Wildlife Watching Wednesday: The Large Yellow Underwing Moth

By: Tom Berg

Moths are interesting creatures.  They usually do most of their flying and feeding under cover of darkness, so most people don’t see them very often.  They are attracted to bright lights at night, though, and sometimes they land on the sides of buildings or on the ground near these lights and can still be found there the following morning.  Checking out these brightly lit areas is a great way to see a variety of nocturnal moths.

One such moth is the Large Yellow Underwing moth.  These inconspicuous moths are fairly large, with a wingspan of more than two inches.  While at rest, this moth folds its wings back so the forewings completely cover its rear wings.  The forewings can be a variety of colors, from light brown or beige (as seen in this photo), to very dark brown or even nearly black.  Its hind wings (or “underwings”) are where the color can be found, as they are bright yellow or yellowish-orange, with a distinct black band along the trailing edge.

The large yellow underwing moth can be found in many places throughout North America, although it is not one of our native moths.  It was introduced to Nova Scotia, Canada in 1979 and spread all the way to the Pacific coast in just over 20 years.  It is native to Eurasia.  As an invasive species, it can be destructive and is known to be a pest in gardens and to farmer’s crops.

The adult moth itself does not cause damage – it is the caterpillars that are harmful.  The large yellow underwing caterpillars are called cutworms, and the name is very fitting since they often chew right through the stem of leafy plants and “cut” them down.  They feed on a wide variety of plants, too, from flowers like marigolds, carnations, dahlias and violets to vegetables like beets, carrots, lettuce and tomatoes, just to name a few.

Another name for the caterpillars of this moth is the “winter cutworm”.  Since they are native to Eurasia and countries like Russia, Turkey, Ukraine, Afghanistan (and others), they are quite comfortable in cold climates.  These cutworms are mostly dormant in the winter, but will emerge on warmer winter days to look for food!

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