A common master of disguise, the brimstone blends perfectly into the alder leaves it lays its eggs on. Spot them in early spring when they emerge from hibernation.
Common name: brimstone butterfly
Scientific name: Gonepteryx rhamni
Family: Pieridae
Habitat: woodland, hedgerows, parks and gardens
Caterpillar foodplants: leaves of buckthorn and alder buckthorn
Predators: birds and predatory invertebrates
Origin: native
Adults: are medium-large butterflies with veined, leaf-shaped wings. Females have very pale, almost white, yellow-green wings and males have brighter yellow-green wings. Both have a small orange spot on each wing.
Wingspan: up to 6cm.
Caterpillars: are green and very well camouflaged, being the same colour as the leaves of their foodplant. They are often found lying along leaf margins.
Credit: Andrew Ashworth / WTML
Adults: feed on nectar. A long proboscis (sucking mouthpart) enables them to take nectar from flowers, such as teasel, that are beyond the reach of many other butterflies. They prefer to drink from purple flowers, and bluebells are an important early nectar source.
Caterpillars: feed on the leaves of buckthorn and alder buckthorn.
The brimstone is long-lived compared to other butterflies: it can live for up to a year in its adult form. The adults travel to mate in the spring, and fertilised eggs are laid on the underside of buckthorn leaves.
Once hatched, the caterpillar goes through several instars (development stages) before pupation over the summer. The adults then emerge and feed until early autumn when they begin to hibernate. This is a time when they are completely inactive before emerging to mate in the spring.
Credit: Kim Taylor / naturepl.com
Brimstones have spread in recent years and are now found throughout much of England and Wales. Look for them in gardens or woodlands, particularly early in the year before other butterflies have emerged.
Brimstones always settle with their wings closed. The shape of their wings helps to disguise them among leaves.
Brimstone is often cited as one of the first butterflies of the year because adults hibernate over winter in woodlands and emerge on warm spring days. New adults emerge from their chrysalis in July and live for a year. Look for them flitting through gardens and along woodland rides, or spiralling skyward with their partners then tumbling down into the bushes to mate.
Credit: Libby Owen / WTML
The brimstone butterfly is not a species of conservation concern. Its population has spread in northern England.
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Amy Lewis • 22 Jul 2019
