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Text and photographs protected by Copyright © Adrian Hoskins 2007, and must not be published in part or in whole elsewhere without prior written permission from the author.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
 
Large Tortoiseshell
Nymphalis polychloros LINNAEUS, 1758
Family - NYMPHALIDAE
subfamily - NYMPHALINAE
Tribe - NYMPHALINI
 
 introduction | habitats | lifecycle | adult behaviour
 
Nymphalis polychloros, Dorset, England
 
Introduction
 
The Large Tortoiseshell is widely distributed in Europe, and common in the Mediterranean region, where it breeds in open woodland areas. It also occurs in Morocco, Algeria and Tunisia; and across temperate Asia from Turkey to Kazakhstan and the foothills of the Himalayas.
 
It can confused with the similar Yellow-legged Tortoiseshell Nymphalis xanthomelas which has much brighter and redder colouring, and enlarged blue lunules on the hind-wings. The latter species is only found in eastern Europe and temperate Asia, where it breeds in wooded river valleys. Old records of it's occurrence in Britain are dubious.
 
Habitats
 
In Britain the Large Tortoiseshell was formerly common, and was recorded from most English counties, but it declined rapidly in the early part of the 20th century, becoming a great rarity by the 1970's. It's decline is thought to be linked to an increase in parasitism, and the loss through Dutch elm disease of one of it's most important larval foodplants, the English elm Ulmus procera.
 
The species undergoes cycles of abundance and scarcity, probably climatically induced, and has been extremely scarce in Britain during the latter half of the 20th century.
 
Since about 1998, occasional sightings have been reliably reported from sites on the south coast of Hampshire and Dorset. Most of these records have been in the late winter or very early spring, of very worn ex-hibernation insects. Although these may have originated in England, the greater likelihood is that they are migrants arriving from France, where the species is still reasonably common.
 
In June and July 2007 several very fresh specimens were seen and photographed at various locations on the Hampshire coast. This species is sometimes bred by amateur lepidopterists, but it is unlikely that these are releases, as the sightings have been scattered over several miles of coastline. The recording of worn specimens from other nearby coastal localities in February 2007 provides circumstantial evidence that the butterfly may now possibly be considered as a rare migrant, breeding in southern Hampshire and / or the Isle of Wight in low numbers.
 
In Europe the butterfly is usually encountered as singletons, encountered widely but never in numbers. It is a highly mobile species, and as such is not possible to describe a habitat for the butterfly, which in theory could breed in woodlands, gardens, parks, or hedgerows where elms Ulmus glabra, U. procera, sallow Salix caprea, poplars Populus alba, P. nigra, aspen Populus tremula or wild cherry Prunus avium grow.
 
Lifecycle
 
The adults emerge in late June or early July, and are only active for about a fortnight, as they enter hibernation very early - typically in late July, and are not normally seen again until the following spring.
 
The eggs are laid in April, and hatch after about 3 weeks. They are laid in large batches, often in a neatly arranged ring around twigs on the higher branches of the various larval foodplants mentioned above, but particularly on Ulmus.
 
The caterpillars are black, covered with pale orange spikes and tiny white dots, giving them a greyish appearance. They live communally in conspicuous silken webs spun on the twigs of the foodplants, feeding diurnally on nearby foliage, and returning to the web overnight, or in wet or windy weather. They gradually split into smaller groups as they get older, but only become solitary just prior to pupation.
 
When fully grown in early June, the caterpillars drop from the treetops, and wander a short distance to pupate. The pupa is brown, marked with gold spots, slightly spiky in appearance, and resembles a withered dead leaf. It is formed hanging by the cremaster from twigs or branches on the lower part of various bushes and trees. In Turkey I have found them commonly suspended from the walls and eaves of buildings. In my experience at least 60 percent of pupae will be found to be parasitised.
 
Adult behaviour

 

The butterflies are seen as solitary individuals, usually either in flight, or when basking on bare ground in lightly wooded habitats. In Britain they have been reported nectaring at sallow catkins in spring, and bramble blossom and various herbaceous garden plants in summer.

 

In Europe they are sometimes seen flying around the tops of sallows, elms and poplars, but are normally encountered in flight, when dispersing in search of breeding sites.

 

In central France I have observed them flying in inhospitable terrain including motorway car parks, petrol stations and town centres, and once found a group of 3 specimens in the company of a dozen Woodland Graylings, feeding at a sap run on a hawthorn bush in a hedgerow. While feeding the Large Tortoiseshells constantly opened and closed their wings, possibly in response to the presence of the Woodland Graylings. As is normally the case with sap-feeding butterflies, both species were oblivious to the presence of humans, and could be approached very closely.

 

In Turkey I have found recently emerged butterflies hanging from twigs along dry river beds. They remained aestivating on the twigs for several days in late May.

 
                                                       
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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