Enough to make anyone flutter

As beautiful as they are fragile, butterflies are one of the true joys of the British summertime. Michael McCarthy pens a love letter to all things lepidopteran

The purple emperor season is upon us. This weekend or next, we will arise early, the children and I, and drive the 80 miles to the great oak-wood near Salisbury where, if it is a warm mid-morning, we will have the best chance of seeing Britain's most magnificent butterfly descend from the treetops where it spends most of the day. Victorian lepidopterists - Anglican clergymen as often as not - thought there was no more spectacular sight to be had in nature than the rare moments when the insect they referred to simply as "the emperor" was flying around you, investigating you, with its royal purple wings flashing in the sunlight.

The purple emperor season is upon us. This weekend or next, we will arise early, the children and I, and drive the 80 miles to the great oak-wood near Salisbury where, if it is a warm mid-morning, we will have the best chance of seeing Britain's most magnificent butterfly descend from the treetops where it spends most of the day. Victorian lepidopterists - Anglican clergymen as often as not - thought there was no more spectacular sight to be had in nature than the rare moments when the insect they referred to simply as "the emperor" was flying around you, investigating you, with its royal purple wings flashing in the sunlight.

Maybe we'll see it. Maybe we won't. (In any case we'll put some crushed sweet fruit on the ground - grapes or peaches - to try to lure it down.) But even if his majesty does not condescend to appear, there will be compensations. There will be white admirals in this wood. They show just how attractive in nature a restrained palette can be - they are simply brown with bold white stripes - and best of all there will be silver-washed fritillaries.

It took me some time to work out just why I found the last of these so heart-stoppingly lovely. They are large, orange and black, and they float through the under-storey of the wood like painted saucers in a psychedelic dream. But it's not just their colour or size that is so pleasing: several of their relatives, like the dark green or high brown fritillaries, are really very similar. It has dawned on me over the years that the attraction lies in a peculiarity of their shape, in the lightly-flattened curve of the forewing. It's the sort of supremely elegant contour you might see in a Georgian silver toast-rack, or in the flattened arch of the Perpendicular style - in the window tops of any late medieval English church. (The Savoy Chapel, say, or St Margaret's, Westminster.)

Once you start looking, the attractions of butterflies (even of the limited number we have in Britain, 60-odd species) seem endless. There is beauty, but there is curiousness too. The marbled white, for example, has a regular, black and white chequered pattern, and where you come across it in numbers, on chalk soil, it's as if one is surrounded by flying boards from pocket chess sets. The grayling, a handsome member of the browns, always rests with its wings closed, and I find myself rushing after it to try and glimpse the attractive wing pattern in flight.

Yet perhaps the greatest delight of our butterflies is that they, unlike fruit, continue to be seasonal (strawberries are all-the-year-round now). The purple emperor and the silver-washed fritillary are insects of the high summer while the appearance of the red admiral signals early summer, while two in particular signal spring. One is the brimstone, which is bright lemon-yellow, and is the first butterfly out, sometimes appearing as early as February. (The word "butter-fly" was probably coined to describe this species, and then spread generically to all the others.) The other is the orange tip, one of the whites: snow-white wings ending in a vivid orange band. I find it hard to describe just how strong is the elation, in any spring, at the first sight of either of these. It's not just the evidence before one's eyes that the cold, hard times are ending and the warm and generous ones are round the corner; it's the intensity of their colour, bursts of brightness in a landscape which is still largely monochrome.

Every now and again I wonder why Gerard Manley Hopkins, whose sensitivity to the natural world was supreme, never wrote (as far as I am aware) a poem about a butterfly. The Jesuit who saw Christ's glory reflected in the flight of the kestrel, and in the "rose moles all in stipple upon trout that swim," would surely have seen it in the vibrant flare of colour of the first orange tip, and he might have enriched our feeling for the sacredness of nature as well as our language. You feel he ought to have done: Hopkins, the great word-coiner, had his own expression for the intensity of existence of things, "inscape", and when you catch sight of the orange tip or the brimstone you know immediately what it is that the poet means.

He was tortured, of course, by the tension between his delight in beauty and his stringent asceticism - that's where the poetry comes from - but it is unlikely that a Hopkins butterfly poem is something he suppressed. The reason none seems to exist is, no doubt, perfectly mundane: the Vale of Clwyd, the area of hills and rivers in North Wales where he studied theology and which inspired much of his best verse about God and nature, is a lovely landscape but not an area noted for butterflies. Neither for that matter is Liverpool, nor Stoneyhurst, nor Oxford, and nor, finally, is Dublin, where typhoid fever carried him off in 1889 at the age of 47.

It's only a fancy, but I wish he had written a butterfly poem in that unique, disturbing and sometimes dazzling voice. Imagine a Hopkins sonnet on the orange tip; even more, imagine one on the purple emperor. Victorian vicars chased after apatura iris and collected it; the Victorian Jesuit would have been similarly stirred by the resplendent purple, but would have chased after and caught something far deeper than the insect itself.