Black Paper Wasp...?
 

I have a single nest of these Black Paper Wasps, anyone seen them before. They look much like a Mud Dauber wasp, except for their communal behavior and nest type.

http://images1.fotki.com/v333/photos...asps007-vi.jpg
http://images14.fotki.com/v336/photo...asps004-vi.jpg

big baseball bat and running shoes! then hit it with fire extinguisher. nasty nasty nasty stings. mega owwwwieeee!

Not these, I walk close to their nest all the time, very non-aggressive, completely unlike the normal paper wasps which prepare for flight by raising their wings when you get within about 6-8 feet. And launch if you get closer, right at you. Extremely aggressive.

Anyway, I've forwarded the photo site I have to the Department of Entomology at Clemson Univ. to see what they think. They think they'll have an answer for me by Monday.

http://www.bugpeople.org/taxa/Hymenoptera/Sphecidae/Chalybion_californicum/Chalybion_californicumPage.htm


http://animaldiversity.ummz.umich.edu/site/accounts/information/Chalybion_californicum.html

No, it's not this kind, but it looks like them. The ones I have are social not solitary, and their nest is paper not mud. That's what makes them so unusual.

I'm pretty sure those are Blue Mud Wasps. Do you have many black widow spiders around? That's the food source for their young.

As for the social behavior you observe (Are you sure they built the nest you're seeing them on?), from the second link: >>"Sleeping" aggregations (see Behavior) may also be part of the mate-finding process (Bohart and Menke 1976).<<

and: >>Sometimes this species is found in groups, sheltering during the night or during bad weather (Bohart and Menke, 1976).<<

Pretty sure it's their nest, but I'll continue to observe them. There are lots of Black Widows around here, so if that's what their young eat, they'll not go hungry. While it rained here last night, they've been on that nest for quite a while, weeks at least.

here's another photo, not very good because of the lens flare, but you can see them.
http://images18.fotki.com/v331/photo...asps003-vi.jpg

I'll try for a better photo later.

we have some here that are wayy big. build huge nests, mega over populate it, and then GUARD IT WITH THEIR LIVES!!!!!! can land on pool water and take off like helio-chopper. then we have the TARANTULA WASP which is even bigger and all black kinda like a blackhawk helio-chopper. had buddy at 5am still drunk passed out on boat berth get bit on arm. he was down for the count for 3 days beyond his hangover. they are wicked. lay their eggs in tarantula that is alive and babies slowly feast off of live host til host is DEAD!