I've been growing nasturtiums between the herbs in my window box for colour. I discovered a few days ago that they've been infested with caterpillars. The gardening websites I looked at told me they were pests and I should get rid of them, but I decided I actually preferred growing butterflies (Large White in this case) to growing nasturtiums (too fluorescent), so I would leave them alone and hope to see them pupate and hatch. This morning I've taken a few pictures so you can appreciate them too. I'll keep watching and snapping and see if I can document their development into adults.