False widow
Steatoda spp.
Not medically significant; identification against black widow usually ends the question.
- Scientific name
- Steatoda spp.
- Size
- 6–11 mm
- Group
- Spiders
- Identification confidence
- Identifiable with care
No licensed photograph yet
We have not yet licensed a photograph for this species. The written description above is complete and is what the identification depends on — it is not a caption for a missing picture.
How to recognise it
These are the features that identify a false widow. Each one is described in words so the identification works without the diagram.
- Glossy dark brown to purplish-black with a globular abdomen, closely resembling a black widow at a glance.
- There is no red hourglass on the underside. A pale crescent or band often marks the front of the abdomen instead — this is the separator.
- Body 6 to 11 mm, slightly smaller and less glossy black than a mature female widow.
What it leaves behind
- Irregular tangle webs in sheds, garages, cupboards, and around window frames.
- Round cream egg sacs in the web, similar to a widow's.
Why an infestation persists
Steatoda species are commonly killed in mistake for black widows. Bites are uncommon and not medically significant, and these spiders prey on widows where their ranges overlap.
Where it occurs
Widespread across the United States.
Where to look for it
- Sheds, garages, and outbuildings, particularly in upper corners and behind stored items.
- Around window frames and inside the reveal, both indoors and out.
- Cupboards and closets that are rarely opened.
- Under outdoor furniture and in the gaps of stacked materials.
When you see it, and why
Most conspicuous in late summer and autumn when females reach full size, matching the period when black widow reports also peak — which is part of why the two get confused at that time of year.
What getting the identification wrong costs you
The whole value of this page is preventing an unnecessary reaction. Steatoda species are killed in mistake for black widows regularly. Check the underside: a black widow has a red or orange hourglass there, and a false widow does not — it typically shows a pale crescent or band across the front of the abdomen instead. Bites are uncommon and not medically significant.
What a professional actually does
There is almost never anything to buy here. A false widow is not medically significant, and the useful actions — clearing webbing, wearing gloves when moving long-stored materials, and reducing clutter in a shed or garage — are a morning's work with a vacuum. If you are being quoted for a spider treatment, ask first whether the specimen was identified, because a great many such quotes follow a misidentified Steatoda.
What prevents it
- Remove webbing mechanically and reduce clutter in sheds and garages.
- Wear gloves when moving long-undisturbed stored material.
Commonly confused with
Black widow Latrodectus mactans and related species
Mature females are glossy jet black with a red or orange hourglass marking on the underside of the abdomen — visible only from below, so the spider must be seen from underneath or in its web.
Sources
Every claim on this page traces to one of these.
- US Environmental Protection Agency Tier 1. Pesticides.
- National Pesticide Information Center Tier 1. National Pesticide Information Center.
- Cooperative Extension System Tier 2. University extension entomology resources.