Small cats on Lime leaves: Bucculatrix thoracella

[poschiavanus]

Over the past couple of days I've noticed that most leaves of Common Lime hereabouts have small pale yellow caterpillars eating little windows from the lower side of the leaf. Also many leaves have several silken patches in the axils of leaf veins, many are vacated, and those with something in are very easily completely wrecked in trying to open them, but one or two seemed to have a caterpillar in them. I also picked up a single ribbed cocoon attached to one of the leaves. Unfortunately all these things proved too small to get useful photos.

After quite a bit of umming and ahhing, I'm now pretty sure these are a second generation of Bucculatrix thoracella. I've recorded the characteristic leaf mines of these before in the same area, but don't recall seeing larvae at this time of year.

Apparently most Bucculatrix caterpillars make a moult in a protective 'cocoonet', and the ribbed cocoon is specific to this species: although more usually found on Lime trunks.

The German site lepiforum has some good images which give me good encouragement that I've got the right ID.

Do take a peek at any local Limes and see if these things are about in your district. It would be nice to get some better photos.