What Are Luna Moths and Their Meaning?

Image used with permission of photographer

A friend posted a picture on Facebook one morning of a huge green moth on a pillar of her patio. Neither of us had ever seen anything like it. It didn’t take long to locate it on Google. It was a Luna Moth, one of the largest in North America. Although, not rare, they are rarely seen.

In Canada they are found from Saskatchewan east and in the United States, east of the Great plains from Florida to Maine. In the northern part of their range they will produce one generation per year while in the southern areas there will be 2–3 generations.

They were first identified and written about in 1700 by James Petiver, the first saturniid moth in North America to be formally identified. Their name refers to their nocturnal nature and the eye spot on the wings resembling a crescent moon.

They have lime green wings and a white body. The adult wingspan is usually about 4.5” (11.4cm) but can expand to as much as 7” (17.8cm). The adult Luna moth will appear around late May/early in the northern areas, around April in the southern areas. Their livespan is 7–10 days.

With such a short lifespan, they don’t waste time on getting the mating ritual underway. The females emit a strong pheromone which males can pick up over a kilometer away. Once discovered the male (or males) will make a beeline to the waiting female. The first to arrive will be the one and only mate.

She will lay about 200 eggs in small batches on the underside of leaves of bushes and then will die. The eggs will hatch about 10 days later. They will molt about 5 times over the next 3–4 weeks as the caterpillar grows to a length of about 2.5” (6.4cm). The fat it develops during the caterpillar stage will nourish the adult when it emerges. The adult doesn’t eat.

The caterpillar’s green colour helps to camouflage it and protects itself from predators through a clicking sound with its mandibles and regurgitating a distasteful fluid. Predators include: hornets, bats, ground beetles, owls, wasps and rodents.

Once the caterpillar has reached full size it will start to spin itself into a silk cocoon wrapped inside a leaf. It will remain in the cocoon until the adult is ready to emerge by cutting its way out with tiny serrated spurs on it’s wings. The adult will emerge…