Indiana homes host a predictable cast of insects and arthropods, with the lineup shifting by season. Some are harmless nuisances that wander inside during fall, others signal moisture problems, and a few can damage your belongings or bite. Here’s what you’re most likely to find and what to do about it.
Fall Invaders: Stink Bugs and Boxelder Bugs
The bugs most Hoosiers notice arrive in early fall, when brown marmorated stink bugs and boxelder bugs congregate on exterior walls looking for warmth and shelter before winter. They’re drawn to sunny surfaces, especially south- and west-facing walls with light-colored siding. Once a stink bug finds a good overwintering spot, it releases chemicals that attract more stink bugs to the same location, which is why you’ll often see dozens clustered together.
Neither species bites, stings, or causes structural damage. Stink bugs earn their name by releasing a sharp, unpleasant odor when crushed or threatened, so vacuuming them up is a better strategy than squishing. Boxelder bugs look similar at a glance but are flatter and marked with red or orange lines along their wings. Both will die off indoors once winter sets in if they can’t find moisture, but in the meantime they can be a persistent annoyance. The Western conifer seed bug, a large, leaf-shaped insect about three-quarters of an inch long, follows the same pattern and often gets mistaken for a stink bug.
Moisture Pests: Centipedes, Silverfish, and Millipedes
If your basement or crawl space stays damp, you’ll likely encounter house centipedes, silverfish, or millipedes. These bugs aren’t arriving because your home is dirty. They’re following humidity.
House centipedes are the fast-moving, many-legged ones that startle people in bathrooms and basements. They hide in dark, damp spots during the day and hunt at night, feeding on silverfish, carpet beetle larvae, cockroaches, and spiders. They enter through expansion cracks in concrete slabs, gaps around sump pump openings, uncapped cement blocks, and floor drains without water traps. In Indiana’s climate, house centipedes can’t survive outdoors through winter, so heated homes with moisture issues become year-round habitat for them.
Silverfish are small, teardrop-shaped, and silver-gray, typically found near paper goods, cardboard boxes, or stored clothing. They feed on starches and sugars, including book bindings, wallpaper paste, and cotton fabrics. Millipedes, dark brown and an inch or longer with many short legs, tend to curl up and die shortly after entering. You’ll usually find them near basement doors or exterior entry points. They’re completely harmless but signal excess moisture around your foundation. Running a dehumidifier and sealing cracks in your foundation slab are the most effective long-term fixes for all three.
Carpet Beetles and Clothes Moths
Carpet beetles and clothes moths are the two most common fabric-damaging pests in Indiana homes. Carpet beetles are small, round, and often mottled with brown, white, and orange scales. The adults are harmless, but their larvae feed on wool, silk, fur, feathers, and other animal-based fibers. You’ll find damage along the edges of carpets, inside closets, and in boxes of stored clothing that haven’t been disturbed in months.
Clothes moths are buff-colored with a wingspan of about half an inch. Unlike most moths, they avoid light and prefer undisturbed closets and drawers. The larvae chew irregular holes in wool sweaters, blankets, and upholstery. Regular vacuuming, cleaning garments before storage, and using sealed containers for seasonal clothing are the most reliable prevention methods. If you’re finding damage, check under furniture and along baseboards where lint and pet hair accumulate, as these provide food for larvae.
Pantry Pests
The Indian meal moth is the most common pantry pest in Indiana. It’s about five-eighths of an inch long with distinctive wings: the inner half is pale gray, and the outer two-thirds are reddish-copper. You’ll usually notice the small, fluttering adults in your kitchen before you find the larvae, which are tiny cream-colored caterpillars that spin silky webbing inside cereal boxes, flour bags, birdseed, pet food, and dried fruit.
An infestation almost always traces back to a single contaminated product brought home from the store. Inspect packages for webbing or small larvae, store dry goods in airtight glass or plastic containers, and throw out anything that looks compromised. Cleaning pantry shelves with warm soapy water removes eggs and larvae that might be hiding in crevices.
Bed Bugs
Bed bugs are reddish-brown, oval, wingless, and about a quarter inch long before feeding. After a blood meal, they swell and darken to a deep red. Nymphs look like smaller, lighter versions of adults and can be difficult to spot. According to the Indiana Department of Health, bed bugs feed on human blood at night, then retreat into cracks, crevices, and recesses of furniture and walls during the day.
Signs of an infestation include small reddish-brown spots on sheets (fecal stains), shed skins near mattress seams, and itchy bites on exposed skin like the arms, face, or back. Bites typically cause itching, pain, or swelling within a day. Bed bugs don’t come from poor housekeeping. They hitchhike on luggage, used furniture, and clothing. Inspect secondhand mattresses and upholstered furniture carefully before bringing them inside, and check hotel mattress seams when traveling.
Ants and Termites
Indiana is home to several ant species that enter homes, including odorous house ants (which smell like coconut when crushed), carpenter ants, and pavement ants. Carpenter ants are the ones to watch. They’re large, typically black, and excavate wood to build nests, which can cause structural damage over time. Unlike termites, they don’t eat wood; they just tunnel through it. Sawdust-like frass near baseboards or window frames is a telltale sign.
Termite swarmers appear indoors in spring, usually near windows. They’re dark brown, about a quarter inch long, with four wings of equal length and a fluttery flight pattern. Seeing swarmers inside your home suggests an active colony nearby, and that warrants a professional inspection. Subterranean termites are the primary species in Indiana and cause more property damage than any other insect in the state. They enter through soil contact with wood, including foundation cracks, porch supports, and wood mulch banked against siding.
Spiders Worth Knowing
Most spiders in Indiana homes are harmless and actually helpful, eating the other bugs on this list. Only two species in the state can cause serious injury: the brown recluse and the black widow. Neither is aggressive, and bites from both are quite rare.
Brown recluse spiders are sometimes called fiddle-back spiders because of a violin-shaped marking on their back. With legs outstretched, they’re about the size of a half dollar and have an unusual feature: six eyes arranged in three pairs, while most spiders have eight. They prefer dry, undisturbed places like barns, sheds, storage boxes, and closets. Black widow females are shiny black with a red or yellow hourglass marking on their underside, roughly the size of a penny with legs extended. They live in undisturbed outdoor locations and are rarely found inside homes.
Bite reactions vary depending on the amount of venom and individual sensitivity. Severe pain, trouble breathing, dizziness, or nausea after a suspected bite calls for medical attention, though fatalities from spider bites in the U.S. are extremely rare.
Spotted Lanternfly: A New Arrival
The spotted lanternfly was first confirmed in Indiana in July 2021 in Switzerland County, near the Ohio River. Since then, populations have been found in Huntington, Elkhart, St. Joseph, and Porter counties. This invasive planthopper doesn’t bite or sting, but it feeds heavily on trees and grapevines, producing a sticky residue called honeydew that promotes mold growth. Adults are about an inch long with gray forewings dotted in black spots and vivid red hindwings. They’re most visible from late summer through fall.
If you see one, the Indiana DNR asks that you report it. The insect spreads easily because it lays egg masses on nearly any flat surface, including vehicles, outdoor furniture, and firewood, so checking items before transporting them from infested areas helps slow the spread.
Keeping Bugs Out
Most indoor bug problems in Indiana come down to three things: entry points, moisture, and food sources. Sealing cracks around your foundation, capping open cement blocks, installing door sweeps, and repairing torn window screens eliminates the main highways bugs use to get inside. For moisture pests, running a dehumidifier in your basement and fixing leaky pipes makes your home far less hospitable. Storing firewood at least 20 feet from your house and away from exterior walls reduces the chance of bark beetles, spiders, and carpenter ants hitching a ride indoors.
In the kitchen, keeping dry goods in sealed containers and cleaning up crumbs promptly handles most ant and pantry moth problems. For seasonal invaders like stink bugs and boxelder bugs, the best time to seal up is late summer, before they start looking for overwintering sites. Once they’re inside, a vacuum is your most practical tool.