Gonepteryx rhamni (known as the Common Brimstone) is a butterfly of the Pieridae family..
On the upper side the male is sulphur yellow and the female white with a greenish tinge but both have a spot in the centre of each wing.
The eggs are laid singly on the leaves of either Common Buckthorn (Rhamnus cathartica) or Alder Buckthorn (Rhamnus frangula) – the only two food plants – and females will wander far and wide in search for these particular shrub.
G. rhamni is one of the longest lived butterflies, living up to thirteen months, although most of this time is spent in hibernation.