Dipterans are among the most common flower visitors and many are known to pollinate. Though often discounted as inefficient pollinators, some researchers have suggested that the efficiency of pollinating flies, midges, and mosquitoes exceeds that of bees in some cases. Further, dipterans appear to be crucial for the pollination of flowers in alpine habitats. In general, however, little is known about the importance of pollination by dipterans, their conservation status, how they may interact with other pollinators, and how such interactions may change if populations of sympatric pollinators decline.

Dipteran pollinators include mosquitoes, such as those of the genus Aedes, which pollinate the blunt-leaved bog orchid, Habenaria obtusata (Family: Orchidaceae), which is considered a sensitive species in parts of the northwestern United States.

Chocolate lovers may be more impressed by another example of pollination by dipterans: biting midges (or "no-see-ums") and gall midges in the Ceratopogonoidae and Cecidomyiidae families, respectively, are the only known pollinators of cacao trees, which produce the beans from which chocolate is made.

In addition to their association with cacao trees, gall midges (Contarinia spp.) form a pollination mutualism with the Malaysian tree, chempedak (Artocarpus integer), which is cultivated commercially in southeast Asia for its edible fruit. This mutualism is unusual in that it is mediated by a fungus (Choanephoraceae , Choanephora spp.). The fungus infects the tree's male inflorescences and the gall midge feeds on the fungal mycelia and oviposits on the inflorescence. When the midge larvae hatch, they feed on the mycelia and pupate in the inflorescence. Pollination occurs because the midges are also attracted to the female inflorescences, possibly due to olfactory cues.

Please browse this section to learn more about the blue bottle fly as a pollinator.