How to Manage Pests
Identification: Natural Enemies Gallery
Syrphid, flower, or hover flies
Flies in the Syrphidae family, 1000 species in North America
DESCRIPTION Life Cycle
Syrphid flies are regularly found where aphids are present in agricultural, landscape, and garden habitats. Adults of this stingless fly hover around flowers, have black and yellow bands on their abdomen and are often confused with honeybees. Syrphid flies undergo complete metamorphosis with 3 larval instars. Females lay their whitish to gray oblong eggs, each measuring 1 mm (1.32 inch), singly on their sides usually near aphids or within aphid colonies. Larvae are legless and maggot shaped and vary in color and patterning but most have a yellow longitudinal stripe on the back. They can be distinguished from caterpillar larvae by their tapered head, lack of legs and their opaque skin, through which internal organs can be seen. Larvae vary in length from 1 to 13 mm (1/32 to 1/2 inch) depending upon their developmental stage and species. Pupa are oblong, pear-shaped, and green to dark brown in color. Pupation occurs on plants or on the soil surface.
Adult syrphid flies feed on pollen and nectar, while it is the larval stage that feeds on insects. Larvae of predaceous species feed on aphids and other soft-bodied insects and play an important role in suppressing populations of phytophagous insects. Larvae move along plant surfaces, lifting their heads to grope for prey, seizing them and sucking them dry and discarding the skins. A single syrphid larva can consume hundreds of aphids in a month. Not all syrphid fly larvae are predaceous, some species feed on fungi.
Publication on syrphid flies: