Caterpillars munch on:
Caterpillars fill-up on food in the autumn before finding an area of leaf litter to nestle into over winter. Once settled, they’ll spin themselves a silk cocoon. They’ll stay in this until the following spring, before changing into a chrysalis and emerging as a moth shortly afterwards in April.
There is even more about this species on the main Butterfly Conservation website
These tiny, day-flying moths are very common in herb gardens and are easily spotted perching on their favourite food plants.