Bugs and spiders in New Hampshire

In New Hampshire the Asian lady beetle is the most-recorded species, and the American dog tick is close behind. Western conifer seed bugs, eastern carpenter bees and yellow garden spiders follow. Cockroaches and bed bugs are only Occasional, and the spotted lanternfly has records but is not known to be established.

Get advice if bitten

These are found in New Hampshire. If you think one bit or stung you, call Poison Help at 1-800-222-1222; call 911 for trouble breathing or swelling.

Common in New Hampshire

Established here or recorded often, most-recorded first.

What to watch for in New Hampshire

Ticks deserve the most attention. The American dog tick and the blacklegged tick are both established and well recorded. The blacklegged tick can spread Lyme disease and several other serious infections, and the American dog tick can spread Rocky Mountain spotted fever and tularemia. The lone star tick and the brown dog tick are also listed as established, though we have no photo records for either here. Rash or fever after any tick bite is worth mentioning to a doctor.

The northern black widow is listed as established with no photo records in the state. A suspected bite means getting medical advice right away, and Poison Help at 1-800-222-1222 can help if you are worried. Among the Be-careful species, eastern yellowjackets, European paper wasps, eastern carpenter bees and dark fishing spiders are the ones most often met, along with the house centipede in basements.

Through the year

Spring
American dog ticks become active by about April, and carpenter bees return to drill, while overwintered lady beetles head back outside.
Summer
Blacklegged tick nymphs peak in early summer, and yellowjacket colonies grow near food and trash.
Fall
Western conifer seed bugs and brown marmorated stink bugs arrive in September and October, Asian lady beetles in October and November, and boxelder bugs from late August.
Winter
Expect the odd lady beetle or stink bug on warm days, and house centipedes, which turn up indoors all year.

Seen now and then

Recorded a few times; often brought in on plants, firewood or luggage.

Recorded, not established

Range maps don't place these here, but people have recorded them. Usually hitchhikers.

Lists come from research-grade iNaturalist sightings (New Hampshire: 194,957 arthropod records) and, for dangerous species, published range maps. A species with few records may be a hitchhiker. Counts pulled Oct 18, 2026.

Identify a bug in New Hampshire