Mining in winter

Brambles are to some extent evergreen - they lose some of their leaves in winter but not all.  It's a good time of year to spot the traces left in the leaves by leaf-mining moth larvae.

These tiny caterpillars eat out the fleshy, green stuff between the upper and lower membranes of the leaf, leaving a translucent white trail.   

When they hatch from the egg laid in the leaf by mummy moth, the tunnel they make is quite narrow, but as they grow fatter so does the tunnel.  Eventually they break out and pupate before emerging as adult moths.

If you look at the top photo you can see there were three larvae in the one leaf.