Our horticulturist found this Luna Moth (Actias luna) caterpillar feeding on the leaves of a river birch tree. He placed his hand behind the caterpillar for scale. The Luna Moth lays its eggs on a variety of deciduous trees including walnut, beech, persimmon, and hickory. Within two weeks, caterpillars hatch from the eggs to begin feeding. The caterpillar will go through a series of molts before reaching its largest size, about 2 ½ inches. Once the Luna Moth caterpillar has fed enough to reach this size, it spins a dark brown, silken cocoon in leaf litter laying on the ground. After a few weeks, the winged adult Luna Moth emerges as a beautiful, large, nocturnal moth with stunning pale green wings, pure white body, and two wavy ‘tails’ (actually extensions of the wings). Adult Luna Moths can have a wingspan of four inches, and they lack mouthparts. The Luna Moths fly in spring and summer, never eating as adults, and instead serve the sole purpose of reproducing. Luna Moth females emit pheromones around midnight that can be detected by males from a long distance, their sensitive antennae picking up the scent. Overall, there are three brood cycles in Missouri; caterpillars found at this time of the year will likely build their cocoon and wait until spring to emerge. The Luna Moth is considered endangered in certain regions, but its numbers are somewhat strong in Missouri.