Commas' seasonal colour schemes

 

Comma butterflies Polygonia c-album produce two generations per year, each with its own colours, shape and markings. When overwintering adults emerge in spring the females lay eggs on stinging nettles, where the caterpillars feed and after pupation emerge in early summer looking like this female, with orange-brown wings bearing rather pale marking. They lay eggs on nettles, where their caterpillars will be feeding now, and when they pupate and hatch the next generation of adults, emerging in late summer, will include many individuals that look like ….

 

…. this, with much richer red-brown background colour, darker and more well-defined markings and a brown border around the wing edges, emphasising the dead-leaf cryptic colouration This one was photographed last autumn, feeding on fallen pears in the garden; most of the commas that overwinter look like this.

Why the difference? I’ve seen speculation that it may the consequence of differences in the seasonal quality of the caterpillars’ diet and that daylength during the caterpillars; feeding period - lengthening in the spring generation, shortening in the summer/autumn generation - may have an influence.

Will this be a 'painted lady summer'?

 

This spring was notable for an early influx of migrant painted lady butterflies that arrived here on warm southerly winds, raising hopes that this might be a 'painted lady summer'.

They began to appear in Weardale in substantial numbers towards the end of the heatwave in May but were reported in southern and western counties from mid-April onwards. There has long been speculation that these early arrivals fly here directly from North Africa. The tattered state of the butterfly in the photo above, nectaring on sweet rocket aka dame's violet Hesperis matrionalis in my garden, suggests that it might have had a long and eventful journey.

L. Hugh Newman, whose family ran a butterfly farm in Kent (that supplied Winston Churchill with butterflies for his garden at Chartwell) kept detailed records of their lifespans. Resident breeding species typically had lifespans of less than a month , with the exception of those that overwintered as adults (10-11 months for brimstone, small tortoiseshell, peacock) and found that 30 days was the maximum lifespan of painted ladies. They are known to fly at night and with a favourable wind, they are reckoned to fly about 150km. per day, so it’s just conceivable that some early spring arrivals here might have made the one-way journey directly from North Africa, but there’s no doubt that the true test of whether we are due a ‘painted lady summer’ depends on their breeding success at various locations in continental  Europe, and favourable summer winds.

Most arrive in relays, crossing the Mediterranean to breed in France and Spain first. With their short life cycle - egg to imago in six weeks - their numbers multiply exponentially as they move northwards, a rolling wave of butterflies that reaches our shores in mid- summer.

Spectacular ‘painted lady summers’ are the stuff of lepidopterists’ legends. I recall walking along the coast near Whitby in 1996, surrounded by hundreds of painted ladies settling to feed in flowery cliff-top grassland. That invasion reached Orkney and Shetland. The most recent mass migration that I remember here was in 2009, but size and frequency of such events are subject to favourable winds and clement weather.

 

A harvest festival of ripe fruit and colourful butterflies

 Apples, pears and plums are ripening faster than we can eat them, so the bird table has been taken over by butterflies feeding on the fermenting juice of over-ripe fruit.

There were are least twenty red admirals and half a dozen comma butterflies getting legless on alcoholic fruit juice in this afternoon’s warm sunshine in the garden. When they are in such a lethargic, inebriated state butterflies are very easy to approach and if they do fly they settle again almost immediately.

Drinkers on the bird table ‘Last Chance’ saloon.

Comma butterflies on pears, a red admiral on a rotting apple, plus a bonus seven-spot ladybird that probably came to feed on the mould growing on the fruit.

Comma butterflies seem to have a particular liking for pear juice

A red admiral with its proboscis sunk deep in the hole left by a plum stalk, drinking sun-warmed plum juice

As sometimes happens, a fight broke out between drunkards when this red admiral and comma butterfly were competing for the same feeding cavity in a pear. Wing blows were exchanged and the comma prevailed. It seems even some butterflies can become aggressive if they over-indulge with alcohol, although most seem to just become semi-comatose, to the point where they’ll crawl onto your finger rather than fly away if you poke them.

Large white butterfly caterpillars

 I sowed nasturtium (Tropaeolum majus) seeds this spring, partly for the flowers but also because I was hoping that large white butterflies might find them and lay eggs. They did, and now the foliage is disappearing fast, thanks to some very hungry caterpillars, A nostalgia trip really, because I remember watching exactly the same thing happening in my parents' garden, seventy years ago. Childhood nature experiences can last a lifetime.

Speckled wood butterfly laying eggs

 Speckled wood butterflies have been expanding their range northwards, into County Durham and beyond, for fifteen years now. They've been visiting our garden for about a decade and for the last five years they've been present from early spring until late autumn, so we guessed that they must be breeding here, producing a second summer generation. Last week I found proof.

A female laying her eggs on grass stems, carefully placing them one at a time.

The tiny, glassy pale green eggs provide an excellent excuse for not pulling up the grasses that are infesting the flower borders.

The Year of the Red Admiral

I can't recall an early autumn when I've seen so many red admiral butterflies. It seems to be an exceptionally good year for them here in County Durham, both in our garden and in the wider countryside. 

A red admiral with its black and scarlet wings outstretched, basking in the afternoon sunshine, is a magnificent sight but the undersides of the the wings have their own distinctive beauty. When they are folded they provide a degree of camouflage, with their dark dead-leaf colours, but closer examination, with the aid of brighter light, reveals an exquisite, intricate pattern of scales in shades of brown, grey, blue and green.

The three plants that attract them most in our garden in September are ice plant Hylotelephium sp., ivy and Buddleia x weyeriana, but they also congregate in the company of comma butterflies on rotting fallen apples and pears, becoming sluggish and inebriated under the influence of fermenting juice. 

Holly blues breeding in the garden

When we first came to live in Co. Durham in 1975 several butterflies that I had been familiar with in the south of the country were nowhere to be seen. Commas had been extinct here for a century and speckled woods, small skippers and ringlets were very uncommon. Since then they have all become common and speckled woods even breed in my garden. 

But in all that time holly blues remained rare. Until 2014, when I found one under the Byker viaducts in Newcastle, of all places, I hadn't seen any. Then in 2017 I saw another in Sunderland.

This year they turned up in my garden in Durham in spring and it's clear that they must have laid eggs on the holly hedge, because the summer generation has now emerged. This one seemed attracted to a few alkanet flowers that were still in bloom in the garden, but it has also been nectaring on devil's bit scabious, marjoram and thyme flowers. 

I'm hoping that this will be the start of a long-lasting colony here. There were numerous other reports on Twitter of holly blues in the North east this spring.

The change in fortunes of these five butterfly species here suggests that the theory that climate change, bringing a lengthening breeding season, is a factor allowing them to extend their range northwards might well be true.

Painted Ladies

Lately a few painted lady butterflies have begun to appear in Teesdale and Weardale, wafted in by warm winds from the south. It's nothing like the spectacular invasion we enjoyed in 1996, when the first arrivals appeared in early July and bred on thistles to produce a second generation, so that there were enormous numbers by early autumn. Sometimes late invasions arrive in early autumn, as they did in 1903 (see below).

Painted ladies are noted for their infrequent but spectacular invasions and some of the largest of these, according to F.W. Frohawk in his Complete Book of British Butterflies published in 1934, coincided with wet summers in 1879 and 1903. 

This is how Frohawk described them:

"In 1879 the first migratory swarm appeared in North Africa in the middle of April. At Barcelona and Valencia enormous numbers occurred at the end of April and reached the island of Minorca on the first three days of May. On June 15th. vast swarms passed over Sevres, flying all day in a north-westerly direction. Similar flights were seen at Strasburg passing in countless numbers to the north, At Angers, on June 10th., an immense swarm flew over the city; it was estimated that between 40,000 and 50,000 passed along a single street in one hour; they were flying so low that pedestrians were inconvenienced by them. At Bisheim, on June 8th., the same phenomenon was observed and their numbers were so enormous that they darkened the sky. On June 11th. the flight that passed through Steyer in Austria, was so great that between one and two o'clock p.m. 90 to 100 per minute were counted in the breadth of 100 paces, the swarm being estimated at 1,000,000. Similar vast swarms were encountered in other places. 

Again, in 1903, a sudden and great invasion of these butterflies occurred in the autumn. They arrived in hundreds of thousands along the southern and eastern coast and dispersed over the whole of the British Islands. The flight was so vast that it extended from the Shetlands to the extreme south of England and Ireland. Their numbers were so prodigious that they swarmed along the whole of the eastern seaboard, from Durham to Kent, and wherever observations were made on the Scottish coast, they were abundant. The first arrivals of this vast invasion reached our shores on September 18th., and the flight continued for five or six days, their numbers increasing daily."

These butterflies look particularly attractive when you view them from below, with the sun shining through their wings that then resemble stained glass windows.

This individual was in Weardale yesterday, feeding on knapweed.

Ringlets

It's peak flowering time for brambles in Teesdale at the moment, which means that it is also peak feeding time for ringlet butterflies Aphantopus hyperantus that like to nectar on the flowers.

When they first emerge their wings are like dark brown velvet, fringed with white hairs, but as the season progresses they lose scales and their colour becomes paler. 
This individual with nicely defined wing spots, sunning itself on a bramble leaf today, is a female. Males tend to have just small dark dots as wing markings.

Ringlets have become much more common in the North Pennines over the last thirty years. There is no shortage of their larval food plants - grasses - and the adults seem very tolerant of dull and damp conditions. I've often seen them flying low over vegetation in very overcast conditions and sometimes even in drizzling rain.

They are very casual about where they lay their eggs. Most butterflies stick them on their larval food plants but ringlets just drop them into the grass. 

Purely by chance, a few years ago I photographed this one in the act of laying an egg, with the egg in mid-air.

Orange tip caterpillar food plants

We have all three of the commonest food plants for orange tip butterflies in the garden - hedge garlic (Alliaria petiolata), lady's smock (Cardamine pratensis) and sweet rocket (Hesperis matrionalis), though I only encourage the last two because hedge garlic is so invasive.

This year, for the first time, I've noticed the caterpillars feeding on the developing fruits of this plant, honesty Lunaria annua.

I think they probably find it tougher to chew than the other three plants but they seem to be growing rapidly on this diet.

The only drawback, from the caterpillar's point of view, may be that they are more conspicuous on these disk-shaped fruits. When they align with the long, thin pods of the other three plants they are quite hard to spot because their countershading colour scheme works very well in those circumstances and they don't cast a bold shadow..

Butterfly alcoholics

Thursday's Guardian Country Diary is all about intoxicated butterflies.

We had our best ever plum crop this year - too many to eat, store in various forms or give away all of them. Branches broke under their weight.

The beneficiaries from those that fell on the ground were red admiral butterflies. I piled some plums on the bird tables, where the natural yeast on their skins fermented the juice to produce an alcoholic liquor that stupified the butterflies that fed on it. The whole area under the tree smelled of vinegary alcohol after a few days in the sun.

Sometimes there were a dozen or more red amirals on the bird table, where they usually tolerated each other as long as their wings or antennae didn't touch. If they did they flicked there wings, clearly irritated.

If  other butterfly species tried to join them - and peacocks and speckled woods sometimes did - the red admirals became more aggressive and chased them away.

The red admirals were clearing drunk and had lost their inhibitions. If I put the fermented plum pulp on my fingers they extended their proboscis and drank from my skin.

And if I deliberately chased them off they just flew around my head, landing in my hair or on my clothes and hands.

Some days they were so drunk that I could poke them on the nose and they wouldn't take flight.

The last of the plums has now rotted and the red admirals have returned to their favourite nectar source in the garden - Buddleia x weyeriana, which flowers right up until the frost. But all the time the plums were available they completely ignored it, confirming my suspicion that they had fallen under the influence of the demon alcohol.