Tuesday, 24 June 2014

A Failed Mission

Having altered the day from our usual late week natural history day out, due to forecasted rain, Nigel Stringer and I went today to the Cilycwm-Rhandirmwyn area. The main aim was to search some upland crags for diurnal moths and other wildlife, with Cwm Merchon, to the NW of Cilycwm being the premier target. I`d botanised in this area in the past, and inspection of the maps showed crags that were likely to hold natural vegetation that was safe from the depredations of sheep.

                    Above: a distant view of the slopes and outcrops at the head of Cwm Merchon.

Unfortunately, I botched up the map reading (!) and we wasted time walking up another cwm - the Gwenlais. We traced back our steps and started the walk up the correct cwm, but it was getting quite hot in the sun and I personally had lost my usual reserves of energy.

We reached this particular field (see photo immediately above), below a brackeny slope where a yellowhammer (now a rare Carmarthenshire bird) was incessantly singing, and decided to turn back as there were no diurnal moths to be found, save two common species of `grass moth`. This south-facing field was flower-rich, with much thyme and I`m certain (along with nearby crags and heather etc) home to some interesting moths. There`ll be clouded buffs on the crags too, I`m sure!

We then decided on an easier `number` and set off for the Nant y Bai lead mines, just north of Rhandirmwyn village (an area very familiar to Sam, with its array of rare lower plants). A feature of this site is the abundance of sea campion, a species understandably more associated with our coastline, though it also grows on the cliffs of Llyn y Fan Fach, and perhaps too on some other crags in the western BBNP.

                               Above: part of the Nantybai site, with sea campion in the foreground.

I suspect that it is this huge population of metal-tolerant sea campion that was the source of the records of marbled coronet at the one-time Rothamsted trap at Ty`r Ysgol, Rhandirmwyn.
I swept the swathes of sea campion and, repeatedly, caught the caterpillars shown in the following photos. They were not found when sweeping other vegetation.

Above: a larger brown larva, with a smaller greenish one to the right, plus seed capsules of sea campion, many of which had entrance/exit holes eaten into them.
Above: another view of one of the smaller green caterpillars. Any opinions as to the identity of the caterpillars will be welcomed.

Not a successful day in terms of moth recording - it just seemed too hot and sunny for them to be on the wing, though several common butterfly species were seen, including a large skipper spotted by Nigel Stringer actually drinking from a stream - everything is so dry and dusty! Keeled skimmer Orthetrum coerulescens dragonflies and the upland bumblebee Bombus monticola seen at Nant y Bai.

Apologies for the lack of moth photos today - there were none to photo, save a few common species. If you want to see some really good moth photographs - and of uncommon or local moths- have a look at the Glamorgan Moth Group website (see link). There`s some superb photos of great moths by Chris Manley,  George Tordoff and others - reward for their moth trapping efforts.




4 comments:

  1. The grown one looks like Tawny Shears, but you'd need to grow it on and/or rear it through to be sure. I wonder if the green one might be a beetle larva? Sorry, suggestions rather than answers!

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  2. Thanks for the quick reply Barry. I`ve just looked at Porter`s `Caterpillars of the British Isles` and it does indeed look like a tawny shears caterpillar, though - as you suggest- it`ll need to be grown on.
    Sam - Can you check please, are there any SN74 Rothamsted tawny shears records?
    Have just put out the home traps - too tired for the away-from-home actinics tonight.

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  3. There are no accepted Carmarthenshire records of Tawny Shears and only on pended one from SN21 (Glyn Coch Rothamstead, det unknown). The foodplant is plausible and trapping at Nant-y-bai at the right time of year would be amazing.

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