First I noticed the frass (that’s pooh, to most of us). Then I thought ‘Something fairly big must be in these Alexanders’ flower heads somewhere’. And, sure enough, with a little gentle pulling aside of leaves and flowers, I found the frass creator, very well camouflaged by its light green colouring. And then I thought, ‘There might be more’. And, sure enough, I found three caterpillars on three different plants, and frass on several more plants. These are the larvae of the Angle Shades moth (Phlogophora meticulosa). I thought it seemed rather early for them but my local Butterfly Conservation expert George tells me you can find them pretty much any time of year.