It is spring on the Front Range of Colorado, which means before long the region will receive an influx of many, many moths.
Colorado is home to thousands of species of moths, many of which are hatching out from a winter of hibernation, known as diapause.
Moths are known to swarm porch, stadium and street lights at night. Each summer, Denver is visited by miller moths as they make their trek to the mountains.
Fairfax Media/GettyImages
At night, porch lights, stadium lights and street lamps are regularly visited by moths, a collective term for most of the nocturnal members of the insect order called Lepidoptera. Butterflies are also part of this order, but they are mostly diurnal, or active during the day. Butterflies are actually just a subset of moths, so all butterflies are moths, but not all moths are butterflies.
The Front Range lies on the path of a springtime migration of a particularly familiar species of moth, usually referred to in this part of the country, including Colorado and neighboring states, as “miller moths.” Miller moth caterpillars are often called the “army cutworm,” a whimsical name referring to the caterpillars’ tendency to reach large numbers that march across fields and roads to find food. Both the moths and their caterpillars are rather drab and brown in color, though the moths are variable in patterning.
‘Miller moth’ is the common name for a moth species that migrates from southeastern Colorado to the Front Range to forage for food.
Chuck Harp, Colorado State University
Many people find miller moths to be a nuisance, and the caterpillars can be a pest. But miller moths are a native species to Colorado and play important roles across the plains and up into the high country.
I am an assistant professor of ecology and evolutionary biology as well as the curator of the entomology collection at the University of Colorado’s Natural History Museum in Boulder. I study moths from around the world. I have a particular fascination for the large moth group known as Noctuoidea, the superfamily to which miller moths and their relatives belong.
As an entomologist, I crisscross the state looking for moths for my ongoing evolutionary, classification and life history studies. During miller moth migrations, they may swarm my moth traps, which are made up of a bright light in front of a white sheet. The crush of miller moths makes finding the less common species that I am looking for all the more challenging in a sea of dusty brown.
To spot and trap moths, entomologists set up bright lights in front of a white background.
Ryan St. Laurent
What makes miller moths so unique?
In temperate regions like most of North America, most moth species hibernate in the cold winter months. During this time, they are in a dormant pupal stage. Some species spin cocoons. They then hatch into adult moths,…
