Margined Calligrapher, Toxomerus marginatus
Syrphidae or Hover Fly Family
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Small fly, about a fifth of an inch
long. The abdomen has an intricate pattern of repeating dark
bands, with symmetrical, upturned comma-shaped lines in the center, on a
yellow to orange background. The thorax is dark brown with a pale
margin. The abdomen also has a thin, pale margin (visible in the
fly at upper right). The legs are generally uniformly colored.
Coloration varies widely, however, from almost completely pale yellow
to almost black. The black and yellow patterns mimic bee patterns
and presumably help protect the flies. Both flies shown are males, which you can tell because the eyes touch in the middle; the females have a wide space between the eyes. According to the online insect information guide, Bugguide, their color depends on the environmental temperature when the larva (maggot) is developing into the adult within the pupa. Hot temperatures lead to pale orange to yellow, while cold temperatures lead to dark colors. The larvae are carnivorous and eat a variety of tiny insects, including aphids and thrips. The adults mostly eat nectar and pollen. The flies pictured were feeding on a Sulfur Cinquefoil in the South Meadow of Wildwood. They are native across Canada and down to Central America, and can be found in a variety of habitats from yards to forests to bogs. There are many other hoverflies, or flowerflies, all small, with similar colors and variable patterns. |
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