Brown Recluse in Michigan: Where Have They Been Spotted?

The brown recluse (Loxosceles reclusa) is one of over 36,000 species of spiders around the globe. But, are there brown recluses in Michigan? North America is home to over 3,700 species of spiders, with around 500 of those spiders taking up residence in Michigan. Out of all those spiders, only a few contain venom that poses a risk to humans. These spiders are known as ‘medically significant’ and their bites should be avoided.

Here, we’ll discuss the brown recluse spider, what makes it unique, whether or not it’s dangerous, and if brown recluses make their homes in Michigan. We’ll take a look specifically at their locations, and how they get to this northern state. Then, we’ll go over the spiders most commonly misidentified as brown recluses, and how you can tell the difference. Finally, we’ll learn about the truly dangerous spiders living in Michigan, and why all spiders are important to the natural ecosystem.

Read on to learn more about the brown recluse in Michigan!

What Do Brown Recluse Spiders Look Like?

Brown recluse spiders are generally light brown to tan, though they may be lighter or darker, depending on their environment. They have only one distinct marking: a medium brown, violin-shaped splotch on their cephalothorax (head). The splotch starts at their eyes, and narrows (like the head of a violin) towards the rear of the cephalothorax. The legs are long and narrow, and the chelicerae (mouthparts) are smaller than in similar species.

Additionally, the brown recluse’s cephalothorax is rounded and short, while the abdomen is narrow and long, with no markings. The violin-like marking has given rise to a few common nicknames, including violin spider, brown fiddler, and fiddleback spider.

Are Brown Recluse Spiders Dangerous?

Brown recluse spider bites are nothing to laugh at, but they may have a worse reputation than they deserve. These spiders are non-aggressive, and only bite humans in instances of contact with the skin. Often, bites occur when people put on clothes or shoes that have brown recluses in them, resulting in the brown recluse acting to defend itself.

The majority of brown recluse bites are no more serious than a mosquito bite. This is because the brown recluse does not envenomate with every bite. When venom is released, symptoms can range from localized pain and itching in mild cases, to necrosis (death) of the surrounding tissue, which can become severe. Children, elderly people, and immunosuppressed people are most at risk from envenomation.

Are there Brown Recluse Spiders in Michigan?

Though the appearance of brown recluses in Michigan has been largely sensationalized, Michigan residents have little to worry about. Brown recluses have only been reported in isolated populations in 10 Michigan counties. These spiders are rare in Michigan; there are no native breeding populations of brown recluses in Michigan or the surrounding states. Contrary to news reports, brown recluse spiders are not migrating north. Michigan residents are safe from all but the occasional wandering brown recluse.

Where Do Brown Recluse Spiders Live in Michigan?

Brown recluses in Michigan have been reported in only 10 counties. These counties include Kent, Lenawee, Hillsdale, Wayne, Washtenaw, Oakland, Livingston, Ingham, Genesee, and Shiawassee counties. All 10 counties are located in the southeastern portion of the state. 

How Common are Brown Recluse Spiders in Michigan?

Brown recluses in Michigan are rare and have been observed only occasionally. Michigan is outside of their native range and lies too far north to ever harbor a permanent population of brown recluses. Outside of the 10 counties previously listed, brown recluses are non-existent in Michigan. Within those 10 counties, they are exceedingly rare. There are, however, several species of spiders often mistaken for brown recluses.

What Spiders are Commonly Confused with Brown Recluses?

Brown recluses in Michigan are scary and for good reason. They have bites that can quickly turn necrotic and even septic. Because of this, people tend to think that any spider they see might be the dreaded brown recluse. In fact, there are many species of spiders often mistaken for their more dangerous cousins. 

The major species among those commonly mistaken for brown recluses are the dark fishing spider, grass spider, nursery web spider, wolf spider, and jumping spider. Luckily, there are several easy ways to tell the brown recluse apart.

First is the violin-shaped marking. Next, brown recluses only have six eyes, whereas most other spiders have eight. Also, the brown recluse’s size is around the size of a penny. Then, there’s the overall brown color, devoid of any markings but for the violin-shaped mark.

Dangerous Spiders of Michigan

There might not be many brown recluses in Michigan, but there are several dangerous spiders native to the state. These include the northern black widow, yellow sac spider, and the northern cobweb spider. Bites from any one of these spiders have the potential to turn serious and may require medical treatment.

Why Spiders (even Brown Recluses) are Important

You might see a spider and think “Ew! Gross!” You might even want to kill it on sight. But before you do, remember that spiders are a necessary part of the ecosystem. They kill and eat millions of bugs a year. Without spiders, including the brown recluse, insects of all manner and sizes would soon overrun our planet. So, next time you see a spider in your house, try taking it outside, instead of smashing it.