Caterpillar control gets unexpected help

When doing research trials on black cutworm control about 10 years ago, we were frustrated by the fact that the black cutworm caterpillars kept disappearing before we could count them. And in a seemingly unrelated event, we noticed swarms of yellow jackets (Vespula) hovering, at ground level, all around our test plots.

We found out that the two observations were actually very much connected, and that the wasps were voraciously feasting upon "our" black cutworms, as shown in the photo…