Unknown insect - Torymus koebelei

Moved

My torymid contact informs me that this is the short ovipositor morph of Torymus koebelei. He says that there are three ovipositor morphs: short, intermediate, and long. The species has been reared from cecidomyiid galls on Baccharis and Artemisia. It is conceivable that a study of the DNA of the morphs would show that they are actually separate species. Torymus calfornicus is an analogous case.

Moved from ID Request.

… Bob Carlson, 20 September, 2010 - 11:12am

Thanks a lot, that will lead

Thanks a lot, that will lead me to some interesting reading. Glad I stumbled on this guy.

… PeteHoban, 22 September, 2010 - 5:46pm

Maybe a parasitic wasp laying eggs in a gall?-Do you have an uncropped picture showing the gall and the host plant that it is on?

… Joe Zito, 20 September, 2010 - 6:48am

The gall is in the attached i

The gall is in the attached image. http://bugguide.net/node/view/456867. It was on the tip of a branch of a scrub oak.

… PeteHoban, 20 September, 2010 - 10:42am

Size

As you describe the bug as tiny, I wonder whether its size was less than 1 mm, rather than cm.

Sorry, I don't know what it is.

… R. Berg, 20 September, 2010 - 1:10am

Re: your question about scale here

I just checked Grissell(1)(1976) and he states in the description for Torymus that body length in the genus (excluding ovipositor) ranges from 1-6 mm.

And in his description of T. koebelei he states:

"Torymus koebelei females range in size from 1.2 to 2.3 mm. Males range from 1.0 to 1.7 mm in length. In koebelei the ovipositor length in proportion to the body seems to be most variable [...] I have used the terms "long" to describe an ovipositor twice the abdomen length, "intermediate" for equal to or slightly greater than abdomen length, and "short" for less than abdomen length. The three morphs seem largely discontinuous.
I just measured the ratio of the total length (from tip of antennae to tip of the ovipositor) to body length (from front of head to tip of abdomen) for the female here, using a ruler on my computer screen. That ratio is approximately 3:1 (i.e. the ovipositor and antennae together are about twice as long as the body...so, adding in the body length, the total is about 3 times the body length). Thus, given a range of 1.2 to 3.2 mm for female body length...this female is presumably somewhere between 3.6 and 9.6 mm long in its totality.

So, Pete's "< 1 cm" appears technically correct...though this female may have been well under half that length. And, in terms of the low-end estimate for body length alone, 1.2 mm is quite near the 1 mm mark you intuited ;-)

… Aaron Schusteff, 16 June, 2019 - 4:24pm