Identification, Images, & Information
For Insects, Spiders & Their Kin
For the United States & Canada
Carrot wasp - Gasteruption assectator - female

Carrot wasp - Gasteruption assectator - Female
Sweeney Ridge, San Mateo County, California, USA
July 24, 2014
A number of these (both male and female) were intently nectaring on the flowers of "Quenn Anne's Lace" (Daucus carota), a weedy non-native member the carrot family, Apiaceae. The thumbnails below show posts of two other individuals from the same time and locale:

I recognized them as Gasteruption from gestalt, but the main characters are: long slender abdomen attached high on the mesosoma, well above the hind legs; long "neck"; and distally swollen hind tibiae. While adults of this genus feed on nectar (and perhaps pollen) from a variety of families of flowering plants, they are known to be especially fond of Apiaceae.

Using Townes (1950), the short ovipositor (i.e. half or less the length of the fore wings) narrows the candidate species down to G. assectator, G. kirbii, or G. amputatum. The last of those three can be eliminated, since it has a white tip on the ovipositor and its range is southern Arizona into Mexico.

Finally, measuring the length-to-width ratio of the 2nd tarsus of the hind leg and the 4th antennal segment, together with the dull sheen of the head, led me to G. assectator. Details of the characters separating G. assectator and G. kirbii can be found here.

Images of this individual: tag all
Carrot wasp - Gasteruption assectator - female

Quotes are hiding the title
The quotation marks in the title cause the entire title to be hidden from the thumbnail browser, preview. (including the genus & species) I suggest that you remove them from any post, unless you are trying to hide them. Thanks!
I like the title Carrot Wasp, anyway!

Probably Gasteruption assectator. Trying to identify Gasteruption from pictures is a bit precarious. I'm not so sure of all of Townes' characters and no longer try.

Is Townes short ovipositor character still good?
It's a bit tough for me to work through Townes papers (with all the idiosyncratic nomenclature, etc.). But am I safe in assuming his ovipositor length character below (from pg. 120) still works?

    1a) Ovipositor sheath 0.35 to 0.5 as long as forewing; (etc.) .....Gasteruption (sensu stricto of Townes)
    1b) Ovipositor sheath 0.8 to 2.5 as long as forewing; (etc.) ....."Rydinofoenus" ( = Gasteruption of others?)

Townes placed just three species under Gasteruption, namely: amputatum, assectator, and kirbii. I believe all the taxa Townes had under Rydinofoenus are treated by others as being in Gasteruption. As catalogued in the 1979 "Red Book", there were 15 species in if the ovipositor length character is still good that narrows things down considerably in the "short ovipositor" case!

Also, I'm assuming that for amputatum the character "ovipositor tip white (on distal 0.12 of length) " is still good (and perhaps the Arizona + Mexico distribution too). Thus I assumed we could easily pick off any posts with short, entirely black ovipositors and move them to the assectator/kirbii guide page.

...but...I'm guessing its Townes "length-to-width ratio for the 2nd hind tarsus" that may be what gave you pause? That's what I used to place my post here...and I could imagine that it may by "iffy". (Especially in photos, where the angle of view may distort that ratio.)

I don't mind moving this post to the assectator/kirbii guide page if you think that's more appropriate. (But I do wonder, if the hind tarsus character is not dependable...then what does one to separate assectator and kirbii?)