Arizona species
Brown widow spiders in Arizona
Latrodectus geometricus
A non native widow spreading in Arizona cities. Its bite is much milder than a black widow's; look for the spiky egg sac.
Source: UC Riverside Center for Invasive Species Research: Brown Widow Spider
Source: UC IPM: Widow Spiders and Their Relatives
How to identify
- Tan to brown with black and white markings.
- Orange hourglass under the abdomen rather than red.
- Banded legs.
- Egg sac covered in pointed silk spikes, the easiest way to tell it apart.
- Size
- Smaller than its larger widow relatives, which UC Riverside says may be why it injects less venom.
- Habitat
- Patio furniture, eaves, block walls, play equipment and other sheltered outdoor spots.
- Where in Arizona
- Not native. Brown widows have spread into Arizona cities, with research grade iNaturalist sightings mostly in the Phoenix and Tucson areas.
Look-alikes
Prevention
- Seal gaps around doors, windows and utility lines.
- Repair screens and add door sweeps.
- Reduce clutter near walls and in garages.
- Cut down on the insects spiders feed on, including near outdoor lights.
Call Hydra if you find widow spiders or spiky egg sacs near doors or play areas. After a bite, contact a doctor or Poison Control at 1-800-222-1222.
When to call Hydra
Call or text us, we answer both. Or send us your details and we'll come back with a free custom quote.
Frequently asked questions
Is a brown widow as dangerous as a black widow?
No. UC IPM and UC Riverside say brown widow bites are much milder than western black widow bites, usually just pain and a red mark, though one verified bite needed a hospital stay. If you're bitten, call Poison Control at 1-800-222-1222. This is general information, not medical advice.
How can I tell a brown widow egg sac?
It is round with many pointed silk spikes, while a western black widow egg sac is smooth.