progress to form a blister, which may develop into an open sore or ulcer. This necrotic lesion appears as a flat or slightly sunken bluish patch with irregular edges, a pale center, and surrounding redness, sometimes resembling a “bull’s-eye” pattern. Such ulcers can take several months to heal and may leave a scar. Systemic reactions like fever, chills, nausea, or dizziness are uncommon but can occur.
Seek medical attention if a brown recluse bite is suspected or if the wound shows signs of infection, such as increasing redness, swelling, or pus. Medical consultation is also advised if severe pain develops, or if symptoms like fever, chills, or difficulty breathing or swallowing are experienced.