The male orange-tip butterfly is immediately recognisable by the distinctive orange sectors on the wing tips. Females lack the orange colouring and so rom the top they might easily be confused with the Small White butterfly, Artogeia napi; however the greenish patterning on the underside of the hindwings of both male and female Orange-tip butterflies (see pictures below) is an aid to identification.
Increasingly common in Britain and Ireland, these attractive, early-season butterflies occur throughout Europe and in most temperate parts of Asia. A similar, closely-related species can be seen in parts of the USA.
In Britain and Ireland the first Orange Tips usually emerge in mid April, but in very warm springs you might see them before the end of March, while a cold start to the year can delay their appearance by a week or two. By mid May there are usually plenty of males and females on the wing, but by early June the males and most of the females will have disappeared. In mainland European countries the flight season in mountainous regions can extend into July.
These meadow butterflies seek out Cardamine pratensis (commonly referred to as either Cuckooflower, Milkmaids or Lady's Smock, although they also have several other common names), Alliaria petiolata (Garlic Mustard - also known as Jack-by-the-Hedge) and other members of the Brassicaceae or cabbage family. Pale green eggs are laid singly, upon the flower stalks and usually just one egg per plant, and after a few days the eggs turn orange and then grey. (When more than one larva emerges on a plant it is not unusual for one to attack and consume any others.
It takes just over a week for the eggs to hatch, and the caterpillars, initially orange but turning green as they mature, feed first on the flowers of their host plant and later on the flower stalks, seedpods and leaves. The mature caterpillars are distinguished by blue-green upper bodies and darker green underbodies delineated by a white lateral line.
When ready to pupate, caterpillars that have been feeding on Cuckooflower attach themselves to a nearby woody stem, whereas those (often emerging a week or two later) on Garlic Mustard nearly always pupate on the stems of their larval foodplant.