Flower Fly (Toxomerus marginatus)
Detailing the physical features, habits, territorial reach and other identifying qualities of the Flower Fly.
Updated: 5/23/2018; Authored By Staff Writer; Content ©www.InsectIdentification.org
Flower Flies in the Toxomerus genus look like tiny wasps, but these flies are interested in plant pests, not people.
Seeing this Flower Fly in the garden is always a win. Not only is it harmless to people, it helps clear vegetable and fruit plants of insects that drain and damage them. They are keen mimics of wasps with similar colors and banding on the abdomen, but a look at their eyes and antennae reveal what they really are. In this species, female eyes are separated (see photo), while male eyes are right next to each other (holoptic). They are much smaller than bees, but they are able to hover like them. Flower flies are often seen doing just that over plants loaded with blossoms.
Active from spring through autumn, females lay fertilized eggs on plants. These hatch into larvae that are adept at eating other creatures that are detrimental to a plant's health like aphids, small caterpillars, and other soft-bodied insects. Larvae look like green worms with a yellowish coloring down the center and a thin dark line along the 'back'. They are well camouflaged for the green foliage they live on. So efficient and hungry are these larvae that they may completely eliminate a population of aphids off of a plant by harvest time. Adults drink nectar.