Many people refer to a fluttering insect appearing indoors as a “miller.” This article clarifies what these insects are and why they are a familiar sight, particularly during certain seasons. Understanding these common visitors can help demystify their presence.
Understanding the Term “Miller”
The common term “miller” generally refers to certain types of moths, particularly those that appear in large numbers. This informal name comes from the fine, powdery scales that easily rub off their wings, resembling the flour dust that would cover the clothing of a miller working in a grain mill. In many parts of the Western United States, the most common moth referred to as a “miller” is the adult stage of the army cutworm, scientifically known as Euxoa auxiliaris. This species belongs to the Noctuidae family, a large group of moths also known as owlet moths.
Physical Traits and Life Stages
Moths commonly called “millers” are medium-sized, with muted brown and gray coloration. Some display subtle patterns on their broad wings. They have feathery or filamentous antennae used for sensing their environment. Like all moths, their life cycle progresses through four distinct stages: egg, larva (caterpillar), pupa, and adult moth. Female moths lay eggs in grassy areas, which hatch into larvae that feed on various plants. After several weeks, the larvae transform into pupae, often burrowing into the soil, before emerging as adult moths. Adult miller moths are primarily nocturnal, meaning they are active at night.
Common Behavior and Management
Miller moths often enter human dwellings due to their attraction to light, seeking shelter from daylight, or accidental entry during migratory flights. They are not considered harmful to humans; they do not bite or sting, nor do they feed on clothing or household items. While the larval stage, the army cutworm, can be an agricultural pest that damages crops, the adult moths primarily feed on flower nectar and do not reproduce or lay eggs indoors.
Managing Miller Moths
To manage their presence in homes, preventative measures are effective. Minimizing outdoor lighting during peak seasons reduces their attraction. Sealing cracks and gaps around windows and doors, and ensuring screens are intact, prevents entry. If moths do get inside, they can be removed by vacuuming or by setting up simple traps, such as a bucket of soapy water placed under a light source.