An extremely hardy caterpillar

Up until last night, my personal best cold weather caterpillar was this animal, a Woolly-bear, Pyrrharctia isabella, the larva of the Isabella Tiger Moth. The heavily bristled Woolly-bears are well known for cold weather wandering, and I made this photo on December 26 when the temperature was 42 degrees and a brisk wind was blowing. The caterpillar was trucking right along. Sorry for the less than stellar photo; I saw it from the car while clipping along at a good rate, and barely had time to jump out and snap this one image.

Well, I was much more surprised to see this seemingly uninsulated specimen crossing the road last night. The temperature at the time was 42 degrees, tying the aforementioned Woolly-bear, but everything was wet. None of this fazed the caterpillar, which was moving quite well. I knew it was some sort of cutworm, and it didn't take long to determine its identity as the larva of the Large Yellow Underwing, Noctua pronuba.

I didn't have a photo of a live adult Large Yellow Underwing, but I did have this specimen photo. It shows the features of this handsome moth well enough. Noctua pronuba is not a native; it is indigenous to much of Eurasia, and was introduced to North America at Novia Scotia, Canada in 1979 and has since spread like wildfire. It is now locally abundant in many areas. Demonstrating the extreme mobility of flighted insects, this moth has made it all of the way to Alaska and California.

The caterpillars are well known for their cold hardiness, and if you see a decent sized plain jane cutworm running around in temperatures less than 50 degrees during winter thaws, it is almost certain to be this one.