A special tribe of Butterflies.

As Summer moves into Autumn, the peak diversity of butterflies has past, but a few species persist in our gardens and in the countryside, even as September becomes October. Speckled Wood (Pararge aegeria, L.) can fly well into November in their sheltered woodland edge habitat. However, these are not the most spectacular of Autumn butterflies. This prize must go to the members of the tribe Nymphalini, sometimes referred to as “the Aristocrats” in old field guides, or rather, a subset of them, the bright, boldly marked and coloured butterflies which dazzle on garden Sedumand even on rotting fallen fruit into early October each year.

Red Admiral (Vanessa atlanta) Enjoying the riches of Autumn, September 2014

These stunning bugs are out and active so late in the year for a reason.  They do not spend the winter as sleepy larvae, hunkered down somewhere out of the way like so many temperate zone butterflies. While my Northern Brown Argus (Aricia artaxerxes) the lycaenid unrelated to the Aristocrats, with which I worked the summer of 2013, remains an unassuming caterpillar, seeking a warm spot among the scrub of its hillside habitat in which to escape the frosts, Red Admirals (Vanessa atlanta)  and Small Tortoiseshells (Aglais urticae) are preparing for the epic ways in which these species escape the cold.  Small Tortoiseshell  and Peacock (A. io) look for sheltered corners, often venturing into homes and outbuildings, in which to roost out the cold, dark months, avoiding the depredations of spiders and other predators and incidental predators somehow, whilst in a state of torpor. Red Admirals, and the closely related Painted Lady (V. Cardui) feed frantically to fuel their ascent to several hundred metres altitude and their long migration back to Southern Europe where they can escape the worst of the North European Weather.

Polygonia c. album at Roding Valley, Essex, April 2014

Aglais io at Two Tree Island, Essex, April 2014

 The Aglais nymphalids, and the related Comma (Polygonia c-album) which also undergoes hibernation as an adult, have larvae which grow and feed communally on stinging nettles (Urtica dioca) and sometimes on Hops (Humulus lupulus) in the case of the Comma.  All have more than one generation on the wing in a year, with large numbers of all three on the wing in July. Their offspring go on to feed, grow and ultimately hibernate as adults. They emerge and embark on a brief but frantic period of feeding. Their bodies are modified for this, they will have no interest in reproduction until the spring.  Their wings, whilst bright and gaudy on their uppersides, are all remarkably plain on the underside, closely resembling a dead leaf. Stationary, and with their wings closed, they can virtually disappear into their winter environment.  On the whitewashed walls of a building, be it a camp site wash block or the attic of a suburban home, they are more conspicuous, but perhaps have less to fear from predators. Peacocks will still flash their eye spots when threatened, in the hope of dazzling of confusing a predator, but in the main they remain still and silent, before, as the weather warms, they become slowly active, before heading out into a new spring, often somewhat faded, to regain their energy levels, and finally go about the business of courtship and reproduction, assured of blackthorn blossom on which to find nectar, and fresh nettles on which to lay their eggs.  All are among the first butterflies to appear in spring. As the weather turns I wonder if I must wait that long to see them, or if stragglers will yet grace my Sedums this year. Nymphalini butterflies, which like all North European butterflies are largely nectar feeders and cannot ingest pollen, in the active state, can typically live a couple of weeks as adults.

The Early bug catches the blackthorn blossom. Overwintered Aglais urticae. Roding Valley, Essex, April 2014.

The genus Vanessa, which includes the hugely widespread Painted Lady (V.cardui), resident on every continent except Antarctica, and the Red Admiral (V. atlanta) have evolved a strategy even more remarkable with which to face the ravages of the North European climate.   It was long thought that these species dispersed from Southern European breeding grounds to Northern Europe, erruptively, settling in Britain and other countries, and produced a brood of caterpillars which fed through the summer, pupated, and then emerged between July and September, only to perish in great numbers when the first frost set in. The evolutionary absurdity of this theory was not explored, and even after Southward movements of Red Admirals had been detected and their migratory habits acknowledged, painted ladies were still thought to colonise Northern Europe afresh every summer only to die in their millions.  This, of course, is not true. Painted Ladies can cross oceans, and they cross them far higher than human eyes can see. Tiny signatures picked up on vertical facing radars, such as the purpose built entomological ones at Rothamstead Research,   show butterflies climbing to altitude, up to a kilometre above the ground, including at night, and carefully selecting a Southerly heading and a Southerly wind back to the areas where their parents or grandparents were pupae.  Large and powerful amongst  butterflies, paper thin and fragile against seas and windy skies, Painted Lady and Red Admiral navigate the chill autumn skies in vast numbers and at altitude, their heights taking them free of bats and diurnal predators, some form of evolved internal compass guiding them to their destination.   If you read as I type, perhaps they could be up there right now. In the spring their descendents make the return journey to take advantage of the flowers and the abundant thistles and nettles of Britain and other parts of Northern Europe.

A world traveller. V. cardui, Arnside Knott, Cumbria, August 2013.

(All photos are original. Do not reproduce for profit. Feel free to enjoy, or use in your essays)