The Purple Empire: Hibernating Emperors

From John Woolmer - Jan 15th 2013

Now is the winter of our discontent made glorious (Richard the Third)

Brine hating could describe winter tactics (11)

There is something mystical about being in the company of real experts. To see Adrian Hollis (world correspondence chess champion) look at a disputed endgame and dissect it in seconds; to hear Rob Sheehan ( former Times bridge correspondent) analyse a difficult hand; to listen to the Amadeus quartet play Mozart in a lofty abbey with perfect acoustics ; to watch Jim Laker and Tony Lock demolish the Australian second innings at the Oval in 1953; to listen to the great mathematics writer CV Durrell, at the age of ninety, interrogate the writers of the once fashionable School Mathematics Project with razor sharp precision; to hear the evangelist; to see Michael Green’s slide of the Sea of Galilee where he spoke from a boat audibly to someone standing half way up the hillside (see Mark 4:1) illustrating the veracity of the Gospel accounts – all this is quite ethereal.

Seeing the paintings of the great Venetian master Carpaccio, in a small church, recounting the engaging legend of St Jerome and the thorn in the lion’s paw; looking at the extraordinary variety of the three hundred carvings in the ceiling of Shepton Mallet Parish Church (and noting the Puritan bullet holes in some of the angels’ wings); listening to George Eliot’s Middlemarch being beautifully read on Radio 4 preceded by a lovely Beethoven bagatelle – all of these could be added to my list!

Savernake Forest was bathed in bright winter sunshine. I used to visit Savernake with my parents. We loved to read the text on the monument, deep in the far side of the Forest far from the A4, which gives thanks for the recovery of King George 111 and also declares that the Earl of Ailesbury received his elevation through merit (and, by implication, not bribery!). Later, with Karl Bailey, I realised that the obelisk is a favourite meeting place for male Purple Emperors. They squabble around the monument like courtiers wanting to take precedence around the King. How fitting that the Emperors should gather round a monument celebrating the recovery of the mad King who probably suffered from an illness which, amongst other things, causes purple discoloration of urine (porphyria).

There I met Matthew Oates, the PE expert, and he showed me many treasures. His knowledge, and expertise and knowledge of appropriate poetry, is of a similar quality to that extolled above. He showed me many trees around which males gather and various sallow bushes, in different parts of the forest, on which females lay their eggs. One highly favoured bush has been visited in each of the last four summers. This year there have been many fewer eggs laid. He pointed out six hibernating Emperor Caterpillars – all with strikingly different colouration perfectly matching the willow branches and buds against which they rest for the long winter. Their colours change gradually over a five week pre-hibernation period. They appear to select resting places which match their remarkably varied colouration. Some of Matthew’s photographs in British Wildlife June 2012 show an even more striking camouflage effect. All known larvae have survived since entering hibernation in November; one has caused Matthew consternation by moving. The rest have remained motionless trying to avoid the sharp eyes and hungry beaks of the long-tailed tits and other predators. Curiously, more eggs do not necessarily mean more butterflies. There is a theory that a relative abundance of hibernating caterpillars leads to greater searching by the efficient predators. It also seems that those which choose cracks in the wood rather than camouflage near buds do better.

Another dangerous time is in the early spring when the caterpillars move to await the opening of the buds and the arrival of food. Matthew calls this ‘the airport departure lounge’ syndrome and it is a time of great danger for the hungry waiting caterpillars. How Matthew finds these minute caterpillars (and he has tracked down a number of other ones in more remote parts) is something of a mystery – evidently he finds eggs and young caterpillars in the autumn which can give themselves away by nibbling at leaves in a very characteristic way. Then he looks nearby for signs of the perfectly camouflaged hibernating insects. Ideally, he likes to lie horizontal and look upwards scanning the bark of every sallow bush with his powerful glasses (O happy servant he in such a posture found! –as a curious hymn line puts it). Dog walkers, he remarks laconically, look perplexed.

He also produced, high up in a sallow bush, the empty base of a chrysalis from last summer. This was discovered, high up a tree, by examining any leaves which hadn’t fallen through powerful binoculars. Then low down, he showed me a Female Brimstone hibernating in a small thicket of bramble. All that was lacking was the perhaps mythical icicle hanging down from the tip of her wings! What a perfect winter day! In the next few days, winter arrived with massive snowfalls making the bright sunlight on January 15 seem even more marvellous. I wonder what the rest of the year will bring…..