4 September 2010

Aristocrat Butterflies

Proboscis of Peacock Butterfly, Inachis io
Image: Ian Dury

The fermenting juice of rotting windfalls brings many wasps and flies, the odd hornet, and, with luck, butterflies. If nearby there are also September flowers – especially Michaelmas daisies and buddleia blossom – the chance of butterflies is increased still more.

By this time of year the majority of butterflies still on the wing are those that spend the winter as adults, rather than as eggs or larvae or pupae. Typical of this group are certain members of the nymphalids, a family which contains some of the showiest and best-known British butterflies, such as the Peacock, the Red Admiral, the Comma, and the Small Tortoiseshell.

So entranced were the early lepidopterists by this family that they called many of its children the “aristocrats” and gave them names to match. The Purple Emperor, the White Admiral (the word Admiral is a corruption of “Admirable”), the Camberwell Beauty, and the Large Tortoisehell are rare in England today. A frequent cause of a butterfly’s decline is increasing scarcity of the plant or plants on which its caterpillar feeds. In the case of the Large Tortoiseshell, for example, the major food plant is elm, and, through Dutch elm disease, we have lost twenty-five million trees since 1970.

But not all is gloom. Many sorts of insects – a number of aristocrats among them – depend either partly or completely on the nettle for food and shelter. The nettle is highly nutritious for hungry caterpillars and, best of all, avoided by grazing animals. It is usually found in association with man, thrives on waste ground, and may be locally abundant.

The Red Admiral, the Peacock, the Small Tortoiseshell and the Comma are all partial or exclusive nettle-feeders, so it is no surprise that these are the aristocrats commonest today. The Comma – a tawny butterfly with its jagged-edged wings spotted with black – has in fact been increasing its numbers since about 1925, for reasons not fully understood.

The Comma gets its name from a small, comma-shaped mark in silvery white on the underside of each hind wing. The rest of the undersides are camouflaged with brown and darker brown pencillings, so cleverly that when a Comma closes its wings it can seem to disappear. Its caterpillar, which leads a solitary life, goes one better in the camouflage game and looks very much like a bird dropping. The adult butterfly is often seen in gardens, where it may form an attachment to a small area – sometimes of just a few yards square – with its own favourite leaves for resting and basking in the sun.

The Peacock and the Small Tortoiseshell also have drab, disguised underwings which contrast with the ostentatious patterns above. The Small Tortoiseshell, marked with orange, brown, contrasting patches of black and white, and with a tracery of tiny blue half-moons along each trailing edge, is perhaps the most familiar of the garden aristocrats.

The Peacock is almost as common. It is so called from its four large “eyes”, the ones on the hind wings being especially like those on peacock’s feathers. The colouring and texture of its wings are almost unbelievably subtle and complex, more inventive and in far better taste than even the most costly Oriental carpet. However long you study a resting Peacock, always apprehensive that at any moment it will decide to flit away, your eye can never take it all in; the brain can remember no more than the crudest essentials of the pattern.

It is no answer to catch and kill the insect and pin it to a board, for then, with its life, its vibrancy is lost and the colours seem to fade. Butterflies must be admired in their totality, and that includes sunlight and air and the liberty to fly away.

The fruit-strewn turf of a neglected orchard is a fine place to see Red Admirals. Drunk on cider and greedy for more, they are more approachable than usual. The wing-pattern is predominantly black, with a scarlet band across each forewing, another on the trailing edge of each hind wing, all offset by white splashes and touches of azure. As it sips the sweet, intoxicating juice the butterfly continually opens and closes its wings as if in ecstasy. The scene is almost one of decadence. In places two or three Red Admirals jostle with Peacocks and wasps for the best places on the decaying fruit.

This taste for decay is reminiscent of some of the really big tropical butterflies which flock to putrefying carrion. At one time Purple Emperors were baited with dead rabbit; besides rotting fruit, the Red Admiral likes the rich sap oozing from damaged oak trunks.

The Red Admiral, like several other nymphalids worldwide, is a migrant. It arrives in May, having flown here from North Africa or Southern Europe, and lays its eggs, singly, on the upper surface of nettles or related plants. These eggs give rise to the resident summer generation; some of the butterflies feeding in the orchard may be on a return migration, for the Red Admiral is unable to withstand the northern cold and does not hibernate north of the Alps.

The Peacock, the Comma, and the Small Tortoiseshell, though, are able to withstand it, and in the next few weeks will be seeking safe places to hide for the winter. With their wings closed, leaving only the camouflaged undersides showing, they are easily missed by predators. They are also easily missed by humans: when giving the garden shed its autumn turn-out it is worth remembering that some of these butterflies may well have staked their all on a crack or crevice in some dark corner.

There they remain, month after month, motionless and with their body functions almost at a standstill. A few warm days in March are enough to wake them, which is why Peacocks or Small Tortoiseshells are among the first butterflies to be seen in spring. Then there is no rotting fruit to attract them; they must break their fast with a purer nectar sipped from banks of heather or other early blooms.

It might be preferable to think of them at that spring, rather than this autumn, equinox, and, tiptoeing a retreat through the dew-soaked grass, leave the orchard and its inhabitants to their orgy of decay.

(Introduction to these pieces; see all)


CandiTrap said...

We have just failed to "sort" our garden this year... And have the juiciest nettle stock in the west.
We were amazed to see a big black wriggling mass of spiky fuzzy caterpillars on our nettles ( doing a beautiful job of "sorting" our garden..

We are very not Lepidopterists but did a bit of internetting on the subject and instantly fell in love with them.

We have since located 3 cats getting their jackets on - one of which has done it against an old wardrobe side I used to stop the cats escaping thru hole- I am puzzled as to why there are so few in the change even though there are thousands getting fat from our nettle forest..

My main question if anyone could answer is, how can I tell the difference between tourtoiseshells and Peacocks as I THINK we have both on nettles... .
Do they co-exist? As they seem overlapped or perhaps I am confused and they both share characteristics?

But to me there seem to be BLack fuzzy ones and slightly less fuzzy, mildly spikes ones with yellow dots/stripes on their lower side... Seems to vary with maturity...

Richard Herley said...

Thanks for your comment and good luck with the nettles ...

Here are some pix that might help with identifying your new pets.

Small Tortoiseshell: