Bugs and spiders in Montana

What to watch for in Montana

The western black widow is established in Montana, and a bite from an adult female can cause severe muscle pain and cramps, so get medical advice right away. The hobo spider is established and rated Be careful, with adult males wandering from August through October. Poison Help, 1-800-222-1222, can advise on a worrying bite.

Montana has several ticks worth knowing. The Rocky Mountain wood tick can spread Rocky Mountain spotted fever, Colorado tick fever and tularemia. Montana State extension reports Colorado tick fever cases west of the Continental Divide, in the southwest and south-central parts of the state. The American dog tick is established too and is placed in eastern Montana. The brown dog tick mostly lives indoors with dogs. Remove any attached tick promptly.

Through the year

Spring

Rocky Mountain wood ticks come out as the snow melts, American dog ticks are active from about April, and rough sowbugs and pill bugs appear after wet spells.

Summer

American dog ticks stay active through August, zebra jumping spiders and European paper wasps are around the house, and western black widows are most active.

Fall

Boxelder bugs arrive from late August, followed by western conifer seed bugs and Asian lady beetles in September to November, and hobo spiders and Carolina wolf spiders wander in.

Winter

Barn funnel weavers stay in houses year-round, and boxelder bugs and Asian lady beetles stir on warm days in late winter.