Wednesday, 22 July 2015

Far from the madding crowds …

Mountain Ringlet (Erebia epiphron)

Seeking peace and solitude …

E. epiphron can be one of the most challenging species to see. It is univoltine, is only found in isolated colonies in remote montane locations, has an extremely short flight period and can be very difficult to locate in unsuitable weather, since the adults tend to remain sheltered deep in grass tussocks during inclement conditions. Given the right temperature and humidity the adults will take to the air, bringing a seemingly dormant landscape to life. As its vernacular name suggests, the Mountain Ringlet is found in mountainous areas, typically at altitudes between 450m and 800m AMSL - though it can be found at both lower and higher elevations. A recent trip to Scotland, to specifically find and observe this species, produced reasonable numbers from around 500m AMSL in the locations searched, including several aberrant male specimens and a mating pair.

E. epiphron is found in two main regions in the British Isles. In England, it is found in the Lake District of Cumberland and Westmorland; where the subspecies mnemon occurs. It is also found in western central Scotland, primarily in the counties of Argyllshire, West Inverness-shire and Mid Perthshire, with a few scattered colonies elsewhere. Here the subspecies scotica - illustrated - is found in damp, herb-rich Nardus grassland. The butterfly is surprisingly absent from Snowdonia and the Pennines. On the basis of four specimens in total, this butterfly is also thought to have occurred in Ireland. There is quite a lot of history associated with the Irish Mountain Ringlet as discussed in the excellent dispar article listed below. It is believed that this butterfly was one of the first to recolonise the British Isles after the last ice age. Despite this heritage, this species is a relatively recent discovery, with the Lake District population being discovered in 1809 in Ambleside, Westmorland, and the Scottish population in 1844 in Perthshire. E. epiphron is one of the more difficult species to monitor, due to the remoteness and unpredictable weather of its montane home, and is generally considered to be under-recorded. However, it is known to have declined at several low altitude sites, possibly as a result of global warming, and is therefore a priority species for conservation efforts.

The images above, in descending order, show male, female (freshly emerged and just mated) and male underside (all generally typical of most examples) and one of several aberrant male specimens. The last two pictures depict the archetypal location and herb-rich Nardus grassland in which epiphron is found.

More at:

Sunday, 19 July 2015

The holly and the ivy ...

Holly Blue (Celastrina argiolus)

C. argiolus is primarily found in the southern half of the British Isles and is a frequent visitor to gardens, churchyards and parks. This species is renowned for fluctuating in numbers, forming a predictable cycle over several seasons, thought to be caused by the abundance of the parasitic wasp Listrodomus nycthemerus whose sole host is the Holly Blue. The wasp lays its eggs in the larvae of C. argiolous, with a single adult wasp eventually emerging from the pupa. In England and Wales this species is widespread and common, south of a line running from Cumberland in the west to County Durham in the east. It is also found on the Isle of Man and throughout Ireland, but is absent from Scotland except as a scarce vagrant.

There are two broods each year, although there may be only one brood in the north. Adults from overwintering pupae emerge as early as the first week of April in a typical season, with the next generation emerging during mid July and early August. The three images above are of summer brood individuals. The first two pictures depict the same male. The third image is a female nectaring on bramble blossom. 

Friday, 3 July 2015

Close Encounters of the Purple Kind …

Purple Emperor (Apatura iris)

The season begins …

The Purple Emperor is a magnificent and elusive insect that is actively sought out by the many subjects of ‘His Majesty’, as the male butterfly is affectionately known. To say that some observers reach a state of obsession is an understatement with many followers making annual pilgrimages to see this species.

The male, which typically emerges in early July, sometimes during the last week of June in good seasons, is undoubtedly one of the most stunning and sought after of all the British butterflies. From certain angles, even at close observation, it appears to have black wings intersected with white bands. However, when the wings are at a certain angle to the sun, the most beautiful purple-blue sheen is displayed, a result of light being refracted from the structures of the wing scales. The female, on the other hand, is a deep brown and does not possess the purple sheen found in the male.

A. iris is generally best seen through the early morning and again during the late afternoon, when the males come down to the ground, on hot humid days, to take in nutrients from damp earth and animal droppings. They are also partial to sweat - a key component of Emperor watching - and readily land on observers. Despite this ‘grounding’ behaviour, both males and females spend the majority of their time resting high in their arboreal home and out of sight …

Wednesday, 1 July 2015