# Blame caterpillar for numerous flies



## Hamilton Reef (Jan 20, 2000)

State environmental experts didn't artificially release large numbers of flies known as sarcophaga aldrichi, which resemble a large housefly. They produce every 10 to 15 years to feed on the forest tent caterpillar.

Blame caterpillar for numerous flies:
Outbreak of annoying insects helps eliminate hardwood tree killers

By Associated Press

MARQUETTE -- State forest specialist Robert Heyd chuckles when people ask whether the Michigan Department of Natural Resources is responsible for the unusually large number of flies this summer. 
Heyd blames the region's fly surplus on the forest tent caterpillar. 
"I've been up here for two or three cycles of the forest tent caterpillar," Heyd told the Mining Journal. "Every time, people think that this certain type of fly has been released artificially." 
Every 10 to 15 years, sections of the Upper Peninsula's hardwood forests are defoliated by the forest tent caterpillar. 
It's the caterpillars' presence that sparks an outbreak of a fly known as sarcophaga aldrichi, Heyd said. 
Resembling a common housefly, only somewhat bigger, sarcophaga aldrichi feed on the forest tent caterpillar pupae while inside their cocoons. 
"They lay an egg on the cocoon that becomes a living maggot," Heyd said. "The maggot feeds off the cocoon and the caterpillar doesn't come out." 
Although the forest tent caterpillar population is reduced, huge numbers of the sarcophaga aldrichi fly are vexing everyone from farmers to fishermen. 
Perhaps the fly's only redeeming characteristic, other than reducing the number of caterpillars, is that they don't bite, Heyd said. 
"In fact, they're called friendly flies," he said. 
"But they are fairly dirty. They like to land on everything and leave a bit of frass (fly excrement) and then take off."


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## Hamilton Reef (Jan 20, 2000)

Trout, I also learned something new with this article. What we see in the general housefly is not always what they are. Our eyes to not see the detail to split out the families and specie. I really appreciate the value of this website for the learning potential and ability to pass on educational articles.


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