Spiders in Illinois: A Guide to the Most Common Species

As an Illinois resident, you’ve probably encountered your fair share of spiders around your home and yard. With over 500 different spider species found in the state, it can be tricky figuring out exactly what’s crawling around. Not to worry though – most spiders in Illinois are harmless to humans and play an important role in controlling pest insects.

In this article, we’ll go through some of the most frequently seen spiders in Illinois, how to identify them, and whether you need to worry about having them around. Consider this your guide to getting acquainted with your eight-legged neighbors!

Jumping Spiders

Some of the most common spiders spotted in Illinois backyards and homes are jumping spiders. There are over 50 species of jumping spiders in the state, with some of the most frequently seen including:

• Bold Jumping Spider: A fuzzy black spider with white spots and stripes on its legs and abdomen. It has a body length of around 0.25 inches.

• Zebra Jumping Spider Identifiable by its black and white striped appearance It grows up to 0.35 inches long.

• Tan Jumping Spider As the name suggests, this jumping spider is tan and hairy It reaches 02 inches in length.

Jumping spiders don’t spin webs to catch prey. Instead, they are active hunters that leap onto their insect victims. They tend to hang out on walls, fences, and vegetation while stalking prey.

The good news about jumping spiders is they are not aggressive and their bites are harmless to humans, comparable to a mosquito bite. So if you find one jumping around your home, there’s no need to panic!

Orbweaver Spiders

Orbweaver spiders spin the classic circular spiderwebs with spokes radiating from a center point. There are dozens of orbweaver species in Illinois, some you may see including:

• Black and Yellow Garden Spider: Large spider (up to 1.1 inch body length) with distinct black and yellow striped markings on its abdomen. It builds webs in gardens.

• Banded Garden Spider: Medium-sized spider (0.4 inch body length) with brown, white, yellow, and black bands on its legs and abdomen. Constructs webs in gardens and fields.

• Arrowhead Orbweaver: Yellow and white spider with red markings and an arrowhead shape on its abdomen. Webs can span 2 feet across.

• Marbled Orbweaver: Brown or black spider with an orange, marbled pattern on its abdomen. Often found in woodlands and gardens.

Orbweavers tend to stay hidden during the day, either in a curled up leaf at the edge of their web or in a nearby retreat. While startling if you accidentally walk through their web, they are not aggressive toward humans.

Wolf Spiders

Wolf spiders are hunting spiders that don’t spin webs to catch prey. Some common wolf spiders in Illinois include:

• Rabid Wolf Spider: Yellowish spider with two thick black stripes on its cephalothorax (head area) and one stripe on its abdomen. Up to 0.75 inches long.

• Wetland Giant Wolf Spider: Large spider (up to 1.4 inch body length) that lives in wooded wetlands. It has a reddish-orange and black pattern on its abdomen.

• Grey Wolf Spider: Medium grey spider (0.5 inch body length) with black and white striping on its legs and light chevron markings on its abdomen.

Wolf spiders actively chase down small invertebrates and insects to eat. They live on the ground, hiding under rocks, logs, and leaf litter. Some female wolf spiders carry egg sacs attached to their spinnerets. Wolf spiders can move quickly, but are not aggressive toward people. Their bites are comparable to a bee sting in severity.

Cellar Spiders

You’ve probably seen long-legged cellar spiders hanging upside down in messy, tangled webs in basements and cellars. These spiders have tiny bodies less than 0.25 inches long with extremely long, spindly legs stretching 2 inches or more across.

Some common cellar spiders in Illinois include:

• Long-bodied Cellar Spider: Pale brown spider with a narrow, stretched out abdomen. Also known as a daddy longlegs spider.

• Eastern Parson Spider: Grey spider with a white stripe across its abdomen resembling a “necktie.” Grows up to 0.4 inches long.

Cellar spiders help control other spiders and insect pests, so they are beneficial to have around. They are non-venomous and harmless.

Cobweb Spiders

Cobweb spiders get their name from the tangled, messy webs they spin in corners of rooms and windows. Their webs easily accumulate dust and become cobwebs. Some cobweb spiders in Illinois you might find include:

• Common House Spider: Light brown spider with streaks and spots on its abdomen, up to 0.5 inches long. Makes messy webs in corners.

• Triangulate Cobweb Spider: Brown spider with a cream abdomen decorated with brown and yellow triangles. Grows to 0.25 inches.

• Western Black Widow: Shiny black spider with a red hourglass shape on its underside. Females reach 1.5 inches long but males are much smaller.

Cobweb spider bites are generally not harmful, except for the black widow which can inflict a painful bite. Control cobwebs by vacuuming and removing them.

Fishing Spiders

As their name implies, fishing spiders live near water and sometimes hunt for small fish and tadpoles. Look for them along pond edges and in wetlands. Some fishing spiders in Illinois include:

• Dark Fishing Spider: Brown spider with light stripes on its legs that lives in wooded wetlands. Up to 1 inch long.

• Six-spotted Fishing Spider: Brownish spider with white stripes and light spots on its abdomen. Reaches 0.8 inches in size.

Bites from fishing spiders are not dangerous but may cause temporary pain and swelling. They help control mosquitoes and other wetland pests.

Helpful Spider Habits

While some people fear spiders, most are actually incredibly helpful to have around because they eat nuisance pests like flies, mosquitoes, roaches, and ants. Their venom also helps them quickly subdue prey.

Here are a few beneficial habits of spiders in Illinois:

• Spinning webs that trap flying insects like mosquitoes and gnats

• Stalking and pouncing on crawling pests such as cockroaches and ants

• Reducing plant pest populations like aphids and caterpillars

• Serving as a vital food source for birds, lizards, and other predators

So next time you come across one of these eight-legged creatures, consider letting it go on its way. It’s likely providing free pest control services around your home! With proper identification and understanding, you can feel at ease sharing your space with Illinois’ helpful spider residents.