A Close Look at Spiders Commonly Found in Wisconsin
Wisconsin is home to a diverse variety of spider species. While not all spiders in the state are considered dangerous, there are a few types that can inflict bites on humans. Examining photos and learning identification clues can help assess the different spiders you may encounter in Wisconsin.
Brown Recluse Spider
The brown recluse spider is one of two venomous spiders found in Wisconsin. It has a distinctive violin-shaped marking on its cephalothorax (fused head and thorax). The violin marking can range in color from white to dark brown. The rest of the body is uniformly colored brown or tan. Legs are long and thin relative to its small body size.
Brown recluse spiders build irregular webs in secluded areas like basements, closets and attics. They are nocturnal hunters preying primarily on insects and other arthropods.
This spider's venom contains cytotoxins that can cause tissue damage. Bites usually only have mild effects but in rare cases can cause ulceration of the skin.
Black Widow Spider
The black widow is the other venomous spider that makes its home in Wisconsin and can be identified by the red hourglass marking on its jet black abdomen. Only the female black widow carries enough venom in its bite to affect humans.
Black widows often live in wooded areas, yards, stone walls and outdoor furniture. The spiderlings spread by ballooning on silk strands. The black widow makes a web with messy, irregular criss-crossing silk near the ground.
This spider's neurotoxic venom can cause muscle pain and rigidity, nausea, elevated blood pressure and breathing difficulty, although antivenom makes serious effects rare.
Fishing Spider
One of Wisconsin's largest spider species is the fishing spider, belonging to the Dolomedes genus. They have robust, hairy bodies with legspans reaching 3-4 inches. Coloration includes brown, gray and black banding or mottling. The eyes reflect light at night, shining teal or green.
These spiders hunt by waiting near water to ambush aquatic insects or small fish. Some species can dive below the water to capture prey. They do not build webs and instead wander in search of food.
Fishing spider bites are not medically significant but may cause mild pain and swelling.
Barn Funnel Weaver
Wisconsin is home to various species of funnel weaver spiders that build sheets or funnel-shaped webs in fields, gardens, and near building foundations. The barn funnel weaver has a large spherical abdomen with fine hairs and striped brown and gray colored legs.
The webs have a tunnel retreat where the spider hides. At night, the spider waits at the small funnel opening to attack prey. When something disturbs their web, these spiders will bounce or sway from side to side.
Funnel weaver bites are essentially harmless to humans beyond minor irritation.
Orbweaver Spiders
Several types of orbweaver live in Wisconsin, spinningcharacteristic spiraling circular webs. Prominent examples include the banded garden spider (yellow and black striped) and marbled orb weaver (yellow and orange patterned abdomen).
Their webs often stretch between branches and vegetation in gardens and forests. Orbweavers have a round, plump body shape and thick spiny legs. They are most visible in late summer and autumn.
These spiders help control insect pests. Although they may bite if threatened, it does not cause medical issues.
Grass Spiders
Grass spiders can inhabit lawns, fields, and meadows around Wisconsin. They have an elongated body, long spindly legs, and a brown-striped cephalothorax. The narrow abdomen features grey and white marks, with males being more boldly patterned.
These spiders do not use capture webs for prey. Instead they hunt actively, relying on camouflage and speed. Their bite is essentially harmless to humans.
Jumping Spiders
There are around 50 species of jumping spider found in the state. Their compact bodies are often hairy and come in black, brown, grey, or green. The Zebra spider has bold white stripes on its legs and body.
Large front-facing eyes give them excellent vision. They move by jumping via contractions of their leg muscles. Jumping spiders do not build webs and instead stalk prey.
They rarely bite humans, and any bite would be harmless.
Wolf Spiders
Wolf spiders thrive throughout Wisconsin and are named for their tendency to actively hunt like wolves instead of building webs. They have a robust body with strong legs and large eyes reflecting light. Coloration includes camouflaging black, brown, and grey tones.
Females carry egg sacs attached to their spinnerets until the spiderlings hatch. Wolf spiders use venom to subdue small invertebrate prey but poses little risk for humans.
Cellar Spiders
Cellar spiders are long-legged spiders that build irregular, messy webs in dark corners of cellars and crawlspaces. Their legs can be several times longer than their small body. Coloration ranges from pale yellow to brown.
They have a spindly appearance from their thin legs and small abdomen. Cellar spiders help control other household pests but are harmless to humans.
Crab Spiders
These spiders get their name from their ability to scuttle sideways like a crab. They come in gray, brown, white or green hues with a flattened oval body. Instead of spinning webs, they ambush prey using camouflage to hide in flowers and foliage.
Crab spiders have the ability to change their color over several weeks to blend in. They occasionally bite humans handling them but it only causes mild pain.
Spider Bite Symptoms
Identifying spider bites can prove difficult, as their fangs often cannot penetrate human skin deeply, or no venom is injected. Also, bites can be mistaken for other insect stings or skin conditions.
However, if a venomous spider like the black widow or brown recluse does inflict a significant bite, symptoms may include:
- Intense stinging pain at the bite site
- Redness and swelling expanding over hours
- Itching or burning sensation
- Hardening of tissue around the bite
- Nausea, fever, headache, cramping
- High blood pressure
In very rare cases, the area may blister or ulcerate. Seek medical evaluation if concerning bite symptoms develop or persist.
Protecting Yourself from Spider Bites
You can take these steps to avoid being bitten by spiders in Wisconsin:
- Wear gloves, long sleeves and pants when cleaning garages and basements
- Clear webs frequently with a broom
- Seal cracks and crevices spiders could enter
- Inspect or shake out shoes, towels and clothing before use
- Install insect screens on windows and doors
- Use caution around woodpiles, stones and brush piles
- Keep the lawn trimmed short
- Employ pest control if needed
Learning how to identify the spiders in your environment can also help assess any potential risks. While most Wisconsin spiders are not considered dangerous, being able to recognize and avoid venomous species is wise.
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.
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