Flower Flies are conspicuous members of terrestrial ecosystems. Their size ranges from 4 mm to over 25 mm and their coloration from bright yellow or orange to dull dark black or gray with a few iridescent forms. Flower flies are abundant on flowers, which are used as mating sites and energy sources. Only the microdontines are not found associated with flowers, but rather with their ant hosts. The economic importance of flower flies is great. These flies are pollinators of major significance. In some agro ecosystems, such as orchards, they outperform native bees in pollinating the fruits.

Syrphine maggots are important predators of pests, such as aphids, scales, thrips, and catepillars, and are rivaled only by lady-bird beetles and lacewings as predators useful for biological control. Some flower Flies, however, are detrimental. Maggots of a few species attack bulbs and tubers of ornamentals and vegetables. And a few species have been recorded as causing accidental myiasis in man. Flower flies are abundant everywhere except in arid areas of the Old World and in the extreme southern latitudes, Although flower flies range to the highest latitudes in the north, they are absent from subantararctic islands and Antarctia.