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The Season of the Miller Moth

27 Jun 2020 10:33 AM | Natalie Love (Administrator)

It’s 9:00 pm and I’m tidying up after my 8-year-old who is running through the house with the 11-year-old on her tail. They aren’t playing tag or hide and seek. They are saving moths from the evil clutches of our ravenous puppy. Like everyone in town, our house is overrun with moths – Miller Moths to be exact. The puppy loves to eat them, the kids don’t want innocent lives to be lost. It’s a continuous battle.

Miller Moths are a normal part of life in Colorado in the summer. Their lives begin as eggs which hatch into cutworms on the plains. The cutworms feed voraciously on alfalfa, wheat, and other plants and continue growing all winter. Then in the spring, they pupate underground and after a few weeks, they emerge as moths and migrate west to feed on nectar in the Rockies. The migration generally begins in late May to early June and lasts for 4-5 weeks with the first 2-3 being the worst. The number of moths flying around town depends on many things; cutworm predation, moth predation, weather conditions, and availability of vegetation to eat.

Experts say this is actually just an average year. The last four years have been below average, skewing memories to make this year appear particularly bad. It turns out 1991 was the “heaviest, most prolonged flight of Miller Moths across Eastern Colorado.” I remember spending hours setting up buckets and bowls of soapy water under lamps in attempts to capture the Miller Moths for removal. The moths were so bad that year they would pile up an inch deep in garage window frames.

In addition to our short memories, why does this “average” year seem so bad? Drier spring conditions in Colorado combined with the late April frost wiped out some of the vegetation, leaving less food and condensing the Millers around Denver to feed on the nectar from the remaining flowers. Whatever the reason, these moths have brought a level of excitement to our house every night. And you may be wondering why they are called Miller moths? According to the interwebs, the scales on the wings that frequently flake off reminded people of the flour dust that millers were covered in after their shift at the mill.

To learn more about Miller Moths, check out these great websites that I referenced to write this blog post: 1) www.denver.cbslocal.com. Think Those Miller Moths are Everywhere? You’ll Be Seeing More of Them. By Karen Morfitt. May 25, 2020. 2) www.animalsake.com Looking for Information About the Miller Moths? Read These Facts. Accessed June 26, 2020.

Natalie Love is the Lab Director at GEI Consultants, Inc. and realizes this story has nothing to do with water or the lab but has been curious about Miller Moths since at least 1991. 

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