Spiders often wander into homes seeking shelter, food, or a suitable environment. Understanding which species commonly inhabit homes and how to identify them can help manage their presence.
Key Features for Identification
Identifying a spider often begins with observing its physical characteristics. All spiders have eight legs. Their bodies are divided into two main parts: the cephalothorax and a soft abdomen. Most spiders also have multiple eyes, typically eight, though their arrangement varies significantly between species.
Beyond these general features, look for cues like overall body shape, color patterns, and leg length relative to body size. If a web is present, its structure—whether irregular, funnel-shaped, or a flat sheet—can also aid in identification.
Common Indoor Spiders
Many indoor spiders are harmless. The common house spider (Parasteatoda tepidariorum) is frequently encountered, typically mottled brownish with a rounded abdomen. These spiders construct irregular, messy webs often found in corners, basements, or garages.
Cellar spiders, often called “daddy long-legs,” have small bodies and extremely long, thin legs, building loose, tangled webs in damp, dark areas. Jumping spiders are smaller, robust, and hairy with large, forward-facing eyes. They are active hunters that use vision to stalk and pounce, not building webs to catch prey. Wolf spiders are large, hairy, fast-moving hunters, typically dark brown with paler markings. They actively pursue insects on the ground rather than spinning webs.
Spiders Requiring Caution
While most indoor spiders are not threatening, some species can deliver medically significant bites. The black widow spider (Latrodectus spp.) is shiny black with a red or orange hourglass shape on its abdomen. Their irregular, tangled webs are usually found in undisturbed, dark locations. A female black widow’s bite can cause muscle pain, nausea, sweating, and increased blood pressure, though fatalities are rare.
The brown recluse spider (Loxosceles reclusa) is light to medium brown, identifiable by a violin-shaped marking on its cephalothorax. Unlike most spiders, they have six eyes arranged in pairs. Brown recluse spiders prefer secluded, undisturbed areas like closets, attics, and basements. Their bite can cause pain, itching, and a blister that may develop into an open sore and tissue damage. If a brown recluse bite is suspected, medical attention is advisable.
Hobo spiders (Eratigena agrestis) are brownish with a mottled appearance, found indoors, particularly in the Pacific Northwest. While once thought to cause severe necrotic lesions, current research suggests their bites typically result in minor skin irritation, if any symptoms at all.
Handling Spider Encounters
When encountering a spider indoors, several calm approaches can be taken. For harmless species, a common method involves placing a cup over the spider and sliding a piece of paper underneath to trap it. The spider can then be safely released outdoors, away from the house. If the spider is in an undisturbed location and not posing a nuisance, such as a basement corner, it can often be left alone.
For persistent spider issues, or if a potentially harmful species is identified, professional pest control may be considered. Some individuals also use glue traps in areas of spider activity to help monitor and control populations.
Keeping Spiders Out
Preventing spiders from entering your home involves several straightforward measures. Sealing cracks and crevices around your home’s foundation, windows, and doors can block common entry points. Ensuring window and door screens are intact and properly fitted also helps deter them.
Reducing clutter both inside and outside the house eliminates hiding spots for spiders. Regularly cleaning and vacuuming can remove webs, spiders, and their food sources. Managing outdoor vegetation by trimming bushes and plants away from your home’s exterior can also reduce spider access. Some natural deterrents, such as essential oils like peppermint or a vinegar and water solution, can be sprayed in areas where spiders are frequently seen.