Local feeder (Lepidoptera: Gelechiidae) in stems of Solidago

Larvae form large, hollow, spindle-shaped stem galls. Prior to pupation the larva prepares a round exit hole in the wall of the stem and seals it with a plug or cap of solid material. This plug is pushed away by the adult when it emerges from the gall.

After a fire in a remnant prairie in early July, I recovered several caterpillars from S. canadensis complex goldenrod stem galls which I am tentatively placing in this record. They were mature or nearly so, robust, and fat, tapering noticably at both ends, pale yellowish-brown in color with a light brown head capsule. A gall that produced one of these larvae was rounder and wider relative to its length than other galls I can more confidently ascribe to G. gallaesolidaginis (such as the gall from a different location and year from which I reared an adult, described in the next paragraph). In fact the rounder, wider gall was more similar to that of Gnorimoschema gallaeasterella in Solidago flexicaulis (record 0523). I am lumping the S. canadensis complex galls together in this record for now until I can learn more about the Gnorimoschema species that make goldenrod galls.

I reared an adult on 9 September from a classic spindle-shaped gall collected in late July or early August. Upon dissecting the gall after the adult moth's emergence, I found two mordellid larvae (record 0518) tunneling in the solid portions of the gall.