What use are moths?

Steve on one of the mothing Facebook groups told us he gave a talk about moths and was asked if we had any use for them. Other than making silk from silk worms (the larvae, or caterpillars, of the domestic silkmoth, Bombyx morihe) was at a loss to suggest any purpose to moths other than their role in the wider concept of life on earth and diversity and all that. He posed the question on the group and was offered quite a few reasons to be cheerful when it comes to moths.

Hebrew Character moth

Shaun suggested that people have an odd relationship with moths as they are used as symbols and in myths in a variety of cultures, as food – some people eat the larvae and they’re an important protein source packed with essential minerals, they can be used as invasive plant controls and for the study of genetics etc. As decoration in jewellery, clothing, tattooing etc. Paul pointed out the traditional food of Aboriginal Australia, the witchetty grub, which is the larva of several moths, most notably the Cossid Moth Endoxyla leucomochla. There are a food source in Europe too and a form of tea that is brewed with moth and other insect faeces in China.

Martin’s take was that we make use of moths for interest, study, research, and in hobbies. They “brighten our lives,” he says. They also act as a gateway into other activities and interests, such as flowers, trees, walking, travel, and friendship.

Common Quaker moth

Antony pointed out that pollination is probably the main use.

Matthew, somewhat tongue-in-cheek asked what do we use blue tits for? Or shrews? It’s not all about utility!

Roly asserted that moths have an important position in nature’s foodchain. Many birds wouldn’t exist without caterpillars for their chicks. He also added ever so slightly flippantly, I think, that his wife reckons she finds moths very handy for making her clothes look moth-eaten, proof that she needs continually to shop, though I’ve never seen a clothes moth in our closets, Roly emphasises.

Pale Brindled Beauty moth

Stewart had a research example of moth usage: Spodoptera frugiperda and Trichoplusia ni cell lines are used in the recombinant baculovirus expression system to produce proteins. The baculovirus most studied for this is Autographa californica multicapsid nucleopolyhedrovirus.

Welcome to the first moths of the year

Okay…first moth I’ve seen this year was a Common Plume (Emmelina monodactyla), which I think may well have been hibernating in our car and flew out when we arrived home on 15th February landing on a Ribes bush to be phone-photographed seconds later.

Common Plume moth

Second moth was in the trap (accidentally, as the timer had lit it up briefly evening of 19th). This moth, a Common Quaker (Orthosia cerasi), usually flies from March onwards. First time I’ve seen one. Added to the lepidoptera list and gallery.

Common Quaker moth

Apparently, to some moth-ers the arrival of brown moths, such as the Common Quaker, are an indicator of Spring being on its way.

Other moth species on the wing in February March that might turn up if you’re trapping over the next few days: Pale Brindled Beauty, Early Moth, March Moth, Dotted Border, The Chestnut, Hebrew Character, Spring Usher, The Satellite, Dark Chestnut, Early Grey, Clouded Drab, The Herald, Oak Beauty, Winter Moth (which I spotted twice in December 2018 outside the trap), Red Chestnut, Angle Shades (which appeared regularly from when I started in July 2018), Small Quaker, Yellow Horned, The Engrailed, Silver Y (another regular visitor last year).

Meanwhile, butterflies. We saw a Small Tortoiseshell on NT Tubney/Burwell Fen 14th February and then a week later (21st Feb) a Brimstone and a Peacock at RSPB Fen Drayton.

First Peacock butterfly of 2019, RSPB Fen Drayton

Winter Moths

By Christmas Eve 2018, it will be five months since I started trapping, identifying, photographing, and releasing (unharmed) moths using an actinic light trap. At the last count, I had ticked 129 moths. As the autumn drew in and winter arrived, the number of new species plummeted although other moth-ers talked of Mervs, November moths, December moths, Winter moths, Mottled Umbers, migrants, and more.

I’d seen none of those species until a Winter Moth (Operophtera brumata) finally turned up on the vanes of the trap and was sitting there when I got back from C5 the band rehearsals last night. I got a quick record shot on my phone and then persuaded him (it’s definitely a male; the females have no wings) to sit on my trusty lichen-encrusted stick for a late-night photo shoot. The inimitable Leonard C on the Moths UK Flying Tonight Facebook group corroborated my identification.

This morning, after a restful night’s sleep, O. brumata was ready for a couple more snaps prior to release back into the wild. As the name suggests, this species flies and breeds during the winter, taking flight from late autumn and on the wing until January-February. It is a relatively common species and its larvae can sometimes be found in numbers so large that they will completely defoliate small trees and so the species is considered a pest, according to UK Moths.

You can view all of the decent shots I’ve got of Lepidoptera on my Imaging Storm website where there’s also a full listing of species common names and scientific binomials.

Mottled Umber – Erannis defoliaria

UPDATE: 25 Nov 2019 First noted appearance of the year of a Mottled Umber, just a day later than in 2018. Didn’t reach the trap, roosted on the conservatory wall, was photographed and released into the front garden. The females are wingless, so these are definitely males. There are two LBAMs on the trap too, but nothing present by morning aside from a caddisfly and some diptera. My detailed mothing records for 2019 are available here.

This was the first new species to the actinic trap (night of 24th November 2018) for almost two weeks, having had numerous blanks and/or just the occasional Turnip Moth and a Dark Chestnut or two.

This species is the geometer moth Mottled Umber (Erannis defoliaria). The “geometers” all have larvae (caterpillars) that appear to measure the earth (they’re called inchworms colloquially in the US, I believe). Geo meaning earth, meter meaning to measure. More mothematics here.

Cloudy night of autumnal moths

We have recently had some clear, cold, and damp nights and some rainy nights recently. The scientific moth trap has been running, but with very few lepidoptera making an appearance. I have been observing one or two specimens only each morning. That said, four species new to me in a couple of weeks and all added to my butterflies and moths gallery. However, the evening of 25th October 2018 was cloudy and thus a little warmer and while I cannot say that the trap was heaving this morning, there had been a few interesting species in the dark and one or two more present by morning.

Feathered Thorn (Colotois pennaria)
White Point (Mythimna albipuncta)
Green Brindled Crescent (Allophyes oxyacanthae)
Common Marbled Carpet (Dysstroma truncata), dark form
Common Marbled Carpet (Dysstroma truncata), light form
Feathered Thorn (Colotois pennaria)

There were two very different colourations of Common Marbled Carpet (Dysstroma truncata), Green Brindled Crescent (Allophyes oxyacanthae), two differently sized White Point (Mythimna albipuncta), and a rather interesting autumnal flyer, a male Feathered Thorn (Colotois pennaria). Also, not pictured, November agg (Epirrita dilutata), not seen any of the underwings recently, but there was a Lesser Yellow Underwing (Noctua comes), and finally, a Turnip (Agrotis segetum).

In that bottom photo of the Feathered Thorn I had to clone out all the yellow and white dog hairs that were on the carpet to allow the moth to stand out in the photo!

Green-brindled Crescent

Isn’t it time to put the scientific moth trap away, they asked. Surely there are no moths flying in the autumn and winter. Well, there are definitely fewer species around now, especially if it has been really damp and chilly overnight. But, there were numerous last night feeding on the ivy blossom: Centre-barred Sallow, Large Yellow Underwing, Vine’s Rustic, Common Plume, and one or two micro moths.

In or around the trap, more Yellow Underwings (Lesser, Small, and Large), Setaceous Hebrew Character, White Point, Lunar Underwings, and a Red-green Carpet.

 

This morning some of those were still in attendance, but a Green-brindled Crescent (Allophyes oxyacanthae) had taken over the morning shift from the RG Carpet. This species was first curated by Linnaeus in 1758, it grows to between 35 and 45 mm according to the UKMoths page. It’s prominently green in colour, but subtly striped (the brindled part of its name). The crescent in its name refers to two white curves on its wings. It has unusually large oval and kidney marks compared with many other noctuid (owlet) moths.

It is mottled brown mainly but catch it in the right light or under the glare of a camera ring flash and its gree metallic scales will shine through. It commonly flies from September to November and is found across the UK, in woodland, hedgerows, and the suburbs, its caterpillars feeding on hawthorn (Crataegus) and blackthorn (Prunus spinosa) and other trees and bushes.

Moth behaviour

TL:DR – Moths, Lepidoptera, are an incredibly diverse group of insects with some very diverse behaviour. There are some 180,000 known species worldwide with about 18000 of those known as butterflies in the English language, but butterflies are just a class of moth.


There is quite a diversity of behaviour among the moths you see in your trap. The various Yellow Underwings almost all flap wildly around inside until the settle down, but if you disturb them they will flap again, flashing their yellow hindwings.

Large Yellow Underwing (Noctua pronuba)

Others are more passive once they have settled down they stay settled down unless disturbed and will generally avoid gripping on to anything other than the original surface on which they landed, Turnip moth is a case in point it seems. But, others will grab on to an offered paintbrush or piece of leaf and happily clamber aboard to be photographed, Angles Shades, for instance, were happy to do this.

Angle Shades (Phlogophora meticulosa)

Agitate some moths and if they’re not quite warm enough they will sit still but vibrate their wings, revving their engines as it were before taking flight, I’ve watched this with Flounced Rustic, Straw Underwing, Setaceous Hebrew Character, and the Elephant Hawk-moth, which oscillates audibly.

Setaceous Hebrew Character (Xestia c-nigrum)

Many of them will, if disturbed, will have a quick flap before landing on their backs and playing dead. If disturbed again they will flap and fly, if they can. I have observed this intriguing behaviour many times in the last few weeks since beginning my mothing career. Most recently, with the nominate form of The Sallow (Cirrhia icteritia), which I’d gently coerced into a jar to photograph and which ended up on its back staring at me. It quickly flipped back over and took flight into the safety of the shrubbery.

The Sallow (Cirrhia icteritia)

Behaviour that was investigated scientifically not too long ago is even more fascinating than any I have seen in the trap or indeed elsewhere. Most moth species have some form of camouflage that allows them to hide on their favoured vegetation. Apparently, the aforementioned Elephant Hawk-moth likes fuchsia bushes and given how the moth looks and the form of that plant’s flowers, you can see why. The Peppered Moth is said to have evolved to cope with soot-covered trees so that during the Industrial Revolution they became much, much darker and better camouflaged on sooty surfaces. This industrial evolution is most likely #DeceivedWisdom given that this species actually roosts on the underside of leaves where predators  would not see them anyway.

Elephant Hawk-moth (Deilephila elpenor) and fuchsia blossom

Another species investigated recently shows an incredible ability to adjust its position on a tree bark to make itself pretty much completely invisible to putative predators. One has to wonder, how does the moth know what it looks like from above to do this? I can imagine that there are two ways it might be able to carry out this feat. Perhaps the most sophisticated is that its brain has some kind of “map” of how it looks and the moth shuffles around on a surface until the surface matches how it perceives it looks from above.

A second simpler explanation, which occurred to me is that in fluttering its wings gently it can see the shadow beneath them of where the pattern changes and can then simply look to see or feel whether its pattern matches up with the bark surface on which it finds itself. You can read the research here and here.

I contacted the research team to see how and if their work in this areas has progressed and to ask whether my possible explanation for the behaviour had been investigated. This is what the Prof, Piotr Jablonski, had to say:

We have thought along similar lines but did not do any experiments...We thought the by raising and lowering its wings, the moth may compare the colour and/or pattern on its wingtips (visible when raising them) with the colour or pattern of the bark around the moth. This would require changing the colour of the wingtips (probably visible to some moths - but not all - during the wing-raising behaviour) and for it to be able to control the change of colour of the wing area that is not visible. Maybe another student can pick up on this soon...Changku Kang graduated a few years ago.

One other aspect of moth behaviour that has intrigued people for centuries is why moths are drawn to a flame or other light source. The argument is that they use the moon to navigate at night and candles and other artificial light sources confuse them. I don’t think this is true. I have my own theory, which I have discussed here.

A momentary leps of reason

Regular visitors to the Sciencebase site and associated social media have probably spotted the leps (Lepidoptera, the butterflies and moths), that have somewhat usurped the previous 18 months of bird photography, although that is still ongoing.

Black Rustic (Aporophyla nigra)

If you haven’t, what have you been looking at, then? Anyway, I was almost set to clean up the borrowed actinic light moth trap and return it to my friend who so kindly lent it to me on 24 July and endowed me with a new addiction.

Red-green Carpet (Chloroclysta siterata)

The reason? Well, there hadn’t really been much new for a while and I was starting to believe that our garden setting is not quite good enough for the moths. I persisted, however, and having had a dearth of new species this last week was rewarded on my return from C5 the band rehearsals last night with several I had not seen before as well as some old favourites.

Lunar Underwing (Omphaloscelis lunosa)

Lunar Underwing (Omphaloscelis lunosa)The new ones included Lunar Underwing, Red-green Carpet and Black Rustic, and the oldies, but goodies were the various Yellow Underwings (Lesser, Large, Broad-bordered), Flounced Rustic, Gold Triangle, Willow Beauty, Brimstone, Common Wainscot, Vine’s Rustic, Shuttle-shaped Dart, Sallow, and several others. You can see the 100+moths I’ve identified and photographed in my Leps gallery on Imaging Storm.

Encouragement from the mothing community, especially from Rob, Brian, Samantha, Leonard, Matthew, Karen, Mandy, Ben, Jade (who told me Lunar UW was just around the corner), Mark, and others, particularly on the UK moths Flying Tonight Facebook group. And, of course, Mrs Sciencebase who was not so keen initially, but has taken a flight of fancy of late, a lep of faith you might say.

 

Mothing about – Waved Black

Well, after the heady days of late July and August with dozens of different moths coming to the actinic light trap that I borrowed, numbers of species have diminished. The chilly and occasionally damp evenings here in VC29 mean there is less nocturnal lepidopteran activity overall, although there always seems to be a good number of Large Yellow Underwings, Vine’s Rustics, and one or two Setaceous Hebrew Characters in the trap by morning. And, usually, there is the one oddity that keeps me lighting up just for the treat of a new species.

There was a Large Ranunculus a couple of nights ago and a hint of a big, dark Hawk-moth that rattled around in the dark among our shrubbery but didn’t get caught in the trap. It may well have been a Red Underwing or an Old Lady, I didn’t get a good look, but I hold out hope that it was actually a Convolvulus Hawk-moth, and if it warms up again, it may well return. [Had to wait until September 2022!)

Anyway, this morning there was a small dark species on the egg boxes, speckly but sooty black to my bleary eye. It had much more apparent creamy yellow markings once I got the photo up on my screen. Unfortunately, I didn’t get a particularly sharp photo, which is a shame.

It turns out to be a Waved Black Parascotia fuliginaria. It’s unusual in that its resting posture (wing position) is more like the moths known as Geometers (so-called because their caterpillars appear to measure out the earth, inch-worms, they’re often called). The waved black is actually a member of the Erebidae within the huge superfamily known as owlets, the Noctuidae.

Admin and master moth-er Leonard C on the Moths Flying Tonight UK facebook group points out that this species is a fungus feeder (the caterpillars also eat rotting wood) and “will certainly be the star of your catch”, while another admin Mark M told me he was very envious of the find and that for his county, Devon (specifically, VC3), there has only been one specimen recorded since 1995. The nocturnal adults purportedly fly June to August, so interesting that there’s one mid-September.