Spider Wasp - Episyron quinquenotatus

AWESOME!

This wasp is Episyron quinquenotatus. On enlargement of this photo the fromt basitarsus appeared to have four comb-spines. The spines were also very long, apparently (from the photos) longer than the 2nd tarsal segment. This species can be marked on the abdomen in the manner that it is or marked with fewer spots, but the other common species, E. biguttatus rarely has this many (only supporting...E. biguttatus occasionally is marked close to this). Another supporting character: the eyes aren't as converging above as in E. biguttatus, but I've learned that photos can often distort this character so I use it with caution. The comb-spines are enough to separate the two species, however.
The little wasp is in the genus Evagetes and is a cleptoparasite. Most species also have a strong tarsal comb on it's front legs and even if the little wasp didn't get in during nest construction it may have dug its way in after the female Episyron left. They'll then eat the host egg and lay one of their own on the provisioned spider. The species of Evagetes that is known to use Ep. quinquenotatus as host is Ev. padrinus. It's possible that's what the little wasp is but relatively little is known about that genus and all hosts are not know so it's possible that it's another species. Great shots!

… Nick Fensler, 11 July, 2006 - 11:23am

A long awaited answer.

Nick, thanks so much for all this needed information! I put a couple of images in today - better pictures of the Evagetes. I have not witnessed Evagetes digging holes, but will watch closely - since all these wasps are right outside my back door. An Anoplius with red on abdomen also hangs around and I wonder if she might be stealing the Episyron spiders. The Episyron dig a lot of holes during the day, but never use them - another mystery. Thanks again.

Cheers

… Jackie, 11 July, 2006 - 4:33pm

Lots going on...

it looks like I need to visit your area to take down some observations. There might be something undocumented going on there. I'd be extremely interested to see what species that Evagetes is, but they unfortunately are usually not identifiable from photographs. I'll look at those pics. There is a complex of species that hang out in part of the country: Anoplius cleora, Anoplius apiculatus, Episyron quinquenotatus, and their associated Evagetes cleptoparasites. The same species are present at Crane Creek State Park in Ottawa County, Ohio (I live in Lima, OH). This is why I love spider wasps!

… Nick Fensler, 11 July, 2006 - 4:44pm

Evagetes

I'll bag, tag and freeze it for you. Found another 'digger' in my files from last September. Will post it shortly.
You are welcome here anytime - we have lots of room. My e-mail address is in my bio.

Cheers,

… Jackie, 11 July, 2006 - 5:44pm

spider species

is an orb weaver in the genus Larinioides, if that helps with ID.

Ah! you already knew this. We looked at the images in the wrong order, sorry.

… john and jane balaban, 11 July, 2006 - 12:58am

Hee..hee

It's getting late and the images are still in the wrong order.
Goodnight.

… Jackie, 11 July, 2006 - 1:05am

We're eager to hear the answers to your questions!

… john and jane balaban, 11 July, 2006 - 1:10am