Michigan is home to an estimated 500+ species of spiders. While most are harmless and even beneficial to the ecosystem, a few spiders that bite are worth knowing about, especially if you live in the Great Lakes State.
This article will focus on identifying the spiders in Michigan that can bite and pose a potential threat to humans. It’s important to remember that while many spiders can bite, only a few species are considered medically significant, meaning their bites could cause serious health problems.
It’s also crucial to understand the difference between venomous and poisonous creatures. Venomous animals, like certain spiders, inject venom through a bite or sting. Poisonous animals, on the other hand, are harmful when ingested or touched.
We’ll discuss the black widow, the (possibly misidentified) brown recluse, and some common non-venomous spiders that are often mistaken for dangerous ones.
Venomous Spiders in Michigan
While most spiders you’ll encounter in Michigan are harmless, there are a couple of venomous species to be aware of: black widow spiders and brown recluse spiders.
Black Widow Spiders
There are around 30 species of widow spiders, but the black widow is the most well-known. You can identify a black widow by its shiny black body and the distinctive red hourglass marking on its underside. Females are larger than males and are the ones responsible for most bites.
Black widows prefer dark, secluded areas, so you might find them in woodpiles, sheds, garages, and other undisturbed spots. They aren’t aggressive spiders and will typically only bite if they feel threatened or are accidentally pressed against the skin.
Black widow venom affects the central nervous system, and a bite can cause a range of symptoms, including:
- Severe muscle pain and cramping
- Nausea and vomiting
- Sweating
- Headache
- Increased blood pressure
These symptoms can last for 1 to 3 days. While black widow bites are rarely fatal, it’s important to seek medical attention if you suspect you’ve been bitten. Treatment may include pain medication, muscle relaxants, and in severe cases, antivenom.
Brown Recluse Spiders
Brown recluse spiders are less than an inch long and are a light to medium brown color. They have a characteristic dark brown violin-shaped marking on their cephalothorax (the body part where the legs attach). Brown recluses also have only six eyes, arranged in pairs, instead of the eight eyes most spiders have.
Like black widows, brown recluses prefer undisturbed areas, such as closets, attics, and basements. Risk factors for brown recluse habitats include having cardboard boxes in storage, cracks or crevices in the foundation, and clutter that provides hiding places.
A brown recluse bite can be more serious than a black widow bite because the venom can cause skin necrosis (tissue death). Initially, the bite may be painless, but symptoms can develop within a few hours, including:
- A bite wound with a pale center that turns dark blue or purple, surrounded by a red ring
- Pain and itching
- Fever
- Chills
Treatment for a brown recluse bite focuses on wound care and preventing infection. Clean the bite area thoroughly with soap and water and apply a cold compress. Seek medical attention promptly, as some bites may require further treatment, such as antibiotics or even surgery to remove the necrotic tissue.
Spiders that get a bad rap
Here are some spiders you might see in Michigan that people often mistake for being dangerous:
Jumping spiders
These spiders are easy to identify because, well, they jump! They’re usually pretty small and have a distinctive look, with large eyes that give them excellent vision.
Even though they might look a little scary, jumping spiders aren’t considered dangerous to humans. Their mouths are super tiny, so even if they did bite you, it probably wouldn’t do much damage.
American grass spiders
You’ll often find these spiders hanging out in funnel-shaped webs in your yard. They’re part of the Agelenopsis genus of spiders.
Like jumping spiders, American grass spiders aren’t really a threat to people. If they bite, it’s generally harmless.
Black and yellow garden spiders
These are the big, showy spiders you see in gardens, with striking black and yellow markings. They’re definitely noticeable!
Despite their size, black and yellow garden spiders are generally harmless. In fact, they’re beneficial because they help control pests in your garden.
Hobo spiders
For years, hobo spiders were thought to be quite dangerous, but our understanding of their venom is changing. Scientists have been doing new studies to figure out just how dangerous these spiders really are.
It turns out they’re likely less dangerous than we once thought. While a bite might still be unpleasant, it’s probably not as serious as previously believed.
Wolf Spiders in Michigan: Are They Dangerous?
Wolf spiders are big and hairy, and there are more than 2,600 different kinds of them. They can look pretty scary, but they’re not usually dangerous to people. Unless you’re allergic, a wolf spider bite isn’t anything to worry about.
Wolf spiders are predators, and they eat insects. They hunt their prey instead of building webs, so they help keep insect populations under control.
There are a lot of misconceptions about wolf spider bites. People think they’re aggressive and that their bites are poisonous, but that’s not true. Wolf spiders only bite if they feel threatened, and their venom isn’t harmful to humans (unless you’re allergic, as mentioned above). So, while they might look intimidating, wolf spiders are actually beneficial to the ecosystem and not a threat to people.
How to avoid spider bites
You can take several steps to reduce your chances of being bitten by a spider, both inside and outside your home.
Around the house:
- Shake out your shoes and boots before you put them on.
- Wear gloves when you’re moving items in places where spiders may live.
- Avoid dark, undisturbed places, such as attics, basements, and the corners of rooms.
- Keep your home clear of clutter.
- Make sure your bed isn’t touching the wall.
- Remove spiders and their webs when you see them.
Outdoors:
- Cover your skin with long sleeves and pants.
- Stay away from gardens and other places where insects are abundant.
- Use insect repellent containing DEET.
Be aware of spider habitats:
It’s helpful to know what dangerous spiders look like and where they tend to live. For example, black widow spiders prefer dark, secluded places, such as woodpiles and sheds. Recluse spiders also like dark, undisturbed areas, such as closets and boxes.
In Closing
Knowing how to identify the few potentially dangerous spiders in Michigan is important for your safety and peace of mind. It’s also important to remember that most spiders are harmless and play a vital role in our local ecosystem, helping to control insect populations.
You can prevent most spider bites by wearing gloves when gardening or working in dark, undisturbed areas, sealing cracks and crevices in your home’s foundation, and regularly cleaning to remove webs and deter spiders from taking up residence.
Ultimately, the key is to strike a balance: respect spiders and their role in nature while taking reasonable precautions to minimize your risk of being bitten. With a little knowledge and awareness, you can coexist peacefully with these fascinating creatures.