14. Calliphoridae – carmageddon

6th April 2019

When my boys were younger I spent a lot of time touring inconveniently-situated car showrooms so that they could paw the shiny bodywork of their favourite models and collect up glossy brochures for their bookshelves. Rather sheepishly, I should explain to the eager salespeople that there was no chance of my buying anything from them, and that the purpose of the visit was to satisfy their fetish. Despite my best efforts, the boys weren’t interested in looking at birds or flowers (or even flies, unbelievably), but they could tell you the make and model of a car just from the shape of the headlights or the radiator grill. When a motorist casually forced my bicycle and its boy-laden trailer off the road before yelling that I shouldn’t even be on the road in the first place, I was able to give the Police the registration number and colour of the offender’s vehicle. “And what make was the car, sir?” – I had no idea, but my two tiny passengers knew. I guess I was the same when I was their age, though of course the cars were more interesting then.

Cars were more benign then too – they gave freedom in comfort and style, and were the symbol of the hopeful future. Now of course they are evil personified. They pollute our cities with their effluent of nose-wrinkling fumes and lung-penetrating particles. Their casual engine and tyre noise is the backdrop to the soundscape even miles away from a road, with the blasting of horns and screeching of brakes adding intermittent annoyance. Their parked carcasses block what are supposed to be thoroughfares – and often enough their moving carcasses do the same thing. Their production is resource-intensive and their life-span barely that of a teenager. Every year they will excrete several times their own weight in carbon dioxide as a result of burning up irreplaceable fossil fuels whose extraction from the ground is a major source of international conflict. Cars isolate us from each other and the places we travel through, giving the illusion of independence

So what’s the connection between cars and this fly from the family Calliphoridae that was attracted to my half-vole trap (thanks to Bear the cat for letting me have his leftover meal)? Perhaps I am alluding to their noisy flight as they bumble about the kitchen looking for uncovered food and leaving fly-spots on any clean surfaces? Could it be because the family includes the omnipresent blue and green bottles that lay their eggs on carrion, enlivening it to a mass of squirming maggots? Is it that others are parasites of toads and frogs, the larvae entering through the eyes, or, mysteriously, eating their way through earthworms as they in turn tunnel through the earth? Is it because this family of flies are the epitome of death, decay and destruction? Of course not – it’s because of this particular fly’s beautiful metallic bodywork!

13. Heleomyzidae – worry wort

Another worrying fly from the pineapple trap, this time without the jutting lip of the Dryomyzidae, although it does sport a fine moustache (known as vibrissae). Worrying, because this fly is from another acalypterate family – one of 49 UK families of small, drab flies with no personality or eccentric habits, that I am going to have to try and recognise. The calypterate flies, jolly beasts like house flies and blow flies, have a prominent bulge in front of the wing, a diagnostic seam on the second antennal segment and a characteristic large flap (calypter) at the base of the wing. They are flies with attitude, not ashamed to be going about their business. In contrast, acalypterates are defined by their lack of these distinctive characters, many of them being small or miniscule skulkers of the undergrowth and the compost heap, the sort of flies that give flies a bad name.

Yet, when you get up close, perhaps even this fly is not without its subtle charms. There is a pleasing contrast between the yellow-brown and reddish brown of the head, legs and abdomen and the stark gray of the thorax, which only here and there blushes with reddish brown. The thorax is also much less bristly than the rest of the fly, and partly for that reason you see that it is not just a uniform block for the wings and legs to be attached to. A small brown spot above the front leg and at the same height as the eye is the anterior (front) spiracle, a breathing hole supplying air to the flight muscles that lie within the thorax. Another spiracle, less easy to spot, lies to the right of the triangle-shape between the front and rear legs. Just above that and to the right is the haltere, all that’s left of what were once (a few hundred million years ago) a second pair of wings. Like the armour of a medieval knight, the side of the thorax is fitted out with oddly-shaped panels with odd names (sternopleuron, pteropleuron, hyopleuron, metanotum) that have been updated to even odder ones (katepisternum, meron, laterotergite). Luckily, I can’t find a key to the genera within the family, and so I am spared further linguistic challenges and can just enjoy having got this far.

Which makes me wonder if identifying flies is the best form of relaxation for a perennial worrier – what if I missed a tiny seam on the second antennal segment or those pre-apical tibial bristles aren’t strictly dorsal? What if it’s another family entirely? Will I be struck off the Dipterists Forum for shoddy identification skills? Actually, I know they won’t because I have already posted a picture on their website of a fly with a very strange wing pattern which I couldn’t identify, and it was gently explained to me that it was actually a wasp with, if I had bothered to count them, four wings rather than two. There is an inescapable tension between the satisfaction of definitively putting something into the right taxonomic pigeon hole, and the worry of having got it wrong. Identifying flies provides me with an existential agony of choice, albeit on a rather small scale – feel my pain.

12. Dryomyzidae – facial recognition

1st April 2019

Anyone who has used an identification key will have come across the feeling at the end of the process of having been encouraged not to see the woods for twiglets on trees. It’s like being told to look out for someone with an elongated brownish mole on the inside ventral surface of their second-biggest toe on the left foot – and discovering that the person in question is six-foot three, wearing a kilt and carrying a live mole! When you look at a fly under a microscope as an individual rather than as a set of taxonomically informative characters, it’s surprising just how different they are to each other in general shape and colour, in the patterns and siltings of the river deltas of their wing venation, in the precision with which their bristles are placed, angled and sized. But most of all, in their faces.

How about this for a face to remember in this otherwise undistinguished visitor to a bottle-trap baited with pineapple? See how the eye crowds the front of the head beneath a just-out-of-bed spikey haircut. The antenna seems slightly too full-bodied with its delicate, drooping arista. Most of all, take in the sharp angle at which the face is undercut before it surges out again with a haughty upper lip. From this angle it’s a fly with attitude, possibly just a little bit grumpy.

But from the front it’s a different matter – a noble, broad golden forehead flecked with purple-brown and minute black hairs, the eyes no longer squeezed on but perfectly fitted to the overall shape, a symphony of curves. Those over-sized antennae turn out to be hollowed out on their inside faces, and even the hairstyle looks more straight-laced head on. It’s a friendly, enquiring face that looks back at you asking what you are about with your katepisternal bristles and setulose wing veins just to pin me down as a member of the family Dryomyzidae (four British species, of which I am Dryopes flaveola)?

So today I announce, a long-term project, the satisfyingly alliterative “Phrenology of Flies Faces”, to replace the mind-numbing, evolutionary-based study of taxonomic characters. Instead we will have a life-enhancing and open-ended study of the inner character of flies as deduced from an empathetic reading of their faces. Subsequent volumes will include “Beguiling Beetle’s Backs” and “Mothing for Mothers” – the only problem being that I can only devote myself to this work once a year ….

11. Muscidae – old friend

Among the fly-related books that I have accumulated over the years is a vandalised issue of the Transactions of The Edinburgh Field Naturalists and Microscopical Society from 1914 (Volume VII). Most of the pages have been cut out, not by me I am sure, leaving only incomplete articles on the geology of Blackford Hill in Edinburgh, somewhere I knew well as boy, and more exotically on “The Olive tree”. However, in full, is a piece on the history and biology of “The common house fly” by Dr W.G.Aitchison Robertson, D.Sc., F.R.C.P. The fly he means is Musca domestica, the most familiar member of the family Muscidae. By way of counter-balancing previous writing on his subject, which is “chiefly of a condemnatory nature” he quotes Lucian, Homer and Ruskin who wrote: “I believe that we can nowhere find a better type of a perfectly free creature than in the common house fly. Not only free, but brave; and irreverent to a degree which I think no human republican could by any philosophy exalt himself to. There is no courtesy in him; he does not care whether it is king or clown whom he teases; and in every step or pause there is one and the same expression of perfect egoism, perfect independence and self-confidence, and conviction of the world’s having been made for flies. Strike at him with our hand … and he alights on the back of it.”

Also in my fly archive is a drawing I made as a boy of specimen #7 from my newly established Diptera collection, a fly that I had caught the previous summer flying around the attic at 9 pm after the window had been left open. I know these details because for each specimen I filled out a record on the back of one of the punched cards that in another century were used to program computers. My father used these at work, and always had a stock in the inside pocket of his jacket in case he needed to write something down. Also from the attic, a diary entry for the day of capture reads: “Tidied up insect stuff in morning. After lunch collected flies. Set some. Program on Olympics. Mr Consigni phoned. Dad to Yorkshire.” I think Mr Consigni was calling about arrangements for the rather miserable exchange trip to France that I was about to set off on. The daily diary, kept faithfully for the previous 18 months, stopped the following day.

I identified specimen #7 a couple of years later, somewhat tentatively, as a male Phaonia rufipalpis, a slightly larger member of the Muscidae, using the rather taciturn key written by E.C.M. d’Assis Fonseca (the M, appropriately standing for Muschamp). I must have been back home from University for the Easter Holidays, though my much more intermittent and introspective diary doesn’t give much context: “If you go through life looking for answers to questions about how you should behave – perhaps there is no answer – you must make what you can yourself of a world that is finite and has no purpose. Each must find his own answer – or you can let a God give it to you and follow blindly – or you can appreciate the immensity of the awaiting task.“

Forty years on and I no longer a diarist but I am using the same key to identify a fly I found sunning itself on the side of the house on a warm March afternoon. I have to look for pre-sutural acrostichals on the thorax, check if the mediastinal vein of the wing is sinuous, and decide if the fronto-orbital bristles between the eyes are reclinate or proclinate – it isn’t any easier than I remembered.

As Dr Aitchison Robertson remarks in his treatise, “The fly is a very old friend.”

10. Culicidae – love story

We spent our honeymoon in India where the bedtime ritual wasn’t quite what either of us had in mind. Whether the bedroom had an octagonal bed (very confusing in the dark) or a twin-seat swing (no idea), each night before turning out the light I would inspect the walls and ceilings for intruders, dispatching them with an expertly-wielded rolled-up newspaper. After this heroic exercise, conducted brazenly with little or not clothing, I would turn out the light and return to the sheets where my beloved would welcome me in a fond embrace, the daring hunter returning to the hearth, two hearts beating as one. But then breaking off she would whisper urgently, “Did you hear that?” An undeniable shrill whine. And so would follow round after round of the bedroom farce until, exhausted, we would fall asleep, only to wake up in the morning to find ourselves peppered with tell-tale spots.

Mosquitoes, members of the family Culicidae, have been getting the better of mankind for a long time, and in the process, have been the cause of considerable human misery. In parts of the world that are warmer than Scotland they carry fever-inducing flaviviruses such as the dengue, Zika and yellow fever viruses, or are vectors for parasites such as the protozoan Plasmodium that causes malaria, and for filarial worms that produce elephantiasis. As the females drill for our blood with their sharp-tipped mouthparts they spit out anticoagulant to stop the blood from clotting, and in the process induce an allergic reaction that produces the spots and itching. And along with the saliva come the pathogens, disease and death. The one I caught was sheltering in a sea cave and looking innocent, apart from its diamond-tipped proboscis!

I had always imagined that the mosquito’s annoying whine was just a consequence of its rapid wing beats, which it is, but it’s also more than that; the frequency of the hum is a love song that allows the sexes to find each other. As the relationship develops they each modulate the frequency of their hum until it matches that of the partner, harmonically rather than exactly, two hums humming as one. Perhaps it’s something to do with age, but after two decades of marriage, the only whining noise I hear these days has a much lower pitch …..

9. Scathophagidae – alchemy

There is no getting away from change – certainly not at Siccar Point in Berwickshire which is famous for it. This is the place where, in 1788, James Hutton saw and interpreted the incongruous layers of rock as indicating that geological history was vast. Rocks had been laid down as sediment in ancient seas, compressed into a harder form and then twisted and folded, eroded and then submerged under subsequent layers of sediment. Human history was but a tiny fragment in this slow story, the Bible an imperfect account of the earth’s long genesis. With this perspective there was room for biological evolution to occur, and it just wanted Darwin and Wallace to come up with a mechanism and the evidence.

Just along from Siccar Point is a spot I dreamed of in the days when I thought I should become a hermit.There is the ruin of house set just above the tide line under towering cliffs, nothing to be seen from it but sea and a raw spur of red sandstone. Here I would escape the world and …. I now wonder what possessed me that I thought it might work – miles to the nearest road, miles more to the nearest shop. Little chance of growing anything on the north-facing, salt-swept patch of almost flat ground beside the house, no electricity or water supplies, no harbour or beach for a boat. The only merit of the place was the absence of other people – which when you are in a misanthropic mood, seems like a good thing. But the farmer whose I needed permission saw sense and said no.

So visiting the spot again in the course of helping in the hunt for hibernating Herald and Tissue moths in the sea caves, and having accrued the wisdom of a few more decades, I could laugh at my former self. Mind you, three of the walls were still standing, and the tideline was heaped with long boards perfect for re-roofing – but I was happy enough to leave these daydream thoughts and head back to a more convenient, comfortable and companionable home. Letting my net hang like a wind sock as we walked back across sheep fields into a stiff breeze, it was soon populated with flies, one of which was this golden-haired dung fly, its furry legs and body glinting in the sun with slender silky fuzz, a drop of amber on the forehead, crisp black bristles and a darkened cross vein on the wing, a dipteran beauty spot. The family name, Scathophagidae, sounds like “dung-eater”, which is what the larvae do. Turning dung into gilt is an alchemy to be wondered at.

8. Sphaeroceridae – caveat emptor!

There have been Clydesdale horses here as long as we have, friendly neighbours cropping our lawn as far as their necks could stretch, occasional escapees, prizewinners or childminders. Sally the horse even had a complimentary subscription to Mills and Boon ( for research purposes). With horses come droppings, and with droppings come flies, so it was a fair bet that even in March a short walk would take me to some dung flies. Fresh dung would be best of course, and that took a bit of hunting down, but when I found some it was pleasingly speckled with flies.

It’s always easier going through an identification key when you already know what you expect the answer to be, and in this case I was pretty sure this would be a dung fly, of which there are two families – Scathophagidae, still to be encountered, and Sphaeroceridae, or lesser dung flies. This was the latter with a distinctive hind leg comprised of a femur (nearest the body), a tibia (the following section) and then a tarsus in which (this being the distinctive bit) the first of five segments was short and thick.

In fact, this wasn’t my first encounter with this species for the year. In the middle of January I bought a poke of chips at an unnamed local establishment, and was very excited, an excitement not shared by the rest of the family, to find a fly embedded in one of the chips. I had a go with the identification key, but couldn’t get anywhere, the head and all but one of the legs being missing. However, I thought that an expert might be able to recognise it anyway despite its deficiencies and so posted the picture on the Dipterist’s Forum website. In little over an hour I had the answer that it was a lesser dung fly – you can see the short and thickened first tarsal segment in the one remaining leg. So I at least was able to sleep easy!

7. Pyschodidae – fairy wings

17th March 2019 – The Year of the Fly

Amongst those unfortunates attracted to the banana trap was a tiny, hunched fly that was too small to pick up with tweezers. With difficulty I transferred its tiny corpse to a drop of glue on a triangle of paper, where it dangled from one wing and eventually fell off leaving the wing and a bit of antenna behind. Under the microscope the fly was a hunched mass of hairs, too dark to see much detail apart – but the torn wing was delicate, shimmering silk with fine threads along the veins, and the fragment of antenna like feathered pearls on a string.

This was a member of the family Psychodidae, otherwise known as an owl midge or hairy-moth fly according to my boyhood copy of Colyer and Hammond’s “Flies of the British Isles”, or more prosaically elsewhere, as a drain fly, sink fly, bathroom fly, filter fly or sewer gnat. Relatives in warmer climates include the notorious sand flies (phlebtomine flies) that bite and suck blood and are capable of transmitting infections such as the parasite Leishmania and several viruses that sound like a strange holiday brochure – Naples virus, Sicilian virus and Toscana virus.

Where to begin with all these resonances? The genome of these viruses is split up into three segments, like tiny chromosomes, that have to be copied before they can be used to produce virus proteins, a bit like printing a photograph from a negative. I did my PhD on influenza virus which has a similar genome organisation, although instead with eight segments, and spread from person to person rather than by flies. As a post-doc I went to Australia to work on a parasitic worm spread by snails, but my friends in the next lab worked on Leishmania, a protozoan that causes skin lesions. Phlebotomy is the making of an incision in the skin, either to extract blood or to inject something in – that something sometimes including viruses such as hepatitis C virus, my next research topic. Not everything is work of course, and there was romance, marriage and holidays that echoed her Italian ancestry, to Naples and Tuscany. Most recently I have dabbled in moths, running a light trap in the back garden and being astonished at the diversity and beauty of these hitherto invisible visitors – and the eccentricity of more serious moth botherers, the blog of one of whom (https://whittingehamemoths.home.blog/) got me started on this on, where I am now back, full circle to flies.

Of course, the “Psycho” in the family name could lead us on to matters psychological – what is this need to collect, identify and order things really about? Why not enjoy these creatures in the flesh or lift my eyes to the wider world,

But the Greek root is “psyche” for which you have a choice of meanings – Psyche the mortal, abandoned on a riverbank by Eros and granted immortality by Zeus, or psyche the soul, for which I follow Wittgenstein “About what one can not speak, one must remain silent.” But psyche also means butterflies or moths, which is clearly the meaning intended, and so I am saved from further revelations induced by, what I hereby christen, fairy flies.

6. Drosophilidae – time’s arrow

21st February 2019 – The Year of the Fly

A long time ago, when I first became interested in flies, my father, through his University contacts, got me set up with my very own colony of the fruit fly Drosophila melanogaster, that workhorse of eukaryotic genetics before DNA sequencing became trivial. I don’t think I managed to keep them going for very long, though I still have some of the glass tubes they lived in. Later, at University I learned all about the genetics of Drosophila eye colour, chromosome translocations and inversions and theories of speciation on Hawaiian islands.

Even later I started making wine from the fruits of the garden, inspired by the intense flavour and intoxicating properties of my parents-in-law’s blackcurrant wine. I tried blackcurrants and redcurrants from the garden, grapes from our greenhouse, birch sap from the woods and elder flowers from the lanes. There were occasional successes where guests didn’t choke on their first sip or leave their glass untouched, but in general the vintages were poor. Some were undrinkable, even for us, and for this the culprit was Drosophila. They could sniff out that alcohol was being brewed in the kitchen and drown themselves in the water-filled airlock. And when the airlock dried out, they were in with their bacterial-laden feet, and our wine would be turned to vinegar.

For the last few years I have been running a light trap in the garden in order to see what moths might be about. The answer was many more than I expected, more than 100 species each year, some unrecorded previously in that 10km square. Last year I experimented with attracting them using a treacle mixture smeared on trees and fenceposts, and attracted a slightly different set of moths (including the beautifully coloured and named Merveille du jour), but also slugs, wasps and flies. So why not use the same techniques for flies instead of pursuing them individually with a net – I could let the flies come to me.

Using a couple of drinks containers I constructed a primitive, but cheap, fly trap. The holes in the side of the bottom bottle let the flies in at the bait, and then those that flew upwards through the neck would become trapped in the top bottle as they wouldn’t find their way back out again.The obvious place to put the trap out was the compost heap which during the summer releases a cloud of flies whenever I peel back the carpet covering to add another bucketful of vegetable peelings, apple cores and coffee grounds. I baited the trap with slices of banana and felt very smug.

In the morning the banana was dotted with mouse droppings as I had just stuck the trap at the side of the compost heap. There were also lots of flies in the top bottle some of which I shook down into my laurel tubes. First to catch the eye were several long legged flies with spotted wings (two top left and one at the neck of the bottom bottle) which turned out to be Anispodidae (3. Anispodidae – the honey trap). Stuck between the two bottles was an unfortunate Trichoceridae (1. Trichoceridae – the ice house). And also a familiar stumpy fly, busy tracking back and forward looking for an escape – Drosophilidae. Which reminds me of the quip that although time flies like an arrow, fruit flies like a banana.

5. Coelopidae – arachnophobia

15th February 2019 – The Year of the Fly

Araneus quadratus lurking on a fence post

There is something about spiders that gives me the creeps – a fear that long predates my years in Australia where spiders are genuinely something to worry about. I am happy with all manner of flies (obviously), even those that bite, like clegs, or have long dangly legs, like crane flies, or that feed on dead animals, like blow flies and flesh flies. But an innocuous spider making its way across the kitchen floor is, if not exactly a terror, certainly a beast that I don’t want to have anything to do with. I now have things sufficiently under control that I can release inch-long monsters from the bath or photograph a monster lurking with evil intent on a fence post.

Another step along the road towards my finding a more adult accommodation with arachnids occurred today when I confronted and robbed a wolf spider of its prey. Tiny it might have been, but it was doing its best to frighten me off with its black and white stripes and menacing stance. I was having difficulty catching flies on rotting seaweed without a net, so when I spotted this terror lurking nearby on a rock with a fly in its fangs, I only hesitated for a moment. Gingerly poking a glass vial under its nose I managed to irritate it enough that it dropped its prey, not into my vial as intended, but on to the sand below. After a few minutes of humiliating myopic searching I eventually spotted the inert fly and potted it and sprinted away in case retribution might follow.

This was another ugly fly, drab, dark, flattened and bristly with tatty wings. But satisfyingly, it was from a different family from the one I had managed to catch myself (4. Sepsidae – suum cuique). This time it was a Coelopidae – commonly known as kelp flies – a single-minded family that has specialised in living on washed-up seaweed and in fact was the target I had in mind when I hunkered down to the rotting wrack. Success – thanks to the more adept, and now hungry, and possibly dangerous, spider.