In case you missed it, in late May, I found a huge row of bright green bugs on Frankfort beach, piled a few inches high and a couple of feet wide as far as I could see in both directions.
They were stink bugs, but were they the Michigan green stink bug or were they the exotic Southern Green Stink Bug? And how did they wind up dead on Frankfort Beach?
The first mystery was solved by Nate Walton, extension agent. I took him a large jar of gross green bugs and he identified them as our common green stink bug.
The second mystery was: Why so many?
Julianna Wilson, tree fruit entomologist with MSU, had an explanation: Adult stink bugs are known to congregate. She said this looked like a group that was picked up and blown into Lake Michigan.
Why were they dead? That’s easy. They don’t swim. They’re built for moving around in vegetation.
Where did they come from? Did an east wind pick them up in a Michigan orchard and blow them into the lake? Or did they blow in from Wisconsin or points west?
After several fruitless phone calls, I consulted the Weather Underground online. I could tell you that the data showed that during the two days before I encountered the stink bugs, Algoma Wisconsin — right across the Lake from Frankfort — had winds out of the west with gusts up to 52 miles per hour.
That’s consistent with my hypothesis that these bugs originated in Wisconsin.
I could tell you that, but that’s way too unscientific. There’s still a possibility that a sudden gust from Michigan carried our own stink bugs over the lake.
No one tracks stink bugs that carefully, so that mystery will remain unsolved.