Spiders in Illinois | Identification, and Risk

The state of Illinois is home to over 500 species of spider! However, you are only likely to come into contact with around 30 to 35 of them on a regular basis. 

If you do happen to cross paths with one of our home-spun friends, there’s a chance it could be a brown recluse, a northern black widow, a black and yellow garden spider, or even a rabid wolf spider It can be hard to identify which species you’re dealing with and also, what potential risk they may pose so here’s a list including the spiders most commonly spotted in the Prairie State.

Most Venomous Spider in Illinois

Illinois is home to over 500 various species of spider but only one has the dubious reputation of being the most venomous! Immortalized in horror and slang, this spider has really earned its renegade status! Learn all about how to recognize the appearance, behavior, and hiding places of this most deadly of visitors below. 

Black Widow

Scientific Name: Latrodectus mactans

Black Widow
A Mature Latrodectus southern Black Widow spider
Credit: Wales by CC 3.0

The black widow is categorized under the genus Theridiidae which contains 34 species this one alone varies greatly in appearance but the most common ones are dark-colored with reddish markings on their underside.

This famous spider is capable of creating a potent venom that contains the neurotoxin latrotoxin so you will be very wise to seek medical attention if you are unlucky enough to experience a bite. Most of the time, symptoms only last for around 30 minutes but it is possible that a medical practitioner will administer a muscle relaxant. 

You may bump into one of these foreboding arachnoids if you’re rummaging through old boxes or woodpiles – anywhere that’s been neglected or undisturbed for a while. Look out for unusual, untidy, and messy-looking webs!

Common Spiders in Illinois Identification

There are 57 incredible species of spider in Virginia and most are harmless, in fact, they contribute magnificently to the environment, not to mention working for free as pest controllers! 

These fascinating creatures all have unique appearances, behaviors, and abilities which you can quite easily learn to tell apart. There are so many that we cannot touch on them all right now so here are some of the most common arachnoids that you may encounter in Virginia. 

Brown Recluse

Scientific Name: Loxosceles reclusa

Brown Recluse
Credit: Rosa Pineda by CC 3.0

The brown recluse (Loxosceles reclusa) is a species of spider native to the southern and central United States. It is also known as the violin spider due to the characteristic “fiddle-shaped” mark found on its back. Brown recluses are typically small, about 3/8 inches in length, and range in color from light tan to dark brown. They have six eyes arranged in three pairs, rather than the usual four seen in other arachnids.

Brown recluses can be found across the southern and central states from Texas to Iowa, and northward into Wisconsin and Ohio. They prefer sheltered spaces such as woodpiles or hollow logs where they are able to build their webs undisturbed. Hunting behavior is nocturnal and solitary – they will only come out of hiding if necessary for food or reproduction.

A particularly notable feature of this species is its venomous bite – it contains a toxin that breaks down tissue causing severe blister-like lesions at the site of infection. Though rarely fatal, individuals bitten by a brown recluse should seek prompt medical attention to avoid serious complications.

Yellow Sac Spider

Scientific Name: Cheiracanthium inclusum

Yellow Sac Spider
Credit: Andrew Hoffman by CC 2.0

The yellow sac spider is also known as the black-footed spider and has two body segments: a fused head and thorax and an abdomen. 

The most usual places to find them are trees and shrubs but don’t rule out stumbling upon them in your home and even in your car as they have been known to have a liking for gasoline!

The females produce two sets of eggs, usually in June or July during which time they will encase themselves in silk tubes to keep them well-protected from prying eyes and potential harm.

Cellar Spider

Scientific Name: Pholcidae

Cellar Spider
Credit: David Short by CC 2.0

Fairly common in Illinois, cellar spiders will not hesitate in letting you know if you have the audacity to disturb them! They are able to make their body vibrate if they feel that their web is being invaded by an intruder!

The Pholcidae family boasts over 1,800 individual species of spider but this is one of the most common. As their name suggests, they like to cozy up to you in basements and lofts, hiding in garages, sheds, and dark, dank corners. 

They will deceive other spiders by vibrating on their nemesis’s web, in turn, making the inhabitant think they have caught an insect – the cellar spider then advances and devours the poor unsuspecting host! 

Researchers have observed that Cellar spiders walk with a very interesting gait: they alternate their legs between first and second on either side. 

Zebra Spider

Scientific Name: Salticus scenicus

Zebra Spider
Credit: David Short by CC 2.0

The Zebra Spider (Salticus scenicus) is a species of jumping spider native to North America. It is typically found in sunny, dry places and is one of the most common spiders in the United States. The Zebra Spider has distinctive black and white striped markings on its back which give it its name.

These spiders measure up to 4 millimeters in length and are usually seen on walls, fences or other flat surfaces where they hunt for prey. They also construct silk webs to catch their prey and protect themselves from predators. Zebra Spiders can jump great distances and are known for their agile nature.

Zebra spiders are non-aggressive towards humans, though they may bite if cornered or disturbed. Their venom is not considered dangerous but may cause some itching or swelling at the bite site.

Wolf Spider

Scientific Name: Lycosidae

Wolf Spider
Wolf spider
Credit: Bidgee by CC 3.0

Wolf spiders are solitary creatures, living and hunting alone. They have incredible eyesight and interestingly, do not spin webs! 

A fascinating trait of the wolf spider is how it carries around its eggs: the sac is attached to the spinnerets at the end of the abdomen but it doesn’t end there! After the eggs have hatched, the spiderlings cling to the mother’s abdomen and she carries them around for several weeks. 

They will inject venom if excessively provoked but do not pose a threat apart from pain and swelling for which an ice pack will suffice. The wolf spider lives in gardens, grasslands, sand dunes, and herb fields. 

They are common in Illinois and may get into your home, especially if you have outside vents but you can help deter them by clearing clutter and using natural repellents such as peppermint oil, boric acid, or diatomaceous earth. 

Orb Weaver Spider

Scientific Name: Araneidae

Orb Weaver Spider
Credit: Tan Pek Nan by CC 4.0

Orb-weavers belong to a family of spiders named Araneidae. Their favorite places are leafy forests, woods, and back gardens where they build their trademark wheel-shaped webs. 

This bulbous arachnoid does not possess stridulating organs and they have eight identical eyes. Some members of this family are very brightly colored and many are so hard-working that they will build a brand new web every day! Conversely, there are some who do not build a web at all. 

Orb-weavers have been known to build communal webs covering incredible distances! 

There is a sub-species of orb-weaver known as the hackled orb-weaver which builds a similar web but uses a different kind of silk. 

Nursery Web Spider

Scientific Name: Pisauridae

Nursery Web Spider
Credit: Tim Gage by CC 2.0

Adult nursery web spiders are robust hunters and run after their prey on foot rather than relying on the arduous process of spinning a web and waiting!

The  Nursery web spider can be found amongst shrubs and grasslands and even scampering around stinging nettles.  The female actually carries her egg sac in her teeth and constructs a luxurious silk sheet tent-like structure when the eggs are about to hatch to create a soft and protective landing until they are old enough to venture out into the world!

This is an extremely prolific species that thrives throughout the world except for unusually dry or cold places.

Nursery web spiders have slender bodies and are light grey-brown in color with light golden brown and black stripes. 

Jumping Spider

Scientific Name: Salticidae

Jumping Spider
Credit: Donald Hines by CC 2.0

This sprightly spider belongs to a family with over 6,380 different species! They vary in appearance but all have the most remarkable eyesight – no surprise when you consider their four pairs of eyes including one forward-facing central pair which helps them with courtship, hunting as well as navigation. 

These spiders do not use a web but rather stalk their prey before ambushing. Despite being fairly small, they can jump up to 6.3 inches (160 mm), often spinning a tiny silk anchor to tether themselves before they leap. 

Jumping spiders thrive all over the world and Illinois certainly has its share. You may see one if you are in scrubland, tropical forests or even mountainous environments – jumping spiders are adaptable and have even been known to inhabit deserts.

Trapdoor Spider

Scientific Name: Ctenizidae

Trapdoor Spider
Credit: Bernard DUPONT by CC 2.0

This species encompasses a wide variety of arachnoids all known as trapdoor spiders. This fascinating creature can build a burrow from plants, earth and silk!

 Fairly common throughout southwest America, Trapdoor spiders have become desirable as exotic pets which is problematic unless the owner is extremely experienced and well-informed about their behavior and requirements. They can bite if they feel provoked and though generally shy, they do have large fangs!

A trapdoor spider has 8 eyes positioned in 2 sets of six with a final pair at the front! They come in all shades of brown from gold or reddish tone to darker brown and shiny black. 

Other Spiders Native to Illinois

  • Black Lace Weaver Scientific Name: Amaurobius ferox
  • Striped Fishing Spider Scientific Name: Dolomedes scriptus
  • Southern House Spider Scientific Name: Kukulcania hibernalis
  • Magnolia Green Jumper Scientific Name: Lyssomanes viridis
  • Broad-faced Sac Spider Scientific Name: Trachelas tranquillus
  • Banded Garden Spider Scientific Name: Argiope trifasciata
  • Marbled Orb-weaver Scientific Name: Araneus marmoreus
  • Shamrock Orb-weaver Scientific Name: Araneus trifolium
  • Banded Garden Spider Scientific Name: Argiope trifasciata
  • Striped Fishing Spider Scientific Name: Dolomedes scriptus
  • Woodlouse Hunter Scientific Name: Dysdera crocata
  • Orchard Orb-weaver Scientific Name: Leucauge venusta