Saturday, 29 November 2014

Nature of Corsica 6: Butterflies

Common Blue, P.icarus
Butterflies were common across the island, and in the course of the week we saw at least 19 species, of which two are endemic to the island. Of the rest, many have a range centred on the Mediterranean, while a few are resident year round in the UK or are summer migrants to Britain.

While many are familiar with the famous migrations of the Monarch in North America, many European butterflies are also migratory. With the Red Admiral in the UK at least, and probably other summer visitors such as Clouded Yellow and Painted Lady, they migrate north in spring, breed for one or two generations in Britain, then the autumn generation migrates back to the Mediterranean to resume breeding when the winter rains result in fresh growth of their food plants. In recent years this has been complicated by a warming climate, which has enabled cold-sensitive species to overwinter and breed further north than they used to.

Swallowtail larva on fennel
One of these is the mainland race of the Common Swallowtail, Papilio machaon – there is a resident English race which is specialised for life in marshland and fen in eastern England, but in the last year or two the continental race has appeared, bred (sometimes in peoples gardens), and overwintered as pupae. Continental Swallowtails feed on a wide variety of umbellifers, but are especially fond of fennel, which grows everywhere on Corsica. We saw several adults, but they are strong fliers and I did not get a decent picture, but we also found one nearly full grown larva.

Clouded Yellow, C.crocea
Various pierid butterflies were seen in the course of the trip. Commonest were both Large and Small Whites, but we also got good views of the Clouded Yellow, Colias crocea. This is a resident in southern Europe, where they breed in Lucerne fields, but every few years the UK enjoys a major visitation, generally referred to as Clouded Yellow years. In extreme cases vast flocks can be seen travelling across the Channel to make landfall in the south of England, but they then filter north as far as Scotland on occasion.

P.icarus showing underside
Many lycaenid butterflies occur on Corsica, and we found four species – Holly Blue, Common Blue, Brown Argus and Small Copper. All of these are resident in the UK.

Small Copper, L.dispar
The brush-footed butterflies, Nymphalidae, get their name from the modification of the front paid of legs, which gives the appearance of their having only four legs instead of the standard six when examined. The family is extremely diverse, and includes a large proportion of the world’s butterflies, with around 6,000 described species.

Two-Tailed Pasha, C.jasius
The most spectacular butterfly of the holiday was seen several times in the maquis, where they are fairly frequent. The Two-Tailed Pasha, Charaxes jasius, is the only European member of a genus otherwise found mostly in sub-saharan Africa, with a few species in southeast Asia and Australasia. They are strong-flying butterflies, and rather than visiting flowers prefer rotting or at least overripe fruit, dung, and carrion. The larvae feed on the leaves of the Strawberry Tree, Arbutus. The African species are often included in the species on show in butterfly houses.

Cardinal, P.pandora
Fritillary butterflies are extremely diverse in Europe, but the only one we saw was the largest of them, the Cardinal Pandoriana pandora. These are flower-loving butterflies, and like many fritillaries the larvae feed on various species of violet.

Corsican Wall Brown, L.paramegara
The classic butterflies of grassy areas are nymphalids in the subfamily Satyrinae, almost all of which feed as larvae on monocotyledenous plants, but in particular grasses. The species we found included an endemic species, Corsican Wall Brown Lasiommata paramegara. This butterfly was formerly considered a subspecies of the more widespread Wall Brown, L.megara, which is found in the UK, but L.paramegara is restricted to Corsica, Sardinia, and a few adjacent islands.

Corsican Heath
Corsican Heath, Coenonympha corinna is a minute butterfly, very similar to the Small Heath C.pamphilus also found in the UK, as is the Meadow Brown Maniola jurtina. The Speckled Wood butterflies we found were the southern subspecies, Pararge aegeria aegeria, much larger and more orange than the dark brown-and-cream coloured version we have in the UK.

Southern Grayling
On several days we found Southern Grayling, Hipparchia aristeus. This butterfly is also found in North Africa, and very similar butterflies, sometimes classed as a separate species H.senthes, are found in the Balkans. Graylings have a very distinctive behaviour - when disturbed by a walker they fly ahead a few metres and then settle, lying almost flat against the ground to conceal their shadow and relying on their camouflaged underside for protection.
Great Banded Grayling
Finally, on the last day we located some of the most spectacular “Browns” of the trip. The Great Banded Grayling Brintesia circe appears extremely large in flight, as large as a Peacock, and we saw several in territorial fights over favourite basking sites. They appear extremely dark, almost black, with the distinctive white bands on the hind wing showing prominently.

Next time, amphibians and reptiles

(Two-tailed Pasha photo from Wikipedia, others are mine)

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