Caterpillars munch on:
Adults take nectar from a range of flowers including:
In summer, around mid-June, fully grown caterpillars wander off in search of a suitable place to pupate. Using silk, they suspend themselves upright on a vertical surface such a plant stem, before changing into a chrysalis. They’ll spend around 10 months in this stage, before emerging as adults in the spring.
There is even more about this species on the main Butterfly Conservation website
Orange-tip caterpillars are cannibalistic; they will eat eggs and other caterpillars if encountered on ‘their’ plant. Female Orange-tip butterflies will usually only lay a single egg on each chosen food plant, to avoid this extreme sibling rivalry.