Brimstone  (Gonepteryx rhamni)

Not threatened.

The brimstone is a common butterfly. The males are bright yellow in colour and it is widely held that the species was the inspiration for the name ‘butterfly’ (4). The females are more greenish-white in colour, with an orange spot in the centre of each wing. The undersides of the wings are greenish, with prominent veins (3). The caterpillar has a green body with blackish flecks, a white line along the sides (2).

Widespread in southern England, becoming less common further north. The range is expanding at present, particularly in northern England (5). Elsewhere the species is found throughout Europe with the exception of the extreme north (2). It reaches Mongolia and North Africa (5).

Found in open, typically damp woodland and scrub, hedgerows and open ground where the foodplants (buckthorn Rhamnus catharticus and alder buckthorn Frangula alnus) occur (2) (5).

The brimstone is univoltine, meaning that one generation is produced per year. During May, females lay their eggs singly on the undersides of leaves of the foodplants. The caterpillars hatch after around ten days; they then feed on the leaves, typically resting along the mid-rib where they are difficult to spot (2). After around a month, pupation takes place; the caterpillars attach their pupae to the stems of the foodplant. Around two weeks later the adults emerge (2); they do not mate at this time but instead spend many hours feeding on nectar, building up reserves for hibernation. This species has a very long proboscis, and can exploit flowers with very deep nectarines, including runner bean flowers and teasels (5).

This species is not threatened at present.

Conservation action has not been targeted at this common butterfly.

For more on butterflies, their conservation and details of how to get involved see: Butterfly Conservation:
http://www.butterfly-conservation.org.uk

For more on butterflies see: The Millennium Atlas of Butterflies in Britain and Ireland by: Asher, J., Warren, F., Fox, R. Harding, P., Jeffcoate, G. & Jeffcoate, S. Published by Oxford University Press.

• Proboscis: a tubular protrusion from the anterior of an animal (e.g. the trunk of an elephant).
• Pupae: stage in an insect’s development when huge changes occur, which reorganise the larval form into the adult form. In butterflies the pupa is also called a chrysalis.
• Pupation: the process of becoming a pupa.
• Univoltine: (also known as ‘single brooded’). Insect life cycle that takes 12 months to be complete, and involves a single generation. The egg, larva, pupa or adult over winters as a dormant stage.

1. National Biodiversity Network Species Dictionary (January2004): http://www.nhm.ac.uk/nbn
2. Carter, D. & Hargreaves, B. (1986) A field guide to caterpillars of butterflies and moths in Britain and Europe. William Collins & Sons Ltd, London.
3. Still, J. (1996) Collins Wild Guide Butterflies and Moths of Britain and Europe. HarperCollins Publishers, London.
4. Buczacki, S. (2002) Fauna Britannica. Hamlyn, London.
5. Asher, J., Warren, F., Fox, R. Harding, P., Jeffcoate, G. & Jeffcoate, S. (2001) The Millennium Atlas of Butterflies in Britain and Ireland. Oxford University Press, Oxford.