Milkweed Tussock Moth

Euchaetes egle, the milkweed tiger moth or milkweed tussock moth, is a moth in the family Erebidae and the tribe Arctiini, the tiger moths. The species was first described by Dru Drury in 1773. It is a common mid- through late summer feeder on milkweeds and dogbane. Like most species in this family, it has chemical defenses it acquires from its host plants, in this case, cardiac glycosides. These are retained in adults and deter bats, and presumably other predators, from feeding on them. Only very high cardiac glycoside concentrations deterred bats as predators. Adults indicate their unpalatability to bats with ultrasonic clicks from their tymbal organs.