Editor’s note: A version of this story was originally published in June, 2018.

Miller moths are here for the season – and they’re hard to miss.

With their erratic flight patterns and tendency to hide in the doorways of homes, cars and garages, millers often find a way to bounce around rooms and hang around indoor lights.

The overall army cutworm moth population will be below average for the 2019 season, according to Whitney Cranshaw and Frank Peairs, two entomologists from the Colorado State University extension-in a question and answers report about miller moths.

The spring flight of army cutworm moths was delayed this year, due to the cool spring. Instead of miller moths being around from May until mid June, like last year, they’ll be here to stay through early July.

“Hot weather will accelerate the flights, and shorten the migration period …cool weather will cause the flight to be prolonged,” said the Colorado State Extension entomologists. This means that they’ll migrate quicker in hotter environments, and slower in cooler ones.

One reason for the below average population is because numbers were low last year, which resulted in smaller amounts of army cutworm eggs being laid in the fall.

The amount of precipitation that eastern Colorado has experienced this spring is another major factor, said the entomologists. Due to the moisture, there is an increasingly large amount of wildflower blooms across eastern Colorado. The moths then spread out, in search for the nectar-bearing flowers.

What is the life cycle of a moth?

Miller moths, the adult stage of the army cutworm, lay eggs in the late summer and early fall, typically in wheat fields, alfalfa fields or turf grass and other areas where vegetation is thick, according to a fact sheet produced by the extension office. In Colorado, this usually happens in the eastern part of the state.

Within just a few weeks, the eggs hatch, and the caterpillars begin feeding on broadleaf plants and grass.

They spend most of the winter as partially grown caterpillars, feeding when temperatures allow them to. By the middle of spring, they burrow into the ground and pupate, making their transition from an army cutworm to a moth.

About a month after that, moths as we know them emerge – and start migrating toward us. After making their way west, they spend a few months out of the summer in higher elevations, resting in sheltered areas and feeding on nectar.

Toward the end of summer, moths head back to Colorado’s lower elevations, lay eggs and repeat the cycle.

Why do they migrate?

According to the extension, moths likely migrate to the mountains for the same reason a lot of people do: to get away from the heat. For moths, cooler temperatures allow them to conserve energy and live longer, making life less stressful for them.

Colorado’s high elevations also provide a reliable source of flowers, which give them enough nectar to feed on for the summer.

According to the CSU Extension, migration periods vary. During a large outbreak in a warm, dry season of 2002, populations stuck around from late April until early July and stayed concentrated around irrigated areas along the Front Range. Sometimes, wet weather and cold winters kill millers before they even get a chance to migrate. Other times, they’re killed by natural predators, such as ground beetles and parasitic wasps.

How do you get rid of them?

There are a few ways to get rid of miller moths. The easiest methods? Swat at them. Point a vacuum hose in their direction. Open the door to let them out.

The extension office had another suggestion for people who want spend a little more time plotting their way to get rid of them: fill a bucket partially with soapy water and hang a light bulb above it.

The moths will be attracted to the light, fall into the water and die. Extension officials said the key is to use soap or detergent – not water alone – to prevent the moths from escaping.

Be careful with this method, the extension warned, because of the electrical danger.

Once they die – either in the home or in the water – dispose of them.

To sum it up

Moths are annoying, but not harmful.

While they enter homes, they don’t feed there or lay eggs. They also do not eat household furnishings or food, and eventually die on their own inside the home without reproducing.

“Probably the greatest damage created by millers is the lost sleep resulting from their flying about the room and the needless worry that they may reproduce in the home and cause harm to household furnishings,” according to the extension sheet.

-Greeley Tribune intern Madisyn Gentry contributed to this story.