What bit me in Iowa?

18 biting or stinging species have verified records in Iowa. The fastest way to narrow it down is where on your body the marks are and how they are arranged — below the knee in clusters points to fleas or chiggers, lines on uncovered skin point to bed bugs, scattered single bumps point to mosquitoes. Bite season here runs roughly April to October.

Active around now in Iowa

Recorded biting species in Iowa

SpeciesLooks likeWhere on bodyRecordsPeak
Mosquito bite single bumps scattered over exposed skin ankles, lower legs 58,102 June to September
Honey bee sting single feet — bees are often stepped on in clover, hands 1,024 June to September
American dog tick bite single scalp, neck 458 April to July
Carpenter ant bite single or a few hands, arms 338 May, June, July, September
Paper wasp sting usually single hands, head 199 July to September
Bald-faced hornet sting often several — the colony defends aggressively head, neck 186 August to October
Deer tick bite single, usually in a skin fold or hairline groin, armpits 130 March, April, May, October
Lone star tick bite single, sometimes dozens at once when larval "seed ticks" swarm legs, waist 124 May to July
Flea bite clusters of three or four, or short irregular groups ankles, shins 100 September to November
Horsefly bite single, occasionally two legs, back 38 June to August
Bed bug bite lines or zigzags of three or more — the classic "breakfast, lunch and dinner" arms, shoulders 20 July
Yellowjacket sting single or several — this wasp can sting repeatedly hands, face 17 August to October
Chigger bite clusters concentrated where clothing is tight ankles, behind the knees 13 May, July, August, September
Brown recluse spider bite single site torso under clothing, upper arms 12 May to August
Wolf spider bite single site hands, feet 12 May, June, September, October
Head lice bites concentrated behind the ears and at the nape scalp, behind the ears 12 July
Yellow sac spider bite single, sometimes two nearby neck, arms 7 April to June
Deer fly bite single or a few, often on the scalp and neck scalp, neck 3 May to July

Record counts come from the GBIF biodiversity database and reflect how often a species is reported and identified in Iowa. They are a guide to what is plausible here, not a census — and they say nothing about how likely you are to be bitten indoors.

Bite season month by month

Of the 18 species recorded in Iowa, 18 are active in June — the peak of the local season. The humid continental climate here is what sets those boundaries: species that need warmth disappear at the edges of the year, while the indoor ones do not care.

MonthSpecies activeNotably
January 2 Bed bug, Head lice bites
February 2 Bed bug, Head lice bites
March 5 Honey bee, Lone star tick, Flea
April 12 Mosquito, Honey bee, American dog tick
May 16 Mosquito, Honey bee, American dog tick
June 18 Mosquito, Honey bee, American dog tick
July 18 Mosquito, Honey bee, American dog tick
August 18 Mosquito, Honey bee, American dog tick
September 16 Mosquito, Honey bee, Carpenter ant
October 11 Mosquito, Honey bee, Bald-faced hornet
November 4 Flea, Bed bug, Head lice bites
December 2 Bed bug, Head lice bites

Narrowing it down in three questions

  1. Where on your body? Below the knee in clusters points to fleas or chiggers. Uncovered skin — arms, shoulders, neck — points to bed bugs or mosquitoes. Along a sock line or waistband is close to diagnostic for chiggers.
  2. How are they arranged? A line or zigzag of three or more suggests bed bugs. Scattered single bumps suggest mosquitoes. A curved group with white pustules the next day means fire ants.
  3. Indoors or outdoors, and when? Bites that appear overnight in one specific bed are a different problem from bites after an afternoon in tall grass. In Iowa the outdoor season runs April to October; the indoor species run all year.

Stings rather than bites in Iowa

Honey bee, Carpenter ant, Paper wasp, Bald-faced hornet, Yellowjacket are recorded here. Stings differ from bites in one way that matters: they can cause anaphylaxis in sensitised people, and that risk does not depend on how bad previous stings looked. Anyone who has had a severe reaction should carry an adrenaline auto-injector.

Species associated with illness here

Most bites from these species transmit nothing. What matters is the follow-up: note the date of the bite, and report any fever or expanding rash in the following weeks to a clinician, mentioning the bite explicitly.

Seek medical care if

Call emergency services now for difficulty breathing, swelling of the lips, tongue or throat, dizziness or fainting, or hives spreading away from the bite.

  • difficulty breathing, or swelling of the lips, tongue or throat after a sting
  • a red area that is spreading, hot and painful, especially with a red streak
  • fever, chills or feeling generally unwell in the days or weeks after a bite
  • an expanding rash appearing 3 to 30 days after a tick bite
  • a bite that is getting worse rather than better after 72 hours

Year-round in Iowa

Weather does not affect everything. Bed bugs, scabies and head lice depend on people rather than season, so a bite pattern in January in Iowa points to those first — see what is biting me at night.

Get a photo assessment in the app

Everything above is free to read. The app adds what a page cannot: point your camera at the bite and get an assessment of the most likely cause, a severity read, and a day-by-day care plan — including the specific signs that mean you should be seen.

Download for iPhone — free

iPhone and iPad. Free to download.