Indiana is home to nearly 400 spider species, and many of them are brown. The vast majority are harmless, but one species deserves your attention: the brown recluse. It’s one of only two spiders in the state capable of causing serious injury (the other being the black widow). Knowing how to tell brown recluses apart from the many harmless brown spiders you’ll encounter is the most practical thing you can learn.
The Brown Recluse: Indiana’s Only Dangerous Brown Spider
The brown recluse is a small spider with a body about 3/8 inch long. With legs extended, it’s roughly the size of a half dollar. Its color ranges from light tan to deep reddish brown, and its most talked-about feature is a darker, fiddle-shaped marking on the front half of its back, which is why some people call it the “fiddleback spider.”
But the violin marking alone isn’t enough to confirm an ID. It can be faint, and several harmless spiders have vaguely similar patterns. The most reliable way to identify a brown recluse is to check for a combination of features:
- Six eyes in three pairs. Most spiders have eight eyes in two rows. Brown recluses have six eyes arranged in three separated pairs (called dyads), one pair at the front and one on each side.
- Uniform coloring everywhere. The legs are a single, even color with no stripes or bands. The abdomen is also one solid color covered in fine hairs, never patterned or spotted.
- No spines on the legs. Many common brown spiders have small spines sticking out from their legs. Brown recluses have smooth, spineless legs.
If a spider fails any one of those checks, it’s not a brown recluse.
Common Brown Spiders That Aren’t Recluses
Most brown spiders you find in an Indiana basement, garage, or garden are one of a handful of harmless species that get mistaken for brown recluses regularly.
Wolf spiders are probably the most common source of alarm. They’re brown, they’re fast, and they show up indoors. But wolf spiders have dark stripes on their bodies, the standard eight-eye arrangement, and no violin marking. They’re also often larger and stockier than brown recluses.
Grass spiders build sheet-shaped webs with a funnel retreat in lawns and garden beds, and they sometimes wander inside. They have multiple colors on their legs and abdomen, which immediately rules out a recluse. Cellar spiders (the wispy, long-legged spiders you see hanging upside down in corners) lack the uniform brown coloring and violin mark, and their extremely thin legs look nothing like those of a recluse.
American house spiders are round-bodied with visible patterns or banding on their abdomens and eight eyes. Yellow sac spiders lean more toward pale yellow than brown and also have eight eyes. Southern house spiders have eight eyes grouped closely together and lack the violin marking. All of these are regularly submitted to entomologists as suspected brown recluses.
One interesting case is the woodlouse spider, which actually does have six eyes like the recluse. However, its eyes are grouped differently (in sets of three rather than three pairs), and it has a very distinct two-tone body: a reddish front half and a tan abdomen. If you see those two colors, it’s not a recluse.
Where Brown Recluses Hide
The name is accurate. Brown recluses are genuinely reclusive. They prefer warm, dry, undisturbed spaces and avoid high-traffic areas. Outdoors, they live in gaps under rocks, boards, and the bark of dead trees. Indoors, you’ll find them in cracks in walls, behind stored boxes, in garages, attics, basements, barns, and sheds.
The key word is “undisturbed.” They gravitate toward things that haven’t been moved in a long time: shoes you haven’t worn in months, gloves left in a toolbox, cardboard boxes stacked in a corner of the garage, woodpiles, and rock piles. They don’t build the classic circular webs you’d notice. Instead, they create small, irregular retreat webs tucked into hidden spots.
What a Brown Recluse Bite Looks and Feels Like
Brown recluse bites are painless at first. You typically won’t know you’ve been bitten until the area becomes red and sensitive three to eight hours later, often with a burning sensation. The bite site may develop a bullseye appearance or turn bluish, like a bruise.
Most bites are mild. If the spider injected only a small amount of venom, the discomfort fades within a few days. In more serious cases, the venom destroys surrounding tissue: an ulcer forms at the bite site within three to five days, and over the next one to two weeks the skin can break down into an open wound. A thick black scab eventually covers the area. The majority of bites heal within three weeks, but severe wounds can take several months. Some people also develop fever, chills, and nausea as the venom spreads.
There is no antivenom for brown recluse bites. Treatment focuses on wound care and preventing infection. If you’re bitten, clean the area with soap and water, apply a cold damp cloth to reduce swelling, and elevate the area if possible.
Bites almost always happen because a spider gets trapped against skin. The classic scenario is putting on a shoe or glove that’s been sitting undisturbed, or rolling onto a spider while sleeping. The spider doesn’t seek people out. It bites defensively when compressed.
How to Reduce Brown Spiders in Your Home
Eliminating clutter is the single most effective thing you can do. Brown recluses thrive in cluttered, undisturbed spaces, so removing their preferred hiding spots makes your home far less hospitable. Tape stored boxes tightly shut. Vacuum regularly around, under, and behind furniture. Remove spider webs from both interior and exterior areas.
Seal entry points. Make sure exterior doors close tightly with no gaps along the bottom or sides. Shield outdoor lighting or switch to yellow bulbs, since bright lights attract the insects that spiders feed on. Reducing the insect population inside your home cuts off the food supply.
Sticky traps placed along walls, inside closets, and under furniture are useful both for catching spiders and for monitoring how many you’re dealing with. Place them in out-of-the-way spots where spiders travel, especially against baseboards. If you’re catching brown recluses on sticky traps regularly, that’s a sign of an established population, and professional pest control is worth considering. A well-entrenched infestation typically requires a combination of insecticide treatment and the sanitation steps described above.
For personal protection in areas where brown recluses are present, shake out shoes, gloves, and clothing that have been sitting undisturbed before putting them on. Pull beds away from walls, and avoid letting bedding touch the floor. These simple habits prevent the vast majority of accidental bites.