Common House Spiders in Illinois: Bites, Venomous Species, and Pest Control

Spiders Found Inside Illinois Homes

Many different species of spiders can be found inside Illinois households. While the majority of these spiders pose no threat to humans, some bites may cause mild reactions and two species found in the state do possess medically significant venom.

Spider Diversity in Illinois

Over 500 species of spiders have been identified in Illinois. This high diversity is made possible by the variety of habitats and microclimates found across the state, from dense forests to tallgrass prairies to urban environments.

While the majority of Illinois spiders live their lives solely outdoors, many species will opportunistically forage or seek shelter inside homes. Usually spider presence indoors is no cause for concern and simply indicates that the home contains insects or other prey that attract the spider.

Common House Spiders in Illinois

Some of the most common spiders spotted inside Illinois homes include:

Cellar Spiders

Cellar spiders (also called daddy long legs spiders) get their name from their tendency to inhabit dark corners of basements and cellars. But they may wander indoors when seeking food or mates.

Jumping Spiders

Jumping spiders are daytime hunters and primarily live outdoors, but sometimes venture inside. These spiders are generally small, fuzzy, and move in a start-stop motion.

Cobweb Spiders

Cobweb spider species like the barn funnel weaver spin lacy webs in undisturbed corners of rooms. The webs catch flying insects which the spiders then feed upon.

Fishing Spiders

Occasionally fishing spiders end up in homes when they accidentally wander inside. These large, hairy spiders thrive near water sources outdoors.

Wolf Spiders

Wolf spiders hunt by day or night on the ground for insects and other small prey. They frequently end up inside unintentionally while pursuing food.

Spider Bites in Illinois

The vast majority of spiders found in Illinois homes do not pose a health risk to residents. Most species lack fangs and venom strong enough to penetrate human skin.

However, spider bites do occasionally happen, usually when people unintentionally contact or trap the spider against bare skin while cleaning, reaching into dark spaces, rolling over onto one in bed, etc.

Signs of a Spider Bite

Identifying a spider bite can be difficult, as reactions can vary widely. Indications you may have been bitten include:

• Mild pain, swelling or redness at the bite site
• An itchy raised welt
• Two small puncture wounds
• A deeper wound with burning pain if bitten by a spider with stronger venom
• Systemic symptoms like fever, rash or headache from a venomous bite

You should seek medical care if bite symptoms seem severe or progress beyond the bite location.

Treating Mild Spider Bites

For mild bites, recommended first aid tips include:

• Clean the wound thoroughly with soap and water
• Apply an ice pack wrapped in cloth to reduce swelling and pain
• Keep the wound site elevated if possible
• Use over-the-counter pain medication as needed
• Avoid scratching or rubbing the bite to prevent infection

Symptoms should begin improving within a few days. Seek medical treatment if they worsen or persist.

Venomous Spiders in Illinois

While most spider bites cause minor effects, two native Illinois spider species can inflict severe bites:

Brown Recluse Spiders

Brown recluse spiders are brown with a dark violin-shaped marking on their bodies. They inhabit sheds, garages, woodpiles, and other dark undisturbed areas. Their venom destroys skin tissues, leaving slow-healing necrotic wounds.

Northern Black Widow Spiders

Black widow spiders have glossy black bodies with a distinctive red hourglass on the underside. They spin messy webs in protected outdoor places but sometimes end up inside. Their venom affects nerve function, causing muscle cramps and pain.

Anyone bitten by one of these species should receive prompt medical care to manage potentially serious symptoms.

Spider Bite Prevention

While most indoor spiders won't bite, minimizing potential encounters can provide peace of mind. Tips include:

• Install screens on windows and doors
• Store woodpiles far from the home
• Seal cracks around the foundation
• Clean up clutter like stacks of materials spiders could hide in
• Keep beds pulled away from walls and tuck bedding in
• Vacuum regularly to remove spiders and webs

Implementing these spider deterrent measures can help avoid surprise spider bites and make homes less hospitable environments for the few venomous species.

When to Call an Exterminator

While occasional spiders should be tolerated, if an Illinois home seems to have an excessive infestation with persistent webs or spider sightings, contacting a pest control expert may be prudent. They can assess the situation, identify problem areas, and implement targeted chemical or physical controls if necessary.

Professional Spider Treatments

To clear out spiders, exterminators may:

• Apply residual insecticide sprays
• Dust spider hiding spots with silica gel or diatomaceous earth
• Seal cracks and holes providing spider entry points
• Remove food sources spiders are attracted to
• Install yellow sodium vapor lights that deter spiders

Following an exterminator’s advice can help homeowners permanently evict persistent indoor spider problems.

Coexisting with Spiders

While finding spiders inside one’s home can cause unease, they play vital roles in controlling insect pests and are an unavoidable part of sharing the environment with nature. By taking sensible precautions, Illinois residents can comfortably coexist with spiders both inside and around their homes.

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.