I spotted a Japanese Beetle out in the yard on a plant, at first it concerned me a little as I know they have no natural predators to keep them in check in the USA.

They eat leaves, leaving behind only the veins as adults, and consume roots as grubs.

Left unchecked they can wreak havoc.



But the introduced Winsome Fly will lay eggs on the beetle body, which when they hatch will enter the beetle and start consuming it, starting with the parts which give the beetle the ability to fly.

The beetles go into defensive mode and bury themselves, but it's too late and the fly larvae kills them off as it continues to feed on the beetle host.



They were actually considered a failed predator when first introduced in New Jersey, because the life cycle wasn't overlapping well.

But it turns out that the flies that made it north, where spring came later, the cycles between the fly and beetle became a bit closer and it's probably why we don't see nearly the kind of Japanese Beetle damage as many other areas.



If you look at the map for Winsome Flies on Inaturalist, they are mostly in the New England/New York area, with a pocket out by Minneapolis and a couple of pockets by Montreal and Ottawa.

It's good to see the eggs on this beetle in person, as I don't feel very concerned about Japanese Beetles going unchecked in the North Country.