Tuesday, March 12, 2013

An extremely hardy caterpillar

Last night showed great promise for a big salamander run. It rained all day, and temperatures crept up into the low 50's. We haven't had a good salamander movement around here as of yet, and I thought last night would be the magical night. My longtime favorite local haunts to seek salamanders is over in the Bellefontaine area west of Columbus. So it was there I headed, stopping by to pick up Bellefontainite and amphibian enthusiast Cheryl Erwin.
March is an incredibly volatile and unpredictable month weatherwise, and last night's sudden shift in conditions bore that out. When I left Columbus, the rain had quit and the ground was soaked - perfect for migrating salamanders. The temperature was 50 degrees - also ideal. Forty-five minutes later, as I entered the Bellefontaine area, the temp had nosedived to 42, which is too cool for big salamander movements. Nonetheless, we trolled some roads anyway, and found a couple of the bizarre unisexual hybrid salamanders - more on those HERE - two Red-spotted Newts, and the prize of the evening, a whopping big Tiger Salamander.
But it was a caterpillar that captured my imagination. Who woulda thunk it? I head out on a cold wet evening to look for hypothermia-defying amphibians, and return with material for a blog on caterpillars.
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.



A.L. Gibson said...

Glad you were somewhat successful and bummer I couldn't join this time around. Still in search of some of those tiger 'manders.

I had good numbers down here in the Athens area last night with spotted, jefferson, and marbled sightings with plenty of red-spotted newts, wood frogs, and spring peepers. Gotta love the spring amphibian rush!

Jim McCormac said...

You didn't miss anything last night, Andrew - it was too cold for much action. Next week or the tail end of this weekend may produce the next good night. If you still want to try for a tiger let me know.