Lepidoptera – Page 22 – David Bradley

Light Emerald, Campaea margaritaria

Another one of those insects almost everyone else thinks of as grey or brown…just look at that pure greeeen.

Light Emerald (Campaea margaritaria). This is a geometer moth, which means its larvae “measure the earth”, they’re inchworms, in other words. Although I think it’s time they went metric AND they’re not worms…they’re larvae (moth caterpillars).

Although this moth is pretty much flat, I took three photos of it at different focus depths and then aligned and stacked them together (using digiCamControl and CombineZP, mentioned as my current free tools of choice for focus stacking some time ago on the blog.)

If you look closely you can see why moths and butterflies (essentially the same thing) are called Lepidoptera. (Lepis means scale, pteron means wing in ancient Greek, so – scaly wings)

Moth of the Month – Maiden’s Blush

The Maiden’s Blush moth, Cyclophora punctaria, Spring form is not as well marked as the Summer form where the blush is more obvious, but you can still see it here.

This species is a geometer moth, which means its larvae (caterpillars) move in such a manner that they seem to measure the earth, they’re known as inchworms in the USA and elsewhere. Specifically, this member of the Geometridae is a member of the sub-family Sterrhinae, which includes the “Least Carpet” and several “Wave” moths as well as the “Blood-veins”. The species was first described by Carl Linnaeus in 1758 in the 10th edition of Systema Naturae.

According to the UK Moths site, the species occurs in oak woodland, its larvae feeding on that tree. It is fairly common in the south of England, but scarcer up north and into Scotland. As with several other moths in the genus Cyclophora, in Western Europe it flies in the spring/early summer (May to June) and then has a second brood in August. The adults of the second brood are markedly smaller than the spring specimens.

This specimen of Maiden’s Blush flew to 40W actinic light trap overnight 24/25 April 2019. Along with a host of other moths: Brimstone, Muslin, Garden Carpet, Early Grey, Spectacle, Nutmeg, Powdered Quaker (another new for me pictured below), Shuttle-shaped Dart (6 of them).

You will not that I have called this post “Moth of the month”, don’t worry there will be more moths than once a month…

Spring Moths

I’m slowly seeing new moths to my actinic light trap as the spring surges forward, a new one or two each day now. But, one of the stalwarts of the British mothing world posts to the major Facebook mothing group how he had almost 300 different moths to his trap, with 50+ species new for the year. I’m not sure I could cope and certainly wouldn’t be able to identify from memory all of the ones he cited.

My “haul” from last night was a lot more modest but interesting nevertheless…and manageable:

Shuttle-shaped Dart (7)
Male Muslin moths (3)
Double-striped Pug (2)
Brimstone
Hebrew Character
Common Plume
Waved Umber
The Mullein
Pebble Prominent
Nutmeg
Spectacle

Recent moths new to my “list” for the year, so I’d never seen before.

Emperor in the house

You will have spotted by now, my current fixation on the Emperor moth, Saturnia pavonia. It’s Britain’s only resident member of the Saturniidae family (related to the Silkworm moth). I have a pheromone lure that has some (6Z,11Z)-hexadeca-6,11-dien-1-yl acetate on it, which I bought from Anglian Lepidopterist Supplies. UPDATE: As of 2023, fifth season of checking on this species in our neighbourhood, still present and showing.

It took me a while to track down the name of that sex pheromone, exuded by the less colourful, night-flying females, to attract the colourful, day-flying males. I had photographed one or two on the wing but used a homemade butterfly net to catch the specimen you see above. I let it chill out in a pot for a few minutes to get a nice snap showing all of his pareidoliac eyes and his enormous pheromone-detecting antennae without him flapping about.

He’s back in the wild now looking for true love rather than olfactory moth porn. Neither the male nor the female has mouthparts, so they cannot eat, they get all their energy from reserves built up when they were larvae (caterpillars) eating heather or brambles. They have to get it together as soon as they can during the flight time of April to May.

Now, who said moths were grey and dowdy? This is surely the most photogenic moth in the UK.

Sex pheromone for an Emperor

I made a rookie research error. Saturnia pavonia, the Emperor Moth, was previously known as Pavonia pavonia, and in my search for the chemical identity of its sex pheromone (which is in the moth lure I mentioned previously) I’d assumed these were its only names. But, apparently, it was also known as Eudia pavonia.

Once I’d realised this, a scientific literature search quickly found a paper discussing the moth’s sex pheromone: (Z)-6,(Z)-11-hexadecadien-1-yl acetate. This is closely related to another chemical gossyplure, a 1:1 mixture of the (Z,E) and (Z,Z) isomers of hexadeca-7,11-dien-1-yl-acetate. That chemical is used commercially to lure cotton-infesting moths to traps to reduce breeding of different species Pectinophora gossypiella.

So, with the systematic name, I could get the InChI string from one converter and then generate a chemical structure, so here it is together with the male moth I photographed, which is attracted to this chemical:

Well-stacked Muslin Moth

UPDATE: 9th April 2020: First Muslin to the lure, conventionally photographed from three angles on stone.

The male Muslin Moth (Diaphora mendica [Clerck, 1759]) that I saw in the trap these last couple of mornings was there again today. I know, because he has a little snick out of the end of his left antenna. I was hoping a female might turn up, their wings are muslin-white, but the only other moth in the trap was a solitary Hebrew Character.

Anyway, the Muslin’s arrival gave me the opportunity to try out some more focus stacking. This time I used a couple of free tools. The first a controller for my Canon dSLR, digiCam Control. This software lets you control you dSLR via a USB cable from your computer and has builtin focus stacking (and many other functions).

I used its simple focus stacking to take a focus-bracketed set of four photos of the moth illuminated with an LED ring flash and natural light from my “studio” window (it’s just our back bedroom, which I use as an office). Anyway, each of the four photographs has its focus from near to far away from the camera. So the moth is pin sharp in each photo but only in a certain plane parallel to the camera’s sensor. The depth-of-field is very short with a macro lens at close quarters even with a small-ish aperture of f/9.5.

I then combined (automated process) the four shots using another piece of free software, CombineZP. I used what seemed to be the simplest option “Do Stack” and the resulting composite image was generated in a couple of minutes.

All very quick and easy. I am sure with practice and more attention to the details of optimising each piece of software and perhaps the lighting for the subject, I reckon it would be possible to get even better sharper shots, without having to spend hundreds of pounds on new hardware.

I also did a sequence of face-on portrait shots with the moth, automatically aligned them in CombineZP and then applied the “Do Stack” command, great result.

Focus stacking an Angle Shades moth

Yesterday, I had a Muslin moth to photograph. Today, I had another go at focus stacking a macro shot, with an Angle Shades (Phlogophora meticulosa).

Focus stacked moth, note how from nose to tail the image is largely in focus

Focus stacking involves taking essentially the same photo several times but focusing first on the foreground, then the mid, then the farthest point on the subject. You can take as many shots as you like to “bracket” the image and get a sequence of shots that have the whole of the object in focus at some point in each photo. As you can see in the photo above.

It works best if you set the camera up on a tripod and take the series of photos using magnified LiveView and manually focusing on different parts of the subject. There are automated systems (software and hardware) and some cameras have focus bracketing built in (think of it as the focusing analogue of exposure bracketing, which lets you create high dynamic range (HDR) photos.

Once you have your set of focus-bracketed photos, you can then use a photo editor to blend them into a single composite image where pretty much all of the shot is in focus. The technique overcomes the very shallow depth-of-field you have with a small aperture when shooting taking close-ups. That said, the technique works to extend DoF for any type of photo.

Today’s subject is the beautifully patterned Angle Shades moth (who said moths were dull and grey?). I had it sat in a pot and perched that on an old patterned chair. If I could have persuaded it out of the pot without it flying away, you could have seen better just how well camouflaged this moth is against such William Morris style arts and crafts prints. In the wild, of course, it finds itself beautifully camouflaged among multicoloured and dappled foliage.

Focus stacking a Muslin moth

It has been a bit quiet on the new-to-the-garden moths, basically because it’s still quite cold and the night-flyers aren’t out in great numbers yet. Nevertheless, a male Muslin moth (Diaphora mendica) turned up last night. Hashtag #floof. Here he is “focus stacked” using half a dozen macro close-ups and Zerene Stacker. The aerial view is a single shot.

Photo stacked Muslin moth

The females don’t have the big pheromone antennae and are white with the black spots.

Overhead view male Muslin moth

The other moths that are around and that have turned up in varying numbers in the last month or so include: Common Quaker, Small Quaker, Twin-spotted Quaker, Hebrew Character, Clouded Drab, Early Grey, Twenty Plume, Common Plume, Early Thorn, Garden Carpet, Nut-tree Tussock, Agonopterix yeatiana, March Moth, The Chestnut, Double-striped Pug, March Dagger, Dotted Border, Pale Pinion, Oak Beauty, Pale Brindled Beauty, Acleris cristana.

Photos of all these updated with the new entries can be found in my Mothematics gallery on Imaging Storm, also includes butterflies, but they’re really just a type of moth, anyway.

Moths, dull, grey, night-flying insects?

Ask anyone who isn’t a moth-er to describe a moth and usually terms such as dull, grey, brown, night-flying, drab, dingy, useless are the ones that arise. Someone might go so far as to describe them as the boring relatives of butterflies. Well semantics aside, butterflies are just a sub-group of the moths, they’re all Lepidoptera, but they’re anything but useless and many of them fly during the day and are incredibly vivid and bright.

Perhaps the most vivid and bright of the British species is a moth I’d not seen until today, only in books. It is the Emperor Moth, Saturnia pavonia, the only member of the Saturniidae, the silk moths, found in the British Isles.

The males are very brightly coloured, the females a version where the colours look as if they have been desaturated. The male flies during the day, the female at night. Both male and female have a vivid spot on each fore- and hind-wing that give them the appearance of having two pairs of eyes looking back at a predator. The species is actually fairly common across the British Isles although it favours heathery heathland and open country, but that does include Fenland, of which we have plenty hereabouts.

Female Emperors [should that be Empress moths? Ed.*] exude a pheromone to alert the day-flying males to their presence and their urge to mate. The males can detect picograms of sex pheromone on the wing with their feathery antennae. Purportedly, they can sniff out a female from up to ten miles.

Other Saturniidae moths in Japan and the Americas seem to use hexadecadienals and esters of those compounds as their sex pheromones. I’m yet to find a paper that isolated and characterised the sex pheromone of S pavonia. Nevertheless, you can buy a little lure impregnated with the sex pheromone. A moth-er might hang such a lure in the garden on a sunny and breezy day in the hope of attracting an Emperor, which is what I did.

First sighting was today. He wouldn’t settleÂ and I couldn’t safely net him, so I snapped away 100+ shots and maybe got 4 where the moth is in focus and in the frame.

*There is no “Ed.” it’s just me.

Luring in the Emperor

I ordered a pheromone lure for the Emperor Moth from ALS today. It’s just arrived and now it’s hanging in one of those little laundry tab string bags, out in the garden, blowing in the breeze purportedly drawing in the male Saturnia pavonia…but nothing yet. It’s getting late in the day for this day-flying moth, so I might pack the lure away in a freezer bag in the freezer and try again tomorrow. Intriguingly, the female which looks like a greyed out version of the male is a night-flyer.

Meanwhile, I cannot find the chemical identity of the female sex pheromone for this species. I can’t seem to find a reference in my usual journal searching, although three US Saturnia species apparently use a long-chain aldehyde, (E4, Z9)-tetradecadienal. I will keep searching. This is where my passion for biology and chemistry overlap, you might say.

UPDATE: I discovered that S pavonia had two older names, not just Pavonia pavonia, but Eudia pavonia. As soon as I learned the latter, it was easy to find a research paper discussing the pheromone – (Z)-6,(Z)-11-hexadecadien-1-yl acetate, which is a close relative of another sex attractant pheromone, gossyplure, which is used in commercial breeding control of pest moths. Read more about it here.

This species is the only member of the Saturniidae that lives in the British Isles, it is found almost everywhere here from heathland to fenland, so there is a chance of at least one turning up. It is the poster-boy of the moth world. You can go away and look it up if you like, but I’ll only post a photo when I’ve snapped one of my own.