Life cycle of the ‘butter-fly’
For many naturalists, their first sighting of a brimstone butterfly is a sure and welcome sign that spring is on its way.
Adults of the species hibernate through winter, often among ivy or bramble leaves, and emerge as early as February. The longest-lived of all UK butterflies with a life span of about one year, males are sulphur-yellow and it is believed that this colouration - that of butter - gives rise to the English word for butterfly. Females are a much paler, yellowish-green and can sometimes be mistaken for ‘cabbage whites’.
Up to 100 eggs are laid on buckthorn, the caterpillars emerging after 10 to 14 days and feeding on buckthorn leaves. The chrysalis is formed after about six weeks and two or three weeks later the adult emerges and flies throughout the summer and autumn before hibernation takes place for the winter.