Gooseberries

Hi

A friend has checked his gooseberries on Monday and all was fine, checked yesterday and nearly all the leaves have been eaten, by thousands of little caterpillars, green in colour banded aparently.  Any ideas what they are, and if I can do anything to protect mine, as I have a really nice crop at the minute.

Secondly do I need to be feeding them with anything?

Cheers

Dave