This “fluff” is also known as the Dogbane Tiger Moth, for the caterpillars’ penchant for dogbanes (Apocynum spp.). They also feed on milkweeds (Asclepias spp.). In our area they stick to low to mid elevation open habitats with dogbane, particularly in canyons and foothills. The mostly nocturnal moths (pictured below) have evolved an impressive defense against bats. Equipped with special ears that are sensitive to the echolocation call frequencies used by bats, they listen for and jam the bat’s echolocation with their own ultrasonic clicks, throwing off the bats’ ability to accurately see the potential meal. Listen to a two-minute Bug Bytes episode to get the full story.
Photo by: Heather Minster 8/16/21 in Johnsrud Park near Bonner, MT
Photo by: Glenn Marangelo on 6/4/21 in Missoula, MT