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Bug of the Week is written by "The Bug Guy," Michael J. Raupp, Professor of Entomology at the University of Maryland.

Coffee and long-legged flies, Dolichopodidae


Dolichopodids can often be seen holding some unidentifiable morsel of invertebrate flesh in their mouthparts as they rest upon leaves.


If you’re like me, a strong cup of coffee is a pretty good way to start the day. This early morning reverie often begins overlooking a sunny flower bed, a good place to watch the antics of insects. Over the past week or so, small brightly colored flies with unusually long legs have been busy dashing about the foliage of my trees, shrubs, and herbaceous plants. These are dolichopodid flies, renowned for the metallic color of their exoskeletons that come in shades of green, blue, bronze, gold, and a variety of other hues. Many species have dark, smoky patterns on their otherwise transparent wings. These patterns are believed to be important in elaborate courtship displays used by males to woo females of their species. As adults, dolichopodids are scavengers or predators of soft bodied prey such as aphids and worms. Little is known about the precise feeding behaviors of the immature stages of dolichopodids, maggots found in stems of plants, decaying wood, under the bark of trees, or cruising the horizons of organic matter in damp garden soil. However, larvae of some species are predators of other invertebrates in the soil. Take a moment on a sunny morning to watch the antics of these beautiful and peculiar long-legged flies.

Dolichopodid flies with their iridescent, metallic exoskeletons are among the most beautiful of all flies as they cavort on foliage. 


The article “Density-and food-resource-dependent courtship behaviour in the fly Poecilobothrus nobilitatus L. (Diptera, Dolichopodidae)” by Klaus Lunau, Andrea Middelmann & Marion Pianka, and the text “An Introduction to the Study of Insects” by Donald J. Borror, Charles A. Triplehorn and Norman. F. Johnson were consulted for this episode.