Third in the series of 'One to Look out for' - the Scarce Bordered Straw

As we leave our hot summer well behind us and drift into the autumn, we find ourselves looking for potential migrant species, especially during those milder spells of weather. This brings us nicely onto our third in our series 'one to look out for', and this time I'm focusing on the Scarce Bordered Straw a species which has only been recorded at three sites in Montgomeryshire during the past ten years and a total of just 16 records in our database.

Scarce Bordered Straw recorded at Commins Coch in October 2011

The Scarce Bordered Straw is as I've already said a migrant species, therefore numbers are like to fluctuate quite wildly each year depending on the weather. It's mainly a coastal species, but can be found inland as well. It has been recorded in every month of the year in the UK as a whole, but in Montgomeryshire it has only been found from mid August to late October. There are currently no records of it breeding in the county, but it has rarely been known to breed in other parts of the UK from adults which arrive early in the season.  The known food plants in the UK are, are Scarlet Geranium, Tree Mallow and Yellow Rattle.

Scarce Bordered Straw

Scarce bordered Straw

The two Scarce Bordered Straw photos above were taken from two moths recorded at Cors Dyfi during an MMG event in August 2006.

The Scarce Bordered Straw is in fact quite a variable species in appearance as the images above clearly show, but there are only two species which it could be confused with, so confusion should be at a minimum. The Bordered Straw, of which we only have one record in the database and the Eastern Bordered Straw, of which we don't have any records, are the two species in question.

So please try to keep your traps going during mild spells of the autumn and this uncommon species may well pay you a visit.

Peter.

Ultraviolet Lepidoptera.

Since my night-clubbing days many moons ago I have often wondered what our British moths and caterpillars may look like when subjected to "black" ultraviolet light, in particular those which appear to have some form of luminosity already, such as the Elephant Hawk Moth, or striking patterns with white such as the Garden Tiger.

Browsing this thought on the internet a few days ago I came across a website by a Canadian guy - Brian Robin from Ontario who has recently looked into this and has the studio equipment to experiment and photograph the results.

He mainly focuses on caterpillars as this caught his attention first. Nonetheless, I found his site very readable, interesting and entertaining.  Well worth a read.

He also delves into macro photography of thin ice formation and light refraction (Birefringence), which I also found quite fascinating!

http://brianrobin.ca/ultraviolet-lepidoptera/

Does anyone out there know if UV light has been tried on moths/caterpillars in this country? I would love to see the results.

Phil McGregor.

Coed Y Dinas event report

Our penultimate event of the year was at Coed Y Dinas the MWT (Montgomeryshire Wildlife Trust) wildfowl reserve near Welshpool. We have trapped here fairly regularly over recent years and found it to be an all round very good site so, we had high hopes that it would be a productive evening.

The two days preceding the event had been mostly overcast and the night time temperatures had been holding up well, so it was very good to see the same weather on Saturday evening, in fact, it was perfect mothing conditions with the minimum temperature not falling below 16.6c.

Those of us with kit were on site by 7:00pm and the traps were set up along all the footpaths. Before they were switched on we all did some dusking with the nets and a fair amount of species, especially micros, were netted - these included Epinotia tenerana, Lathronympha strigana, Acleris variegana, Celypha lacunana and Yponomeuta cagnagella; then the traps were fired up by 8:30pm.

The white sheet

Even as the last glimmer of evening light was melting away, filled pots were coming in thick and fast to the table, species included Common Carpet, Snout, Devon Carpet, Heart & Dart, Setaceous Hebrew Character, and a cracking Bulrush Wainscot. The micros didn't slow down either: Pyrausta purpuralis, Pandemis corylana, Epinotia nisella and a very nice Ypsolopha sequella.

Head shot of a Feathered Gothic

Bulrush Wainscot

Ypsolopha sequella

As darkness descended Trisha turned up with a box containing about a hundred micro moths which she wanted to run past me to id what I could. So, I had Trish's moths on one side of me and lots of moths coming in from the event, on the other side, all needing to be id'd; to say things got a tad hectic at the table would be rather an understatement, but, I ploughed my way through and kept going somehow although my brain was rather addled by the end of the evening!

A selection of species in one of the egg trays

Including; Large Yellow Underwing, Copper Underwing Agg. Flame, Flame Shoulder

and a Hornet (top left)

This site has been known to attract hornets at past events and we weren't to miss out on this wonderful insect on this occasion either. They were coming to the readily to the white sheet and especially to the trap which was set up in the meadow, in fact, they were attacking and eating some of the moths and it was in this trap that we found the wings of an Old Lady (moth that is) - there should have been a sign saying 'handle with care' when checking through this trap!

One of the Hornets

By mid-evening macros were still coming in in good numbers, these included: Centre Barred Sallow, Straw Dot, Sallow, Canary-shouldered Thorn, Barred Sallow, Clay Triple-lines, Brown-spot Pinion and Dusky Thorn. The micros also were also still very active: Clepsis spectrana, Hypatima rhombiodella, Acleris rhombana, Cataclysta lemnata and an excellent Prays ruficeps all came to the table.

Brown-spot Pinion

Barred Sallow

Clay Triple-lines

Sallow

As it drew towards midnight moth activity was on the wain, so it was decided that we should start packing up. Final species added to the list included: Yellow Shell, Angle Shades and a rather nice Acleris forsskaleana. For a full species list please click here.

Acleris forsskaleana

The only migrant species of the night was the Silver Y.  
  

Silver Y

Many thanks to members of the 'events team' for doing an excellent job as always, and thanks to Gavin for taking the photos, and to Paul (standing in for Sue) for supplying us all with a selection of biscuits during the evening.

Peter.

'One to look out for' - the Lesser Treble-bar.

This is the second in my series of  'One to look out for' and this time I'm focusing on the Lesser Treble-bar, a species which has only been recorded five times in the county as opposed to the much more common Treble-bar. The last time it was recorded in Montgomeryshire was in August 2009.  The Lesser Treble-bar tends to be most frequent and best distributed in central southern and south-east England, the Midlands up to Northumberland in the northeast. It is however very local in Wales and it gets more uncommon the further west you go. It is double brooded May-June and August-September. It frequents a wide range of habitats, including grassland, woodland rides, field margins, sea cliffs and sand dunes and gardens.

Treble-bar Aplocera plagiata

Lesser Treble-bar Aplocera efformata

On the diagram below (and the photos above) note the difference between the shapes of the two inner bars where they meet the leading edge of the wing this can easily be seen with the naked eye or a low powered hand lens. 

                           

This is certainly one to look out for in the county - so make sure you examine all your Treble-bar records very carefully just in case there's a Lesser Treble-bar lurking amongst them.

Peter.

A red data book species at Commins Coch

Five days ago a fairly worn moth came to my trap, I didn't think I could name and was going to discard it, but had second thoughts and potted it up for a closer look later. A few minutes later in another egg box I came across another moth which was obviously the same species as the first one I potted, but this time it was in far better condition and feeling came over me that I had got a very important record. I photographed both moths and sent them of to Douglas, hoping that he would confirm my thoughts, which he indeed did - incredibly, I had recorded two Rosy Marsh Moths a red data book species.

Rosy Marsh Moth - one of the original two

I don't know what this species was doing at my site, the nearest population to me is at Cors Dyfi about twelve miles away. I suppose the very warm weather we've had recently could have made the Cors Dyfi population wander from the reserve - or the other possibility is that I've now got a small population breeding at our nature reserve - the only problem with the second hypothesis is that we don't have any of the normal foodplant here, which is bog myrtle although we so have narrow leaved willow which the reference books state has also been used as a foodplant. I suppose we'll just have to wait and see if it turns up again next year, which will give us a better indication of whether it's now breeding here - great record though, however you look at it.

Rosy Marsh Moth - a better marked later specimen

Over the next three days two more individuals turned up....and there may still be more to come - watch this space!

Peter.

Moth event at Wern Claypits Nature Reserve, near Arddleen

This was a joint moth-bat event with Montgomeryshire Wildlife Trust, and was the first time that MMG have trapped at this wetland site. The target species for the evening was wainscots - more of that later.

At 16 degrees C the evening was a little cooler than of late, but it was good to see 13 people enjoying the chance to locate both bats and moths. Tammy entertained an eager group, quizzing them on their bat knowledge, and then demonstrating the bat detector’s ability to pick up the high frequency calls used by bats, which are normally inaudible to humans. Here’s Tammy’s rundown of the evening’s bats:

“As we stood admiring the beautiful display from the white Frogbit flowers, carpeting the water’s surface in places, the first bats made an appearance. The Soprano Pipistrelle was probably the most numerous bat species, with almost constant activity all evening and great views of them flying and feeding against the gorgeous clear sky. Common Pipistrelle bats were also about, seeming to avoid directly competing with the Sopranos by flying around the tree tops, rather than over the water. Myotis bats were frequently picked up on the Anabat Walkabout bat detector; this is a group of five very similar bat species, which can be hard to distinguish. One of these species, that we had expected, was the Daubenton’s Bat, however none were seen during the evening and later analysis of the recorded calls was inconclusive. Some Myotis recordings were identified as either Whiskered or Brandt’s Bat, with over 80% likelihood.”

Meanwhile, the moth-ers were busy setting up 10 traps, with the ‘white sheet’ at base-camp, 2 Heath actinics,1x125W MV Robinson and 4 Skinner traps around the path which encircles the lagoons on the reserve.

Even before the traps were switched on, there were large numbers of Small China-mark to be seen above and amongst the vegetation in the water. Once the traps were up and running, it was the Brown China-mark which was particularly numerous - in fact it was the most common moth of the evening, with numbers probably in the hundreds. Before long, Beautiful China-mark had also been recorded, and it was interesting to learn that the larvae of this group feed below water level on aquatic plants.

As several of the group were new to 'mothing', they were particularly taken by the more colourful or unusual moths, and there were plenty to be seen, including Large Yellow Underwing, Iron Prominent, Gold Spot, Canary-shouldered Thorn and Svensson's Copper Underwing. But perhaps the most striking moth for many of us was a pristine Leopard Moth, which was photographed from every angle by several mothers eager to capture its bluish sheen, spotted furry thorax and seemingly translucent spotted wings. It was very accommodating, remaining on the white sheet for the rest of the evening. Douglas explained that its larvae overwinter for several years, in the stems of the trees on which they feed, eventually pupating under the bark.

The distinctive bright greenish yellow caterpillar of another species, Pale Tussock, was found on willow, and delighted the group with its four tufts of yellow hairs and the black bands between each segment, and a rather striking red tuft at the tail end.

As a car rally was due to pass the 'mothing' spot in the early hours of the morning, it was decided to pack up before any conflict of interests ensued - typically some of the 'best' moths turned up right at the end - a Lesser Cream Wave and (a suspected) Monochroa lutulentella - both specialists of damp habitats.

But as for our target group, only a tatty Smoky Wainscot decided to play ball.......................... another time maybe.

- Sue S.

They were there all along!

I unfortunately couldn't make the Lake Vyrnwy daytime event earlier this month to look for Welsh Clearwing, but as RSPB Warden one of the jobs on my to do list when I got back from holiday was to survey a couple of plots for the clearwing in the same area.

1+ BOS score

No BOS score

This survey involves looking at individual trees and taking measurements to determine whether they are suitable for Welsh Clearwing and make an assessment as to what management we could do to improve the tree. As mentioned in Sue's blog of the event, clearwing required the lower trunk to be exposed to the sun and therefore we remove some of the lower overhanging branches. There is a score we give each tree which is called the Branches Over Skyline (BOS) score that is a figure between 0 and 8. Splitting the tree into eighths (if looking down on it) you need to decide how many segments have a gap between the lower branches and the horizon. To make the tree favourable for clearwing it should have a score of 4 along with a girth (circumference) of 100+cm.

Welsh Clearwing exuvia

With no signs found during the event I didn't have my hopes up for finding anything, so when I came across a tree that was riddled in old exit holes and spotted the distinct orangy exuvia protruding from the bark I was rather surprised and pleased! But even more surprisingly was the fact that I found a total of 9 exuvia on this single tree. I didn't find anymore signs during my survey but I was only surveying specific areas so there could have been more elsewhere. Hopefully these 9 adults will have had a successful breeding year and we will have more to find in the future!

Denisia similella

The excitement didn't finish there though! While walking through the wood I happened to look down on my survey sheet and noticed a small micro moth sitting there. A quick look revealed it to be Denisia similella which I stumbled across 3 years ago while doing the same survey. In 2015 it was considered to be a first for Wales and we at the RSPB soon nicknamed it 'Dennis'. So I'm assuming this to be the second record and evidence that there must be a small population in the area.

Gavin Chambers, RSPB Warden

More clearwing hunting

Last Sunday I took a trip to Llanymynech Rocks on the hunt for Six-belted Clearwing.

Following on from a day of disappointment, I did not have high expectations - the previous morning I had failed to find Large Heath up on the Berwyns in perfect weather, and that same afternoon it was our event for Welsh Clearwing (spoiler alert: we didn't find any - see Sue's excellent write-up below). I didn't even bother to bring my proper camera....

However, I was to be pleasantly surprised. Within minutes of deploying the lure, a tiny wasp-like insect arrived. Moments later, a much larger one clumsily flew in. In total, I saw at least four individuals (within about ten minutes). Expecting to find a mate, these excited males must have been pretty disappointed to instead find a chunk of rubber in a teabag...

The feeling at the last event was that the daytime format worked well so an afternoon session targetting this species is pencilled in for the 2019 MMG programme.

Event report: Welsh Clearwing afternoon at Lake Vyrnwy

The Afon Nadroedd valley

Last Saturday we departed from our usual evening event format to hold a daytime event, in the picturesque Afon Nadroedd valley just north of Lake Vyrnwy. Hopes were high as the emphasis was on finding the Welsh Clearwing, a nationally important Red Data Book species. Most of those attending the event had never seen any species of Clearwing, and were optimistic that Douglas' pheremone lures would have the desired effect.

The weather was very warm and dry, as it has been for several weeks now, and fifteen optimistic moth-ers congregated beneath a large sycamore beside the Nadroedd stream, enjoying a shady picnic spot before the serious searching began.

The recently purchased MMG butterfly nets proved popular, and there was much sweeping along the roadside and over the extensive marshy area. Peter lost count of the number of Agriphila straminella he netted, but declared he'd be a wealthy man if he had three- halfpence a moth!

Old emergence holes

It was good to meet Andrew Graham, butterfly and moth recorder for Merionethshire and Anglesey, and also butterfly recorder for Caernarvonshire. He explained that the Welsh Clearwing is rare in North Wales, and reliant on old Downy or Silver Birch trees with exposed lower trunks, such as those to be found alongside the lane we were exploring. His online database, North Wales Lepidoptera, describes the life cycle fully, and explains that the larvae feed on the inner bark for several years. When fully grown they tunnel to just under the surface of the bark, construct a cocoon out of frass granules, and then pupate within it. When ready to emerge, the outer end of the cocoon is neatly severed and a wriggling motion enables the pupa to move outwards until partially exposed to the atmosphere. Interestingly, backward pointing spines on the pupa ensure that only forward movement is possible. The adult moth then emerges from the pupa, often leaving the pupal case (exuvia) remaining in the emergence hole.

A hopeful crowd formed around the pheromone lure

Because this is a scarce species, every occupied birch is important, and Douglas set up pheromone lures in trees where the species has been located in the past, as the adult male moth responds well to this technique. As the sun shone, and we were within the expected flight period, we remained hopeful, although the last positive record from this site was in 2012, when two exuviae and a fresh cocoon were recorded. We were able to see the tell-tale 5mm circular emergence holes though, which remain visible for many years, and also observed the larval tunnels in places where some of the surface bark was missing. But despite our perseverance, there was no evidence of either the moth or a fresh emergence.

Scalloped Hook-tip

However, there were a few other day-flying macro moths to be seen, including several Silver Y, a Barred Straw, and a Straw Dot. Two more micro moths, Celypha lacunanna and Scoparia ambigualis were recorded. It was also a chance to look for larvae, and the distinctive green and yellow striped caterpillar discovered on bracken was identified as Broom Moth. Shortly afterwards, a caterpillar closely resembling a birch catkin was found on a birch and identified as a Scalloped Hook-tip. A tiny 'looper' caterpillar was collected by Douglas when beating but has yet to be identified.

Butterfly species were predictably more numerous than moths, and a pristine Small Copper was much admired. Ringlets were common, as were Green-veined Whites and Small Heath. Also flying were Meadow Browns, Large Whites and a Large Skipper. A Small Tortoiseshell and Red Admiral put in an appearance as well.

Several minutes were spent trying to photograph dragonflies over and around the stream. Mark managed to capture on camera what he identified as a Golden-ringed Dragonfly, although it eluded the rest of us.

Other eye-catching invertebrates included a large and conspicuous orbweb spider with a distinctively patterned globular abdomen, and a Forest Bug.

Despite drawing a blank as far as seeing Welsh Clearwings went, it was an interesting afternoon enjoyed by all - and if another daytime event is planned, no doubt there will be plenty of attendees. As people prepared to head for home, a group of ponies grazing the hill came down to the stream to drink, as if to see us off!

Thanks to Douglas for organising the event, and for adding another moth to our rather short list - A Small Seraphim which found its way into his car and travelled home with him!

Sue S.

The species list can be found here. And all the photos from the afternoon at the link below:

MMG event: Welsh Clearwing(less) afternoon -14/07/18

Moths rock at Llanymynech

Bee Orchid (CB)

The June event was timed to take place on (national) Moth Night 2018 (which counterintuitively takes place over 3 days). The target group this year was pyralids. The moth group assembled before dark to put out an array of 13 traps along this botanical paradise.

As the wildflowers were putting on a good display, some of the group took the opportunity to botanise before the light faded. We were well rewarded with five species of orchid found: Common Spotted, Pyramidal, Bee, Greater Butterfly and a single Twayblade.

Although dry and still, (the wind having dropped after the recent storms), the temperature was a disappointing 12 C. However, activity at the moth table quickly heated things up. Fitting with the Moth Night theme, the first moth brought to the table was Homoesoma sinuella. This limestone grassland specialist proved a common pyralid at the site. Another 11 species of pyralid contributed to the total of 50 micro moths found. The more unusal species included Rhyacionia pinivorana, Metzneria lappella and a larval case of Coleophora limosipennella which protruded from a Wych Elm leaf.

Coleophora limosipennella (DBo)

Just as it got dark, Sue arrived with a tin of her delicious shortbread. Her bag would have been a lot lighter on the way down the hill as not a crumb remained.

A Lime Hawk-moth was a star attraction, obligingly perching on Lottie’s finger for photographs; and a fresh Lilac Beauty was much admired by all. A number of specialist moths of the site were brought to the table including Pretty Chalk Carpet, Heart & Club, and Haworth’s Pug. Other noteworthy moths included Satin Wave, Galium Carpet, and right at the end of the night, a surprising Bilberry Pug. The Montgomeryshire flora indicates that bilberry (a plant usually associated with acidic soils) has been recorded nearby, so perhaps it had just wandered a little from its main base. There were 72 macro moths recorded over the evening so the total list was 124 species – not bad for a cool night.

Lime Hawk-moth (GBC)

The event was well supported with 21 attendees, including a family of four who were out for a walk, but were quickly persuaded to join in with the fun. The children proved adept at catching moths – one even catching a moth in a pot as it flew by. It was great to see their enthusiasm and we all hoped that they may have caught the mothing bug!

As we were putting away the traps, long after midnight, a dog walker came to inform us that he had seen something glowing green on the top of the hill – the photographs were clearly of a Glow Worm – another great record from a site which always has a surprise in store!

Clare B.

The full species list is available here. Link to additional photos: (by GO, GBC, DBo & CB)

MMG event - Llanymynech Rocks - 16/06/18