In my recent post on a lady beetle colony, I posted a picture of a wasp which I'd identified as Polistes dominulus. Unfortunately, the wasp didn't exactly look like the prototypical P. dominulus, as one of my commenters, Julie Stahlhut also noticed. I'm still not exactly sure if it was the same species or not--I'm still looking into it. The rest of the wasps around are easy to identify, like the ones shown here. For a quick comparison, try the site that Julie suggested or check out the same species of wasp in her neighborhood (Rochester, NY.)
Another wasp, hunting remarkably close to a large Adalia bipuncta larva:
That orange-antennaed wasp in the above photos is P. dominulus. As it happens, I'm at an entomological conference, where I'm sharing a hotel room with P. dominulus researcher Aviva Liebert, and she concurs.
I believe that this species has only become established in Colorado within the last 5 years, so you're right on the cutting edge of the invasion!
It really is a small world... I e-mailed Aviva yesterday about my wasps. The two of you have changed my views on entomological conferences. I'd always pictured nerdy boys with cases full of beetles stuck with pins... now I want to go!
In her email, Aviva suggested the wasps might be a different but similar species of Polistes, one that is actually native to the region. (That makes more sense to me, as these wasps seem to be well adapted to hunting the local beetles.)
The more I watch this tree, the more variation I find. I suspect there are several species of wasps and several species of lady beetles up there. It's a small world, true, but filled with an astonishing amount of variation and specialty. I wonder how you guys ever manage to keep track of it all!
It gets smaller. Aviva and I actually collaborated on a publication recently. She's really the P. dominulus expert; I work on an endosymbiont that infects P. dominulus and many other insect hosts.
As for the entomological conference, it's still going on. The attendees make up one of the most fun groups I've ever been in. Of course, it is a social-insects congress!
I just checked in to read Julie's comments and your responses, and I wanted to state that the photo on this page is clearly P. dominulus. In my previous message to you, I was referring to the photo on your lady beetle colony post. The wasp in that photo appeared to be a different Polistes species, perhaps P. aurifer.
Also, about the adaptation to hunting local beetles -- one aspect of its behavior that seems to contribute to P. dominulus being such a good invader is its apparent flexibility in hunting a variety of prey to feed its offspring. So it might not be too surprising to find this recently introduced wasp species hunting beetle larvae along with the more typical caterpillar prey.
And finally I want to say I totally agree with Julie about the fun group of people at the social insects conference -- very much like their study subjects!