The small tortoiseshell is one of our most familiar butterflies, often appearing in our cities and gardens. It is a beautiful bright orange and black butterfly; the upper side of both the fore and hind wings are a bright orange-rusty red colour with three black spots interspaced with yellow on the leading edge. A ring of dull blue spots or crescents lines the edge of both wings. The under wing is rather a drab mottled dark brown-grey colour providing camouflage when the wings are closed and the butterfly is at rest.

Behaviour

Instead of migrating like many butterflies, small tortoiseshell butterflies hibernate (frequently communally) over winter in their adult form, often in garages, barns or sheds.  They emerge again in the first warm sunny days of spring to feed on nectar and lay large amounts of green eggs on the underside of nettle leaves. In southern parts of the range there may be two broods each year. In Scotland, there is usually only a single generation, emerging in June or July, entering hibernation in August, and reappearing in March or April.

The caterpillars hatch after ten to twelve days and have dense black speckling with two yellow lines down their back and one along each side. They have black spines along their sides and back. They feed on nettles, spinning leaves together. After about four weeks the caterpillars pupate. The chrysalis varies in colour but often has a metallic sheen and resembles withered leaves.

The courtship ritual of the small tortoiseshell involves a male chasing the female until she settles on the ground. If she is receptive, she opens her wings and the male steps onto her hind wings, which he drums with his antennae. The pair then flies a short distance and the ritual is repeated.

Size

• Wingspan: 45-55mm (male); 52-62mm (female)

Status

Despite its wide geographical distribution across the British Isles, the small tortoiseshell has recently become a species of concern, due largely to its rapid decline, particularly in the south.

Distribution

This is one of our most widespread butterflies, occurring throughout the British Isles including Orkney and Shetland. Look out for the adults on nectar-rich flowers such as buddleia, heathers, dandelions, thistles and daisies.

When to see

March-September

Facts

• This butterfly’s scientific name, Aglais urticae is partly derived from ‘urtica’ meaning stinging nettle. ‘Aglaia’ was a daughter of Zeus admired for her beauty. The choice of this name reflects the elegance of the small tortoiseshell.
• The small tortoiseshell is a highly mobile species which can occur in almost any habitat, including woodlands, grasslands, heaths, gardens and even in city centres. It is a strong flyer, with high powers of dispersal, reaching remote islands and high mountain peaks. Adults have been recorded at altitudes as high as 1200m in Scotland.