Butterflies of the World - Lifecycle, Ecology, Taxonomy, Conservation, Photography, Butterfly Holidays, Photo Galleries, Book Reviews and more.........
Text and photographs protected by Copyright © Adrian Hoskins 2007, and must not be published in part or in whole elsewhere without prior written permission from the author.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
 
Speckled Wood
Pararge aegeria tircis BUTLER, 1867
Family - NYMPHALIDAE
subfamily - SATYRINAE
Tribe - SATYRINI
 
 introduction | habitats | lifecycle | adult behaviour
 
Speckled Wood Pararge aegeria, male, Powerstock, Dorset, England
 
Introduction
 
This common woodland butterfly was originally known in Britain as the Enfield Eye or Wood Argus. The name Speckled Wood first appeared in 1766, in Moses Harris's famous book The Aurelian.
 
The butterfly is widely distributed in Europe, but absent from sub-arctic areas of Norway and Sweden. Beyond Europe it occurs in the Atlas mountains of north Africa and extends into Asia as far east as the central Ural mountains.
 
The British and northern European subspecies tircis is marked with pale creamy spots, but in southern Europe the normal form of the butterfly has the wings patterned with large orange blotches, and can be mistaken for the Wall Brown Lasiommata megera.
 
There are 2 other very similar Pararge species - xiphiopides which is endemic to the Canary Islands, and xiphia which is endemic to Madeira ( where aegeria also occurs ).
 
The Speckled Wood is unique among British butterflies in that it can hibernate as either a caterpillar or chrysalis. Consequently the spring emergence of adults tends to be very staggered. At any individual site however the adults tend to emerge in synchrony, which implies that the hibernation stage is dependent on habitat and local climate, rather than being random.
 
The butterfly usually produces 2 generations a year in Scotland, or 3 generations a year in southern Britain, where it can be seen at any time between March and mid November.
 
Beech woodland with dappled sunlight - a Speckled Wood habitat in southern England
 
Habitats
 
In Britain the Speckled Wood is regarded as a common woodland butterfly, which breeds in damp areas where dappled sunlight filters through the trees. It can commonly be seen basking on low foliage, or on forest paths in deciduous woodland, but is quite tolerant of shade and can also be found in conifer plantations, where it breeds along grassy rides.
 
In recent years it has increasingly expanded into more open habitats, and can regularly be seen in gardens, along hedgerows, and even in bushy areas of open grassland.
 
Lifecycle
 
There are either 2 or 3 broods per year in Britain, depending upon location. Normally the first adults appear in late March. The emergence is very protracted however, extending well into June, and overlapping with the second brood, which flies between late June and September. The third brood ( if and when it occurs ) usually begins in August, but late emerging insects may still be flying as late as mid November. Individual adults have a lifespan of between about 7-20 days.
 
The spherical egg is straw coloured, and finely ribbed. It is laid singly on the underside of grass blades, always where the grasses are growing in dappled light, usually at the base of bushes. It hatches after about a week.
 
Unlike most other Satyrine larvae, which are generally nocturnal, the caterpillar of the Speckled Wood feeds by daylight. It is pale green, marked with thin longitudinal yellow and whitish stripes, and is perfectly camouflaged at rest on grass blades. It feeds on soft grasses, principally cocksfoot Dactylis glomerata, couch Agropyron repens, wood millet Milium effusum, Yorkshire-fog Holcus lanatus, creeping soft grass Holcus mollis, and wood meadow grass Poa nemoralis.
 
The chrysalis is formed hanging by the cremaster from woody stems, and is variable in colour, some being pale green, while others can be quite dark, particularly those of the over-wintering brood.
 
Speckled Wood Pararge aegeria, male, Purbeck Hills, Dorset, England
 
Adult behaviour

 

The Speckled Wood flies in shadier habitats than most other British butterflies, and is commonly active on dull overcast days when other species refuse to fly.

 

Speckled Wood Pararge aegeria, female, Crab Wood, Hampshire, England

 

On sunny mornings males take up residence in areas of woodland where dappled sunlight filters through the trees. Each male selects a "perch" in the form of a sunlit leaf, from which it can survey passing females. During the course of the morning, the changing position of the sun causes the various perching places to be periodically shaded, at which time each male has to move to establish a new perch. Inevitably this results in a high number of male-male encounters.

 

When males meet, they engage in a sortie, spiralling upwards to the tree tops, after which a "winner" emerges to return to his chosen perch. Experiments have shown that the winning male is usually the one which first established the perch. The intruding male is ousted, and has to establish a new perch elsewhere in the vicinity. In experiments when 2 males have been introduced simultaneously into an area, and both believe they have ownership of a perch, the ensuing sortie can last for many minutes.

 

Males leave their perches to intercept Speckled Woods of either sex, but generally ignore other butterfly species. When a female is intercepted, the pair settle on foliage, and the female spreads her wings. The male then approaches from below, gently walking onto the hindwings of the female. Butterflies have olfactory ( pheromone-detecting ) sensors on their feet, so this ritualised behaviour may enable the male to "taste" whether or not the female is a virgin.

 

Copulation takes place in the late morning and lasts for about an hour.

 

The adult butterflies feed mainly on honey dew ( aphid secretions ) on the upper surface of leaves, typically in ash or oak trees. I have also observed them nectaring at pear blossom, buckthorn, hawthorn and the flowers of the wayfaring tree. The commonest nectar source however is probably wood spurge.

 
                                                       
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.
 
Website designed, produced and owned by Adrian Hoskins