Purple Emperor (Apatura iris)
Male. Taken at Fermyn Woods, Northants, on July 7th 2016.
(1/320th sec at f14. Approx 1.4x lifesize)
Male underside. Taken at Fermyn Woods, Northants, on July 7th 2016.
(1/640th sec at f14. Approx 1.4x lifesize)
© David Hastings
DescriptionWing span: 73 - 90 mm
The male Purple Emperor ("His Imperial Majesty") is one of the most beautiful of all of the butterflies found in Britain. From certain angles he appears to have black wings intersected with white bands. However, when the wings are at a certain angle to the sun, a purple sheen is displayed (the result of light being refracted from the structures of the wing scales). The female is a deep brown colour and does not have the purple sheen found in the male.
This butterfly is restricted to central southern England, particularly south Wiltshire, Hampshire, West Sussex, Surrey, the Oxon/Bucks border and south Northamptonshire.
It is found in well-wooded areas, often on clay soils where the damp conditions are favourable for willows.
The flight period is from the end of June to early August. The larva is the over-wintering stage.
The primary larval foodplant is Goat Willow. Crack-willow and Grey Willow are also used. Adults feed mainly on aphid honeydew and tree sap. They do not visit flowers.
This butterfly spends most of its time in the woodland canopy, with the occasional close encounter when it comes down to feed on sap runs or, in the case of the male, animal droppings, carrion or moist ground that provide salts and minerals.
This species is listed as Near Threatened in the latest Red List of British Butterflies (PDF).