Wednesday 21 February 2018

Norfolk Sawflies in 2017

Summary

Sawflies are not a well-recorded group at present. I took on the role of Norfolk sawfly recorder in 2017 and have managed to collate a grand total of 176 records for the year, from a variety of sources, involving 79 identified species. Given that there are likely to be about 250 species in the county, and many will be ubiquitous, this suggests we have much to do in establishing the status of this group of insects. However, there’s plenty to discover, which is what makes it exciting.

Of the 176 records, 160 were considered to be acceptable species records, with the other ten being difficult to confirm to species level. Identification (and likewise verification) of sawflies is not easy. The main reason for this is the lack of modern literature; for many species, the most recent published identification guide dates from the early 1950s, although there is a good guide (Wright 1990) that will help you get to genus level. There is further information available online but it is patchy. Although some species can be identified from a good photo, many cannot and need examination under a microscope.

Records were collated from 34 recorders, most of whom submitted single figures of records with the exception of Andy Musgrove (38), Tim Hodge (34), Andy Brown (15), Steve Lane (13) and James Emerson (13). I look forward to seeing these figures rise in years to come! As the map shows, the majority of records originated around Norwich and the Broads, with fewer submitted from West Norfolk.


Norfolk sawfly records in 2017 (thanks to QGIS, Bing maps and the TomBio biological recording plugin)

The first sawfly in 2017 was noted on 18th March, when Dolerus nitens was found. The highest monthly total of records was in May, then records declined steadily, with the last adult sawfly being Athalia rosae on 3rd October, followed by a handful of larval records into November.

A number of species were noted for which there currently appear to be no previous records for Norfolk. This needs to be taken with a pinch of salt, however, since the historical record remains somewhat uncertain due to changes in taxonomy, some recorders not having submitted their previous observations, and the generally very low level of recording. Having said that, Strongylogaster mixta, Hoplocampa fulvicornisPachynematus annulatus, Nematus vicinus and Pristiphora testacea do currently represent the first records in the county database for these species.

By far the most frequently recorded species was Athalia rosae, sometimes called the Turnip Sawfly, with 19 records (the only species recorded more than five times). In late May and early June, this species was noted in large numbers on the coast at Salthouse/Kelling and Great Yarmouth. It is unclear whether this represents migration from the continent, and/or very high numbers of home-born insects dispersing and running up against the barrier of the North Sea.

For anyone interested in recording at least one sawfly next year, Athalia rosae is the species to look out for. It is a striking orange and black insect, quite small (6-8 mm from front to back), with a distinctive “football socks” appearance formed by alternating orange and black on the legs. There are a number of similar species; in rosae, the leading edge of the wing is black and the top of the thorax is orange at the front and back, but black on each side. The dark grey larvae can be a pest on cultivated cruciferous plants, including Oil-seed Rape Brassica napus. Other relatively distinctive sawflies for visual identification in the field include Tenthredo scrophulariae (a large black/yellow wasp-like insect with all-orange antennae flying slowly around Figwort Scrophularia) and Eriocampa ovata (a black sawfly with deep red upperside to the thorax found around Alders Alnus, although beware of confusion with the smaller Eutomostethus ephippium where the red extends to the sides of the thorax also). However, perhaps the easiest “evidence” of a sawfly species to come across is the gall of Pontania proxima, which is a red pea-like blister in the leaves of longer-leaved species of Willows Salix.

The best way to submit records is to use iRecord, but I'm willing to take anything, so long as you tell me at least the date and location (with as precise a grid reference as possible). Ideally, tell me the species too, but I'm happy to try to help identify photographs or specimens if I can. Finally, I'm sure there are other Norfolk sawfly records for 2017 out there - I'm more than happy to receive these still (and for earlier years).

Systematic list


Family Cephidae
Calameuta filiformis: Buxton 1/7.
Cephus pygmaeus: Shotesham 23/5; Shotesham 29/5; Sculthorpe 29/5; Norwich 5/6; Norwich 12/6.
Cephus spinipes: Shotesham 23/5; Coltishall 31/5; Shotesham 4/6.

Family Siricidae

Sirex noctilio: Wells East Hills 30/9.
Urocerus gigas: Cringleford Woods 25/6.

Sirex noctilio (Ben Lewis, Matt Stainthorpe)

Family Argidae

Arge berberidis: Breydon Water 17/7; Walcott 22/7; Horsey 23/7; Norwich 7/8.
Arge cyanocrocea: Norwich 21/5; Norwich 27/5; Shotesham 3/6; Holme 22/7.
Arge gracilicornis: Horsey 27/5; Alderfen 15/7.
Arge pagana: Strumpshaw 29/5; Holme 22/7; Whitlingham 12/8; Shotesham 26/8 (larvae on Rosa).

Family Cimbicidae

Abia fasciata: East Winch 28/5; Bowthorpe 21/7.
Abia lonicerae: Norwich 2/4; Salthouse 18/5.
Cimbex connatus: How Hill 28/7; Catfield 24/8.
Cimbex femoratus: Beeston Common 11/5; Knapton 23/5; Beeston Common 31/5 (larva); Acle 31/7 (larva).

Abia lonicerae (James Emerson)

Family Diprionidae

Diprion pini: Catfield 21/9 (larva on Hedera).

Diprion pini (Andy Beaumont)

Family Tenthredinidae

Subfamily Allantinae
Caliroa cerasi: Lingwood 9/7; Waxham 12/9 (both larval records).
Endelomyia aethiops: Horsey 4/5, 8/5.
Ametastegia albipes: Winterton 7/5.
Ametastegia glabrata: Holme 5/6.
Eriocampa ovata: Woodbastwick Fen 29/5; Fairhaven Water Gardens 2/8; Whitlingham 31/8 (larva on Alnus).

Subfamily Athaliinae
Athalia circularis: Shotesham 11/6; Earlham Park 15/7; Horsey 6/8; Great Yarmouth (undated).
Athalia cordata: Holme 5/6, 22/7.
Athalia liberta: Shotesham 13/5.
Athalia rosae: Great Hockham 6/5; Sculthorpe 14/5; Holme 20/5; Cley-Salthouse-Kelling 28/5; Howe 3/6; Thetford 5/6; Great Yarmouth 11/6; Shotesham 11/6; Wheatfen 18/6; Buckenham Carrs 25/6; Lakenham 28/6; Holme 22/7; Salthouse 22/7; Norwich 17/8; Howe 28/8; Horsey 3/10.
Athalia scutellariae: Thetford Nunnery Lakes 14/6 (many around Scutellaria).

Athalia rosae (Steve Mathers)

Subfamily Blennocampinae
Blennocampa phyllocolpa: Strumpshaw Fen 9/7; Shotesham 14/7; Thetford 7/11 (all larval signs on Rosa).
Periclista albida: Whitlingham CP 7/4.
Fenusa dohrnii: Hoveton 6/9 (larval signs on Alnus).
Heterarthrus nemoratus: Hoveton 6/9 (larval signs on Betula).
Metallus lanceolatus: Horsey 9/10 (leaf mine on Geum urbanum).
Profenusa pygmaea: Thickthorn 9/6; Whitlingham CP 7/9 (vacated leaf mine on Quercus)
Eutomostethus ephippium: Swangey Fen 20/5; Horsey 7/6, 8/7.
Eutomostethus luteiventris: Holme 5/6.
Monophadnus pallescens: Holme 5/6.
Phymatocera aterrima: Billingford 17/6 (larva in moth-trap)
Rhadinoceraea micans: Holme 22/4 (many emerging on Iris)
Stethomostus fuliginosus: Thickthorn 14/6.
Haldamia affinis: Horsey 28/4, 1/6.

Phymatocera aterrima (Richard Thomas)

Subfamily Nematinae
Cladius compressicornis: Shotesham 13/5.
Cladius pectinicornis: Great Yarmouth (undated).
Cladius pilicornis: Shotesham 20/5.
Hoplocampa crataegi: Acle 3/5; Wheatfen 5/5.
Hoplocampa fulvicornis: Thetford Nunnery Lakes 6/4.
Craesus septentrionalis: Beeston Common 11/9; How Hill 16/9 (both larval records)
Euura mucronata: Acle 3/5.
Nematus vicinus: Wheatfen 5/5.
Nematus myosotidis: Shotesham 17/6.
Pachynematus annulatus: Shotesham 23/5.
Pontania pedunculi: Holme 22/7
Pontania proxima: Thetford 15/6 (galls in Salix); Shotesham 14/7 (galls in Salix); Buxton 6/9 (galls in Salix).
Pristiphora brevis: Roydon Fen 23/6.
Pristiphora testacea: Tasburgh 16/7 (larvae on Betula).

Craesus septentrionalis (James Emerson)

Pristiphora testacea (Mike Dawson)

Subfamily Selandriinae
Dolerus ferrugatus: Holme 1/5.
Dolerus triplicatus: Holme 1/5; Shotesham 13/5.
Dolerus vestigialis: Frogshall 15/4; Wheatfen 5/5.
Dolerus aericeps: Thickthorn 11/5; Buckenham Carrs 25/6; Shotesham 9/7; Sea Palling 20/8.
Dolerus aeneus: Buckenham Carrs 25/6.
Dolerus niger: Thetford 15/6.
Dolerus nigratus: Holme 1/5; Shotesham 14/5; Ongar Hill 1/6.
Dolerus nitens: Barney Wood 18/3.
Dolerus picipes: Thetford Nunnery Lakes 6/4; Shotesham 13/5.
Strongylogaster mixta: Bilney Warren 28/4.
Strongylogaster multifasciata: Beeston Common 16/5; Beeston Common 2/6.

Subfamily Tenthredininae
Macrophya duodecimpunctata: Norwich 27/5; Nunnery Lakes 14/6.
Macrophya montana: Coltishall 31/5; Norwich 3/6; Bodham 24/6; Alderfen 15/7.
Macrophya punctumalbum: Thickthorn 14/6.
Aglaostigma aucupariae: Caistor St Edmunds 26/4; Shotesham 1/4.
Aglaostigma fulvipes: Surlingham Church Marsh 15/4.
Tenthredopsis nassata: Shotesham 23/5.
Rhogogaster chlorosoma: Ringstead Downs 12/6.
Rhogogaster viridis: Thickthorn 9/6; Wheatfen 18/6.
Tenthredo amoena: Norwich 18/7.
Tenthredo arcuata: Coltishall 31/5; Pigney’s Wood 4/8.
Tenthredo colon: Bracon Ash 12/8 (larvae on Circaea lutetiana)
Tenthredo mesomela: Shotesham 23/5; Horsey 27/5; Sculthorpe 28/5.
Tenthredo notha: Holme 22/7; Pigney's Wood 4/8.
Tenthredo omissa: Holme 12/8, 13/8; Ludham 20/8.
Tenthredo schaefferi: Horsey 23/7; Little Hautbois 10/8.
Tenthredo scrophulariae: Stoke Holy Cross 7/6; Beeston Common 19/7; Holme Dunes 20/8.

Macrophya montana (Vanna Bartlett)

Tenthredo amoena (Vanna Bartlett)

Tenthredo scrophulariae (Nick Elsey)



Contributors in 2017:

Iain Barr, Vanna Bartlett, Jeremy Bartlett, Andy Beaumont, Andy Brown, Dave Buckingham, Bex Cartwright, Mark Clements, Richard Comont, John Crann, Mike Dawson, Nick Elsey, James Emerson, Francis Farrow, Tim Fawcett, John Furse, Martin Greenland, Gary Hibberd, Tim Hodge,  Michael Hoit, Tony Irwin, Robin Jeffries, Steve Lane, Ben Lewis, Neil Marks, Steve Mathers, Andy Musgrove, Adam Parker, Rob Smith, Matt Stainthorpe, Emily Swann, Richard Thomas, Matthew Wilkinson, Robert Yaxley

Note: this summary was originally written in February 2018. The article was updated in September 2018 following collation of further information.

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