Fly Captures Attention

This fly caught my eye because it was hunched over another on a grass inflorescence. At first I assumed it was mating, but upon closer inspection I saw it was eating the smaller fly. Turns out this beauty is a tiger or hunter fly, Coenosia sp. There are over 400 species in the genus coenosia; not sure which one this is. Their larvae feed on other creatures in the soil, often the maggots of destructive fly species feeding on the roots of crops, aka root maggots. Some of these coenosia flies are used by humans as biological control agents, especially in greenhouses where they are especially good at controlling . . . fungus gnats whose larvae feed on fungus in the soil, then emerge from the soil of house plants as annoying adults .

The adult tiger flies are what's called generalist predators, typically feeding on other dipterans, that is, flies. After a bit, this tiger fly flew off, leaving a speck of processed fungus gnat behind. That is the fungus gnat carcass on my fingertip.







I found an article about a researcher who trained (well, enabled and observed a repeatable behavior in) a tiger fly which flew from his finger perch to capture prey, returning to his finger much like a hunting falcon would return to its trainer's shoulder. However, I'll be darned if I can find the link; sorry. 3/29/09: Found it!