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Text and photographs protected by Copyright © Adrian Hoskins 2007, and must not be published in part or in whole elsewhere without prior written permission from the author.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
 
Wood White
Leptidea sinapis LINNAEUS, 1758
Family - PIERIDAE
subfamily - DISMORPHIINAE
 
 introduction | habitats | lifecycle | adult behaviour
 
Wood White Leptidea sinapis, 1st brood male, Surrey, England
 
Introduction
 
When seen in flight, novice observers can confuse this butterfly with the Green-veined White, female Orange tip, or Small White, but when settled the differences are very obvious. Experienced butterfly watchers can also recognise differences in the flight patterns. The other "whites" have a direct and purposeful flight, and periodically rest on leaves. The Wood White however floats delicately and aimlessly at an almost constant height just above the herbage, and is very reluctant to settle in sunny weather.
 
Wood White Leptidea sinapis, female at common spotted orchid, Dorset, England
 
At first glance this seems to be a plain and perhaps uninteresting species, but is amongst the most fascinating to watch. The courtship behaviour for example is very complex, and arguably demonstrates a degree of "intelligence" equal to that of ants, bees and other social insects.
 
The Wood White is distributed throughout Europe and western Asia. There are 3 other extremely similar species found in Europe, including Real's Wood White ( also found in Ireland ). The latter can only be reliably distinguished from sinapis by examining the genitalia under a microscope.
 
Wood White Leptidea sinapis, 1st brood female at roost on bugle, Surrey, England
 
Habitats
 
In Europe this butterfly is adapted to breed in a wide variety of habitats including alpine meadows, woodlands, roadsides, gorges and heaths, but in Britain, at the edge of it's range, the butterfly is much fussier. The larval foodplants are common and widespread, but the butterfly is very localised, confined to a small number of sites in southern and central England.
 
Wood White Leptidea sinapis, 1st brood female, Dorset, England
 
In Surrey, Sussex and the Midlands it is found in several large woodlands, where it breeds in recently opened clearings, and along ride edges. In Dorset and the west country it occurs along disused railway cuttings, wooded undercliffs, and old meadows adjoining woodland. In Hampshire a small colony exists in a heathland / woodland mosaic.
 
The features that these sites have in common are that they are warm, sheltered, damp, and have the larval foodplants and nectar sources growing in profusion.
 
In former times the butterfly was far more widespread, but has become far scarcer since the virtual cessation of coppicing and the abandonment of hay meadows. At woodland sites where ride widening, scalloping of ride edges, and creation of semi-permanent glades has been undertaken, numbers have increased dramatically, but it is very unlikely that the butterfly will recolonise sites from which it has already been lost, as it is a far from mobile species, and will not venture away from it's isolated breeding sites in search of new habitats.
 
Wood White Leptidea sinapis, 2nd brood female, Surrey, England
 
Lifecycle
 

In Surrey and West Sussex the butterfly is sometimes double brooded, the first brood emerging as early as late April, or more typically in May; and the second brood ( which may be partial, or absent entirely ) emerging in late July or early August. In south Devon the butterfly is always double-brooded. In the remainder of Britain it is always single-brooded, emerging in late May, and remaining on the wing until late June or early July.

 

The egg, like that of other Pierids, is skittle-shaped, ribbed, and shiny. It is whitish in colour, and laid singly on the underside of leaves of various vetches and trefoils.

 

The foodplants used vary from site to site, and from brood to brood. At one Surrey wood for example, the first brood oviposits almost exclusively on bird's foot trefoil Lotus corniculatus, while the second brood lays on greater bird's foot trefoil L. uliginosus. At another nearby wood the eggs are laid much more commonly on bitter vetch Lathyrus montanus; and at sites in Dorset and Northants, meadow vetchling L. pratensis or tufted vetch Viccia cracca seem to be favoured.

 

The caterpillar is thin, pale green, with a yellow line along each side, and a dark green line along the back. It rests by day along the midrib of the leaves, or on the stems of it's foodplants, and feeds mainly nocturnally, leaving characteristic nibble marks on the edges of the leaves.

The chrysalis, like that of the Orange tip, is pointed at both ends, boomerang-shaped, and slightly flattened. It is pale yellowish-green, with a thin pink line running down each side, and is attached by the cremaster and a silken girdle to a stem on, or close to the foodplant.

Finding the chrysalis in the wild is very difficult, as the camouflage is superb. The easiest way to find it is to mark oviposition sites, and to revisit and carefully search them in the winter, when the foliage has died back. Hibernation occurs during the pupal stage.

Adult behaviour

 

 
Wood White Leptidea sinapis, 2nd brood female, Surrey, England
 

Wood Whites visit a wide range of nectar sources including greater stitchwort, wood forget-me-not, bird's foot trefoil, cut-leaved cranesbill, common spotted orchid, bugle and bitter vetch. They can also sometimes be seen imbibing mineral salts from damp ground, from the edges of stagnant puddles, or from herbivore dung.

 

Wood White Leptidea sinapis, 1st brood male, Surrey, England
 

A ritual is often observed in which male and female sit face to face on a leaf, with wings closed. The male flicks out his proboscis and whips one hindwing of the female, and then the other, repeating the process many times whilst periodically flicking open his wings. The female responds by flicking open her own wings. At the same time there is antenna interplay similar to that seen when ants and bees exchange chemical "messages". This ritual often continues for half an hour, but from my observations does not lead to copulation, so the nature of the messages is unclear.

 

On sunny mornings males patrol back and forth along woodland rides and around the edges of clearings in search of newly emerged females. In a Surrey wood, early one morning in May 2004, I found a mated pair of which the female was newly emerged and still drying her wings. The implication is that the true courtship ritual is probably a brief affair, and that the ritual described above may be conveying messages unconnected with courtship.

 

Wood White Leptidea sinapis, 1st brood male, Surrey, England

 

Overnight, and in dull weather, the butterflies roost in sheltered spots, often in little groups of 2 or 3, typically on the white flowers of stitchwort, or on the flowers of pendulous sedge, dandelion "clocks", or cock's foot grass heads.

 
                                                       
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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