Thursday, 27 June 2013

Black magic ...

Bernwood Meadows, 27 June 2013

The Black Hairstreak (Satyrium pruni) is one of the rarest and most elusive butterflies in Britain. It is also one of the most recently discovered (1828), due to the similarity with its close cousin, the White-letter Hairstreak (Satyrium w-album).

S. pruni is not a great wanderer and an entire colony will often restrict itself to a single area within a wood, despite there being suitable habitat nearby. This inability to colonise new areas at a pace, in balance with habitat loss, may partially explain the scarcity of this species. This butterfly has a very restricted distribution that is confined to a line of clays between Oxfordshire in the south-west and Cambridgeshire in the north-east. Colonies are typically located in small woods or nearby hedgerows, where blackthorn, the main larval foodplant grows. Sites are located in sheltered but sunny positions and typically have a southerly aspect to them.

The adult stage has an extremely short flight period, being typically seen in the last two weeks of June and the first week of July. There is a single generation each year. Upon emergence, the adults spend much of their time resting high up on maple, ash or the larval food-plant, crawling over leaves and twigs, in search of aphid honeydew from which they feed. Primarily an arboreal species they will occasionally come down to feed on various nectar sources including man made attractants. As with all hairstreaks, when active, they are extremely difficult to follow. To make matters worse, the Black Hairstreak is often found in the company of both White-letter and Purple Hairstreaks and distinguishing these three species in flight is almost impossible.

A male feeding pictured below ...

Saturday, 22 June 2013

Vespa crabro ...

West Sussex, 20 June 2013

Royal appointment ...

The European hornet, Vespa crabro, is the largest European eusocial wasp; the queens averaging around 3cm in length (the queen pictured below measured 3.5cm, with a wingspan of 5.5cm). With the exception of the Median Wasp, Dolichovespula media, whose queens resemble small worker cast hornets in size and colour (D. media is yellow and black with small areas of red whereas V. crabro is a brown, red and yellowish-orange species lacking any deep black markings), it is unlikely to be confused with any other species.

Once only common in central southern England, it has now extended its range from Cornwall to Kent and northwards into Yorkshire. It has also been recorded from The Isles of Scilly, Isle of Wight and the Channel Islands. It is found in many lowland habitats, but is particularly associated with ancient deciduous woodland.

Queens emerge from their over-wintering sites in early April and nests are initiated, usually in hollow trees or similar cavities, in May with the first workers generally appearing around late June to early July. New queens and males, which emerge from the nest from September to October, mate and then disperse, with the males dying and the newly-mated queens seeking over-wintering hibernation sites. Back at the nest, which may persist into November in mild seasons, the old queen and remaining workers eventually die-out. V. crabro predates on a number of invertebrate species including other social wasps, honey bees, flies, butterflies, moths (hornets can forage in moonlight) and spiders. Prey is often taken from flowers and the vegetation of trees. In late summer and autumn, workers are sometimes attracted to exudations from deciduous trees; particularly oak. Workers, males and new queens will also visit Ivy, Hedera helix, blossom for nectar.

Tuesday, 18 June 2013

Big game ...

Iping Common, 17 June 2013

There are five species of Tiger Beetle in Britain: Cicindela campestrisCicindela hybridaCicindela maritima, Cicindela sylvatica and Cylindera germanicaOf these, the Heath Tiger Beetle (Cicindela sylvatica) and the Cliff Tiger Beetle (Cylindera germanica) are both UK Biodiversity Action Plan (UK BAP) species; meaning they are species of conservation concern and action is being taken to protect and conserve them and their habitats. Two species have been recorded in Sussex. These include Cicindela campestris and Cicindela sylvatica.

The commonest, and possibly the most attractive of the British species, is the beautiful Cicindela campestris, the Common or Green Tiger Beetle. C. campestris is a fast, long-legged, agile predator that is easily recognized due to its iridescent green and purple colouring, along with its distinctive yellowish spots on the elytra. The adults, which can be seen from April to September on dry heaths and other sandy places, fly and run actively in the sunshine.

Saturday, 15 June 2013

Grizzlies ...

West Sussex, 10 June 2013

The tiny Grizzled Skipper (Pyrgus malvae) typically occurs in small colonies of less than 100 individuals. It is found in England south of a line extended from West Gloucestershire in the west to North Lincolnshire in the east, with strongholds in central and southern England. There are scattered colonies further north and in Wales. This species is absent from Scotland, Ireland, the Isle of Man and the Channel Islands. Despite the suggestion in its specific name, malvaeP. malvae larvae do not feed on flowers of the mallow genus; though several closely related European species do feed on Malvaceae.

The adult emerges in late April, the first of the British Skipper species, and usually flies until the end of June. There is one generation each year, although there may be a small second brood in some seasons, when conditions are favourable.

This is a warmth-loving species, and both sexes bask in the sun for long periods, typically on a stone, leaf or bare earth. This is an active insect which will fly at most times the day, and even into the evening, if conditions are warm enough. The male is somewhat territorial and will chase any butterfly, irrespective of size, from its area. Females entering the territory are courted for a short period and, if the female is receptive, pairing occurs. The butterfly can be found roosting on heads of flowers and grasses during cool weather and at night.

Wednesday, 12 June 2013

New definition required ...

West Sussex, 3 June 2013

DINGY: Adjective: Gloomy and drab.

Despite its name, a freshly-emerged Dingy Skipper (Erynnis tages) reveals a most delicate pattern of browns and greys that is undoubtedly quite beautiful. Despite its decline due to changes in farming practice, this is our most widely-distributed Skipper. Colonies can be found throughout the British Isles, including northern Scotland and Ireland (ssp. baynesi) where, although scarce, is found on outcrops of limestone. It’s strongholds are in central and southern England.

And I almost didn't take my camera ...

Tuesday, 4 June 2013

Serpentes ...

West Sussex, 1 June 2013

Natrix natrix (Linnaeus, 1758)

The Grass snake, Natrix natrix, is Britain's largest native terrestrial reptile, and probably its most common species of snake. It is non-venomous and completely harmless to man; and rarely bites, even when handled.

With regards to the British subspecies, helveticaN. natrix is most easily identifiable by the interlinked black and yellow collar, which usually forms a band or ring immediately behind the head. The upper body is typically olive-green, olive-brown or greyish in colour, with a variable row of black bars along the sides; occasionally with smaller round markings along the back in double rows. The ventral scales are off-white or yellowish, with dark triangular or rectangular markings. The face has marked black bars on each side below the eye and these provide a key method of individual identification. Melanistic and albino forms are rare but occasionally arise. The sexes are similar in appearance, although females are usually larger. Males can be identified by the presence of a swelling at the base of the tail and by the fact that they have longer tails relative to females. In addition, the head of the female is much more pronounced in being triangular in appearance with the eyes deep set into the cheeks; whereas the male has an altogether more slender head with eyes that often protrude beyond the line of the face and jaw. The majority of females also tend to possess two postocular scales (behind the eyes), as opposed to the males three. The female may grow up to 1.2 metres in length (snout to vent); however, more mature individuals have been reported up to 2 metres in length. The male is generally much smaller in comparison, and individuals of around 600mm are usually among the largest specimens recorded.

Ponds, lakes and rivers are their preferred habitat. They are strong swimmers. Not only are features such as bank-side vegetation important to provide cover against their predators, there must also be readily identifiable passages of ground cover in the form of ditches, hedges or banks of brambles which lead up to the banks. If such passages are removed from the surrounding environment, then the frequency at which N. natrix will visit a particular water body will reduce.

From March, when the snakes emerge from hibernation, until mid may, they eat large quantities of small fish; mainly because these are spawning during this period and are easier for the snakes to catch amongst the weedy fringes of water bodies. From May to early July, the diet emphasis falls onto newts, and again, this is because the newts own life cycle doesn’t include a land-borne phase until after July. From July, N. natrix gradually disperses away from ponds and into forest clearings, wooded copses and longer grasses / ground cover and a higher number of frogs and toads will then be taken as a result. The frogs and toads themselves have generally moved away from the ponds by April, although some are obviously predated upon between the cross over of snakes arriving at ponds in spring and while the frogs or toads are migrating away from them. Nests of very young chicks such as moorhens are sometimes consumed (mainly to supplement an otherwise restricted diet), as are mice and voles, especially by the more mature female snakes, but these incidents are rare.

Sunday, 2 June 2013

Beauty in miniature ...

Springhead Hill, 1 June 2013

After much of the day’s heat had passed, I paid a visit to the beautiful Springhead Hill today with the sole aim of capturing the tiny and charismatic Small Blue (Cupido minimus) at roost. Arriving at around 5pm insects were still on the wing, though it wasn’t long before the first of a number of Small Blue were found roosting amongst grass tussocks in sheltered locations.

The Small Blue, our smallest resident butterfly, has a wingspan that can be as little as 16mm. The sexes are similar in appearance, although the male upperside is a dark black/brown with a variable dusting of blue scales at the wing bases; whereas the female is typically dark brown in colour and without the blue scaling. Both sexes have an underside that is silvery-grey in appearance with a light variable peppering of black spots.

As is the case with this location, the Small Blue is a butterfly that favours sheltered sites, which contain a suitable quantity of its larval foodplant, Kidney Vetch (Anthyllis vulneraria), together with grasses, and shrubs, which are used for perching and roosting. A wide variety of habitats is used, including unimproved chalk and limestone grassland, abandoned quarries, road and railway embankments and woodland rides and clearings. The first image shows a male at roost. The second and third images are both females.

With the light fading I said goodbye …