Our best guess for this trio of blister beetles is the Ashgray Blister Beetle (Epicauta fabricii), although the sunflower they’re feeding from doesn’t seem to match their common host plants in the legume family. They’re also less common west of the Mississippi. Regardless, adults in this genus (Epicauta) are velvety and come in gray, tan, or black, or a combination thereof. Larvae feed on egg capsules of grasshoppers, adults are occasional crop pests. Like other blister beetles, if they are handled and squeezed they employ a chemical defense that will blister your skin …so better to observe and not touch. They are also highly toxic to animals (humans included). According to the Kaufman Field Guide to Insects of North America, “[Epicauta] Beetles baled with hay have caused the death of horses that unwittingly consumed them.”
Photo by: Diane Kromarek on 8/6/21 in Great Falls, MT