|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.
|Brimstone pupa, day 1|
|Brimstone pupa, day 2|
|Brimstone pupa, day 14|
|Brimstone pupa, day 16 and emerged 24 hours later|
Brimstones always land with their wings closed. They feed on a variety of flowers, including Clover, Dandelion, thistles and Fleabane etc.