Secondly do you prefer it this way up?
And finally, and really the most interesting, what do you think it’s an image of? You can mull these questions over while you trawl through the rest of this blog post, and I’ll reveal more at the end.
After the couple of brief frosts at the beginning of the month, the weather has returned to high pressured stasis, though sadly this hasn’t meant either dry, or sunny conditions. We’ve been stuck under pretty much one hundred percent cloud cover for over 10 days now, with a brief morning interlude, which saw me excitedly standing, watching a quiet, unspectacular dawn, just to see a little more than just variations in grey.
The PV inverter read out for last week tells this story, and this week has been nearly identical, and bear in mind that the total productive output, and thus input to both the land and us of useful solar radiation for the whole week, is about half what you might expect on a single cool, sunny day at the beginning of April.
Thank goodness for the colours which autumn leaves are still providing in a myriad of hues, mainly from home sown seed grown Acers. In the very light winds which have been another constant feature of this autumn thus far, they’ve lingered on several of the trees much longer than normal, but the great thing is that, purely by chance, they have a staggered timing for their leaf colour change, and even once fallen still provide interest, with wonderful carpets of mixed colour for a few days before the inevitable browning and decay sets in.As I still wait for the first gems of Cyclamen coum and snowdrops to emerge in what looks like being a later season than the last few years, such colour washes are invaluable in the garden. It’s either this, or computer jiggery-pokery to inject a little visual interest.
I’m not sure I’ve used this phrase before, which is thought to have its origins in the 1800’s and probably derived from the Scottish word, jouk, which means to skillfully twist one’s body to avoid a blow, or to manipulate oneself like an acrobat. This word jouk led to the notion of joukery or jookery to describe underhanded dealing or trickery. Pawky is another Scottish word, meaning artfully shrewd. A pawk, on its own, is a trick. And by 1686, someone had combined the words in the phrase joukery-pawkery, which they used to refer to clever trickery. Click here for more. Perhaps any Scottish readers can correct any errors here?
Thinking about another word, the verb “marvel” one morning, and how little it tends to be used these days, took me to a look at its definition “to be filled with wonder or astonishment.”
And next to it’s etymology – “c. 1300, Middle English, merveillen, of persons, “to be filled with wonder,” from Old French merveillier “to wonder at, be astonished,” from merveille (see marvel (n.)).”
Why don’t we really marvel more?
Clasped Demoiselles, Merveille du Jour,
Or finely scribed and silver spangled
Dark shed roosting, drop-dead Herald?
Though more appropriate for me,
I’d focus on the honeybee.
The hidden dance floor’s trembling greets –
Those waggled meets, for floral treats.
Or stand amidst a swarming cloud
In May’s mad exodus, so loud.
Watch the scouts return to muster,
Up their tempo, raise the cluster,
Depart en masse, for pastures new,
In scout led comet, trailing through
And thronging round their chosen tree,
Within an hour, the scene’s bee free
The lemony scent a guiding cue.
Whilst deep inside, now hid from view
They waste no time, construct their comb,
To fashion such a special home.
Secure from winter’s frosts, now here,
A memory, from that time of year –
Lift stored super, careful, prise a frame.
Cut the comb, and taste the honeyed rain.
After keeping regular watch on the 2 underground wasp nests I’d located earlier in the year, all activity ceased. I waited another week, then on a dry day decided to excavate them, since as with bumblebees, the colony completely collapses at the end of each year.
In each case I was amazed by just how large the structures actually were, and in spite of the torrential downpours at the end of October, just how dry and intact they were. In each case the nest seemed to be slightly offset from the main entrance, with a dog leg in the access mouse/mole/vole tunnel, and suspended by a stalk (pedicel) attachment from the roof of the domed cavity.
The exterior of the nest was a sheeted laminar form, similar to the appearance of above ground nests, but inside the larger than football sized nest, the hexagonal cell structure was just as precise as the wax made honeycomb found inside a honeybee hive. With parallel sheets of cells held apart, or possible even suspended in horizontal planes by a fairly regular series of narrow pillars, a bit like the supports in a multi-story car park.
Initially I was certain that in the larger nest, these sheets were constructed horizontally, but the in-situ torch illuminated photo of one of the nests possibly suggests otherwise. Perhaps I’d rotated the whole structure to manipulate it out of the hole, intact? No matter, this was a superbly constructed home, requiring, I estimate, around 25 to 30 kg of soil to have been mined and removed from site, by the wasp workers as the colony expanded in late summer, using the frequent mud carrying sorties, which I’d witnessed and described in this earlier post.
A little bit of reading revealed more differences about the social wasp lifecycle, in this case the common wasp, Vespula vulgaris, its survival strategy, and its differences with honeybees. The bees are obviously capable of overwintering as a colony, in large part because of their ability to make and store honey as an overwintering food store in their wax comb cells. They also produce a special caste of worker bee with larger body fat stores at the end of autumn, and are able to form tight clusters within the hive over winter, to conserve heat. The single, fertile, mated queen survives in the middle of this cluster, although she stops egg laying until the worker bees begin to find fresh pollen and nectar sources and bring these into the hive in midwinter. This is still a risky strategy, and every year many “wild” colonies will fail to survive to spring. In addition, the honeybee larvae are fed, largely with a pollen based food, and complete their metamorphosis within a pupa, inside a cell capped with wax by the workers.
The social wasp underground nest will have been begun in early spring when an overwintered, hibernated, mated queen wasp emerges and begins her quest to find a suitable location to begin her new colony. At which point it’s worth asking why build underground? To do so, commits to a potentially wetter, more humid, and cooler space with the added effort involved in mining out the cavity. Equally it might create a safer space and a more stable temperature range than experienced in any above ground location.
The queen will build the early cells from harvested wood fibre, in her own form of papier-mâché, and into these she’ll lay eggs destined to become (female) worker wasps. Whilst collecting mainly nectar and honeydew secretions from aphids as her own food, she provisions each of the larval cells with collected invertebrates. These are typically aphids, spiders, caterpillars, flies, for these common wasps, which are the protein rich animal food the larvae require to develop. Apparently no pollen, or indeed honey/nectar, is used for larval nutrition. Another interesting aspect in the evolutionary history of wasps is how they carry this food back to the nest. Sometimes whole, sometimes chopped into pieces, using their strong mandibles, and using a variety of strategies to physically move the bugs into their nest. The earliest and most primitive wasps just dragged them backwards, along the ground, a technique still used by some solitary wasps. However gradually, different species developed the ability to carry food either in their mandibles, or suspended beneath their bodies and grasped by their legs.
The first larvae, which will have been nursed and supported by the solitary queen, take around a month to develop, pupate and emerge from a silken cocoon which they spin in their open topped, uncapped cell. Once the first workers have emerged, they begin to take on other nursing and management behaviours within the nest, as well as foraging for food, including an unusual proctodeal trophallaxis, which involves the nurse wasps consuming the sugary excreta produced by younger wasp larvae. No waste here! Meanwhile the queen is now able to concentrate on egg laying, with around 200 to 300 per day being laid.
As a result the colony can now grow in size rapidly, but towards the end of the season, the queen concentrates on laying different, fertilised eggs which will develop into new queens, and also eggs destined to become drones/males, so that the majority of the larger cells in the huge sheet above, were probably occupied by future queens, since in a large colony over 2,000 will be produced! The largest comb of cells measured around 11 inches in diameter, and contained roughly 40 X 50 cells across. At this stage one can imagine just how many invertebrates are being collected from the locality, and it’s been estimated that across the UK, over 14 million Kgs of invertebrates are caught by common wasps annually – a hugely valuable, natural pest control service.
The emerged, sexually active virgin queens and males mate, and then eventually the mated queens look for suitable hibernating locations for the winter, the old queen dies, and with no new workers to replace the workforce, which have a typical lifespan of just a few weeks, the existing colony collapses. It’s very unlikely, currently, that a colony would survive the winter in the UK, though this can happen in warmer climates.
Click here for more wasp facts from The Natural History Museum, pending the publication of Sirian Sumner’s upcoming book titled “Endless Forms – Why we should Love Wasps“, now due for publication in April 2022. For those who can’t wait, here’s a really superb lecture by the incredibly enthusiastic Professor Sumner, given earlier this year, explaining why we should all become wasp lovers! And do listen to the Q&A for even more great insights into the world of wasps from a world expert.
The old colony’s wasp nest being entirely made of paper, would probably (if I hadn’t dug them up!) degenerate and be recycled by other invertebrates and fungi within a few months.
Which has given me much food for thought as we continue with our own personal decluttering drive, about the ecologically brilliant circular economy of these social wasps. Spending all that time and effort constructing these amazing structures, undergoing massive population explosion, exploiting the natural resources all around and in so doing limiting the population of other potentially damaging invertebrate species. Then as food supplies dwindle, sacrificing the vast majority of their number in inevitable planned mortality, with the hoped for regeneration the following year, once conditions and food supplies become favourable once more.
With around 10 (quite lengthy) trips to the tip so far, and a huge amount of time spent sifting and sorting, one realises that eventually the best we can hope for is to pass on the buildings and land as a home for someone else in a better state than they were when we arrived. At least now materials can be recycled. But as efficient in resources from an ecological perspective, as the humble and much maligned common wasp?
I really don’t think so, which is why we’ve (Homo sapiens) created the big pickle the world now seems to be cursed with.
Finally, back to where we started, and the early images. This week we did one of our regular bike rides up the mountain, and having reached the summit and at last managed to ease off a bit on level terrain and pick up speed, I suddenly jammed on the brakes, and walked back past a surprised Fiona who was following me, and a passing car, to pick up the small feathered body, I’d glimpsed on the very edge of the verge. Thinking it was probably a woodcock, Scolopax rusticola, something I’ve only ever seen in the dim dusk light, flying out of the woods to feed higher up the mountain, I decided to take it home to photograph and possibly even eat, since they’re highly valued by that band of people who try to shoot these creatures, for game.
In the end, after a couple of simple photos in poor light, I left it on the slate wall hoping for better conditions. The following morning, after an un-forecast 3 mm of overnight drizzle, I drew back the front door quilt to one of those rare pink-grey gloomy mornings, when you know that the sun is there, hidden behind the low clouds, but that they’re unlikely to ever break. Immediately, the richness of the reflected colours of the woodcock’s plumage, now completely covered in water droplets of multiple sizes, and all balanced precariously on the sloping bird’s breast had me grabbing the tripod and camera for some very slow exposure, time delayed photos before the rose-dawn grey light had vanished.
Trying to move the bird slightly to get a different angle, the merest touch saw droplets move, coalesce, and race off the plumage, leaving water free bands of clear, exposed feathers. Look at the image again very closely though, and some of the droplets give the clue to this avian example of superhydrophobicity, a phenomenon I wrote about in relation to moth wings back in January 2014. You can see the banded stripes of the underlying feather structure, magnified. If I’d remembered all about contact angles of hysteresis and droplet shedding, I’d have realised that this water shedding would inevitably happen as soon as I moved the bird, ever so slightly.
To review the information, if you follow this link, click here, to ultrahydrophobicity you will be plunged into a world of complex formulae and the interesting names of several people who’ve grappled with defining the forces involved with the formation of such droplets on certain surfaces in nature. Thomas Young kicked things off in 1805. That’s over 200 years ago! What was going on at Gelli Uchaf back then? Smoke filled rooms and tallow candles to stave off the long winter nights?
He defined the ‘contact angle’ by analysing the forces acting on a fluid droplet sitting on a solid surface surrounded by a gas. Since then, Wenzel, Cassie and Baxter have added their own formulae, and more recently Nosonovsky and Bhushan have studied the nature of surfaces which exhibit superhydrophobic properties.
They found that to be superhydrophobic, surfaces have to be what are called hierarchical combinations of extremely tiny ridges and grooves (nanostructures) sitting on top of slightly larger but still very small ridges and grooves (microstructures). The reason is that in this way, the very small channels of the nanostructures trap gas (or air) and prevent liquid coming in contact with the actual substrate material.
However it seems that in the case of bird feathers the critical hierarchical structure of the moth scales, where nanostructures sit atop microstructures, isn’t replicated in quite the same way. Rather the morphology is considered to be pseudo-hierarchical and based on the structure of linking barbs and barbules which make up a bird’s feather.The barbs of the feather are shown below as the curving ridges beneath the water droplet. These are close enough together to trap air, allow the water to bead, and prevent it moving through the feather surface.
In addition, the bird has access to the oily secretions of its uropygial, or preening gland which can improve the water shedding capability of the feathers. It seems that whilst these properties are common to most feathers, and birds, some species of birds which regularly dive under water for food capture – think cormorants and darters, have developed wing spreading/drying behaviour precisely because their barbs and barbules have wider spacing than many ducks, and thus their feathers are less resistant to water penetration of the feather layer under the higher water pressure involved in deep diving.
As with moth scales, all the papers relating to this phenomenon, are heavy in algebra and formulae, but this early short paper by A. M. Rijke, is probably the easiest to access.
An hour and a half later, the drops were still there, but the rich colours had gone. To be replaced by multiple frogspawn like reflections, of the black camera lens in the droplets, overlying tawnier feathers. Still beautiful, and still, I find, captivating for my brain’s visual sensation and perception pathways. Scan a scene of leaves, or a landscape and we’re used to processing and “comprehending” the image in a flash. But I keep coming back to these, rotating them, and being drawn in, for seconds at a time, trying to take it all in.
Both here, and perhaps shortly, in physical form.
For a closing musical interlude I include this recording of one of Chopin’s sublime nocturnes, Nocturne Op. 27 No. 2 in D flat major, composed in 1835 in Paris. This was recorded last September by the Ukrainian pianist Anna Fedorova, who I see has just released a CD of her favourite Chopin works which inspired her greatly through the lockdown months. I find the music, empty auditorium, low lighting and un-intrusive camera angles riveting. Perhaps with some European nations moving to even more draconian options of late, we’ll need such music to comfort us again through the dark winter months ahead.