Q: I found a huge green moth on my front door! What is it, and do they visit flowers so I can attract more?
A: This beauty is one of my favorite insects…a Luna Moth, a native species and one of our largest North American moths. Their green color, rare among our local moths and butterflies, ranges from medium to pale celery-green or a pistachio ice cream hue. Their long hindwing tails and eyespots combine to give them a look resembling an elephant’s face. I imagine those eyes give foraging birds a moment’s pause, though the bigger predator for these moths is probably bats since they are night-flying.
Adults have vestigial mouthparts and cannot feed, so flowers won’t attract them. They rely on body fat stored from the caterpillar stage (which grows gleefully big) to fuel their brief search for mates and egg-laying sites. You can support breeding populations by caring for caterpillar host plants, which for Luna include hickory, walnut, sweet gum, and white oak, among other trees.
Avoiding pesticide use in home landscapes is of critical importance, though communities that are subjected to aerial forest sprays for Spongy Moth or other pests may, unfortunately, experience population declines, even though such treatments are relatively targeted. Gardeners attempting to rid a tree of nuisance aphids, Spotted Lanternfly, scale, and other insects could inadvertently affect harmless species like these moths in the process. Remember that any tree roots infiltrating a lawn that is treated with a systemic insecticide (like for grubs) might absorb some of those chemicals and transport them into the canopy.
Light pollution is another big detriment to these and many night-active insects (like fireflies), with home landscape accent lighting, porch lights, street lights, and other sources of illumination interfering with their ability to navigate at night.
For anyone curious about moths, I encourage you to participate in or follow National Moth Week, a citizen science project taking place the last full week of July each year. Check out what visits your porch lights, flowers (there are some day-flying nectar-feeding moths), and see if you can ID the caterpillars that wander the landscape or chew holes in tree, shrub, or perennial leaves. So few are truly pests so you won’t need to worry about managing them; leave them to fulfill their part in the food web of our local ecosystem.
You can also sign up to learn about nighttime pollinators and how to support them in the upcoming free webinar: “Working the Night Shift: Pollination After Dark,” taking place on August 3 from noon to 1:30 pm.
By Miri Talabac, Horticulturist, University of Maryland Extension Home & Garden Information Center. Miri writes the Garden Q&A for The Baltimore Sun and Washington Gardener Magazine. Read more by Miri.
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