The brown recluse spider, Loxosceles reclusa, evokes concern due to its reputation. Many individuals in Iowa wonder about the presence of this spider within the state. Understanding the distribution and characteristics of the brown recluse is important for accurately assessing any potential encounters. This information helps to clarify common misconceptions and provides practical guidance.
Presence in Iowa
The brown recluse spider’s established range primarily covers the warmer Midwest and Southern United States, including states like Missouri and Indiana. Iowa is at the northern edge of this spider’s natural distribution. While sightings in Iowa do occur, particularly in the central and southern regions, they are rare and often due to accidental transport rather than established, widespread populations.
Specimens found in Iowa are typically “hitchhikers” that have traveled from their native range further south. In Iowa, brown recluse spiders are predominantly found indoors, as they struggle to survive outdoors in the state’s natural environment. The occasional confirmation of a brown recluse does not indicate they are common or widely distributed throughout the state.
Identifying Features
Brown recluse spiders are typically light to dark brown, with a uniformly colored body and legs, meaning they lack stripes, bands, or mottled patterns. Adult brown recluses are relatively small, usually ranging from 6 to 20 millimeters (about 1/4 to 3/4 inch) in body length.
A notable feature is the violin-shaped marking on their cephalothorax, which is the fused head and thorax region. The “neck” of this violin shape points towards the abdomen. A more definitive identification feature is their unique eye arrangement: brown recluses possess six eyes arranged in three pairs, with one pair in the front and two lateral pairs. Most other spiders have eight eyes.
Common Misidentifications
Many spiders commonly found in Iowa are frequently mistaken for the brown recluse. Wolf spiders, for instance, are often larger and hairier than brown recluses, and while they can be brown or gray, they typically have distinct dark stripes or patterns on their bodies, which brown recluses lack. Wolf spiders also have eight eyes arranged in three rows, differing from the brown recluse’s six-eye pattern.
Funnel web spiders, also known as grass spiders, are another common look-alike. They are typically brown or gray with patterns on their abdomen and construct a distinctive funnel-shaped web, unlike the irregular, messy webs of brown recluses. Common house spiders, while also brown, often have a more muddled pattern on their abdomen and create irregular webs, but their eye arrangement and lack of a distinct violin marking differentiate them. Cellar spiders, often called “daddy longlegs,” have very long, slender legs and small bodies, making them visually distinct.
If You Encounter One
If a spider suspected to be a brown recluse is encountered, it is advisable not to handle it directly. These spiders are reclusive and typically bite only when they feel threatened or are accidentally pressed against skin, such as when putting on clothing or shoes. For identification purposes, it can be helpful to safely capture the spider in a sealed container, without direct contact, to allow a pest control expert or entomologist to confirm its identity.
In the event of a suspected brown recluse bite, cleaning the affected area immediately with soap and water is recommended. Applying a cold compress or ice to the bite area can help reduce swelling and discomfort. Elevating the bitten limb, if applicable, can also assist in managing swelling. Medical attention should be sought, especially if symptoms worsen, if significant pain, or if signs of infection like oozing fluid, fever, chills, or nausea develop. If the spider was captured, bringing it along for identification can aid medical professionals in diagnosis and treatment.