These boldly patterned beetles are common on yarrow (pictured here) and other flowers in western North America (Alaska-California to Northwest Territories-Saskatchewan-Texas). Adults feed primarily on pollen and occasionally on small insects, while the larvae parasitize leafcutter bee or wasp nests. After hatching on flower heads, larvae wait for a visiting bee or wasp, attach themselves and hitch a ride to the nest. Bee or wasp larvae are their targets, although the literature suggests they can sustain themselves on pollen, which results in a lengthier development time.
Photo by: Rose Marchak on 6/19/21 in Missoula, MT