Sunday, 19 April 2015

Extinct and very rare British butterflies that live in Portugal - Black-veined White and Large Tortoiseshell

Black-veined White

Black-veined White (Aporia crataegi). Photo by Christian Fischer

There are several British butterflies that are either extinct now or very rare that can be found in Portugal, though possibly not in great numbers there too. 

The Black-veined White (Aporia crataegi) mysteriously became extinct in the UK back in 1925. It is a mystery because the food-plants of its caterpillar are plentiful. The caterpillars feed on Hawthorn (Crataegus monogyna), and various Prunus (Plum) and Pyrus (Pear) species.  

The caterpillars overwinter and it is thought that mild winters in Britain may have led to their demise. Predation by birds and disease are also other suggestions as to why this species has vanished. Its last colony was in south-east England and it had also been established in Hampshire, Gloucestershire and Sussex.

The Black-Veined White, as its name suggests, has white wings veined in black. It lives in colonies and has a liking for orchards. Although it has become extinct in Britain it is still surviving in Portugal, where it has been reported from the south-eastern Algarve area, though it is not common there. This butterfly can be found in some other parts of Europe, in North America and in temperate Asia.

Large Tortoiseshell

Nymphalis polychloros Photo by Algirdas 

 The Large Tortoiseshell (Nymphalis polychloros) looks very much like a larger version of the Small Tortoiseshell (Aglais urticae), hence its name, but unlike the smaller species it is very rare in the UK and its caterpillars feed on very different food-plants. While Small Tortoiseshell larvae feed on Stinging Nettles (Urtica dioica), those of the Large Tortoiseshell eat the leaves of various trees including Willow (Salix spp), Elm (Ulmus) and the White Poplar (Populus alba).

The Small Tortoiseshell was once a very common British butterfly but has been declining in numbers drastically in recent years, though it is still widely distributed, however, the Large Tortoiseshell has nearly vanished from the UK.  

The Large Tortiseshell can still be found in the Cork Oak (Quercus suber) forests  of the western Algarve and elsewhere in Portugal at times, though it is uncommon and regarded as a threatened species of butterfly. 

Bath White 

Illustration from John Curtis's British Entomology Volume 5 Bath White in Public Domain
The Bath White (Pontia dalidice) is a very rare migrant to the UK but is common in Portugal and much of southern Europe. It frequents rough ground and dry slopes. The caterpillar of the Bath White feeds on various plants in the Cress family (Cruciferae) and also on wild Mignonettes (Reseda spp).

The Swallowtail Butterfly 

Swallowtail. Photo by Steve Andrews

The Swallowtail (Papilio machaon) is a large and very pretty butterfly that is common in Portugal and even breeds in the gardens of many towns and cities where it can be seen flying throughout most of the year. 
Its caterpillar feeds on Fennel (Foeniculum vulgare) and Rue (Ruta graveolens). 

The Swallowtail is a very rare butterfly in the UK and only lives in the Norfolk Broads area where the caterpillars feed on the Milk Parsley (Peucidanum palustre). 

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