Lepidoptera – Page 8 – David Bradley

December will be magic, again

I’ve waited patiently for one particular species of moth to turn up in the garden and the night before Halloween 2022, it made its inaugural appearance, drawn to a 15-watt fluorescent, ultraviolet lamp – the December Moth. Poecilocampa populi (Linnaeus, 1758). If the name seems anachronistic don’t blame me. The Lepidoptera textbooks tell you it can make an appearance any time between October and January, peak is mid-November.

When I first started mothing back in late July 2018, I hinted to one of the very experienced enthusiasts I know, a guy called Leonard Cooper, that I’d probably switch off the lamp and put the trap away for the winter. His retort was one of shock and awe, “What, and miss the December Moths!?!?”. So I didn’t and I kept lighting up almost all the way up to Christmas. That year and for the three subsequent seasons I didn’t see a December Moth. I did see a few November Moths, however. They are a very different affair.

Where the December Moth is a chunky and fluffy, lasiocampid*, type moth, with a strand of what Mrs Sciencebase referred to as Christmas lights on its wings, the November is a grey geometer moth. In fact, the November is not really a single moth, there are several species that are superficially identical – November, Pale November, Autumnal Moth, and Small Autumnal Moth. Unless you examine their DNA, raise them from larvae, or examine the males’ genitalia, you cannot know for sure which of the three you are looking at and they are generally recorded as November agg, or more properly Epirrita sp.

Anyway, I am glad I took heed of Leonard’s lament and also pleased that my lighting up into the winter was also useful to another moth expert, our County Moth Recorder (CMR) Bill Mansfield, who urged me to continue logging Lepidoptera at least periodically through the winters for the scientific benefits. Moths are a very useful indicator of ecological health and so monitoring their diversity and numbers is useful not only because #MothsMatter but for the wider world of biology so that we can understand how climate change, habitat loss, and other factors are affecting the world around us.

The larvae of December Moths feed on birch, oak, elm, lime, and, indeed, most species of deciduous tree. There is certainly a handful of oak and lime not too far from our garden, so the arrival of a December Moth, at long last, was not to be unexpected. The arrival felt likely as the moth is widespread in the UK and especially as another oak eater, the green and black & white moth with the formidable name Merveille du Jour had turned up in previous years.

The Lasiocampidae are known in the vernacular as eggar moths because of the relatively large size of the eggs laid by the female. Others in the group include the Oak Eggar, Grass Eggar, Fox Moth, The Lappet, The Drinker, and The Lackey.

Little and Large

My friend Andy, who, like myself, is a keen amateur wildlife photographer, often asks me questions about the birds and butterflies he photographs. I can usually come up with an answer. But, today, we were talking about Little Owls and he casually referred to the species as the Small Owl. As far as I know, there is no species known as the Small Owl. I pointed this out and he came back with an intriguing question. Why are the birds “Little” but the butterflies “Small”?

For example, among the birds, we have Little Owl, Little Gull, Little Stint, Little Ringed Plover, Little Egret, Little Auk, Little Grebe, Little Tern. But, for the butterflies, we have Small Blue, Small Tortoiseshell, Small Skipper, Small Heath, Small Copper, Small Pearl-bordered Fritillary, Small White.

The Large Skipper has a Small Skipper counterpart

It’s puzzling…there is a subtle difference in our perception of what we mean by “little” and “small”, but it’s hard to define. Small is the opposite of big, little is the opposite of large. The Oxford English Dictionary suggests that while little is generally synonymous with small, it can have emotional implications associated with it that the word small does not, I can’t quite put my finger on what those differences are. When we discuss dwarfism, people with that condition are often referred to as “little people” but “not small people”…

Etymologically, the word small, a word of Germanic origin, means “thin, slender, narrow, fine” but also refers to a diminutive animal. Indeed, the true root in proto-Indo-European (PIE) is the prefix (s)melo- used to talk of a “smaller animal”. Little, etymologically speaking, is also Germanic in origin, the PIE root is “leud” meaning small.

So, back to Andy’s question why are the birds “little” but the butterflies “small”? I wondered whether it had something to do with the etymology of the words or perhaps whether the naming happened at different times and one descriptor was favoured for some reason at a given time.

Another possible explanation is that the use of small for the butterflies was done because there is a large counterpart. For the Small Tortoiseshell, there is a bigger but similar species the Large Tortoiseshell. Similarly, for the Small Skipper, there is a Large Skipper. However, there are no pairings among the birds, there are lots of different species of gull, but there is no Big Gull nor Large Gull to be a counterpart to the Little Gull, the same with the Little Owl, we do not have a Big Owl or a Large Owl species.

Often these kinds of differences are related to Anglo-Saxon versus Norman etymology, as in the peasants grow the pigs, cattle, and sheep, while the Norman aristocrats eat the pork (porc), beef (boeuf), and mutton (moutton). Stephen Moss just reminded me that he alludes to this in his excellent book Mrs Moreau’s Warbler: How Birds Got Their Names. “I noted that three groups of birds have Norman French names – ducks and gamebirds, which were eaten by French aristocrats, and raptors, which were used to hunt them. Same principle as farm animals and meat!”

Then there are the Great birds…

Great White Egret, Great Tit, Great Shearwater, Great Black-backed Gull, Great Crested Grebe, Great Grey Shrike, Great Northern Diver, Great Crane. The “Great” also essentially means big and there are “lesser” birds that are generally smaller than the common species: Lesser Redpoll, Lesser Whitethroat, Lesser Black-backed Gull, Lesser Spotted Woodpecker…

Moss also points out that in the US there are birds with “least” in their names ‘Least Grebe’, ‘Least Sandpiper’, and ‘Least Bittern’, for instance, we don’t have “least” birds in UK English…which maybe a throwback to US English etymology and the great divide between English and American.

UPDATE: Moss put me in touch with fellow nature writer Peter Marren, author of the excellent Emperors, Admirals, and Chimneysweepers. He had this to say:

“I have never really thought about why birds are great/little/lesser but butterflies are small/large, and I don’t really have an explanation. I suppose traditions in naming spring up early, and that namers therefore tend to follow an established formula. Some of the small/large butterfly names are 18th century or even, with Small Heath, late 17th century, so it might reflect usage at the time – Georgian vs Victorian? Simple English vs 19th Century elaboration?”

Marren points out that there are a few ‘little’ moths eg the Little Thorn – named later, perhaps. But again more usually large/small. He adds that “Great’ just seems the wrong word for a British butterfly or moth, somehow, but not sure I could explain why. ’Large’ is often (usually?) used where there is also a ‘small’, eg Large and Small White, Large and Small Blue, Large and Small Tortoiseshell. But I guess the same pairing is true of birds.”

A pub conversation with a retired friend who was an English teacher, had me saying “All creatures great and small”, which is almost a crossover usage…the hymn should perhaps be “All creatures great and lesser” or “All creatures large and small” but neither would sound quite so poetic as the original hymnal words by Cecil Frances Alexander.

Male moths and butterflies often fire blanks but nobody knows why

A few days ago I tweeted about a famous picture of a moth, the Death’s Head Hawk-moth used in the artwork surrounding the 1991 psychological thriller “The Silence of the Lambs”. At first glance, the moth looks genuine, but closer inspection reveals that what is thought of as markings resembling a skull on the moth’s thorax is, in the movie illustration, actually an imprint of a well-known 1951 creation of Salvador Dali and photographer Philippe Halsman.

In that image, In Voluptas Mors, a group of naked women were posed in such a way as to create the illusion of a skull. Of course, this morbid allusion fits perfectly with the theme of a murderer who skins his female victims in the movie. The women are lambs to the slaughter, their fleeces flayed from their bodies by the serial killer and a symbolic moth placed on their tongues to silence them forever.

Although a representation of the Death’s Head Hawk-moth (Acherontia atropos) features in the promotional materials for the film. Fellow science writer Rowan Hooper reminded me that in the movie itself, it is the pupae of a different moth, the Carolina Sphinx Moth (also known as the Tobacco Hawk-moth (Manduca sexta) that feature in the plot. In our chat, I mentioned that I wasn’t particularly interested in moths when that movie was first on release, but he said he was very much interested in Lepidoptera (moths and butterflies) at the time, Indeed, Hooper was specifically working in research trying to figure out something rather odd about Lepidoptera.

It turns out that the males of all Lepidoptera, all 180,000 species of moths and butterflies produce two types of sperm. They make sperm that carry their genetic material, their DNA, in the sperm’s nucleus, so-called eupyrene sperm, but they also make sperm that lack that DNA, apyrene sperm, or parasperm. Indeed, at least half of the sperm are blanks. In one type of swallowtail butterfly, 90 percent of the male’s sperm lack DNA. That percentage is 96 in Manduca sexta. Even more bizarrely, Lepidoptera are the only creatures that do this.

Obviously, the fusion of sperm with egg is fundamentally all about fusing the genetic material from the male with that of the female to fertilise the egg and create offspring from both parents. So, why would males make sperm that contain no genes to pass on and more to the point would be incapable of fertilising the female’s eggs. To cut to the money shot: nobody knows, for sure.

There are hypotheses, of course. It might be that the blank sperm act as some kind of useful filler, inactive biological padding. The blanks perhaps take up the female’s resources somehow while the active sperm do their job. Maybe this precluded further matings with other males ensuring that the first male’s active sperm are the ones that fertilise her eggs. Alternatively, perhaps Lepidoptera females have defences within their reproductive tract to ensure that only the fittest sperm reach their eggs and so the males produce these blanks as decoys (after all blanks would require fewer material resources and energy to produce, if many are going to be wasted). An alternative theory might be that the blank sperm are some kind of nuptial gift for the female, not so much inactive filler as nutrients.

There is evidence that a gene known as Sex-lethal (Sxl) is involved in the production of apyrene sperm in Lepidoptera. A paper in PNAS looked at the activity of this gene in the Silk Moth, Bombyx mori, and found that it was partially responsible for the generation of apyrene sperm. Moreover, the team showed that apyrene sperm have to be present in the male moth’s ejaculate to allow the active eupyrne sperm to travel from the female’s genital opening, the bursa copulatrix, to her spermatheca (where she stores sperm prior to egg fertilisation).

So, while no definitive answer is known for all Lepidoptera that produce eupyrene and apyrene sperm, for the Silk Moth at least it seems that firing blanks is the best way for the active sperm to hit the target.

Hacking the moth trap

I’ve had to hack my moth trap, or more specifically, I’ve had to hack my two moth traps.

The white, plastic vanes are broken on my original moth trap (the collapsible wooden one bought from an ex-mother and cabinet maker friend mentioned here years ago). The UV U-tube also failed in the night a week or so ago, So, having previously also acquired a spare moth trap from yet another friend in the village who is also an ex-mother, I have now hybridised the original box and funnel with the vanes and UV tube from the second trap. The U-tubes were 40 Watts, the linear bulb is just 20 Watts, so will be half the electricity cost on lighting-up sessions (although not as cheap to run as the 1 Watt LepiLED, good success with that on a couple of field trips).

As you can see, the Perspex shoulders of the box have clouded over a lot since I acquired the original trap and I ought to replace those. The point of having a transparent upper is so that plenty of light from the lamp gets into the box so that the moths don’t simply head for the exit hole once they’re in the box. As regular readers will know, the box is filled with egg trays to give the moths somewhere to roost overnight until they’re logged, photographed and safely released the next day.

There are at least seven mothers in our village, although only four of us are currently active, I believe. Three are definitely ex-mothers. I have the old traps of two of them and the third disposed of her trap for ethical reasons, although I think having people trap for scientific purposes is more ethical than not knowing anything about the local moths. We are a big village, very long, flanked by farmland and some trees. So, for the County Moth Recorder, it is useful to have records from across the patch and the area is big enough that individual trapping is very unlikely to disturb moth populations and biology in any significant way.

Anyway, it’s mid-October and last night was wet but brought in a fair number of moths, more than the previous session with the now-defunct 40W kit: Beaded Chestnut 3, Black Rustic 2, Box-tree Moth 1, Light Brown Apple Moth 4, Lesser Yellow Underwing 1, Large Yellow Underwing 3,
Red-line Quaker 2, Shuttle-shaped Dart 1, Strawberry Tortrix 2, Vine’s Rustic 1, White-point 1.

Mothing stats

UPDATE: 29th October 2022 – Finally added December Moth to the list of Lepidoptera I’ve logged and photographed. This was my 463rd moth species, and 64th new species logged in 2022.

One might ostensibly refer to mid-October as the point in the year at which the mothing season is beginning to draw to a close. There are still plenty of autumnal moths to be seen, (various Sallows, Merveil du Jour, Red-line and Yellow-line Quakers, Bricks etc, and then winter moths (Winter Moth, November Moth, December Moth etc) around and a chance of rare migrants but from now on, a cold lighting-up night might give you a blank from here on until mid to late February…it can be a gloomy time for moth-ers, although perhaps not quite as gloomy as it is for the moth-ers we know as butterfliers.

One of several Convolvulus Hawk-moths that nectared on my garden tobacco plants in the summer of 2022

Anyway, I’ve done sone totting up from my records. Just in case you’re interested in the details of this year’s mothing here in Cottenham and with a couple of off-site sessions. I have counted about 7500 moths of some 318 species in 200 lighting-up sessions so far this year. I’ve been mothing since July 2018 and have recorded 460 species in that time. 60 of those species were new to me this year alone.

Light Crimson Underwing was drawn to the LepiLED in the New Forest session in 2022

In the previous three seasons, the new-for-me numbers were in the 30s. However, a mothing session in the New Forest, one in Dorset, and success with garden tobacco plants here, bumped up the NFMs, that and my being more diligent in logging micro moths. If I remember rightly, I did far fewer sessions in 2019, but had some nights with several hundred moths and my total that year was 12500 moths of almost 300 species.

Male Oak Eggar seen in the summer while butterflying along Devil's Dyke, Cambridgeshire in 2022 — Male Oak Eggar seen in the summer while butterflying along Devil’s Dyke, Cambridgeshire in 2022

Another new moth, Clancy’s Rustic – Caradrina kadenii

TL:DR – I’ve been mothing since July 2018. In 2022, I recorded almost 50 new species in my garden. It was just 37 in 2021, and 30 in 2020.

As the year rolls by, the number of new moth species a novice moth-er with 3-4 years experience is likely to see on any given night declines with the arrival of autumn. All the moths I saw in my first season were pretty much new-for-me (NFM), about 127 species. In 2019, lighting up for a longer period, I recorded 125 NFM. 2020 wasn’t a great year not many moths at all after an unseasonably warm and sunny pre-Spring and I recorded just 30 NFM. Similarly, 37 NFM in 2021. However, despite odd weather again in 2022, I’ve recorded 49 NFM in the garden and a dozen with the LepiLED in the New Forest.

Among those NFM species was the fabulous and rather rare Convolvulus Hawk-moth. Several (perhaps 5) have turned up in our garden, perhaps drawn to the nectar of the tobacco plants we grew especially for them.

There are, of course, plenty of autumnal moths and maybe a clutch of those have not been ticked. Then, there are the recent additions to the British List, such as Clancy’s Rustic. Clancy’s Rustic Caradrina kadenii
(Freyer, [1836]) which was first reported by Sean Clancy in Kent in 2002.

One turned up in the garden last night, looking quite fresh. I thought I’d seen one before in 2020 but when I double-checked my records it turned out to have been the rather similar-looking Pale Mottled Willow, which is quite common in my garden. So, at last I can tick one of the rarest of the rare moths, Clancy’s Rustic as NFM.

Hairstreak butterflies

There are so many “hairstreak” butterflies around the world, members of the Theclinae, with lots of tribes. Indeed, nobody knows for sure how many of these delightful little creatures adorn our world. In the UK, we have just five of them as native species, and they’re quite rare and tend to live and breed only in small pockets.

In 2021, I saw my first Green, Purple, and White-letter Hairstreaks with a little bit of guidance from some butterflyers I’ve mentioned before. In 2022, I made a concerted effort to try and find at least one of the two others that are not too far to drive from home – the Black Hairstreak. I may have glimpsed it in 2021, but I definitely saw and photographed it in a place called Monks Wood one of its rare habitats.

The fifth the Brown Hairstreak has a flying season August-September and we tried to spot it on our final day on the edge of the New Forest where there was plenty of fresh blackthorn (the larval foodplant) but with no luck. A possible trip to nearer Suffolk might have been productive, but it’s probably too late in the year for it now, so Brown HS is going to be a target there for me in 2023 instead.

In the meantime, you can catch up with some of the 50 butterflies and 460 moths I’ve photographed and videoed for Reels on the Sciencebase Instagram

The Convolvulus second coming

UPDATE: A rather battered Connie turned up on the night of 8th September. That’s three nights we’ve seen the species in the garden, it’s possible there were two on the first occasion (27 August), but just one on 2nd September, and just one last night. Although there’s no way of knowing for sure, there may have been others on those nights and other nights, all may well have been attracted by the scent of the garden tobacco plants we grew specifically to attract this species. All were subsequently drawn to the UV lure.

Usually, one relies on Attenborough and his marvellous army of photographers and researchers to bring the dramatic natural world closer to home. At a push Spring Watch and its ilk can give you a slightly less educational fix with their low-level narrative and low-level cameras. But, nature impinges on even the most urbane of urban gardens at times.

Indeed, we see various butterflies in the garden on warm and sunny summer days – Comma, Painted Lady, Red Admiral, Peacock, Whites (Large and Small), Holly Blue, very occasionally Common Blue and Small Copper, even (once) Marbled White. Hummingbird Hawk-moths turn up during the day and with a little luring, Emperor Moth and various Clearwings. I’ve listed the birds elsewhere on Sciencebase.com, we’ve ticked 30 species in the garden or over it. At night, there are hedgehogs and the Common Frogs are active in and around the pond. Speaking of which various dragonflies and damselflies around the pond and their larvae in it. Also at night, Pipistrelle bats circulating, hunting for moths…oh…moths.

As regular readers will know, surely…I light up with an ultraviolet “lemp” to attract moths and record and photograph them. 459 species so far in four years of mothing. One of the most intriguing and, I feel, exciting visitors was the Convolvulus Hawk-moth. It nectared on Nicotiana (garden tobacco plants) planted specifically to give it something to eat should it turn up. As you know, it did and then again this evening. It’s a huge beast, three or four inches across, it makes a lot of noise whirring and whirling around the garden and clacking into walls and plant pots in between bouts of unfurling its enormous proboscis to feed.

A second, possibly third, one appeared to nectar and then was distracted by the lemp. I got some video of the Convolvulus Hawk-moth just before it dived into the trap. But, I couldn’t leave it there to fester overnight so I lifted the lid to let it out. It soured away into the night sky, like a whirring wraith in a pink and black stripey mohair rollneck. Who needs Sir David, when you’ve got plain David? Hah!

Let’s twist again with the Garden Rose Tortrix

Having written about one of the bigger moths we see in the UK, Connie, the migrant Convolvulus Hawk-moth, it only seems fair to give a mention to a micro, as opposed to macro moth. So, here’s the Garden Rose Tortrix.

Now, the macro versus micro label may well have been historically about size. The larger moths being macro, the smaller moths being micro, as you might imagine, but there are so many enormous micro moths and so many tiny macro moths in the world that this really doesn’t hold. In fact, the division is one of evolutionary history, the micro moths being a much older grouping.

The micro grouping includes all of the butterflies, which are essentially just a family of micro moths. The only physiological difference between what British English thinks of as butterflies and moths is that the butterflies cannot unhook their forewings from their hindwings. That’s it. Asking what’s the difference between a butterfly and a moth is like asking what’s the difference between a ladybird and a beetle, or a dog and a mammal…

Anyway, back to today’s micro. This tiny two-toned moth is known as a Garden Rose Tortrix, Acleris variegana. It is one of about 11000 worldwide moths that are members of the tortrix family, the Tortricidae. They’re so-called because their larvae roll themselves up in a leaf to pupate and metamorphose into the winged, adult. The word tortrix has the same etymology as the word torque, the word for a twisting force – torquere, meaning to twist.

Egging on Toadflax Brocade caterpillars

As regular Sciencebase readers will know by now, this once workaholic science writer is now a highly dedicated mother. As in I am an enthusiastic amateur Lepidopterist. A moth-er, like a bird-er, birder, someone keen to see, observe, understand, and perhaps photograph the subject. This year and last, I’ve also been a bit more focused on being a butterflyer too.

Toadflax Brocade larva with foodplant, Purple Toadflax — Toadflax Brocade larva with one of its foodplants, Purple Toadflax

Anyway, part of being a mother usually involves finding ways to see moths. Commonly that involves some kind of lure – a pheromone bung or an ultraviolet (or other) light. And, again, as you will know, I’ve got several lures for enticing moths for observation and the inevitable photoshoot. At the time of writing, I’ve lured and photographed about 450 moths of the 2600 species found in the UK.

The standard approach to nocturnal mothing is to have a box above which a bright light or bright UV source is suspended, often above a funnel or vent. Moths are drawn to the lamp, like moths to a flame but without the fire risk. They might circulate a while and will often spiral or dive into the funnel opening or the vent and then find it rather difficult to navigate their way out again. A good mother will have pre-filled the trap with lots of empty cardboard egg trays. The trapped moths will settle down in the nooks and crannies of these trays for the night ready to be logged and photographed in the morning.

Moth-trap lamps do not only attract moths, beetles, flies, wasps, hornets, worms, snails, slugs, all kinds of creatures will be drawn. But, it also seems so will the larvae of moths, the caterpillars. A few mornings back, while logging the night’s moth haul (before release into undergrowth away from the garden) I found in one of the egg trays, a couple of caterpillars, larvae of the Toadflax Brocade moth. They must have wriggled all the way from the other side of the garden, about 12 metres where there is a patch of Purple Toadflax or perhaps 15 metres from the Common Toadflax (Butter-and-Eggs) patch to the patio whereupon the moth trap sits on lighting-up nights.

Toadflax Brocade cocoon — Toadflax Brocade in its cardboard cocoon

The two larvae were pupating and using tiny fragments of the cardboard egg tray to make their protective cocoon. One had made a good start and was almost completely enclosed ready for its metamorphosis, the other had a long way to go and so was still very exposed and so obviously a Toadflax Brocade larva. I’ve relocated the egg tray to an under-cover bench outside the garden shed where hopefully the two will finish their transformation and emerge at some point in 2023 as adult moths. I’ll keep you informed as to their progress if anything changes in the meantime.