It can be a bit unsettling if you’ve just spotted a red or reddish-brown bug in your home or, worse, in your bed. But before you panic, remember that not every red bug is out for blood. Some are harmless wanderers who accidentally stumbled inside, while others might be feeding on crumbs or old grains. Here’s a rundown of 20 red bugs you might run into, along with what they’re up to and whether they’re the type to bite.
1. Bed Bugs
These blood-feeders live in cracks and crevices around beds and furniture. Adults are about 5-6.5 mm long, reddish-brown, and oval-shaped. They generally come out at night to feed on blood (but if they are hungry enough, they’ll feed any time of day).
2. American Roaches (American Cockroach)
These large reddish-brown cockroach species can grow up to 40 mm. They eat anything from crumbs and paper to soap and glue. They prefer warm, damp areas like basements and sewers, but you can find them roaming anywhere!
3. Concrete Mites
Concrete mites feed on organic debris and tiny arthropods around concrete surfaces. They’re small but visible, about 1 mm long. Being that they are bright red, you’ll spot them outside on sunny days. They don’t usually come indoors in large numbers. Recently, I saw one in a bathroom crawling fast on the floor. When this happens, it must have fallen off of your clothing.
4. Flour Beetles (Red and Confused Flour Beetles)
These small reddish-brown beetles (about 3–4 mm long) infest flour, grains, and stored food products. They’re a common pantry pest, but many clients see them in a bed because they wander. They can live for several months and thrive in warm, humid places.
5. Spider Beetles
Spider beetles are reddish-brown, round, and about 1.5–3.5 mm long. They feed on all kinds of dried foods and organic matter, including wool, grains, and old food debris. Their shape makes them look like tiny spiders. Spider beetles are one of the most common bugs people misidentify as bed bugs. One of the top bed bug lookalikes!
6. Roaches (Cockroach Nymphs)
Nymphs of many cockroach species, including German and American roaches, can be reddish-brown. They eat almost anything organic, including crumbs and paper. Size varies by species and age, ranging from 3–15 mm. Learn more about baby roaches here.
7. Red Velvet Mites
These bright red, velvety mites feed on insect eggs and other tiny arthropods. Adults can be up to 4 mm long and are mostly outdoor visitors. They’re harmless to people but can occasionally wander inside.
8. Soapberry Bug Nymphs
These nymphs are reddish with black markings and grow up to 5–10 mm long. They feed on the seeds of soapberry trees, sucking out the juices. They’re typically seen outdoors but may come inside if they’re around your yard.
9. Lice
Lice are tiny (about 2–3 mm), reddish after feeding on blood. They live on or near (depending on the species) humans and pets, feeding on blood multiple times daily. Lice are not household pests; instead, they’re direct parasites. Check out our article on lice vs bed bugs, for more in depth identification help.
10. Fleas
Fleas are small (1.5–3.3 mm long), reddish-brown, and laterally flattened to move through the fur. They feed exclusively on blood, mainly from pets like cats and dogs. They can also bite humans if the opportunity arises.
11. Bird Mites
Bird mites are tiny (about 1 mm long) and turn reddish after a blood meal. They feed on birds but can bite humans if their primary hosts are gone. They usually come inside when birds nest near or on your home.
12. Rodent Mites
Rodent mites, also reddish after feeding, are around 1 mm long. They feed on rodents’ blood but can bite humans if rodents leave or die. They’re most common in homes or buildings with nearby rodent infestations. You don’t have to have a rodent issue directly in your home to get rodent mites. The rodents can live outside, and the mites can migrate in.
13. Earwigs
Earwigs are reddish-brown and about 12–25 mm long. They feed on decaying plant matter, other insects, and organic debris. They’re mostly outdoor insects but can wander indoors in search of moisture.
14. Drugstore Beetle
This small (2–3.5 mm) reddish-brown beetle feeds on stored dry goods, spices, and even book bindings. It’s a notorious pantry pest. Its larvae can live in small cracks and dried food debris.
15. Red House Spider (Nesticodes rufipes)
This reddish-brown spider is small, only 3–6 mm long. It feeds on small insects caught in its messy webs, often built in corners of homes. It’s harmless to humans.
16. Woodlouse Spider (Dysdera crocata)
This reddish spider grows up to 15 mm and preys on woodlice (pillbugs). It has strong fangs that pierce woodlice shells. You’ll find them in damp, dark areas like basements and under logs.
17. Boxelder Bugs
These bugs are about 12–14 mm long, with red and black markings. They feed on boxelder tree seeds and leaves but don’t cause damage inside homes. They often come indoors in the fall to overwinter.
18. Rice Weevils
Rice weevils are reddish-brown and about 2–3 mm long. They feed on whole grains like rice, wheat, and corn. They’re pantry pests that infest dry foods.
19. Red Fire Ants
These reddish ants are 2–6 mm long. They eat proteins, sweets, and dead insects, making them omnivores. While usually outside, they can come in for food or water.
20. Termites (Isoptera)
Depending on the species, some termite workers and soldiers can have a reddish tint. Workers are about 3–6 mm long and feed on wood and cellulose-based materials. They’re usually found in hidden colonies and can do severe structural damage.