Do caterpillars eat leaves that have fallen off trees? They're still green, mind you. Not the dried brown ones

Question

Or are they picky and only eat the leaves when they're still on trees?

Am helping a colleague to ask this question as she's editing a Science school book. :)

Answer 1

caterpillars eat only green leaves...that may include the fallen green leaves too

they wont eat the dried up leaves

Answer 2

I don't know anyone has done a study of when in the drying process a caterpillar would stop feeding on a green leaf.  You could do it yourself by finding a feeding caterpillar and snipping the leaf after you support in in position.  But then the question becomes was it just time to move to a new leaf or was it a lack of freshness.  Many caterpillars do not consume the whole leaf before moving on to another.  Also how would you measure the "freshness" of a leaf.  The moisture level, the color?