Varying in color and size by the species, this beetle flies after dusk and is attracted to light. The various common names, may beetle, June bug, June beetle, refer to the season when adults are active, but it’s the earlier larval form that should worry gardeners. Also called white grubs, the larvae resemble Japanese beetle grubs in both appearance and in the damage they do. Adults nibble on leaves of shade trees and roses, but their activities seldom cause problems.