Brimstone
(Gonepteryx Rhamni)
The word butterfly its believed, was first used to describe this butter-coloured insect. It is a common species and is often the first and last butterfly seen each year, flying possibly during every month but usually February-November. 'Butterfly' eventually came to include all species and the Brimstone acquired its present name which relates to the colour of Sulphur.
The distribution of the Brimstone mirrors the distribution of its two foodplants; Buckthorn (Rhamnus Catharticus) and Alder Buckthorn (Frangula Alnus), on which its caterpillars are entirely dependent for their food. The butterflies are powerful flyers and males are sometimes seen miles away from their foodplants, possibly migrating to fresh territories. Brimstones are usually found on the margins of Woodland, along hedgerows, in scrubby areas and thickets. They are strongly attracted to wild flowers for nectar and often stay for long periods at one flower, always with their wings shut.
The underside colours and shape alllow Brimstones to blend in with vegetation, and they successfully hibernate through winter as adult butterflies. There is one generation a year, and individual butterflies live for up to a year.
Larva (caterpillar):
Upon hatching from the egg, the tiny caterpillar begins to feed on the tender, upper sides of the young leaves of Buckthorn or Alder Buckthorn of which they are totally dependent. Creating irregular holes all over as the leaf unfurls and expands, these are an obvious sign to those looking. As the larvae grow, the larger chewed areas appear and entire leaves are devoured. At this stage they are easy to spot, regardless of their superb, green camouflage.
Caterpillars are often found on isolated Buckthorns and may be mistaken for the similar looking Small White or Orange Tip larvae but both of these feed on totally different foodplants, unrelated to the Buckthorn.
Between feeding, caterpillars rest along the midrib on the upper surface of the leaf with their heads usually facing outward. When disturbed they will lift the front of their bodies above the leaf.
Many larvae in the final 5th instar fail to reach the chrysalis stage, their obviousness to us is apparently as clear to birds, wasps and other predators; some preyed upon by parasitic tachinid flies. I myself have seen wasps search out and pick off Brimstone caterpillars in my own Bournemouth garden.
Those that do survive, go on to pupate. The majority leaving the Buckthorn on which they spent this stage of their lives, to find a more suitable, sheltered area, to make the change. Some remain and pupate on the underside of the foodplants' leaves. On my own Buckthorn, two larvae spun up on the undersides of leaves, towards the middle and bottom of the short trees.
Taken on June 15, 2012
Pupa (Chrysalis):
Pupae are situated in sheltered areas, attached by a single silk pad and girdle, usually on the undersides of leaves or plant stems away from the actual foodplant, however I once discovered one in the garden half way up a small Buckthorn tree; quite exposed in comparison to usual hiding places.
The chrysalis is a pale green colour and mimics the shape of a rolled up leaf, the camouflage working so well that if one looks away for a moment it can be a while before you are able to relocate the pupa.
Taken on July 1, 2013
On Alder Buckthorn, Chorlton Water Park, Manchester - 17.6.07
Female
Taken on September 7, 2014 Nectaring on Devils-bit Scabious. Lower Woods, Gloucestershire © Dave Sims
Taken on June 7, 2014 © Claire Sell
Taken on September 20, 2009
Seeking an egg laying site, Suffolk
Imago (Adult):
Appearance-
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Wingspan (57mm)
The male of the species has superb yellow/sulphur camouflage; appearing as a leaf lit up by sunlight in Spring and Summer an then an aging autumn leaf in fall and Winter. The females wings are much paler than those of the male. Individuals so much so, its possible for them to be confused in flight or from afar, with the Large White, which is of a similar size. Both sexes have an orange spot on each of the four wings.
The veins of the Brimstone are unusually pronounced which some experts believe is a camouflage technique that has evolved to mimic the Ivy leaves amongst the butterfly hibernates.
The pinkish/reddish colour to the head, antennae and wing base may have evolved as further camouflage against predatory spiders sat on the flowers of their favourite flowers of the same colours; Thistles and Knapweeds.
Resident Status: -Range Expanding
Conservation-
UK BAP Status: -Not Listed
Butterfly Conservation Priority: -Low
European Status: -Not Threatened
-Protected in Northern Ireland
Distribution and Habitat-
Brimstone are common and highly mobile butterflies in areas of scrubby grassland, woodland, hedgerows and open ground wherever the foodplant grows. Found throughout the majority of southern England but in particular on calcareous soils, where Buckthorn grows and on moist acid soils where Alder Buckthorn grows.
Surprisingly the Brimstone is actually a nomadic species but only at a regional level; this means it is not a true migrant but is able to travel short distances to find new habitat, nectar, foodplant sources, mates and egg laying sites.
The distribution of the Brimstone almost exactly mirrors the distribution of its sole foodplants; Buckthorn and Alder Buckthorn, restricting the butterflies range. Consequently the species is predominantly absent from the Uplands, West Wales and a large swathe of Northern England; except the Lake District and south-east Wales where it is relatively common.
In Ireland, the butterfly has a wide distribution but the lack of Buckthorn means the insect is uncommon in many of these areas. The Burren in County Clare is one of the only locations in Ireland where the butterfly can be seen in numbers on the limestone landscape.
Buckthorns limiting actions on the Brimstone have regional effects even in counties where the insects are otherwise common. On the south coast in Dorset for example, both species of Buckthorn are widespread in the majority of the region, apart from an area in the Purbeck Hills where they and the butterfly are largely absent.
Flight Times-
There is one generation each year, the butterflies emerging over a period of several weeks, starting in early July through to August. Male butterflies emerge from the chrysalis a week or two earlier than the females, allowing them to establish territories to secure successful pairings.
These butterflies either begin hibernation almost immediately or fly through the Autumn on warm days.
The Brimstone chooses to fly during the heat of the day but can be seen retreating to the cooler shade on hot summer days; roosting early from 3-4pm onwards. Butterflies rest on the underside of leaves in bushes always with their wings shut to avoid detection, pulling it off superbly with their unique camouflage.
Hibernation-
After emergence (hatching) in July, the adult butterflies remain in their breeding territories for almost 2 or 3 weeks. In some regions of the UK however, after this time the butterflies disappear; migrating to new areas in search of food and new habitat. Here they chose to feed, building up fat reserves in preparation for a long winters sleep.
Some begin hibernation as early as August where they sit quietly surrounded in evergreen shrubs such as Ivy or Holly until the following February or March.
Brimstones are often the first butterfly to be seen in the year with eager males flying in earlier February on days warm enough for flight.
Reproduction and Pairing-
Male Brimstone butterflies develop sperm in autumn but mating is delayed until the following spring. Christer Wiklund discovered that although the male and females emerge at fairly similar times in summer, in spring it is the males that wake up first. For up to 2 weeks before the females have even woken from their long winter sleep, males are up and busy patrolling woodland margins and hedgerows in preparation.
When they do finally awaken, males are soon to catch on and a mesmerising courtship follows with both butterflies spiralling high into the sky. At first the female is reluctant to pair but eventually both descend and settle into the undergrowth, the female resting with wings half open, shivering as the male approaches to mate.
It is likely that the female releases an aphrodisiac at this point because many other males are able to find a mating pair despite being hidden in thick foliage.
Nectar Sources-
Brimstones that recently emerge spend their days feeding, favouring wild flowers which are purple in colour. Brimstones' favourites include: Wild Teasel, Thistles, Purple-loosestrife in the countryside but Buddleia is often visited in gardens. Each butterfly quickly establishes its preferred nectar plants, focusing on those providing the most and strongest; proving to be the best source.
The Brimstone has a very long proboscis (tongue) compared to other butterflies as seen in the photograph below. This exceptionally long drinking tool comes in useful, taking advantage of nectar sources (Wild Teasel for example) that are unreachable to some other butterflies.
During spring in woodlands, the Brimstone is the primary pollinator of primroses and can be seen in April or May flitting in clearings or along hedge rows searching for them. Their long proboscis yet again taking advantage of the early nectar the Primroses provide, allowing them to reach deep within the flowers base. This has an advantage for the Primrose. By attracting the butterfly to the flower with its scent, promises of nectar and colour matching that of a Brimstone, the butterfly inadvertently pollinates the plant. There are two arrangements of sexual parts within the flower, the proboscis picks up pollen from the male organ (stamen) and deposits the pollen in the female organ (Stigma) of another flower; helping it to reproduce.
Taken on July 19, 2011
Fraud-
In 1702, shortly before his death, William Charlton (1642-1702) sent a butterfly specimen to entomologist James Petiver who lived in London. Astonished Petiver wrote, "It exactly resembles our English Brimstone Butterfly, were it not for those black spots and apparent blue moons on the lower wings. This is the only one I have seen."
Carl Linnaeus examined the apparent rarity in 1763 and declared it to be a new species, naming it Papilio ecclipsis. He even incorporated it in the 12th edition (1767) of his Systema Naturae.
Thirty years passed and in 1793, the Danish entomologist John Christian Fabricius examined it more closely and realised it was a fake. The black spots had been painted on the wings. The rare butterfly, the only one of its kind ever seen, was too good to be true and turned out to be an ordinary Brimstone.
Dr. E.W. Gray was keeper of National Curiosities at the British Museum where the "Charlton Brimstone" specimen was stored. Apparently when he heard of the fraudery, he is said to have become so enraged that he "indignantly stamped the specimen to pieces".
The lepidopterist William Jones created two detailed, replica specimens that are now preserved as "The Charlton Brimstones".
Nobody knows whether Charlton was committing deliberate scientific fraud; hoping he would be credited with the discovery of a new species or it was intended as a mere practical joke.
Ovum (Egg):
The white or yellowish, bottle-shaped eggs are laid singly, however several may occur on one leaf but each are laid by different females. These butterflies are very particular where they choose to lay their eggs and this can depend on the location. Some prefer Buckthorns that are growing both in sunshine and areas sheltered from wind, laying at all different heights on these particular bushes, where branches protrude into sunlight.
On the other hand, in contradiction; females, will only lay on small, young plants of 60cm-1m in relatively exposed, open places near ride edges that appear to be completely insufficient to support hungry caterpillars. The larger, mature, seemingly more suitable shrubs are almost totally ignored.
Some experts believe the young trees are chosen for they provide more nourishing food with a lower level of toxins built up within the leaves.
The conspicuous eggs are relatively easy to find if you've first located a Buckthorn and know the habits of the picky female butterflies that laid them. Chosen, are twigs in the sunshine where the eggs are placed on unfurling leaves. When unavailable, butterflies are forced to lay beside the unopened bud, where they will sit quietly for the usual period of 10-14 days.
© John Chapple
Egg laying female:
'Photographed looking for egg laying sites on Alder Buckthorn in our garden. Funnily enough, despite visiting numerous shoots on this Buckthorn, not a single egg was deposited' - Dean Morley
'Pictured egg-laying on alder Buckthorn in our garden' - Dean Morley
© Adam Grochowalski
Taken on April 13, 2012
Taken on May 13, 2012
Taken on May 31, 2010
Taken on October 13, 2012
Taken on April 9, 2014
Foodplants:
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Changes over time-
To early entomologists the Brimstone was well known but by the name 'butter-coloured fly' which some believe led to the formation of the word butterfly. Whether this has any truth cannot be proven but in any case, the Brimstone is one of the most well-known and pleasing butterflies.
One cannot be sure of the changes the population of Brimstones has faced in recent times. It is very likely that their numbers were higher when traditional methods were used to tend the British countryside.
Global warming and rising temperatures in the UK could one day expand the range of this beautiful butterfly but as it stands only 6 specimens have ever been recorded to cross the border into Scotland.
In the Brimstones case, global warming is not the main cause of its expansion in recent years but instead due to the planting of Buckthorn trees in Northern England's gardens and hedgerows.