I’m finally getting around to updating you on the caterpillars that repel down from the oak trees during the middle of May.
I put some soil, old oak leaves, and other debris from the ground in a screened terrarium and captured a bunch of the caterpillars as they descended down from the trees. At the end of the day, I checked in on the caterpillars and some of them had already started spinning small webbed cocoons in the leaf litter and even under the lid of the terrarium. A month later there were small moths fluttering around inside. They were beautifully camouflaged on the old oak leaves. They held their bodies in a diagonal position with their front legs propping up the front of their bodies. They have long stripped antennae that are the length of their bodies. They reminded me of the delicate tip of a watercolor brush.
iNaturalist identifies them as a moth in the genus Caloptilia. The larvae begin as leaf-mining sap-feeders. The latter instars usually exit the leaf and feed within a folded roll at the tip of a leaf lobe. You can see the tissue being eaten away leaving a brown spot on the leaf with the leaf veins exposed. When I unrolled some of the leaf tips, I found caterpillars inside some of them. They were either still crawling around or starting to spin a cocoon. With the leaf tips that were empty, I guessed they were the ones where the caterpillars decided to descend from the trees and spin their cocoons in the leaf litter on the ground. That certainly seems like a good strategy for avoiding chickadees.
Now I am wondering where things go from here. The caterpillars spun their cocoons and hatched out into moths. Do the moths overwinter and lay their eggs in the spring? Or do they mate and lay eggs that overwinter and hatch out in the spring? Also, I don’t remember seeing the caterpillars again later in the summer the same way I see them in the spring. So my guess at this point is that there isn’t a second generation this year. I’ll just keep trying to stay aware, be curious, observe, and research them.
Nature is an inexhaustible source of wonder. I hope to see you out there!
