The brown recluse spider is not native to or commonly found in Pennsylvania. Its presence in the state is almost always due to accidental transportation from its native range. Pennsylvania’s climate is generally not suitable for their long-term survival, especially outdoors during winter.
Identifying the Brown Recluse
The brown recluse spider is typically light to dark brown, measuring about 0.25 to 0.75 inches in length, excluding its legs. A distinguishing feature is a dark, violin-shaped marking on its cephalothorax. The “neck” of this violin shape points towards the spider’s abdomen, though this marking can vary and may not always be clearly visible, especially in younger spiders.
A more reliable identification method involves its eye arrangement. Unlike most spiders, which have eight eyes, the brown recluse has only six eyes arranged in three pairs: one central pair and two lateral pairs. Their legs and abdomen are uniformly colored, lacking distinct patterns or banding. The body is covered in fine hairs rather than prominent spines.
Native Habitat and Range
The brown recluse spider’s native range primarily spans the central and southern Midwest United States, including states like Kansas, Missouri, Illinois, Indiana, Ohio, Kentucky, Tennessee, Arkansas, Oklahoma, Texas, Louisiana, Mississippi, Alabama, and parts of Georgia and Iowa. These spiders prefer secluded, dry, and undisturbed environments. Outdoors, they are often found under rocks, logs, and in woodpiles.
Indoors, they typically inhabit dark, quiet spaces like closets, basements, attics, and garages. They are particularly attracted to cardboard, as it mimics rotting tree bark. Any presence of brown recluse spiders outside this established native range, such as in Pennsylvania, is generally attributed to accidental transport through items like boxes or furniture, and these isolated occurrences do not indicate an established population.
Common Spiders Mistaken for Brown Recluse in Pennsylvania
Many brown spiders in Pennsylvania are often mistaken for the brown recluse due to similar coloration. Wolf spiders are common and confused with brown recluses due to their size and hairy, dark brown to gray bodies. However, wolf spiders are larger, lack the violin marking, and have eight eyes arranged differently. They are also active hunters, unlike the more reclusive brown recluse.
Funnel weaver spiders, also known as grass spiders, are another frequently misidentified group. These spiders build distinctive funnel-shaped webs and are mottled brownish or grayish with longitudinal stripes. While similar in color, they lack the violin marking and the specific eye arrangement of the brown recluse. Sac spiders, particularly yellow sac spiders, are small, pale yellow to greenish-yellow and often found indoors. Their bites can sometimes be misdiagnosed as brown recluse bites, but they do not have the violin marking, and their bites are generally less severe. Common house spiders and cellar spiders (daddy longlegs) can also be confused with brown recluses due to their brown coloring and tendency to inhabit similar indoor spaces, but they lack the distinct identifying features.
Responding to Suspected Spider Bites
If a spider bite is suspected, clean the wound thoroughly with mild soap and water. Apply a cool compress or ice pack to the affected area for 15 minutes each hour to reduce pain and swelling. Elevating the bitten limb can also minimize swelling. Over-the-counter pain relievers can be used for discomfort, and antihistamines may help with itching.
Most spider bites result in only minor, localized reactions and heal on their own within about a week. However, seek medical attention if the bite causes severe pain, significant swelling, an enlarging wound, or if symptoms such as fever, muscle cramps, or difficulty breathing develop. Seek medical care if there is uncertainty about the type of spider that caused the bite.