Eco Mural Project 13: Luna Moth, The Cube at 30th Street Station, Philadelphia, PA
Few moths are as beautiful or as striking as the Luna Moth. Its vibrant green wings, magenta markings, and graceful elongated hindwing tails make them the subject of much admiration amongst entomologists and nature-lovers alike.
The Luna Moth is the largest moth in North America, averaging a wingspan of about 3-4 inches. Luna Moths prefer to live in deciduous forests and have an expansive range that covers the eastern half of North America. Their beautiful coloring serves as camouflage amongst the bright green leaves of the trees that they prefer to lay their eggs on. In addition to their striking green coloring, they feature distinct markings that emulate twigs with buds on their forewings to further the camouflage illusion. Scientists believe that the silky tails on the hindwings of adult Lunas may be used to disrupt the sonar calls that bats use to locate prey in the dark. Luna Moth caterpillars also have unique ways to foil predators: if camouflage fails them, they rear up into a “sphynx” position, emitting a clicking sound, and regurgitating a foul-tasting liquid.
Luna Moths are often used in classrooms to show their lifecycles. Once a caterpillar hatches from an egg, it will go through five molt stages, also called instars, before wrapping itself in leaves and a papery cocoon to begin its metamorphosis into an adult Luna. Luna caterpillars eat the leaves of several tree species native to eastern North America, including hickory, beech, cherry, willow, and birch. After three weeks inside the cocoon, the metamorphosed Luna cuts its way out of its cocoon using serrated “teeth” near the base of its forewings and emerges with folded, uninflated wings. Lunas tend to exit their cocoons in the morning, allowing a day for them to inflate and dry their wings in time for the evening. Adults do not eat, living only to find a mate and reproduce within a week before they pass away. This process can be repeated up to three times between April and August, with the final round of cocooned caterpillars (pupae), falling to the leaf litter on the ground, and going dormant until the next warm season the following year.
Luna Moths are experiencing population loss in large numbers due to several factors: ecological degradation, human encroachment on wild spaces, use of pesticides, poaching, and light pollution.
The Trump administration has taken a relaxed stance on enforcing the sanctity of our national parks and lands set aside for conservation, and we have seen an increase in development on previously protected lands. Regulations on air and water pollution are also being rolled back in the name of supporting big business and endless profit growth. Pesticides are a significant factor in the destruction of wild spaces, as they have ripple effects on wildlife surrounding agricultural areas. Pesticides lead to mass deaths of pollinators, and as a result destroy intricate chains of predation, causing destruction for both plants and animals alike. To learn more about the threats facing pollinators, especially honeybees, please visit our Honey Bees and Pollination page.
Luna Moths are particularly affected by light pollution, which is largely unregulated within the United States. Luna Moths are attracted to light, but drawing them to our nighttime lamps and streetlights causes major harm to their reproductive cycles, which depend upon a single week’s worth of nights for Luna Moths to pick up on female pheromones, track them, locate a willing partner, and reproduce. Light pollution often thwarts those efforts, dramatically reducing the ability of Lunas to reproduce with enough numbers to support healthy populations. Due to their large size, Luna Moths are high-value prey for owls, bats, birds, and other insectivores, and as moth populations suffer, so do these valuable predators. It doesn’t take much to break the delicate chains of prey and predator within our precious wild spaces, and the fallout from the dwindling populations of Luna Moths is a great example of how that can happen. It is paramount that citizens who care about maintaining America’s ecological heritage, for both moths and the millions of creatures that share their habitats, push back against the rollback of regulations in the name of profit over people and nature. Insects are largely unrepresented in the United States’ protected species list, and so encouraging widespread wildlife conservation to ensure insects like Luna Moths have habitats to flourish in is extremely important.