House spiders are a common sight indoors, representing various spider species that have adapted to living alongside humans. Identifying these arachnids often involves observing their physical characteristics and behaviors. Understanding their general appearance and the specific traits of common types can help differentiate them.
General Appearance of House Spiders
Spiders, including those found in homes, possess a body divided into two main segments: the cephalothorax (a fused head and thorax) and a soft, unsegmented abdomen. They have eight legs, all attached to the cephalothorax, and range in size from small to medium, though leg span can make some appear larger. Most house spiders exhibit muted color palettes, appearing in shades of brown, gray, or black, sometimes with subtle patterns or markings.
Their bodies can vary in texture, from hairy to relatively smooth, and their overall shape can differ depending on the species, with some having more bulbous abdomens while others are more elongated. Spinnerets at the end of the abdomen are a universal trait, though their visibility can vary.
Common Types of House Spiders
Several spider species are referred to as house spiders. The American House Spider (Parasteatoda tepidariorum) is widespread in North America. These small spiders are dull brown, gray, or tan, often with white markings and a round, bulbous abdomen. They are known for spinning messy, tangled webs, often found in corners, attics, and basements.
Cellar Spiders (Pholcus phalangioides) are common inhabitants, often called “daddy longlegs” due to their long, thin legs and small, pale body. Their color ranges from gray to light brown or yellowish, and they create loose, irregular webs in damp, dark areas like basements and crawl spaces. When disturbed, they may vibrate rapidly in their webs, appearing as a blur.
Funnel Weaver Spiders, such as the Giant House Spider (Eratigena atrica) or barn funnel weaver (Tegenaria domestica), are common. These spiders are brownish or grayish with mottled patterns or longitudinal stripes and can have a leg span up to 2 inches. They construct distinctive sheet-like webs that narrow into a funnel-shaped retreat, often found in corners, basements, or woodpiles.
Key Identification Clues
Observing certain visual cues can aid in distinguishing different house spiders. Body proportions are telling; for example, cellar spiders are characterized by their long legs compared to their small bodies, while American house spiders have more proportionate legs and a round abdomen. The presence and appearance of hairs on the body and legs is also a clue, with some species like funnel weavers being noticeably hairy.
Web structure provides clues for identification. While eye arrangement is an identification tool, it requires close examination and specialized knowledge, as spiders have varying numbers and patterns of eyes, usually eight, though some have six.