Category: Science

This beautiful, shimmering bronze creature with the creamy markings on its wings is Dewick’s Plusia, Macdunnoughia confusa. It’s one of the many “Noctuid” moths sometimes known as “owlets” and was a rare visitor from the Continent where it is fairly widespread. Related to the Burnished Brass, Silver Y, and Ni Moth.

It was first seen in Essex (Bradwell-on-Sea) in 1951 and the total number recorded in the 20th Century was just 40. There are almost 500 records now. There is some evidence that this continental vagrant has become established in the South-east and elsewhere, Derbyshire, Warwickshire, Somerset…

I’ve seen it a few times in our Cambridgeshire garden (mid-September 2019 and early August 2021, previously) and I know others locally see it too. Still, it remains a relative rarity across most of the UK although there is anecdotal evidence of it becoming resident. As far as I know, it hasn’t been recorded on the island of Ireland, yet.

Dewick’s Plusia sits within the Noctuid sub-group known as the Plusiinae, which includes the likes of The Spectacle, Burnished Brass, the Ni Moth (it’s attracted to the Ni sex pheromone), the Silver Y, and others. Photos of all the Noctuids I’ve recorded feature in the macro moths section of my Imaging Storm galleries.

This is one of those moths that could be any of half a dozen different species. You cannot know for sure unless you’ve raised it from larvae, done DNA testing, or what the lepidopterists call “gen det”, which is where you dissect the male’s genitalia, which are different across the species…and I’m really not going there! “Gen det” is an abbreviation of “determination by genitalia examination”.

So, we have to record it as a generic member of its genus, or actually in this case two geni:

Swammerdamia/Pseudoswammerdamia sp. Some people might use the term agg. (for aggregated species) instead of sp. (meaning any of a number of species).

The vernacular name for the various species in these two geni is Ermel, so this could be a Birch Ermel, a Rowan Ermel, Little Ermel, a Scotch Ermel etc…

These moths are about 5mm long, so I used a 45mm extension tube to get closer with my macro lens and even then couldn’t fill the frame. Incidentally, while the term micro (meaning small) and macro (meaning large) was perhaps an original division for Lepidoptera, as new species were discovered it was realised that many micros are far bigger than some of the macros and vice versa. Turns out, although these things are never set in stone, that the micro moths are evolutionarily older than the macro moths. The butterflies, which can be very big, are loosely micro moths and sit somewhere in a fork in the family tree.

Shot taken with a mirrorless Canon R7 camera using the onboard focus stacking feature and then a touch of sharpening with Topaz Sharpen AI.

Despite its name, the Scorched Carpet moth does not eat carpets, its larvae feed on spindle Euonymus europaeus. There are in fact just a handful of moths, of the 180,000 or so species of moth worldwide, that eat wool and other textiles.

Indeed, this species has nothing to do with carpets. Many of the geometer (inchworm) moths are so named because the early Lepidopterists thought they resembled the patterns of luxury carpets. They were honouring the moths by naming them carpets.

The Scorched Carpet species is mainly creamy with brown splodges the edges of which have a hue as if they have been slightly burnt. Although the underside looks even more scorched. Overall, however, when at rest the moth looks like a small splat of bird poo. There are many moths that have evolved this camouflage strategy. I’ve only seen it a few times, twice in 2023.

I was tidying up the mothing equipment, which is basically a box and egg cartons when I noticed a Least Carpet roosting on a window frame in the conservatory, I stepped up with a pot to catch it so I could release it into the back garden but spotted another tiny moth next to it. At this point, I wasn’t even sure it was a moth. It looked orange with what seemed to be white stripes. I grabbed a quick phone macro shot, before potting it.

It wasn’t a species I’d noticed or recorded before, but the ObsIdentify app ticked it as the Horse-chestnut Leafminer, Cameraria ohridella. This was confirmed by a quick look at the species page on UK Moths. LabLit on twitter has now told me that the moth’s species name “ohridella” is named for Lake Ohrid in Macedonia.

I set up my macro “studio” and got some closeups of the moth against a matte white background, once it would sit still for more than a second or two. The moth is a mere 4 millimetres, I’d say, thank goodness for macro lenses and extension tubes.

As the moth’s name would suggest, the tiny larvae of this moth species, grow inside leaves of the Horse Chestnut tree, nibbling their way around the interior of the leaf and forming what are referred to as leaf mines. An infestation of this moth can ravage a tree leaving its leaves brown and withered at the end of summer and giving the appearance of imminent death in the tree. Thankfully, the damage done by the leafminers, while more than cosmetic, does not seem to harm the Horse Chestnuts. They lose their leaves in the autumn, as all deciduous trees are wont to do. Incidentally, the UK Moths site points out that a fungal infection has a similar effect on the appearance of the leaves of this tree.

The moth species was first recorded in Macedonia in 1985 and took just 15 or 16 years to reach the UK. It was recorded in Wimbledon in 2002 but was abundant so may have arrived just after the eponymous tennis tournament the year before. First seen in my village of Cottenham in 2004 and recorded by a fellow mothing friend at the other end of the village in 2022. I may well have seen it last year without realising, of course.

UPDATE: 27 July 2023, we camped under a Horse Chestnut at Cherry Hinton Hall for the Cambridge Folk Festival. The tree was covered in larvae and lots of adults flying about.

A quick blog post as I approached my fifth anniversary of garden mothing. That’s six summers of lighting up! You’ll recall how it started.

I have recorded 487 different species of moth in my garden as of 24th October 2023. I have photographs of most of those species, with the exception of the marvellous Hornet Clearwing moth which I saw (drawn to a pheromone lure) but didn’t net. I have also seen and recorded 44 other species on campsites, nature reserves and in holiday house gardens (New Forest, Dorset, Anglesey, and at Chippenham Fen and Les King Wood).

My first season began late, 24th July 2018 and I didn’t keep full logs, but saw roughly 127 species of moth, most of which I’d never even noticed nor photographed before.

In 2019 I ran 272 sessions with a 40W Robinson trap and recorded 12373 moths of 315 species 125 of those were new to me. That represents 45 s/s avg, specimens trapped (and released) per session on average.

In 2020, COVID-19 lockdown year, I ran 294 sessions and had 8529 moths of 309 species, 30 of those species were new to me, and that’s a per session average of 30 s/s avg. Way down on 2019.

2021 – 288 sessions, 7608 moths of 278 species – 38 NFM – 38 s/s avg

In 2022 – 244 sessions, 7900 moths of 321 species – 64 NFM – 32 s/s avg last NFM of the year was the much hoped for December Moth, which arrived at the end of October.

UPDATE 24th October 2023

197 sessions, counted 8086 moths of 334 species so far – 44 NFG as of 24th Oct – 45 s/s avg. I switched to a Skinner trap with a 20W Wemlite from my old 40W Robinson trap, in early June 2023.

If I just select out the peak season 1st of May to 30 September, things are slightly different in terms of per-session averages

2023 – 7551 specimens over 116 sessions – 65 s/s – 330 species

2022 – 7253 specimens over 130 sessions – 56 s/s – 321 species

2021 – 7194 specimens over 141 sessions – 51 s/s – 278 species

2020 – 8002 specimens over 137 sessions – 58 s/s – 309 species

2019 – 10966 over 128 sessions – 86 s/s – 315 species

Obviously, 2019 was an interesting year, my first full season and I seemed to get large numbers of moths and quite good diversity appearing in the trap during almost every lighting-up session. Things were not so good the next summer, with a drop from almost 90 per session to just under 60, but we’d had a warm and early spring with cold snaps at night. 2021 was not like 2020 in terms of how the seasons panned out and I saw another drop in per session average to just over 50. 2022 was half way back up between the 2020 and 2021 averages. 2023 has been quite bizarre, numbers seemed to be way down early in the season, but diversity and numbers picked up. I was also more aware of various micro moths and so my new-for-garden (NFG) was 44, with a few new macros, like Leopard Moth, but not the NFG numbers of my earlier years, obviously.

I expect to see similar total numbers and diversity next year, but perhaps with fewer NFGs, but who knows, it’s rather unpredictable.

UPDATE: They’re still at it, night of 23 Jul, three Holly Blue, two  Red Admiral, and a Gatekeeper roosting in the ivy.

A few days ago, I noticed a Holly Blue on a plant stem on the lawn at dusk. Actually, there have been hundreds of this species in the garden this year. But, this one was settled, it was at roost, in its nocturnal torpor state.

Asleep, in other words.

I put a metal basket over the top of it so that nobody would tread on it if they were mothing around the garden (me) or counting frogs (son). Once it got properly dark, I took a short stroll around the garden (the only thing possible with a short garden) and shone a torch up at the overhanging ivy, ostensibly I was looking for moths, but there was another Holly Blue roosting under an ivy leaf. Down below roosting on some apple mint, a Green-veined White.

Inspired, I plodded around the rest of the garden peering under bushes and around the potting shed expectantly and was rewards with a Small Tortoiseshell, a Red Admiral, and a European Peacock, all asleep in different spots in the garden.

It was an odd revelation, I’ve been mothing for six summers now and have seen lots of moths flying around the garden, nectaring on the wildflowers and the (un)cultivated flowers, and of course, a lot drawn to the UV light…but I’d never noticed roosting butterflies before.

Has something changed or is it just my level of observation? Last year was particularly hot and dry, it’s likely that lots of gardens, hedgerows, and bushes and wild plants out in the nearby countryside died. Of course, there’s also the issue of the two new housing estates being built not half a mile from us on old farmland. That could have removed their usual nocturnal roosting spots forcing the ones that survived the upheaval to spend the night in our garden.

I usually do a couple of Big Butterfly Counts for the UK’s conservation agency, along with millions of other people, hashtag #CitizenScience. When it was sunny earlier in the week, I counted 30 Holly Blues during the 15-minute recording period as well as loads of Large and Small Whites. The Comma, Marbled Brown, Gatekeeper, Red Admiral, Small Tortoiseshell, and European Peacock, all stayed away until just after the time was up! I’ve not seen a Marbled White in the garden this year, yet, nor Common Blue, they less commonly seen around here, but they the former has been on the outskirts of the village in numbers. There are dozens of Red Admirals around at the moment.

Anyway, I will survey the garden again and see what other strange bedfellows are sleeping among the campion and toadflax.

I asked the question on one of the mothing groups and one respondent suggested that butterflies roosting in one’s garden is perfectly normal. I’m sure it is, just not seen it before in our small garden.