Brimstone (Early Stages)
Posted: Fri Jul 13, 2012 3:22 pm
The adults of most butterfly species in Britain live for as little as a few days to a couple of weeks. The Brimstone however is generally acknowledged as being the longest lived of all, with some individuals lasting for 11 months. After emerging in early July, the adults feed urgently in preparation for the forthcoming winter hibernation. At this time the males pay little attention to the females and both sexes can be easily be approached. After entering hibernation, usually in a clump of evergreen vegetation such as ivy or holly, but also bramble and privet, they can become active on any sufficiently warm day in winter and so could possibly be seen in every month of the year. In mid to late March they start to appear regularly on the wing. These are mainly males which are now avidly searching for females which have yet to become active.
A female Brimstone is not only very good at finding isolated larval food plants (which are sometimes great distances apart), but she is also a very determined egg layer and can sometimes be seen barging through undergrowth to get to the host plant. Two plant species primarily support the larvae of this butterfly; Common Buckthorn (Rhamnus cathartica) found on calcareous soils and Alder Buckthorn (Frangula alnus) which prefers damper acid soils. Usually a single skittle-shaped egg is laid on a leaf or developing leaf bud, but small groupings may also be found. Sometimes, larger groupings of eggs can also be observed on the buds of favoured bushes which are visited by numerous females.
Part 1 - The Egg and Larva
The egg is white when newly laid, but then turns pale yellow and then orange as it develops. It finally turns pale grey before the larva emerges.
After hatching, the 1st instar larva moves to the nearest fresh leaf and commences feeding by chewing holes in either the upperside or underside. When at rest it will either align itself along the midrib on the upperside of the leaf, or against a rib on the underside, particularly so in periods of poor weather. From the 2nd instar onwards, they are usually found feeding, resting and moulting on the upperside of the leaf. It soon progresses to feeding on the leaf edges and then whole leaves as it develops. After every moult the newly emerged larvae will consume their old larval skin before they recommence feeding on the plant. One has even been observed eating the shed skin of a sibling that has just moulted.
Although well camouflaged, the larvae are quite easy to detect in the wild due to their characteristic feeding damage and of course they get quite large towards the end of their development. At the slightest disturbance they adopt a characteristic posture where they raise the front half of their body slightly, tucking in the front 3 or 4 pairs of legs as they do so. They can also be seen resting in this position.
The posture can also be more aggressive.
This is one of the species which produces droplets of a orange-coloured secretion at the tips of some of the short hairs which cover the body. This has also been observed on Orange-tip larvae, but is more noticeable on the Brimstone because it is a much larger beast. The purpose of this fluid has been the subject of some debate.
When fully grown the larva stops feeding and its colour lightens as it prepares to pupate. It may leave the food plant to seek a safe location in vegetation nearer the ground, but some stay on the host plant. It then suspends itself in a horizontal or head-up position by means of a silken pad at one end and a long silken girdle at the mid-line.
Vince
A female Brimstone is not only very good at finding isolated larval food plants (which are sometimes great distances apart), but she is also a very determined egg layer and can sometimes be seen barging through undergrowth to get to the host plant. Two plant species primarily support the larvae of this butterfly; Common Buckthorn (Rhamnus cathartica) found on calcareous soils and Alder Buckthorn (Frangula alnus) which prefers damper acid soils. Usually a single skittle-shaped egg is laid on a leaf or developing leaf bud, but small groupings may also be found. Sometimes, larger groupings of eggs can also be observed on the buds of favoured bushes which are visited by numerous females.
Part 1 - The Egg and Larva
The egg is white when newly laid, but then turns pale yellow and then orange as it develops. It finally turns pale grey before the larva emerges.
After hatching, the 1st instar larva moves to the nearest fresh leaf and commences feeding by chewing holes in either the upperside or underside. When at rest it will either align itself along the midrib on the upperside of the leaf, or against a rib on the underside, particularly so in periods of poor weather. From the 2nd instar onwards, they are usually found feeding, resting and moulting on the upperside of the leaf. It soon progresses to feeding on the leaf edges and then whole leaves as it develops. After every moult the newly emerged larvae will consume their old larval skin before they recommence feeding on the plant. One has even been observed eating the shed skin of a sibling that has just moulted.
Although well camouflaged, the larvae are quite easy to detect in the wild due to their characteristic feeding damage and of course they get quite large towards the end of their development. At the slightest disturbance they adopt a characteristic posture where they raise the front half of their body slightly, tucking in the front 3 or 4 pairs of legs as they do so. They can also be seen resting in this position.
The posture can also be more aggressive.
This is one of the species which produces droplets of a orange-coloured secretion at the tips of some of the short hairs which cover the body. This has also been observed on Orange-tip larvae, but is more noticeable on the Brimstone because it is a much larger beast. The purpose of this fluid has been the subject of some debate.
When fully grown the larva stops feeding and its colour lightens as it prepares to pupate. It may leave the food plant to seek a safe location in vegetation nearer the ground, but some stay on the host plant. It then suspends itself in a horizontal or head-up position by means of a silken pad at one end and a long silken girdle at the mid-line.
Vince