Venomous spiders in Iowa
How to recognize them
Black widowMedically significantFew open records
Brown recluseMedically significant4 records, 2 counties
Black widow Latrodectus mactans, L. variolus, L. hesperus
- Shiny black female with a round abdomen
- Red hourglass or two red marks under the abdomen
- Messy, strong web low to the ground, often in garages, wood piles and water meters
Brown recluse Loxosceles reclusa
- Dark violin shape on the back, neck of the violin points to the rear
- Six eyes in three pairs (most spiders have eight)
- Plain tan abdomen and legs with no bands or spines
Almost all spiders have venom, but very few can hurt people. We list the ones with medically significant bites plus a few that people often worry about.
Counties with records
- None recorded
- 1 species
- 2
- 3 to 4
- 5 or more
Active months
Harmless spiders people mistake for them
- Brown Recluse vs Wolf Spider Wolf spider: harmless
Quick answers
Questions
How many venomous spiders are in Iowa?
2 species live in the state: Black widow and Brown recluse.
Which venomous spiders in Iowa are dangerous?
Black widow and Brown recluse: bites or stings need medical care.
Which harmless spiders get mistaken for venomous ones in Iowa?
Wolf spider. See the side-by-side comparisons below.