Wasp ID

[schmiggle]

Sadly I couldn't catch any pictures of the wasp I saw today--it flew away as I took out my phone--so I will describe it.

A little over an inch long, deep blue wings, black body (all segments and eyes), orange tarsi, legs otherwise black, carrying a brown cockroach about half an inch long which it (probably she) occasionally stung. Build standard for a wasp--very skinny abdomen-thorax connection, large eyes, wide head, normal wasp mandibles (for lack of a better description). Found in the woods near Boston, MA.

 

[cold blood]

I see these regularly...I believe you are describing the "great black wasp" (Sphex pensylvanicus). A very unbothersome wasp.

 

[schmiggle]

I see these regularly...I believe you are describing the "great black wasp" (Sphex pensylvanicus). A very unbothersome wasp.

I don't think it's that, for two reasons:

1. Sphex pensylvanicus has entirely black legs, whereas my wasp had orange tarsi (and maybe tibias)
2. Sphex pensylvanicus preys on katydids, whereas this wasp had a cockroach.

I'm pretty sure, after a bit of looking around, that what I found was Podium luctuosum. It's got the orange legs, and it preys on wood roaches. It seems it's uncommonly collected, but I'm not sure it's actually uncommon. I haven't found any records for MA or WI, so I'm really curious if we actually saw the same thing.

 

[cold blood]

• Sphex pensylvanicus has entirely black legs, whereas my wasp had orange tarsi (and maybe tibias)

• Sphex pensylvanicus preys on katydids, whereas this wasp had a cockroach.

HMMM, the pics I looked had the orange on the legs just like that.

Main prey doesn't mean exclusive


You are probably right though...lol, you saw t

 

[schmiggle]

HMMM, the pics I looked had the orange on the legs just like that.

Main prey doesn't mean exclusive


You are probably right though...lol, you saw t

Haven't been able to find any pics of S. pensylvanicus with orange legs, but I do get other results for Sphex with orange legs (funerarius, for example, or ichneumonius). Perhaps that's what you're thinking of? The abdomen on those has an orange stripe, though, and the wings aren't quite the right color. I've seen them before, I'm sure, but that wasn't this.

I also found Sphex nudus, which almost looks right, but it doesn't have the blue wings.

Honestly, I didn't get that close a look at it, but what convinced me about the genus was that it was carrying a cockroach. You're right about primary prey, generally speaking, but a cockroach is different enough from a katydid, and these wasps sound sufficiently specialized, that I bet they wouldn't even recognize each others' prey as suitable baby material