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Photo#1231023
Black Widow - Latrodectus

Black Widow - Latrodectus
Mt. Vernon, Lawrence County, Missouri, USA
September 14, 2014
Sorry, no ventral view. I was thinking male black widow due to large palps, but the abdomen is round, which I have read is more typical of female.

Intersex?
It has been suggested by James C. Trager that this could be an intersex specimen, displaying large male palps and a round more "feminine" abdomen. Thoughts?

 
It
Is a penultimate male, and a well fed one, hence the fat, round abdomen.

As widows grow, both males and females, they have to feed and basically sate in order to molt to the next instar and eventually reach maturity. Females and juvenile males that are well fed or sated will have fat, ‘round’ abdomens.

While adult males do eat, their abdomens are smaller, so even a well fed adult male widows abdomen will be smaller in proportion to the rest of its body compared to a well fed immature male.

I think I posted examples of sated immature male L. bishopi and adult males if you want to compare, and the mactans and variolus pages should have examples as well.

The specimen in your image is a typical subadult male Latrodectus, just not sure if it is variolus or mactans, though leaning towards mactans.

It
is a well fed subadult male, probably was consuming beetle at bottom right of image.

Moved
Moved from Spiders.

Moved
Moved from ID Request.

Looks like a female
Latrodectus mactans to me.