House Spiders Identification Guide

House Spider Identification Guide

Physical Characteristics

The common house spider (Parasteatoda tepidariorum) is a small to medium-sized spider with a distinctive rounded, bulbous abdomen. Females are larger than males, measuring 5-8mm in body length, while males are typically 3.8-4mm. Including legs, house spiders can appear 0.5 to 1 inch across.

Their coloration is highly variable, ranging from yellowish-brown to dark brown with mottled or spotted patterns on the abdomen. Many specimens display chevron-like markings or a whitish patch behind the highest point of the abdomen. The legs are typically banded with darker rings at the joints, a helpful identification feature.

House spiders have eight legs and eight eyes arranged in two rows. Their legs are relatively short compared to cellar spiders, and their overall appearance is more compact and rounded.

Web Characteristics

One of the easiest ways to identify house spider activity is by their distinctive webs. Unlike the symmetrical orb webs created by garden spiders, house spiders build irregular, three-dimensional cobwebs (also called tangle webs). These messy-looking structures are typically found in:

• Upper corners of rooms and windows
• Basement ceilings and floor joists
• Garage rafters and eaves
• Behind furniture and appliances
• Around light fixtures

The webs often contain small, papery, teardrop-shaped egg sacs and the dried remains of captured prey. House spiders may build multiple webs if the first location proves unsuccessful for capturing food.

Common Species in Homes

While Parasteatoda tepidariorum is the species most commonly called the “common house spider,” several other species frequently enter homes:

• American House Spider (Parasteatoda tepidariorum) - The most common indoor cobweb spider
• Domestic House Spider (Tegenaria domestica) - A funnel-web builder, often in basements
• Giant House Spider (Eratigena atrica) - Larger, found primarily in the Pacific Northwest
• Cellar Spider (Pholcus phalangioides) - Long-legged, often confused with daddy longlegs

House Spider Behavior and Biology

Habitat Preferences

House spiders are synanthropic, meaning they have adapted to live alongside humans in structures. They prefer sheltered, relatively undisturbed locations with adequate humidity. Common indoor habitats include:

• Basements and crawl spaces
• Attics and storage areas
• Closets and rarely used rooms
• Behind and under furniture
• Window frames and door corners

Outdoors, they may be found under eaves, in woodpiles, under rocks, and in sheds or outbuildings. However, many house spider populations live their entire lives indoors.

Diet and Feeding Habits

House spiders are opportunistic predators that feed on whatever insects become ensnared in their webs. Their typical diet includes:

• House flies and other flying insects
• Mosquitoes and gnats
• Ants and other crawling insects
• Moths and small beetles
• Other small arthropods

When prey becomes trapped in the web’s sticky threads, the spider rushes to subdue it with venom and wrap it in silk. House spiders are beneficial because they help control populations of pest insects.

Reproduction and Lifecycle

Female house spiders can produce multiple egg sacs during their lifetime, with each sac containing 100-400 eggs. The papery, spherical or teardrop-shaped egg sacs are typically attached to the web near the spider’s retreat. Females often remain near their egg sacs, providing a degree of maternal protection.

Spiderlings emerge from the eggs and may remain near the maternal web briefly before dispersing. Young spiders may use “ballooning” - releasing silk threads to be carried by wind currents - to travel to new locations. House spiders undergo several molts before reaching maturity, and the entire development process can take several months.

Seasonal Activity

House spider activity follows predictable seasonal patterns:

• Winter (December-February): Low activity; indoor populations remain but are less visible
• Spring (March-May): Increasing activity as temperatures rise and prey insects become more active
• Late Summer-Fall (July-October): Peak activity; males actively wander searching for mates, web production is highest
• Fall (October-November): Continued high activity, then gradual decline as temperatures drop

Indoor populations in heated structures may remain active year-round, though activity peaks remain in late summer and fall.

How We Treat for House Spiders

House spiders require a specialized approach because they don’t always enter homes through typical pest entry points and their behavior differs from crawling insects. Our comprehensive treatment strategy addresses both the spiders and the conditions that attract them.

Our Treatment Process

Step 1: Thorough Inspection

We begin by identifying areas of high spider activity both inside and outside your home. This includes examining corners, eaves, window frames, and other typical web locations. We also assess factors that may be attracting spiders, such as:

• Exterior lighting that draws prey insects
• Moisture problems that attract other pests
• Wood rot or structural issues providing harborage
• Entry points like gaps around windows and doors

Step 2: Targeted Exterior Treatment

We apply a non-repellent spray to exterior areas where spiders are active. Non-repellent products are essential for spider control because spiders will walk through treated areas without detecting them. Treatment focuses on:

• Window frames and doorways
• Eaves, soffits, and roof overhangs
• Foundation perimeter
• Areas where webs are commonly found

Step 3: Interior Spot Treatment

Interior treatment is limited to targeted applications in high-activity areas. Unlike broad surface sprays, which are ineffective for spiders, we focus on:

• Corners where webs accumulate
• Around entry points and utility penetrations
• Basements and crawl spaces (including preventative dusting in void areas)

Step 4: Web Removal (De-Webbing)

We remove accessible spider webs around the eaves and front porch (up to approximately 6-8 feet high). Regular web removal discourages spiders from rebuilding in the same locations.

Step 5: Ongoing Maintenance

Our seasonal protection plan includes quarterly follow-up visits to:

• Reapply exterior barrier treatments
• Perform additional de-webbing as needed
• Monitor spider activity levels
• Address any new concerns

Customer Guidance

For best results, we recommend these complementary measures:

• Reduce exterior lighting or use yellow “bug lights” that attract fewer insects
• Close blinds at night to prevent interior lights from attracting insects to windows
• Address moisture issues in basements, bathrooms, and crawl spaces
• Repair wood rot and seal entry points
• Vacuum visible webs and spiders inside the home as they appear
• Reduce clutter to eliminate hiding spots

Why Regular Service Matters

Spider control is not a one-time solution. Regular treatments are crucial because:

1. Spider populations continually rebuild as new individuals mature and migrate
2. Egg sacs may hatch weeks after initial treatment
3. Prey insect populations must be controlled to reduce spider attraction
4. Weather and seasonal changes affect spider pressure

Our quarterly service plan maintains the protective barrier around your home and addresses other common household pests that serve as spider food sources. This comprehensive approach provides lasting control rather than temporary reduction.

Safe, Effective Products

We have removed 9 of the harshest chemicals commonly used in the industry. Instead, we use reduced-risk products like Essentria, Alpine, and Borate-based solutions that effectively control spiders while considering environmental impact and the safety of your family and pets.