Orange Tip Butterflies

Late April is the peak time to see one of our early butterflies flitting up and down hedgerows, the Orange Tip. Easily recognised by the bright orange tips of the forewings, the males are very obvious and common in the valley.

The females on the other hand are less obvious because their wings are tipped with dark grey and they look like the Small Cabbage White. If you can wait until it lands, you will see that the female Orange Tip has a beautiful green mottled camouflage on the underwing, this is the same in the male.

The scientific name, Anthocharis cardamines translates as flower beauty of the Cuckoo Flower. The flower beauty is obvious when you see the butterfly. April into May is when the females lay eggs and one of the favourite food plants of the caterpillars is the Cuckoo Flower, a delicate pale pink member of the cabbage family that lives in the damp meadows which are the main habitat of the females.

They also lay eggs on Hedge Garlic, another member of the cabbage family that is common in the hedgerows that surround the meadows. As you might guess, the leaves smell and taste of garlic, although it is not related to Wild Garlic at all. Hedge Garlic is much more robust than Cuckoo Flower and there is evidence that males reared on it end up larger than males raised on the much smaller Cuckoo Flower.

The females need to find a sturdy plant with newly opened flowers. They prefer plants growing in full sun, these will have nutritious seeds ripening by the time the caterpillar hatches. Plants with older flowers are avoided, possibly because they may already have had an egg laid which will hatch before the new one.

I say egg because the eggs are laid singly, and for a very good reason. When the caterpillar hatches, it eats its egg case will cannibalise any other eggs on the plant.

The caterpillar goes through five moults as it grows and then moves down to the base of the plant to pupate in July. The pupa is very well camouflaged as a bud protruding from the lower stem of the plant. Sometimes there is a summer hatching of the adults in late August but mostly they overwinter and emerge the following spring.

There are two main predators of the caterpillars, spiders and muntjac deer. The spiders hunt the caterpillars directly, but the deer are accidental or incidental consumers, eating the caterpillars while browsing the plants. Some estimates have the deer eating up to 19% of the caterpillars, but I am not sure how they were counting that.

Records show that the changing climate is definitely affecting the butterflies. The average first sighting of Orange Tips is 17 days earlier than fifty years ago, and the data for that is much more reliable than the deer munching. As the plants are also flowering earlier this is unlikely to affect the breeding success and the population numbers are stable at present, so you can look forward to these beautiful creatures brightening our spring landscape in the future.

Ed Dolphin