The nectar and pollen of the flowers attract primarily small bees and various flies. Among the bees, these flower visitors include Cuckoo bees (Nomada spp.), Mason bees, Halictid bees, and Andrenid bees. Among the flies, these flower visitors include Syrphid flies, dance flies (Empididae), bee flies (Bombylius spp.), Tachinid flies, blow flies (Calliphoridae), and Muscid flies. Other flower visitors include butterflies, skippers, hummingbird moths, and ants, which seek nectar. The caterpillars of the butterfly Celastrina argiolus (Spring/Summer Azure) feed on the flowers and buds of Viburnums, while later caterpillar instars of the butterfly Euphydryas phaeton (Baltimore) occasionally feed on their leaves, after migrating from the original host plant (e.g., Aureolaria spp.). Several moth caterpillars also feed on Viburnums (see Moth Table). An introduced beetle, Pyrrhalta viburni (Viburnum Leaf Beetle), feeds on the leaves. Among vertebrate animals, the drupes are occasionally eaten by birds, primarily during the fall migration (see Bird Table); they are also eaten by the Eastern Chipmunk, tree squirrels (Red, Gray, & Fox), and the White-Footed Mouse. White-Tailed Deer browse on the twigs and leaves.