The Coming of Spring: Moths on the Front Range of Colorado

As spring arrives on the Front Range of Colorado, residents can expect the return of a familiar sight: a vast number of moths. These fascinating insects emerge from a winter hibernation known as diapause, signaling the onset of warm weather and longer days.

The Rich Diversity of Moths in Colorado

Colorado boasts a remarkable diversity of moth species, many of which are now hatching after months of dormancy. Moths—members of the insect order Lepidoptera—are primarily nocturnal, unlike their daytime-active relatives, butterflies. In fact, butterflies are simply a subset of moths; while all butterflies fall under the moth category, not all moths can be classified as butterflies.

Miller Moths: A Local Phenomenon

One of the most recognizable moths during this time is the “miller moth.” These nocturnal travelers are often referred to as “army cutworms” in their caterpillar stage due to their propensity to march in large numbers across fields and roads in search of food. Both the adult moths and their caterpillars are usually drab brown in color, although the moths exhibit variability in their patterns.

Despite the annoyance they may cause to some, miller moths play significant ecological roles in Colorado’s ecosystems. As an assistant professor of ecology and evolutionary biology at the University of Colorado’s Natural History Museum, I study moths from various niches around the world, with a focus on the Noctuoidea superfamily, which includes miller moths.

Unique Life Cycle of Miller Moths

Unlike most moths that undergo a dormant pupal stage during winter, miller moths spend the cold months as partially developed caterpillars on the eastern plains of Colorado, Wyoming, Kansas, and Nebraska. This head start allows them to capitalize on fresh, nutrient-rich foliage from crops like wheat and alfalfa as spring arrives. However, their early feeding can sometimes cause significant agricultural damage.

Pupation occurs later, and once the adult moths hatch, they embark on an extraordinary migration westward, traveling over 100 miles (approximately 160 kilometers) to higher elevations. There, they seek out flowering plants, feeding on nectar and pollinating along the way.

Into Our Homes: The Moths’ Quest for Shelter

This migration often leads miller moths to seek refuge in homes and vehicles, where they can slip through small gaps. Inside, they don’t feed or reproduce; rather, they simply rest. A gentle disturbance can cause them to flutter about, prompting a chase from curious pets. If you find a miller moth in your home, they can easily be relocated using a cup or jar.

After spending their summer in the mountains, these moths will return to the plains in August or September to complete their life cycle by laying eggs in agricultural fields.

The Nighttime Pollinators

While most people are aware of the importance of daytime pollinators, moths contribute significantly to the polination process after dark. Surprisingly, they account for a larger number of pollinator species globally than both bees and butterflies, yet their contributions are still not fully understood. Scientists are working diligently to uncover the specific plants that miller moths may pollinate.

My research aims to reveal what caterpillar stages of certain moths consume, while my colleague, Dr. Julian Resasco, explores the feeding habits of adult moths as they engage in pollination.

Ecological Role and Conservation

Moths are vital to the food web, serving as a primary food source for bat species and even larger animals like bears during migration seasons. Despite their significance, factors such as light pollution, habitat destruction, and agricultural chemicals are leading to declining moth populations worldwide.

Conclusion: An Invitation to Appreciate Moths

The next time you spot a miller moth flitting about during the night, remember that this seemingly nuisance is playing an essential role in our ecosystem. Consider turning off outdoor lights to help facilitate its journey, allowing these hardworking pollinators to do what they do best.

This article is republished from The Conversation under a Creative Commons license.