Bugs and spiders in Illinois

What to watch for in Illinois

Three spiders worth knowing are established in Illinois. The brown recluse is the most recorded, the northern black widow comes next, and the southern black widow turns up far less often. Bites from adult female black widows can cause strong muscle pain, and some recluse bites leave slow-healing wounds. Get medical advice after a worrying bite, or call Poison Help (1-800-222-1222).

The American dog tick, lone star tick and blacklegged tick are all established, with the American dog tick recorded most. Each can carry disease, and lone star bites are linked to alpha-gal syndrome. Brown dog ticks, which breed indoors and feed mainly on dogs, are listed too. Brown widow records exist, but that species is not known to live in the state, and the spotted lanternfly is rated harmless.

Through the year

Spring

Carpenter bees start hovering and drilling in April, black carpenter ant swarmers appear indoors in March through June, and varied carpet beetles gather at windows.

Summer

Oriental cockroaches are most seen in late spring and early summer, spotted lanternfly adults appear from July, and yellowjacket nests grow larger all season.

Fall

Asian lady beetles, brown marmorated stink bugs, boxelder bugs and western conifer seed bugs all push into houses, and greenhouse camel crickets begin turning up in basements.

Winter

House centipedes and Indianmeal moths can be found indoors, and a stray queen paper wasp or stink bug may appear on a mild day.