Saturday, 28 May 2016

Early morning blues ...

Small Blue (Cupido minimus)

West Sussex, 23 May 2016

C. minimus is our smallest resident butterfly with a wing span that can be a little as 16mm. The sexes are similar in appearance, although the male (top image) upperside is almost black with a light dusting of blue scales, whereas the female (lower image) appears dark brown in colour. Both sexes have an underside that is silvery-grey, which is not dissimilar to that of the Holly Blue (Celastrina argiolus).

This beautiful little butterfly has a large distribution, being found from northern Scotland to the south of England, with colonies also in Wales and Ireland. Outside of its strongholds in the south of England, colonies are often merely isolated pockets, typically in coastal locations, with most populations consisting of just a few dozen adults. In Sussex, minimus has not yet recovered from the weather-related population crash occurring between 2007 and 2012. With 2015 having been a testing season for this species, we wait with some trepidation as to its fortunes in 2016.

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Thursday, 26 May 2016

A is for aberration ...

Duke of Burgundy (Hamearis lucina)

West Sussex, May 2016

When it comes to natural selection, we should consider two classes of aberration [a characteristic that deviates from the ‘normal’ type] - those that are passed from generation to generation in the species’ genetic make-up, and those, which are not e.g. those that are determined by the environment. Such variation may be caused by changes or mutations in the genetic composition as the individual develops, or to changes in the physical makeup of the individual as a result of environmental conditions. Aberrations caused by environmental factors e.g. extremes of temperature, are probably not influenced by natural selection since they are not part of the gene pool and are therefore not likely to be inherited; this includes certain examples of colouring and markings. Aberrations may also be the result of a reproduction ‘error’ that is neither genetic, nor associated with the environment, such as gynandromorphs and hybrids.

Those aberrations that are carried in the gene pool [and from generation to generation], and that are visible in terms of colour and markings, clearly do not provide the population with any advantage otherwise they would be widespread. This is where the term ‘aberration’ really doesn't stand up to scrutiny. An individual is considered an aberration if it deviates from the norm. But if it becomes widespread, it is the norm and therefore no longer an aberration. A case in point is ab. caeruleopunctata (Rühl, 1893) in the Small Copper (Lycaena phlaeas) that has a row of blue spots above the copper marginal band on the hindwing. It could be argued that individuals without the blue spots are actually the ‘aberration’ in some populations where this feature occurs frequently. However, answering the question of why this occurs, these aberrations should simply be seen, in my opinion, as a reflection of the rich gene pool available that potentially allows populations to respond to changes in their environment.

2016 has been a good season for aberrant Duke of Burgundy in Sussex. In descending order the above images show a ‘normal’ female, a female referable to ab. albomaculata (Blachier, 1909), and a rather exciting find of a female currently referable to ab. gracilens (Derenne, 1927) + ab. albomaculata (Blachier, 1909). However, with regards to the third individual, albomaculata is only a hindwing aberration whereas this specimen has the same condition on the forewings as well. In addition, the spots in the lunules to the forewings are streaks instead of spots. The underside was also of a paler appearance than ‘normal’. It is therefore quite possible, as none of the existing combinations of names really cover it, that a new name may be required for this form.

My thanks to Peter Eeles, Alec Harmer and Rupert Barrington for their assistance.

More at:

Ford, E.B. (1945). Butterflies. London: Collins (New Naturalist), pp. 219-247.
Harmer, A.S. (2000). Variation in British Butterflies. Lymington, Hampshire: Paphia Publishing Ltd., pp. 53-96.

Sunday, 22 May 2016

Rise of lucina ...

Duke of Burgundy (Hamearis lucina)

West Sussex, 19 May 2016

Long-term distribution and population trends show that H. lucina is in serious decline. It is one of the two most threatened species of butterfly in the UK which, together with the High Brown Fritillary (Argynnis adippe), now faces potential extinction unless conservation measures are successful in reversing the current trend of population losses. It is therefore a priority species for conservation efforts. It is believed that fewer than 100 colonies remain, with West Sussex being at the retreating eastern edge of its southern geographical range, leaving just isolated colonies in Kent. The vast majority of remaining populations are very small, comprising no more than a handful of adult insects on the wing at any time during its late April to early June flight season.

Writing in November 2013, Neil Hulme wrote, “Populations where maximum daily counts exceed 30 butterflies are now very rare and in 2003 the total number of Duke of Burgundy adults seen in the county [Sussex] was 8”, and, “In West Sussex there are now less than a dozen sites supporting the Duke of Burgundy and many of these could be lumped together, leaving just 5 population centres”. Writing further, "At the moment everything seems happy, while the results achieved so far for the Duke of Burgundy have been nothing short of remarkable. As changes in the habitat management took effect maximum daily counts began to rise; 7 and 8 in 2008 and 2009, then leaping up to 51 in 2010 and a mighty 115 in 2011"H. lucina is a fighter and with dedicated conservation work is making a comeback. 2016 is evolving into a fantastic season with numbers that have not been seen in Sussex for three-quarters of a century. My own visits to several sites have revealed respectable numbers. Neil, further to a survey of Heyshott Escarpment on 20th May 2016, recorded, “I generally prefer not to estimate or extrapolate, but it is important to record, even imprecisely, the unprecedented recovery of the Duke of Burgundy, on a site where it had come so perilously close to extinction. Today there were at least 200 Dukes on these remarkable slopes”.

Long may this conservation success story continue …

Watch this space ...

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Wednesday, 18 May 2016

Greenstreaks ...

Green Hairstreak (Callophrys rubi)

Chiddingfold Forest, 17 May 2016

If asked where I would go to stand a good chance of seeing C. rubi, my local Chiddingfold Forest, both the Surrey and Sussex sectors, would typically not be at the top of my list - well to be fair it still isn’t but this season I have seen more specimens there than in all previous seasons put together. The main area where I am finding them is comprised of self-seeded Silver birch (Betula pendula) and winter-cleared Bracken (Pteridium aquilinum) with a mixed ground flora comprising Bluebell (Hyacinthoides non-scripta), Greater stitchwort (Stellaria holostea), Bugle (Ajuga reptans) and Garlic mustard (Alliaria petiolata), to name but a few of the more prominent species. Broom (Cytisus scoparius) and Gorse (Ulex sp.) are also present.

A butterfly I never get bored of watching …

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Saturday, 14 May 2016

Dukes a plenty ...

Heyshott Escarpment, 14 May 2016

Duke of Burgundy (Hamearis lucina)

Despite the early forecast of variable and cloudy conditions we need not have worried as the coats were soon off as I led a party of 20 members of the Haslemere Natural History Society around the fabulous Heyshott Escarpment reserve earlier today, Saturday, 14th May. Located due east of the village of Cocking and just south of the village of Heyshott in West Sussex, this wonderful downland reserve is the jewel in the crown of the Murray Downland Trust; its riches being revealed in some plentitude today.

In descending order of abundance we recorded 9 species of butterfly including Duke of Burgundy, Green Hairstreak, Dingy Skipper, Grizzled Skipper, Red Admiral, Green-veined White and singletons of Peacock, Small Heath and Orange-tip. In addition and further to Neil Hulme’s walk on Sunday, 8th May when, referring to the Duke of Burgundy at Heyshott, he reported, “following several false starts, it appears that this species might now be colonising the western flank”, we too found a single female prospecting this area of the reserve. This is excellent news and long may this advance continue …

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Thursday, 12 May 2016

It’s true, fairies do live in the woods …

Chiddingfold Forest, 12 May 2016

Green Longhorn (Adela reaumurella)

A. reaumurella is a small day-flying micromoth belonging to the family Adelidae, the fairy longhorn moths. They have a wingspan of approximately 14 to 18 mm. The upper wings of both sexes are a beautiful metallic green, their under wings metallic bronze. The males (figured above) have extremely long white antenna and have rough black hair on their heads. In comparison, the females have relatively short white-tipped black antenna with shorter and lighter hair on their heads. It is a fairly common species in England, Wales and southern Scotland, though more localised in Ireland. They typically fly from April to June and can often be observed flying in swarms.

They are simply gorgeous …

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Wednesday, 11 May 2016

Beacon of the bog ...

West Sussex, 8 May 2016

Bog Beacon (Mitrula paludosa)

M. paludosa grows to around 4cm tall, has an ovoid or club-shaped yellow or orange swollen fertile head, which is held aloft on a delicate white or translucent stem. M. paludosa is a saprotrophic fungus [feeding on dead organic matter] and is usually found on the remains of higher plants, mosses and algae in areas of seeping or standing water. Although widespread in Britain it can be difficult to find and, despite its bright orange head, easily overlooked.

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Tuesday, 10 May 2016

A fondness for faeces ...

West Sussex, 8 May 2016

Red Admiral (Vanessa atalanta)

As with most insects, butterflies do the majority of their growing and eating during the larval stage. Nevertheless, the adults still require nutrition. This is predominantly obtained in the form of floral nectar, along with tree sap and other sugar-based foods for flight energy, with other micronutrients being required for egg maturation and successful reproduction. It is these that are gained from a number of apparently strange sources including urine, human sweat, rotting fruit, fermenting juices from timber, dead fish, animal carcasses, honeydew (sugar-rich excrement produced by aphids), dew covered embers from fires and animal faeces.

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Sunday, 8 May 2016

Emerald skies ...

West Sussex, 7 May 2016

Green Hairstreak (Callophrys rubi)

C.rubi is the most widespread of the British hairstreaks. However, it is also a local species, forming distinct colonies, which can be as small as a few dozen individuals, although larger colonies exist. During good seasons the adults can be locally very common on the West Sussex downs.

Both sexes always settle with their wings closed, the brown uppersides only ever being seen in flight when they can be notoriously difficult to follow. The undersides, by contrast, provide the illusion of being green, an effect produced by the diffraction of light on a lattice-like structure found within the wing scales, which provides excellent camouflage as the butterfly rests on a favourite perch. The sexes look very similar and are most readily told apart in the field by their behavior. Rival males may often be seen in flight close to shrubs, while the less conspicuous females are more often encountered whilst egg laying.

A male defending his territory is depicted above …

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Friday, 6 May 2016

Abiding beauty ...

West Sussex, 5 May 2016

My first this season ...

The beautiful but vulnerable Pearl-bordered Fritillary.

Once considered common and widespread, including throughout my home county of West Sussex, the Pearl-bordered Fritillary is now one of our most-threatened species. The cessation of coppicing which resulted in the loss of suitable habitat is believed to be one of the major causes of this drastic decline. Conservation efforts have therefore focused on habitat management and there have been a number of success stories. However, this butterfly is still declining and, as such, continues to be a priority species for conservation efforts.

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Wednesday, 4 May 2016

In the valley of the Alyn …

Dipper (Cinclus cinclus)

C. cinclus is a bird of fast-flowing rivers and streams in mountainous and hilly regions. Typical habitat contains numerous rocks and boulders but the mainstay of foraging habitat is shallow water with a gravel bottom and aquatic or bankside vegetation. Territories, which are established along suitable rivers, are maintained against incursion by other pairs. Territories must contain a good nesting site and suitable roosting locations. The main factor affecting the extent of the territory is the availability of sufficient food to feed the adults and their offspring. Their nests are usually large, round, domed structures made of moss, with an internal cup of grass and small roots, and a side entrance hole. They are frequently built in confined spaces over, or close to, running water. The site may be on a ledge or bank, in a crevice or drainpipe, or beneath a bridge, both parents being involved in nest construction. Mosses and other suitable materials are collected and wetted, as illustrated above, before being used in nest assembly; on drying the materials contract giving a compact construction.

Feeding predominantly whilst submerged and walking on the streambed, large aquatic invertebrates, especially the larvae of caddis flies, provide the primary food source. Small fish, crustaceans and molluscs are also taken. Its main feeding technique under water is to move stones and pebbles and feed on items exposed underneath. Smaller items are swallowed under water whilst others, such as fish and caddis fly larvae, are brought to the surface. The above images are from a recent audience …

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