Great Basin Naturalist


Bionomics of a gall midge that emerged from nodulelike structures of herbaceous sage, Artemisia ludoviciana, was studied as a part of a larger investigation on possible nitrogen fixation by this plant. Infested plants collected from the field were regularly examined in the laboratory where some of them were grown in a liquid nutrient medium. In the laboratory, adult midges were reared from pupae and induction of infestation was attempted. Apparent nodulation of these plants is caused by the subterranean bud galls of a previously unknown gall midge, Rhopalomyia subhumilis Gagné. Life history of this midge is reported. These midges have one generation per year in the study areas and overwinter as larvae. There were no indications of paedogenesis. These midges are parasitized by a species of Platygasteridae.