West Virginia Syrphid Flies Page 1

Family Syrphidae

This magnificent family has many admirers among entomologists and entomophiles. These admirers are attracted to the bright colors, bold patterns, variety of shapes, and to the astounding mimicry of honey bees, bumble bees, mason bees, and wasps.

Oddly enough for a family with so many human admirers, Syrphidae doesn’t have a generally accepted common name, and in fact the family is quite often referred to by the shortened version of its scientific name, Syrphid flies. Others prefer the name Flower Flies, for the adults’ favorite food source, or Hover Flies, in admiration of the family’s specialized flying abilities. Some bee-mimic species, especially Eristalis tenax, go by the common name House Flies.

This is one of those families that can be difficult to characterize—some Syrphids are large while others are small, some are slender while others are plump, some have clear wings while the wings of others are spotted or dark. There is, however, one key trait of the family Syrphidae, and that is the presence in nearly all Syrphid wings of a “spurious vein.” Another trait shared by the syrphid wings is a closed R5 cell. Yet another is a long anal cell that is closed near the rear wing margin (Borror and White, 1970).

In some cases larval Syrphids feed exclusively on aphids. The larvae of other species live only in ant nests. In genus Cheilosia the larvae dine on fungi or other plants, in Copestylum the preferred food source is often cacti, while Syritta and Rhingia larvae often develop in dung. In tribe Eristalini the larvae are aquatic (Vockeroth and Thompson, in McAlpine, 1987).

Adults feed on flowers, consuming nectar for energy and pollen for the nutrients required for manufacturing ova and sperm. Syrphid Flies’ exposed position on flower heads may be what has led so many of these species to evolve into mimics of creatures with stings.

Favored plants of Syrphids include Umbellifers like Queen Anne’s Lace, flowers that have short corollas. Syrphids also have a preference for flowers that are yellow or white.