Brimstone Butterfly - Gonepteryx rhamni

Phylum: Arthropoda - Class: Insecta - Order: Lepidoptera - Family: Pieridae

The Brimstone butterfly is one of the most beautiful of the Pieridae 'whites'.

Description

The Brimstone is a less deep yellow than its southern European close relative the Cleopatra, the males of which have orange patches on their forewings. In other respects these two species are very similar, with wing shapes which when closed look remarkably like pale green leaves. The raised veins on the undersides of the wings of this and other Gonepteryx species when at rest further reinforce the illusion of leaves. (And the wings are invariably closed when this butterfly is at rest.)

These large and impressive butterflies have a wingspan ranging from 6 to 7.4cm. The males are on average slightly smaller than the females.

Distribution

In Britain the Brimstone butterfly is found throughout most of England and Wales but is rare vagrant in Scotland. Gonopteryx rhamni ssp. gravesi is present in small numbers over much of Ireland, where it is more often seen in the west.

On mainland Europe and in eastern Asia the distribution of Brimstones coincides with the availability of its larval foodplants Alder Buckthorn and Common Buckthorn. This butterfly's range extends from the southern edge of Scandinavia down to the northern fringes of Africa and eastwards to western Siberia and Mongolia.

Lifecycle

Generally having just a single brood, the newly-emerged adult Brimstones can be seen from late June or early July through until late August or early September, when they hibernate as adults until the following spring.

The larval foodplants of the Brimstone butterfly are various kinds of buckthorns and in particular Alder Buckthorn Frangula alnus and Common Buckthorn Rhamnus cathartica.

The eggs, larvae and chrysalises of the Brimstone are various shades of light to mid green.

Acknowledgements

This page includes pictures kindly contributed by Betty and Tony Rackham, James Wainscoat and the Countryside Council for Wales (CCW).

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