Cecidomyiidae

Cecidomyiidae, commonly known as gall midges or gall gnats, is a family of small flies within the order Diptera. Members are typically 0.2 to 3 millimeters in length, with slender bodies, long antennae, and wings that often show reduced venation. The family is diverse and cosmopolitan, comprising thousands of described species across many genera.

Ecology and life history of Cecidomyiidae are varied. The most conspicuous group consists of gall-inducing species whose larvae manipulate plant tissues to form abnormal growths, or galls, in leaves, stems, roots, or flower buds. Gall formation often reflects complex interactions in which plant hormones and other signals are redirected to nourish the larva. Other species feed on fungal spores, decaying organic matter, or plant tissues without producing galls, and a few are predatory or parasitoids of other insects. Life cycles can range from one to multiple generations per year, and voltinism is strongly influenced by temperature and host plant availability.

Economic and scientific significance is notable. Some Cecidomyiidae species are important agricultural pests, such as the Hessian fly (Mayetiola destructor), which attacks wheat crops. Conversely, many species participate in natural pest control through parasitoids and predators, or serve as model systems for studying plant-insect interactions, gall formation, and coevolution. Taxonomically, the family is placed in the superfamily Cecidomyoidea and encompasses numerous genera with a primarily herbivorous or fungivorous lifestyle.