Getting under the skin

Down in the woods I noticed the splotches created by holly leaf miner grubs burrowed into the living leaves. 

"The tiny adult leaf-miner flies lay their eggs at the base of the midrib on the underside of the leaf in June. On hatching, the larvae enter the midrib, slowly eating their way forward until the months of September through to November when they enter the mesophyll. Further feeding produces the meandering mines which reach maximum size in March. Larvae pupate within the cuticle of the last larval stage from March to May. "


The parasite does very little (if any harm) to the holly but can itself be parasitized by a tinier wasp.
 The larvae can also be picked off by blue tits, leaving a V-shaped tear in the leaf. I must look out for evidence of that.