Thursday, October 10, 2013

Syrphid Fly and Wasp Warning

Erika and I had a bad September. Underground Paper Wasps, 10,000 of them, built their nest under our peony bush. Erika was stung three times, I, twice. We didn’t do anything to deserve this viscous attack—we were just standing in the garden. I swelled up, but did not go into anaphylactic shock like I did the last time I was stung. Erika ended up in the emergency room of the Northfield Hospital as she broke out in hives, lost her vision, and passed out. One thing that saved us was our taking two Benadryl right after being stung.

So, in the past few weeks, we have not been outside much. Only now, after dispatching the wasps, have we ventured into the garden. I took a few meadowhawk photos on Tuesday. I gasped upon seeing this bee—had the wasps returned? No, this creature turns out to be a fly, probably an American Hover Fly, famous for mimicking bees and wasps. This look-alike strategy is called Batesian Mimicry, since the fly is harmless to humans.

But hover flies are not harmless to aphids, often the scourge of gardeners and farmers. The larval flies eat aphids and scale insects. Researchers are trying to use hover flies as a biological control of the smaller pests. The adults feed on nectar and pollen. The maggots require aphid meals to complete their development—they are “aphidophagous”—a new word I learned while writing this blog. Releasing hover fly larvae into fields quickly reduces aphid infestations or even eliminates the aphids (University of California).


  1. I noticed a nest or yellow jackets building a nest in the vent of my shop building and I had my daughter spray it and we knocked it down but there is a piece of the nest left and a few of them are still hanging around.

  2. We dealt with our wasps late at night, around midnight.