Common House Spiders in Washington State: Identification, Facts, Bite Info

Introduction to Common House Spiders in Washington State

Washington state is home to a fascinating diversity of spider species that can be found in and around homes across the state. While the vast majority of these spiders are harmless to humans, some can deliver a painful (but not medically significant) bite if provoked. Understanding the most common house spiders found in Washington can help homeowners identify species they may encounter and take appropriate cautionary measures if needed.

Common House Spider Traits

House spiders are generally small to medium-sized, with body lengths ranging from 3 to 20 mm. They build irregular webs in undisturbed areas and hunt prey that become trapped in their silky nets. While house spiders may startle homeowners, they do not post substantial danger and provide benefits by capturing household pests.

Common traits of house spiders in Washington include:

• Most species have eight eyes arranged in two rows
• Two fangs that inject venom to subdue prey
• Eight legs covered in fine hairs that detect vibrations in their web
• Abdomens appearing swollen or rounded after feeding
• Lifespans around 1-2 years on average

Bites from house spiders are uncommon, as they prefer to avoid confrontation. Their venom is designed to paralyze small insects, not large animals. However, people may experience mild pain, redness, and swelling if bitten.

Common House Spider Groups in Washington

While hundreds of spider species may reside in Washington homes, a few major groups account for many sightings by homeowners:

Cobweb Spiders

Cobweb spiders (family Theridiidae) are some of the most common house spiders. They build messy, tangled webs in dark corners or crevices. The black widow is perhaps the most notorious cobweb spider, but most others have minimal impacts on humans.

Jumping Spiders

Jumping spiders (family Salticidae) are named for their ability to leap substantial distances to ambush prey. They have a fuzzy appearance and prominent eyes. Jumping spiders don't spin webs to catch food and often appear wandering on walls.

Cellar Spiders

Cellar spiders (family Pholcidae) build loose, irregular webs in dark places like basements and crawl spaces. They have long, spindly legs and small bodies. Cellar spiders help control household pests but may startle residents by their webs near doors or windows.

Funnel Weavers

Funnel weaver spiders (family Agelenidae) make flat, funnel-shaped webs often seen near foundations, windows, or in gardens. Most species are large and hairy but not dangerous. Their prey includes nuisance flies, mosquitoes, and other insects.

Major House Spider Species in Washington

While many spider species inhabit Washington homes, a few stand out due to their commonality and potential interactions with humans.

Giant House Spider

The giant house spider (Eratigena atrica) has a legspan up to 7 cm across. They are brown with chevron markings on their large abdomens. Giant house spiders build sheet webs in dark places and may wander into the open at night in search of prey.

Hobo Spider

Hobo spiders (Eratigena agrestis) have long legs, broad abdomens, and a herringbone pattern on their backs. They make funnel-shaped webs in basements or sheds. Hobo spider bites may cause mild skin lesions in some cases.

Yellow Sac Spider

Yellow sac spiders (Cheiracanthium inclusum) are pale yellow and up to 10 mm long. They do not spin webs for catching prey, instead wandering at night to hunt. Their venom can produce mild skin irritation in humans.

Cellar Spider

The long-bodied cellar spider (Pholcus phalangioides) has very thin, fragile legs spanning around 25 mm. Their messy webs help snare flying insects in basements or crawlspaces. Cellar spiders are harmless to people.

Jumping Spider

Jumping spiders like the daring jumping spider (Phidippus audax) have fuzzy black and white bodies and can leap up to 10 times their 5 to 10 mm length. They are common in homes and help control flies, mosquitoes, and other small insects.

Fun Facts About Washington House Spiders

• Jumping spiders have excellent vision and can see color, unlike most other spiders.
• Female black widow spiders sometimes eat the male after mating.
• Spiderwebs are made of silk stronger than steel but extremely elastic and flexible.
• Some jumping spiders dance or wave their legs to attract mates.
• Cellar spiders vibrate rapidly to defend territories from intruders.
• Young spiderlings often disperse by releasing silken threads that let them "balloon" on wind currents.
• The hobo spider was accidentally introduced to the Pacific Northwest from Europe in the 1920s.
• House spiders may consume up to 10% of their body weight in food daily.
• Spiders molt, shedding their outer skin to grow. Young spiders may molt 5-10 times annually.
• Spider silk was used as cross hairs in optical equipment like telescopes before lasers.

Spider Bite Treatment and Prevention

Treating Spider Bites

While most house spider bites are harmless, take these steps if bitten:

• Wash the bite with soap and water to prevent infection.
• Apply an antiseptic cream to the wound.
• Use an ice pack to reduce swelling and pain.
• Take an oral antihistamine for itching.
• See a doctor if symptoms worsen or persist beyond a few days.

Avoiding Spider Bites

Reduce the odds of accidental spider bites with these prevention tips:

• Clear clutter to eliminate hiding spots for spiders.
• Seal cracks and crevices around windows and doors.
• Keep wood piles and debris away from home foundations.
• Shake out clothing, linens, or shoes stored in closets or basements.
• Install insect screens on windows and vents.
• Use insecticides or barriers to treat heavily infested areas.
• Inspect before reaching into dark, unseen spaces.
• Wear gloves and protective clothing when cleaning in infested areas.

Conclusion

House spiders in Washington play important roles in controlling insect pests and are fascinating creatures to observe in their natural web-building behaviors. While a few species may bite if threatened, they pose minimal risks to people and pets in homes. With proper identification and simple precautions, homeowners can co-exist with these helpful predators.

Disclaimer: This article is for informational purposes only and does not constitute medical advice. Always consult with a healthcare professional before starting any new treatment regimen.