I had several reports of large flights of the Green June Beetle this summer over the last several weeks. The males fly low to the ground actively searching for females. After mating, the females begin laying eggs in tunnels in the soil. The larvae will feed on humus, mold and the roots of plants. Larvae overwinter in soil below the frost line and emerge next summer.
Some larvae will fall prey to the digger wasp, Scolia dubia. These wasps can be seen flying low to the ground searching for tunnels that contain beetle larvae. The wasps enter the tunnels and lay eggs on the developing larvae. The female wasp stings a grub, paralyzing it and lays an egg on the paralyzed grub. The larva of the wasp will consume the grub during its development and emerge the next summer.