Grapevine beetles (Coleoptera: Scarabaeidae: Pelidnota punctata) can be found throughout much of eastern North America. Although larvae feed on decaying wood, the adults feed on the leaves and fruit of both wild and cultivated grapes (Vitis spp., Vitaceae).
These beetles can grow to over in inch in length, making them one of the larger insects that can be found in the eastern US. In spite of their impressive size they’re usually incapable of causing serious damage to the grapes they feed on.
Although wild grapes are common here in southeast Michigan I have yet to observe a grapevine beetle feeding. They’re attracted to lights, however, and I occasionally find them near my porch light in the morning.