Types of Spiders Found in Illinois: Identification, Bites, and Safety Tips

An Overview of Common Spiders Found in Illinois

From tiny jumping spiders to large wolf spiders, Illinois is home to a fascinating diversity of arachnids. While the majority of spiders pose no threat to humans, a few venomous species can inflict painful bites. Understanding spider identification, behaviors, and habits can help residents co-exist safely with these abundant invertebrates.

Spider Anatomy and Characteristics

All spiders share some key anatomical features that set them apart from other creatures:

• Two body segments: the cephalothorax (head and thorax fused together) and the abdomen
• Four pairs of walking legs attached to the cephalothorax
• No wings or antennae
• Multiple simple eyes
• Fangs and silk-producing spinnerets on the underside of the abdomen

Spiders are arachnids, a class that also includes scorpions, mites, and ticks. They are not insects, which have three body segments and six legs.

There are over 47,000 known spider species globally, from tiny dwarf spiders to large tarantulas. About 500 species are documented in Illinois, inhabiting diverse habitats from backyards to prairies to forests.

Common Spider Groups in Illinois

Some of the main spider categories found in the state include:

Orb Weavers

Orb weaver spiders construct circular webs with spokes and sticky spiral patterns to trap prey. Some common Illinois orb weavers are garden spiders, barn spiders, and marbled orbweavers. They are generally harmless to humans.

Jumping Spiders

Jumping spiders actively hunt rather than building webs to catch food. As their name suggests, they can leap distances much greater than their body length to ambush prey. Jumping spiders have large front eyes and come in many colors and patterns.

Crab Spiders

Crab spiders have a laterigrade leg posture like a crab, with the first two pairs of legs held out sideways. They do not spin webs but patiently ambush prey. Some crab spiders can change color to camouflage with their surroundings.

Sac Spiders

Sac spiders get their name from the silken tube or sac they construct for shelter in bushes, corners, or trees. They hunt at night and have a venomous bite, though not considered medically significant.

Fishing Spiders

As their name suggests, fishing spiders hunt insects, small fish, and tadpoles near the edges of ponds and streams. They do not build webs but seize prey directly. Some fishing spiders can dive and swim underwater.

Wolf Spiders

Wolf spiders are robust, swift hunters living on the ground. Females carry egg sacs attached to their spinnerets. Wolf spiders have good vision and do not use webs to trap prey.

Venomous Spiders in Illinois

While the majority of spiders in Illinois pose no danger to humans, a few species can inflict painful bites:

Brown Recluse Spider

The brown recluse has a violin-shaped mark on its cephalothorax. Its hemotoxic venom can cause tissue damage, though bites are rarely life threatening. They build irregular webs and hide in dark places.

Black Widow Spider

Identifiable by the red hourglass on the female's underside, black widows have neurotoxic venom that can cause muscle spasms, nausea, and breathing difficulties, although antivenom makes deaths rare.

Hobo Spider

Hobo spiders have a herringbone pattern on their abdomen. Though they have venom similar to the brown recluse, the bite severity is still debated. They build funnel-shaped webs in dark corners.

Yellow Sac Spider

Yellow sac spiders have potentially cytotoxic venom that can cause skin lesions. They are pale yellow to greenish with dark markings on the abdomen.

Spider Bite Symptoms

Many spider bites are harmless and may cause temporary redness, irritation, or swelling. Seek medical care for:

• Intense pain spreading from the bite site
• Blistering, oozing wound, or necrotic lesion
• Redness and swelling spreading extensively around the bite
• Nausea, vomiting, fever, chills, or head/body aches after a bite
• Muscle cramps, spasms, weakness, tremors, or paralysis
• Breathing difficulties, excessive sweating, or elevated heart rate

Spider Bite Treatment and First Aid

For mild spider bites, using basic first aid strategies can help manage symptoms:

• Wash the bite with soap and water to lower risk of infection
• Apply a cold pack wrapped in cloth to reduce swelling
• Elevate the bite site if possible
• Use over-the-counter pain medication if needed for discomfort
• Avoid scratching or rupturing blisters to reduce scarring

If the bite is from a venomous spider or you experience severe symptoms, seek medical care immediately. Antivenom may be prescribed for certain species like black widows. Professional wound care and antibiotics are needed for necrotic lesions.

Spider Bite Prevention Tips

You can reduce the chances of being bitten by taking these spider bite precautions:

• Avoid putting bare hands in areas you can't see clearly
• Wear gloves when moving boxes, firewood, debris, or items in storage
• Clear excess clutter to minimize dark hiding spots
• Inspect or shake shoes and clothing before use
• Install sealed screens on windows and doors
• Apply pesticides carefully only if absolutely necessary

Identifying Common House Spiders in Illinois

Many different spider species make their way indoors seeking food and shelter. Some of the most common house spider types in Illinois include:

Parson Spider

Medium-sized brown spiders with white bands on the abdomen. They build messy webs in corners of basements and crawlspaces.

Cellar Spider

Long, spindly spiders with light brown bodies building lacy, chaotic webs in dim rooms. Also called daddy longlegs spiders.

American House Spider

Chunky grey spiders with mottled patterns on the abdomen. They construct messy webs in corners of attics, garages, and sheds.

Southern House Spider

Fast-moving brown spiders with tiger-like stripes on the legs. They wander walls and floors hunting prey rather than building webs.

Cobweb Spider

Tiny white, tan, or grey spiders leaving messy cobwebs in undisturbed areas like windows, walls, and ceiling corners.

Controlling Spiders Effectively and Safely

While most indoor spiders are harmless, you may want to control excessive numbers. Some tips include:

• Vacuum regularly to remove webs and spiders
• Seal cracks and openings where spiders may enter
• Reduce lighting and clutter that attracts insects for spiders to eat
• Use essential oils or natural repellents around entry points
• Limit pesticide use which may paradoxically increase spider populations later

Outdoors, encourage natural spider predators like birds, reptiles, and beneficial insects. Only use pesticides directly on spider infestations if necessary, not broadly.

When to Call for Professional Spider Removal

In most cases, you can handle occasional spiders yourself through vacuuming, sealing cracks, and tweaking environmental conditions. However, you may need professional spider control if you experience:

• Unexpected bites or recurring spider encounters
• Large infestations of venomous spiders like black widows or brown recluses
• Severe spider phobia impacting quality of life
• Failed attempts at DIY spider removal

A qualified exterminator can use targeted treatments and habitat modification to safely mitigate extensive spider problems. This is often a better solution than choosing to live with an abundance of spiders or resorting to risky broad-application pesticides.

Coexisting with Spiders Safely

The majority of Illinois spiders play a valuable ecological role as insect population regulators. They generally only bite in self-defense and pose little risk with proper precautionary measures.

Learning key spider identification traits, habits, bite symptoms, and effective control methods allows residents to safely manage these abundant arachnids around the home.

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.