Local feeder (Diptera: Cecidomyiidae) in stems of Andropogon

In late July in a remnant prairie, I came upon shoots of big bluestem with dead, browned tips, and dissecting one of these revealed a Lepidoptera larva (record 0054) feeding concealed within the shoot. I collected several similarly affected shoots for rearing. In mid-August I removed the shoots from the rearing container and dissected them; some contained these cecidomyiid larvae and/or puparia of chloropid flies (record 0052) rather than caterpillars. The cecidomyiid larvae possessed a pair of lobes on the terminal segment that somewhat resemble those on the undetermined larva from figs. 89-90 in Gagné (1989), which was collected from seeds of the same host.

The plant material was decaying at this point, so it was not possible to tell with certainty, but it appeared the cecidomyiid larvae were sandwiched between the culm and its enveloping curled leaves, rather than actually inside the culm. The external appearance of the plant at the precise location where the larvae dwelled was not recorded; nor was it clear if the larvae were primary or secondary invaders of the plant tissue or what they were feeding on. Given the uncertainties, this record is listed tentatively.