Caterpillars much on plants of the cabbage family including:
Adults take nectar from a range of flowers including:
In the early autumn, the caterpillars wander around, looking for somewhere to pupate. They usually choose somewhere away from the foodplant such as a fence, a tree or the eaves of a building; somewhere with a bit of protection from the weather. They turn into chrysalises and stay like this for around 8 months, until emerging as a butterfly in the spring.
There is even more about this species on the main Butterfly Conservation website
As they feed, caterpillars accumulate mustard oils from their foodplants in their bodies, and so don’t taste very nice! Their black and yellow colouring warn birds and other potential predators of their unpleasant taste.