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Text and photographs protected by Copyright © Adrian Hoskins 2007, and must not be published in part or in whole elsewhere without prior written permission from the author.
Butterflies of Britain & Europe
 
Wall Brown
Lasiommata megera LINNAEUS, 1767
Family - NYMPHALIDAE
subfamily - SATYRINAE
Tribe - SATYRINI
 
 introduction | habitats | lifecycle | adult behaviour
 
Wall Brown Lasiommata megera, male, Dorset, England
 
Introduction
 
This species is distributed across most of Europe with the exception of northern Britain and northern Scandinavia. It also occurs over much of north Africa, and in temperate regions of western and central Asia.
 
Habitats
 
In Britain the Wall Brown was formerly more widespread, occurring in a wide range of habitats throughout England and Wales. In the latter part of the 20th century it became evident that most of the inland colonies were dying out, and the species was contracting it's range westward, and towards coastal regions.
 
At the current time ( 2008 ) the species is restricted largely to sites within about 10-15 miles of the coastline, and is most frequently encountered at coastal habitats : cliff-tops, undercliffs, south-facing grassy slopes, shingle banks, sea walls and sand dunes.
 
There is some evidence that the butterfly is beginning to regain lost ground, recolonising inland sites e.g. in Dorset, Wiltshire, and in the north of England. The most northerly colonies occur around the coast of southern Scotland.
 
Wall Brown Lasiommata megera, male, Dorset, England
 
All habitats are characterised by having extensive areas of exposed ground in the form of well trodden paths, eroding banks, scree, rabbit scrapes etc.
 
The colonies tend to be small, comprising no more than about 20 or 30 individuals, even at the best sites.
 
Wall Brown Lasiommata megera, male, Dorset, England
 
Lifecycle
 
The butterflies are double-brooded, the first generation emerging in late April and early May, and the second generation in late July or early August. In exceptionally long and warm summers there may be a partial third brood emerging in October.
 
The pale greenish-white eggs are laid singly or in clusters of 3 or 4, on the roots of grasses where they overhang into sunny recesses at the edge of eroded ground. Rabbit scrapes, path edges, and crumbling undercliffs are typical situations. I have also seen females laying on grass blades at the base of gorse and bramble bushes on south-facing chalk grassland slopes. The eggs hatch after about 12 days.
 
The caterpillars feed nocturnally on coarse grasses including Brachypodium sylvaticum, Brachypodium pinnatum, Dactylis glomerata, Deschampsia flexuosa and Holcus lanatus. The summer brood caterpillars hatch in August and enter hibernation while still quite small. In late February they re-awaken, becoming full grown by late March or early April. The mature larva is pale bluish-green, with whitish stripes along the back and sides
 
The pupa is virtually impossible to locate in the wild, and varies in colour from pale green to deep olive and sometimes almost blackish. It has reportedly been found hanging from grass stems around the base of small bushes. The pupal stage lasts for about 2 weeks.
 
Wall Brown Lasiommata megera, male with ocellus raised
 
Adult behaviour

 

Wall Browns tend to spend long periods settled on bare ground on paths, rabbit scrapes or overhangs. In lightly overcast weather, or when temperatures are cool early or late in the day, they bask with wings outspread. This enables them to maintain the high body temperatures which are essential for rapid take-off and interception of potential mates.

 

Males will intercept all passing butterflies of roughly similar size and colour, including Peacocks, which they chase away from their territories. Smaller butterflies, and those with much brighter colouring such as Orange tips, Large Whites, Clouded Yellows and Brimstones are ignored.

 

In warm conditions Wall Browns close their wings immediately on landing, with the fore-wings raised so that the apical ocellus is visible. This probably acts as a decoy, so that any bird which spots where the butterfly has settled, attacks the "false eye" marking, rather than the butterfly's body. After a moment, when the butterfly is sure it has not been followed, it lowers the forewing to hide the ocellus. This behaviour is shared with several other Satyrines, notably the Grayling and the Meadow Brown.

 

The butterflies are at all times extremely alert, and are notoriously difficult to approach. Even in cool conditions they react instantly to the slightest disturbance, rapidly flying up and disappearing over the top of tall bushes. The following tale helps demonstrate just how incredibly fast their reflexes are :

 

 

I’ve always had problems photographing Wall Browns, and I’m well used to playing hide and seek with them - clambering up slopes, peeking over tussocks of grass at them, hoping I can press the shutter release before they detect me. It takes more than careful stalking to get the better of a Wall Brown however !

One day in May 2008, I spent over 4 hours attempting to photograph various individuals of this species, but each time, although the butterfly was static and composed nicely in the centre of the viewfinder, by the time the shutter had fired it had flown. I took over 20 photographs, but in 18 of them the butterfly was absent from the final image, or caught in flight at the edge of the frame.

Incredible as it seems, Wall Browns are able to detect the sound of the SLR mirror as it flips up, and shoot into flight before the shutter opens. The delay between mirror-up and shutter release is just a few milliseconds, but in that time the butterflies can not only detect the sound and register it in their minds as a threat, but can trigger an escape response and take flight, becoming nothing more than a blur at the edge of the image.

 

Wall Brown Lasiommata megera, male, Dorset, England

 

Both sexes patrol back and forth along a short regular route, often along paths or areas of broken ground, high on hillsides or cliff tops. They go through a regular cycle of patrolling, resting and nectaring.

 

Favoured nectar sources include buttercups, dandelions and common vetch in spring, and scabious in summer.

 
                                                       
Almost every British and European species of butterfly is declining rapidly in numbers, due in most cases to loss or degradation of habitats.
 
You can help to reverse the decline by supporting conservation organisations which purchase and manage habitats as nature reserves, and which lobby government at local, national and international levels, often very successfully, to bring about changes in farming, forestry and urban development policies.
 
Please contact the conservation organisations for advice on how you can help protect British and European butterflies and their habitats. You may be able to offer practical help e.g. by monitoring butterfly populations or helping to manage nature reserves. Donations to these organisations enable them to employ ecologists and biologists. Even if you are unable to provide such help, merely having your name on the membership list can be a powerful tool for conservation organisations wishing to demonstrate the levels of support they have for their policies.

 

 
Text and photographs protected by Copyright © Adrian Hoskins 2007-2008, and must not be reproduced or published in part or in whole elsewhere in any form without written permission from Adrian Hoskins. Breach of copyright will be pursued by litigation.
 
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