Butterflies of the UK. an insight into their lives: Brimstone

Brimstones can be seen just about anywhere in England and, is common in both Wales and Ireland but still has not reached Scotland. The Brimstone hibernates through our winters here in the U.K. and, is probably the longest living butterfly in Britain, some possibly living for about a year, if not slightly longer, if only by a few days, and a few of them could live long enough to be flying at the same time as their offspring.

This female Brimstone was photographed on, 29th June,which was born the previous year
and has hibernated through a long winter it's offspring could be flying about 7th July onwards

The females lay their eggs [ovum] on Common Buckthorn and, Alder Buckthorn, normally on the back of small fresh leaves. But, they can also be laid close to a leaf bud, on the stem of a small branch and, even on the upper side of the leaves.The eggs are laid from the beginning of May to early June, the latest i have witnessed a female Brimstone laying eggs was on the 9th and 10th June on Common Buckthorn in my garden.

A freshly laid Brimstone egg on the back of a unfurling
Common Buckthorn leaf

3 Brimstone eggs having been laid just below the unfurling
Common Buckthorn leaves

Several Brimstone larva on the top of a mature Buckthorn
leaf, photo taken, 8th June

Female Brimstone ovipositing on, 9th June

The eggs are quite light in colour when first laid, turning a dirty yellow after a few days and, 24 hours before the larva hatches the egg turns grey. The tiny larva emerge after about 8-15 days.

A freshly laid Brimstone egg

A brimstone's egg after a few days

The larva have 4 moults, [5 instars]. The caterpillars when they first emerge tend to live/feed on the back of the leaves. From the 2nd instar larva to the 5th instar larva, they tend to feed on the top of the leaf, and rest on the rib. This stage lasts between 4-6 weeks.

A newly emerged 1st instar Brimstone larva on the back of a Common
Buckthorn leaf showing it's first feeding damage

2nd instar Brimstone larva at rest on the rib of a leaf

3rd instar Brimstone Larva

4th instar Brimstone larva

5th instar Brimstone larva, having attached itself to the Cremaster,
it is busy attaching the girdle to the leaf and itself

5th instar larva ready and waiting to pupate

The pupa is joined to a leaf, plant stem by a Cremaster [joined to the abdomen] and a girdle, [around it's waist]. This stage lasts between 15-18 days.