Black Widow - Latrodectus hesperus

seems variolus occurs in northern CA, and judging by the hourglass, it would appear to be one, but hesperus sometimes have a split hourglass, too.

Compare guide page images for the two.
Also, hesperus generally orient their webs toward the ground, primarily preying on terrestrial insects and spiders.
The variolus I observed in north FL were primarily arboreal, most of them with webs in low tree branches (between four to six feet high). Their webs were small to massive cobweb sheets with snares extending a foot or more above the sheet, effective for capturing flying insects.
Where was this one?

… Jeff Hollenbeck, 25 May, 2007 - 5:05pm

Ground Level

Her web is built over dirt very close to the ground, alongside a cement walkway in my apartment complex. She's about 3 inches off the ground in this picture. I watched her repair her web a few days ago and it was quite interesting to see the way she "squats" to attach the silk to the ground. I've seen three other female black widows (one of which also has a split hourglass) around my apartment complex and their webs are all within 6 inches of the ground. One of the others (with a fully connected hourglass) lives only about 5 feet away from this one; is it common to find different species so close together?

… Timothy Boomer, 25 May, 2007 - 6:54pm

Tim,

I forgot about this image, yet another example of hourglass inconsistency.

… Jeff Hollenbeck, 19 June, 2007 - 6:33pm

Thanks

for pointing out that example. I went for about a half mile walk around my neighborhood the other night and saw several more widows. They were all pretty close to the ground and about half of them had split hourglasses. Is it unusual for that high of a percentage of hesperus species to have split hourglasses? I wonder if it is affected by climate. It's been very hot here (90s and 100s recently) and much less humid than some other parts of the US (southern CA for example). Just some thoughts. Thanks again for all your great info. =)

… Timothy Boomer, 19 June, 2007 - 9:30pm

sounds like they are all hesperus. Widows (of the same species) are often found close together where abundant.
L. geometricus is the only NA species that consistently has a complete hourglass, and it's introduced!
Take a good look at the lines she attaches to the ground. If they are snare lines, you will see sticky viscid droplets on them where attached to the ground to about half an inch up.

… Jeff Hollenbeck, 26 May, 2007 - 9:34pm

Thanks for all the great info

Thanks for all the great info, Jeff. To be honest, I couldn't really make out the droplets you described, but that's probably due to my reluctance to get my face that close. But if I can somehow manage to get a clear picture of the snare lines, would it be useful to post it on BugGuide? If so, should I add it to these images or put it somewhere else?
~Tim

… Timothy Boomer, 4 June, 2007 - 7:13am

would be a neat addition, and useful. If the same specimen, add to these, otherwise the hesperus page is fine.

… Jeff Hollenbeck, 4 June, 2007 - 9:46pm