Early spring is a great time to be investigating signs of insects on plants, because with all the leaves being fresh, there is a good chance of finding the insects themselves, perhaps even catching them in the act of leaving the signs in question. I spent the past week or so in Ohio, and on one walk in the woods I started paying attention to the leaves of Ohio buckeyes (Aesculus glabra).
Right away I noticed some tiny holes in the leaf blades, which I imagine were made by some kind of flea beetle (Chrysomelidae: Alticini), but I never got around to photographing or investigating those because I got distracted by the subtler feeding sign left by lace bugs (Tingidae) sucking the leaf juices from below.
It didn’t take long to find some of these buckeye lace bugs (Corythucha aesculi) hiding on the leaf undersides.
My attention then turned to some leaves that were conspicuously drooping and wilting.
Close examination revealed that each one had a tiny hole at the point where the petiole began to droop.
A couple of days later, I revisited these drooping leaves, and this time found the tiny holes covered by extruded frass.
I brushed away one of these frass accumulations, and immediately a little caterpillar face appeared, putting a new fecal pellet in place.
Splitting the petiole open, I got a better view of the caterpillar. It was evidently working its way toward the tip of the leaf, presumably finding less physical and chemical resistance from the plant in the wilted portion.
Since I’ve been on the road with limited internet access, I haven’t had a chance to try and figure out what kind of moth this caterpillar will turn into. This may a well-documented life history; possibly the answer is even in my book, but for the moment it’s a mystery to me.