The Local newsletter is your free, daily guide to life in Colorado. For locals, by locals.
It’s a memory that lives rent-free in my brain. I was about five, and my parents and I lived in a Lakewood house with a sunroom you had to pass through before reaching the front door. Every spring, flurries of miller moths would swarm that godforsaken room. My parents would urge me to sprint through while they stayed behind to valiantly swat at the flapping chaos. My heart pounded as I dashed to safety, convinced these shadowy beasts were seconds away from sinking invisible fangs into me.
Now, I know miller moths don’t bite. Or sting. Or really do anything except flop around like drunk little paper airplanes. But that early terror is hardwired into my nervous system, and I’ve since declared them my sworn enemies. They fly directly at my face like they have a personal vendetta. They leave behind a gross dusty powder on any surface they touch. And when they perch on a wall with their wings folded behind them, they look like triangles. I’m sorry, but no trustworthy animal is shaped like a triangle. I simply don’t believe a benevolent higher power would create geometrical beings.
My mother had enough of my fear one spring day in 2012, a year I recall as having far more millers than usual. Then 13 years old, I was getting dressed and one crawled out of the sock I was about to put on. I screamed so loud that I woke my grandmother from her afternoon nap. That’s when I got sent to a therapist to deal with phobia and anxiety. As a stubborn teenager, I only went twice, but The Anxiety Workbook for Teens still lives in my mother’s basement—a depressing reminder of my failed attempt to overcome my fear.
This year, when I saw a moth outside my kitchen window at the end of May, I ran to my husband to declare that Colorado’s annual invasion had begun. But I haven’t seen one since (and I inspect my car for them before driving). I’m not alone: Commenters on Reddit noted that they’ve seen far fewer miller moths than usual this year, too.
Read more: How Scientists Are Working to Reverse Colorado’s Bug Decline
Lisa Mason, a horticulture specialist with Colorado State University Extension who holds a master’s degree in entomology (bug science), says that moth numbers in Denver depend on conditions in Colorado’s eastern plains. Each fall, the army cutworm moths (their official name, as many moth species have been dubbed millers) lay their eggs in alfalfa fields on the plains. The caterpillars that hatch from those eggs spend the winter munching on grass before they burrow underground in the spring to become pupae. Once fully grown (anywhere from mid-May to mid-June), the moths fly more than 100 miles to the mountains to spend the summer in cooler temperatures, passing through Denver (and my folks’ sunroom) on the way. By late summer, they return to the plains to lay their eggs, and the cycle starts over again.
“There might just be less moths migrating west than usual,” Mason says, “and that could be due to anything from drought to farmers mowing their alfalfa fields at the wrong time.”
The low numbers could also be influenced by weather and moisture, according to Mason. This year has been Denver’s warmest spring in 13 years—which means that the army cutworms likely aren’t hanging out in the city to sightsee, but are instead hustling straight to the cooler mountain air.
While that’s great news for me, Mason says that miller moths are incredibly beneficial for the ecosystem. They pollinate flowers and serve as yummy snacks for Denver’s birds, which are currently busy feeding their chicks. Still, this year’s low numbers aren’t cause for entomologists to panic. While it’s true that insect populations are declining nationwide, this year’s lack of moths isn’t necessarily indicative of any bigger trend—yet. “Moth numbers ebb and flow,” Mason says. “This is probably just a slow year.”
3 Tips for Keeping Miller Moths out of Your Home
Whether you welcome moths as pollinating pals or, like me, are considering a move to Alaska to escape them, use Mason’s best ideas for keeping your home miller-free.
1. Seal your home.
“Sealing any open crevices where moths can slip into your house is the best way to keep them out,” Mason says. That includes putting screens and weatherstripping on your doors and windows. Carefully look around your home for any crannies (including in your garage, which the bugs seem to consider a VIP entrance).
2. Reduce outdoor light.
Moths are attracted to light, so turning off your porch light at night will keep them on their way. “Keeping outdoor lights to a minimum is also beneficial to a lot of bird species that are migrating right now,” Mason adds.
3. Skip the pesticides.
Army cutworm moths are unaffected by pesticides, according to Mason, even those brands that are marketed to kill them. If they’re already flapping around your kitchen, try placing a bucket of soapy water underneath a lightbulb. The moths will bump into the bulb and fall to their soapy demise. If that feels too brutal, Mason—who is, let’s remember, Team Bug—suggests gently catching with a cup and releasing them outside.
