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For Insects, Spiders & Their Kin
For the United States & Canada
Photo#12922
False Widow Spider - Steatoda grossa - female

False Widow Spider - Steatoda grossa - Female
Fort Bragg, Cumberland County, North Carolina, USA
March 12, 2005
Bad focus, but honestly I was a bit nervous. I am wondering if this could be a young black widow. I checked the entire spider...and there was no red anywhere. It sure has the look of a widow. This spider (body only) was about 8 mm.

Male Black Widow Look alike?
Last night I removed a small (8mm) all black spider that looked exactly like a male black widow spider from the eaves of the attic closet. We live in Oradell, NJ which is in Bergen County, Northern New Jersey. Question, we do have these here, correct and if there is one, there are more, correct?? I placed it carefully outside and sorry I did not take a picture. Could not see any red. Also every October we have many, cone shaped webs on our ivy. Is this when they make their webs? Thank you for this wonderful site. Joanne

 
New Jersey black widow....
First I'll say I do think you have black widows in New Jersey, probably the Northern Black Widow.

But you mention that your spider was 8 mm and ALL BLACK. While the size would be correct for a male, male black widows are not all black.

You probably have some Steatoda sp. like the one pictured above.

See male Northern Black Widow here:

Steatoda?
This could be a species of Steatoda, some of which are convincing mimics of Latrodectus spp (widows). If this was quite a small spider, it probably was NOT a widow. Immature black widows of both genders are mostly white, gradually becoming black and immaculate (or nearly so) on the dorsal surface of the abdomen as they age. Ultimately, the only way to tell is by the eye arrangement.

 
only way to tell is by the eye arrangement
Ok, the "only way to tell is by the eye arrangement"?? Please tell me what the differences are!

I have either a number of widows, or steatodas, that I have found in my house and shed on a regular basis over the last year. I am accustomed to the black widow, having lived many years in the west, now I'm in central Mass. I am used to a high level of variation in widow coloring, but never completely without red. I know we brought a few widows along, packed up in moving boxes, but they were decimated by freezing weather. However, the ones I am finding are a glossy black, with no red anywhere, but a slight brown-ish, purplish mottling on the under-side of the abdomen. Very slight, regular in shape, but not hourglass. Compared to the widows I'm accustomed to, the abdomen MIGHT be slightly smaller in comparison to the rest of the body and legs, the legs MIGHT be slightly larger in diameter, and slightly less long in comparison to the body, but these differences are slight enough to be a population variance! Haven't managed any decent photos yet! Tell me what is different about the eye arrangement, please!

 
False widow vs. Widow - Mass.
In your area you most likely have the Northern Black Widow. You can see images of them here. I'm not sure, but I think that the most common Steatoda in your area is the Boreal Cobweb Spider. I think if you look through the pictures you will see the difference between the two. If you are unsure, just err on the side of caution.

 
Latrodectus vs Steatoda - eye arrangements
Lynette, thank you, but I was hoping Eric or someone would chime in with eye arrangements, as Eric stated that was an "ultimate" test. I'm quite sure, but not 100%, that what I see are not widows.
The spiders I am seeing are surprisingly similar, but lacking a few key features/behaviors. For instance, I am seeing these spiders in my basement areas. I have lived with widows for many years, and I have very occasionally found them in a well-kept shed, but never in the house area. Under it, yes, not in. The only time I ever found a widow in the house was after moving, when I found them in moving boxes. Another thing, is that the spiders I'm now finding, are glossy black, but lack any red. The only coloration is on the underside of the abdomen, and that is VERY faint. I have seen instances of spiders with a similar appearance at other local residences. While I think they are probably Steatoda something, I am not 100% sure.
The pics you mentioned did have one of Steatoda eye arrangements. I will look for a similar pic of widow eyes.

Thanks;
Mark

 
Eye arrangement
I did an article on eye arrangements. You can see it here. According to the spider experts I talked with eye arrangment is not what you should be looking for to ID to species. However, there is an eye arrangement of a widow in the article.