Despite its larger-than-life name the Duke of Burgundy is quite a small butterfly, and with its upper surface brown with vivid orange spots it is unlikely to be confused with any other species found in the British Isles. The larvae feed on the leaves of primroses and cowslips, transposing to winged adults in May and early June or occasionally a little later. The adult males of this now very rare (in Britain) butterfly species can be seen flying low over their territories, which are usually quite small areas of a few tens of square metres at the most; they defend their patches aggressively, seeing off invaders many times their size. The females are more secretive and therefore harder to spot. It is rare to see this butterfly seeking flowers, but they alight on leaves - particularly ferns and other tall green vegetation often just long enough to allow you to focus a camera, departing just as you press the shutter!
Males have a typical wingspan of 3cm, while females average around 3.3cm; however, the easiest way to determine which is which is by observing the behaviour. The males are extremely territorial; they patrol small areas of warm, sheltered scrubland and will see off even very much larger butterflies that invade their territory.
Loss of suitable woodland-clearing and coppice habitat as well as restricted migrating corridors limit the prospects for recovery of this now very rare butterfly, which is now restricted to just a few sites in Britain and is absent from Scotland and Ireland. They are most often found in chalk and limestone grassland, although in Cumbria we found a few of these lovely butterflies among hazel scrub and ferns in the limestone pavement at Gait Barrows National Nature Reserve, just inland from Morecombe Bay.
Elsewhere in Europe colonies of the Duke of Burgundy are found in central Europe and as far south as Northern Spain and Portugal; it also occurs in temperate Asian countries as far east as the Urals.
Emerging as a winged adult in late April or early May, the female Duke of Burgundy lays her tiny cream eggs in small groups on the undersides of leaves of Cowslips (Primula veris) and Primroses (Primula vulgaris) as well as on the hybrid of these two plants, False Oxlip. True Oxlips, (Primula elatior) are very rare in Britain, but no doubt the larvae of this butterfly would be very happy to munch thereon.
Caterpillars of the Duke of Burgundy are pale green in the first instar, becoming greyish brown and slightly hairy. Like so many larvae of day-flying insects, they feed at night, hiding away at the base of their foodplants during the daytime and so reducing the risk of predation. Towards the end of July the caterpillars pupate in leaf litter beneath bushes or under hedges. The Duke of Burgundy pupa, which is often attached to a curled-up dead leaf that aids it camouflage, is cream with dark-brown spots on the thorax and abdomen. The pupation stage lasts about nine months, during which time the helpless insect is potential food for slugs and snails as well as small mammals such as shrews, voles and mice.