Invertebrate surveys for the Wildlife Trust of South and West Wales
Two nature reserves near Talgarth in mid-Wales were surveyed for invertebrates in 2018. Both are owned and managed by Wildlife Trust of South and West Wales, so the surveys aimed to inform management as well as inventory the sites. All invertebrate taxa were recorded where identification was possible, focussing on Coleoptera, Diptera, Hymenoptera and Hemiptera.
Trewalkin Meadow
Trewalkin Meadow is a small (0.75 ha) traditionally managed wet meadow, surrounded by pasture and arable fields. There is little other semi-natural habitat in the area around the site, so it is a valuable resource despite its small size. A hay cut is taken once a year in summer and it is lightly grazed in winter. The site had few historic invertebrate records, mostly butterflies and moths, along with a few bees and hoverflies.
211 species of invertebrate were recorded in 2018. Records of note included:
The RDBK planthopper Paraliburnia clypealis NB: have photos of this
The Nationally Scarce Water Avens Blacklet Cheilosia pubera
The Nationally Scarce false flower beetle Anaspis costai
The Nationally Notable click beetle Ctenicera pectinicornis
The Nationally Notable Sharp-collared Furrow-bee Lasioglossum malachurum
The cranefly Ormosia lineata, which is rare in Wales
A probable male Cryptic Bumblebee Bombus cryptarum, though this species can only be reliably identified from queens and this record remains questionable.
P. clypeus was considered the most significant species from a management perspective. It is a species of relatively long-turfed wet meadows that could be negatively impacted by over management, such as heaving grazing.
Pwll y Wrach
Pwll y Wrach is 17 hectares of broadleaved ancient river valley woodland surrounded by pasture and other connecting woodland in the river valleys. Parts were managed as long rotation coppice. The site has significant recreational access from the public. It had a history of invertebrate recording, with 321 records of butterflies and moths, spiders and molluscs, along with a few plant gall formers and hoverflies.
Two traps were installed to supplement netting and hand searching: one pitfall and one vane trap. To ensure that they were undisturbed there were installed on and near an old alder pollard in an area with no public access.
222 species of invertebrate were recorded in 2018 and subsequent years. Records of note included:
The Nationally Scarce false flower beetle Anaspis costai
The Nationally Notable rove beetle Aleochara brevipennis
The provisionally Nationally Scarce and exposed riverine specialist shore fly Athyroglossa ordinata
The provisionally Nationally Scarce lesser house flies Fannia subpubescens and
Piezura graminicola
The rarely recorded bethylid wasp Cephalonomia formiciformis
It was concluded that the existing site management is likely to be beneficial, or at least not detrimental, to all of these species.
Three species were recorded as new to Wales:
The Water Avens Blacklet Cheilosia pubera (this species has since been recorded at another site near Merthyr Tydfil)
The silken fungus beetle Cryptophagus uncinatus
The introduced minute hooded beetle Sericoderus brevicornis
A further fifty-two species had apparently not been previously recorded in Breconshire that are listed below. Whilst some are rarely recorded, a surprising number are common and widespread in lowland Britain. This suggests that the Vice County is poorly recorded for many invertebrate taxa, despite the presence of a National Park.
Beetles (Coleoptera):
The rove beetle Aleochara brevipennis
The minute hooded beetle Sericoderus lateralis
The silken fungus beetle Cryptophagus pubescens
The round fungus beetles Apocatops nigrita, Leiodes badia and Sciodrepoides watsoni
The sap beetles Meligethes carinulatus, Meligethes morosus and Soronia grisea
The weevils Mecinus pascuorum and Stenopterapion tenue
The water scavenger beetle Cercyon terminatus
The flea beetles Longitarsus gracilis and L. parvulus
True bugs (Hempitera):
The planthopper Paraliburnia clypealis
The planthopper Javesella pellucida
The leafhopper Euscelis incisus
The leafhopper Limotettix striola
The leafhopper Sonronius dahlbomi
The leafhopper Wagneripteryx germari
The bug Loricula elegantula
The mirid bug Apolygus lucorum
The flower bug Orius (Heterorius) vicinus
Bees, wasps and sawflies (Hymenoptera):
The Sharp-collared Furrow-bee Lasioglossum malachurum
The Cryptic Bumblebee Bombus cryptarum
The bethylid wasp Cephalonomia formiciformis
The sawfly Athalia liberta
The sawfly Claremontia waldheimii
The sawfly Empria excisa
Flies (Diptera):
The cranefly Ormosia lineata
The long-legged fly Dolichopus festivus
The big-headed fly Pipunculus campestris
The Long Marsh Boxer Platycheirus europaeus
The Water Avens Blacklet Cheilosia urbana
The shore fly Athyroglossa ordinata
The vinegar fly Hirtodrosophila cameraria
Collin’s Reed-fly Anthomyza collini
The Streakless Greenbottle Lucilia ampullacea
The Tufted Clusterfly Pollenia pediculata
The Tooth-bellied Flesh Fly Sarcophaga aratrix
The Slim-claspered Flesh Fly Sarcophaga crassimargo
The Incise-lobed Flesh Fly Sarcophaga incisilobata
The tachinid Dufouria chalybeata
The muscid flies Helina vicina and Hydrotaea palaestrica
The Pale-shinned Azelia Azelia cilipes
Zetterstedt's Azelia Azelia zetterstedtii
The Hairy-legged Morellia Morellia hortorum
The Hairy-thighed Bristleshin Phaonia erronea
The lesser house flies Fannia aequilineata, Fannia subpubescens, Fannia umbrosa and Piezura graminicola