Life in a leaf

After my delight finding lots of different galls on trees and other plants last week, I was stuck at home for a family event today. As everyone was leaving, I looked along the road and realised there was an example of the most impressive take-over of a tree by an insect we've seen in recent years. This is a Horse-chestnut leaf partly occupied and discoloured by the leaf mining larvae of the moth Cameraria ohridella. There was great concern a few years ago when Horse-chestnut trees started showing the dramatic leaf browning in late summer caused by this moth. However, it is now known that the trees survive despite massive infections in some cases. The larval activity is too late in the tree's annual growth period to do much damage. So here we have a clever insect making massive use of a plentiful food source after the tree has ceased to need the chemical factories of its leaves and just before it drops them anyway. Mind you, it does leave an ugly mess for a while, but nature has never minded this.