Northants and Peterborough Diptera Group

Newsletter No. 13
Winter 2012/2013

Diptera Group News

This newsletter covers 2012 from July up to the end of the year plus some late arriving earlier records. Despite the often very poor weather conditions a number of interesting records have been made and the total number of records for the season is about 1800.

In July Tony White found another location for the Scathophagid Norellia spinipes (Meigen) in Byfield. Kev Rowley recorded Chrysotoxum verralli Collin near Harlestone and also at Pitsford Reservoir. A visit to Denton Wood on a bright, sunny day, produced a succession of hoverflies and butterflies at a large patch of brambles, the highlight of which was Criorhina floccosa (Meigen) and a silver-washed fritillary (JS). Also there, was the horsefly Hybomitra bimaculata (Macquart). At Twywell John Wheeler found the soldierfly Oplodontha viridula (Fabricius) on a leaf adjacent to one of the ponds. The group field meeting at Pitsford Reserve added several species to the site list, including the Tachinid Phasia obesa (Fabricius) (AW).

At the beginning of August I continued with my 2 hour Hoverfly watch at Stoke Wood and turned up Epistrophe grossulariae (Meigen) and Volucella inflata (Fabricius). This method has turned up some interesting species, as I mentioned in the previous newsletter. We have very few records of lance flies, Lonchaeidae, so it was good to get a record of Setisquamalonchaea fumosa (Egger) from Byfield (AW). Also Muscids are not frequently recorded, considering their ubiquity, although identification can be tricky. Tony White reported three species from Hartwell Pocket Park: Muscina prolapsa (Harris), Phaonia incarna (Wiedemann) and Spilogona denigrata (Meigen) and Lophosceles cinereiventris (Zetterstedt) and Phaonia tuguriorum (Scopoli) from Byfield. The Diptera Group visit to Southwick Wood was accompanied by near tropical rainfall but we did manage to see Volucella inanis (Linnaeus) and Conops flavipes Linnaeus (GW). The following meeting at Ditchford had much better weather and we recorded many hoverflies and a few long-legged flies, Dolichopodidae, including the rather attractive Rhaphium caliginosum Meigen, with its long, broad antennae(JS). The Boddington Meadow Diptera Group visit was also successful. The meadow had plenty of field scabious flowers in bloom and these were attracting a wide variety of insects. It was good to see several Helophilus trivittatus Fabricius, as this hoverfly is not well recorded in the county. As it happens, 2012 was a bumper year for them in Northants. Of the 22 records I have of this species, 15 were made in 2012 and from 9 different sites. This seems to be a genuine increase, possibly augmented by immigration from the continent. On 19th August the group visited Stoke Bruerne Brickpits Reserve. Several less well-recorded hoverflies were found there, including H. trivittatus, Chrysogaster cemiteriorum (Linnaeus), Orthonerva nobilis Fallén, Eristalinus sepulchralis Linnaeus (BH) and Anasimyia lineata (Fabricius) (KR). Tony White  continued to turn up species from poorly recorded families with the Clusiid Paraclusia tigrina (Fallén) in his garden at Byfield.

We had no field meetings in September but several people continued to record flies and send me records. Sphaerophoria batava Goeldlin de Tiefenau was recorded at Harlestone (KR). This is probably the only remaining site for this species in the county as it is closely associated with Ling. The Byfield area produced more muscids, including Helina depuncta (Fallén), H. impuncta (Fallén), H. pertusa (Meigen) and Myospila meditabunda (Fabricius) and the calliphorids Pollenia angustigena Wainwright and P. pediculata Macquart (AW). However, probably the most spectacular calliphorid was Cynomya mortuorum (Linnaeus) found by Tony in allotments at Byfield. This is the first county record, that I am aware of, of this striking species. I have not seen it locally but did manage to photograph it in Glen More, Scotland at the Dipterists Forum Summer Field Meeting. Look out for it next year, especially where there are corpses about!

© John Showers 2012.    Cynomya mortuorum (Linnaeus)

October produced more records of Muscids (Autumn has many adults active) with 22 species recorded, the vast majority by Tony. Autumn is also a good time to look for galls and leaf mines caused by flies. On a beech tree leaf at Sane Copse, Yardley Chase I found small upright galls caused by the gall midge (Cecidomyiidae) Hartigiola annulipes (Hartig).

November continued to produce a few records. The Tachinid Siphona geniculata (De Geer) was recorded in the Byfield area (AW). Many gall flies overwinter as adults and on a cold, frosty day at Cold Oak Copse near Yardley Hastings Mike Killerby beat a couple out of dead foliage and passed them onto me for identification. They were Tephritis formosa (Loew) and T. leontodontis (De Geer).

December records were, as one would expect, rather few. The appallingly wet weather discouraged field work for much of the month. Mike Killerby beat a number of fungus gnats from dead oak leaves in Denton Wood and I have been having a go at identifying them. As I am not too confident about them I will not bother to name most of them at this stage, however the genera Exechia, Mycetophila, Rymosia and the species Stigmatomeria crassicorne (Stannius) were in the sample. The window gnat, Sylvicola fenestralis (Scopoli) was also present. The last record of the year that I have received was of a specimen taken by Tony Richardson at Castle Ashby on the 18th and which I determined as Eristalis tenax (Linnaeus).

My thanks to everyone who has submitted records. Initials used above are:
BH - Brian Harding, KR - Kev Rowley, JS - John Showers, GW - Graham Warnes, AW - Tony White.

Hoverfly Recording to Date

I thought it was about time to review how we are doing with fly recording. Rather than try to analyse all species I have looked at just the hoverflies. This is because all Diptera recorders record this family and it represents about half of all the records we have.  I have only taken the data that has been either sent to me or to the Northants Biodiversity Records Centre so there is a big gap in records that have gone directly to the Hoverfly Recording Scheme. For a complete picture I need to include these but need to get hold of the data first. However, even with these limitations it shows us what we have recorded over the last 10 years and what the distribution of records is like. The map is plotted at the tetrad level (2km x 2km) using DMAP 7.4b.

There are clearly some hotspots. To what degree are they hotspots of species diversity, or of recording effort? Clearly the two are linked as we all tend to like to go to "good" sites. Looking at the map where there are high diversities (>45 species) we can see that they all fall in well-recorded areas. The cluster near SP55 is Tony White's domain around Byfield and Boddington, with High Wood just to the East at SP5855. SP76 is Northampton where we have recorded at a number of sites as well as having a number of recorders living there. SP85 is the Yardley Chase area, which has a lot of records but no high diversity hot spot as yet. (I must try harder!). In SP86 we have Summer Leys, where Graham Warnes was a warden and did a lot of recording. The red dot in SP77 is Pitsford Reserve where Tony White and I have recorded for years and we have had several group meetings there. SP68 includes Sulby Gardens where Alison Lowe has kindly let me record regularly and has contributed records herself. The West side of SP88 is my domain so many records have come from my garden and surrounding countryside as well as from Stoke Wood. Up in the extreme North of the county in TL09 is Old Sulehay and Ring Haw where we have been running Hoverwatch for several years. Undoubtedly the map is more a measure of recorder effort than real distribution of diversity. It does give some idea of how much effort is needed to record over 45 species of hoverfly on a site as all of these are major areas of effort.

As to the rest of the county - well we cannot cover everything with such a small group but it does show where there are opportunities to advance our understanding of the distribution of species in the county. With the Dipterists Forum Spring Field Meeting being in the Rockingham Forest area we should be able to fill in a few gaps in the North-East of the county but what about the West and extreme South? If anybody fancies a bit of "square-bashing" there are plenty of opportunities to fill in some gaps.

Dipterists Forum

Last November's AGM at Bristol was well attended and we were entertained and informed by a number of very good presentations. One presentation was by Jolyon Alderman, who talked about his research on swarming at Delapre Woods and on making equipment for studies.  The AGM this year will be at the Natural History Museum in London so will be easily accessible for a day trip on the train.

The Spring weekend field meeting will be held in the Rockingham Forest area over 17 - 19th May.  This will be a great opportunity for local members to meet some people from further afield. I have made some good friends from these field meetings and always enjoy catching up with them. I have scheduled our VC32 field meeting on the 19th May at Southwick/Short Woods to coincide with this. Look out on the DF website for details of these meetings.


Last year, a very comprehensive book on flies, "Flies" by Stephen A. Marshall, was published. Jolyon Alderman is reviewing the book for the BENHS Journal so I won't steal his thunder. However I can say that I am finding it fascinating and some of the photographs are stunning.

Roger Morris and Stuart Ball's book on Hoverflies has gone to the printers and they are hopeful that it will be available by the start of the season.

Cranefly Identification Workshop

John Kramer, joint organiser of the Cranefly Recording Scheme, has kindly agreed to run an identification workshop at Pitsford Reservoir's Holcot Lodge on Thursday 28th March. John will be using the revised keys being developed for the new cranefly identification guide so part of the exercise will be to test the keys with people new to the families. Contact me to book a place (limited spaces available).


Northants and Peterborough Diptera Group

Newsletter No. 12

Summer 2012

Diptera Group News

This newsletter covers 2012 up to the 8th July field meeting.

Well, it has been a funny old year weather-wise so far. The early season started promisingly with warm dry weather, although it may have been too dry for many flies. With the start of the county cricket season, the Easter school holidays and the hosepipe ban all falling on the same day, the weather changed and it feels like it has not stopped raining since. Still we have managed to get out and about and some interesting records have come in.

The earliest hoverfly so far reported this year was Episyrphus balteatus at Olney Lane End, Yardley Chase on 16th February (JPS) with the next being over a month later. The warm spell at the end of March produced Syrphus torvus and Meliscaeva auricollis at Stoke Wood, Desborough on 23rd (JPS). The earliest Bombylius major record so far was on 21st March in Northampton (RWB). Two male Gonia picea were found in a former sand pit near Yardley Hastings on 15th March (JPS). I mentioned this to Chris Raper at the Dipterists Forum field meeting in the New Forest and he said that the Tachinid Recording Scheme had received many records of this species this year from a wide area. Also in March, the distinctive Scathophigid, Norellia spinipes was found at Castle Ashby on 22nd (PS) and Pitsford Reservoir on 30th (JPS). This species is unusual for a scathophagid in that the larvae are leaf-miners of daffodils. It is not widely recorded locally and is worth looking out for next Spring where there are good, well-established drifts of daffodil.

April did not produce many records. Highlights were the metallic green Tachinid Gymnochaeta viridis on 5th at Yardley Chase (AR) and the hoverfly Cheilosia chrysocoma at Stoke Wood on 30th (JPS). On 26th, an unusual looking fly was collected in a garden in Kingsthorpe (PS) and passed on to me. I keyed it out to be the conopid Myopa strandi, but I need to get it checked as it is rare and would be a county first.

May continued cool and wet. Otites guttatus was recorded at Stoke Wood and Pitsford Reservoir (JPS), the only picture-winged fly records I have received up to the end of May. The attractive cranefly, Tipula flavolineata was taken at Yardley Chase MOD section on 31st of the month. The hoverflies produced a few interesting records in May. The Big Hoverwatch 2-hour count at Stoke Wood turned up Rhingia rostrata and it was recorded there again just over a week later, along with a swarm of a few male  Brachyopa scutellaris, which were hovering around the base of an Ash tree in sunlight (JPS). Xanthogramma citrofasciatum was photographed at Twywell Hills and Holes (DG) during a butterfly transect. Anasimyia contracta was found during a Big Hoverwatch at Barnes Meadow (GW).

June was disappointing too. However the value of a focused survey like the 2 hour Big Hoverwatch was again demonstrated when I found Epistrophe grossulariae on Hogweed and another Brachyopa scutellaris in Stoke Wood. I also carried out a similar survey in Holcot Bay, Pitsford Reservoir and that turned up 3 specimens of Epistrophe diaphana. Another interesting record of a conopid turned up in June. Myopa testacea was found at Sulby Gardens (JPS). As a by-catch to the hoverfly recording at Pitsford I also found the picture-winged fly Melieria crassipennis and the Lauxanid Calliopum aenum. Next year's Dipterists Forum Spring Workshop will cover Lauxanidae and Heliomyzidae. Graham Warnes's Big Hoverwatch survey at Abington Meadow turned up Anasimyia lineata and Parhelophilus versicolor, neither of which have had many records in the county (GW). These latter two species were also at Barnes Meadow, together with Parhelophilus frutetorum and Anasimyia contracta (GW). The Calliphorid, Pollenia pediculata was recorded at Summer Leys (JA). We have very few records of Calliphoridae in general.

Early July hoverflies included Syrphus torvus and Volucella inflata at Denton Wood on the 1st (JPS) and Eristalis horticola at High Wood (AW). The robberfly Leptarthrus brevirostris was also recorded at High Wood (AW). Whistley Wood in the south of the county produced some good records during another Big Hoverwatch session - Sericomyia silentis and Pipiza austriaca (HE). The latter was also recorded in the May Big Hoverwatch in the same wood, which also produced a Stratiomys potamida, which Hils photographed (Below).
 Hils Erenler, 2012

Recorders mentioned above: Jolyon Alderman (JA), Bob Bullock (RWB), Hils Erenler (HE), Doug Goddard (DG), Tony Richardson (AR), Pete Sharp (PS), John Showers (JPS), Graham Warnes (GW), Tony White (AW). My apologies if I have failed to mention any particular records/recorders.

Some Late News

As I am rather belatedly finishing off this newsletter at the August Bank Holiday weekend I can report that there have been a number of sightings of Volucella inanis from all parts of the county. I have probably as many records already this year as in the the last three years combined. Keep a look-out for it.

The Future for Northants Diptera Recording?

© Jo Gamble, 2012
Charlie and Harry Gamble, with their mum, Jo, joined us at our High Wood field meeting in July.


The following is the abstract of a paper covering the behaviour of swarming Diptera, which was published in part 2, volume 25 of the BENHS journal: 



Landscape and Biodiversity Research Group, School of Science and Technology, University of Northampton, Newton Building, Avenue Campus, Northampton  NN2 6JD


One of the challenges faced by swarming Diptera is that of detecting and identifying an approaching flying insect on the basis that it may present a potential mating opportunity. This paper discusses the measurement of the visual field and orientation changes exhibited by males of the common swarming hoverfly Episyrphus balteatus (De Geer). The visual field extended 320 degrees in the horizontal plane and 315 degrees in the vertical plane. The probability of detecting an approaching flying insect was an estimated 0.97. Members of the swarm turned 25 degrees at each change in orientation. Changes in orientation are a proposed method of placing an approaching insect within the visual field of the dorsal fovea for early recognition. This enables male E. balteatus to initiate a chase without the reaction response and consequent delay which would otherwise occur.

Some Diary Dates

5 October -
AES Exhibition, Kempton Park. A chance to stock up on equipment.
24/25 November -
Dipterists Forum Members Day and AGM, Bristol. On Sunday morning a workshop on preparing genitalia for examination will be held.
1 December
Wildlife Trust workshop on identifying hoverflies (for people who have completed a basic identification training in hoverflies). Roger Morris and Stuart Ball, Ring Haw.

26 January
BENHS Identifying Larger Brachycera workshop, Dinton Pastures, Reading.
9 February
BENHS Tachinidae Identification Workshop, Dinton Pastures, Reading

22-24 February
Dipterists Forum Spring Workshop, (Lauxanidae and Heleomyzidae), Preston Montford
18-19 May
Dipterists Forum Spring Field Meeting, Rockingham Forest, Northants.

Further details on these events can be found on the web sites of the organisations hosting them. Note that as Dipterists Forum is affiliated to the BENHS, members are entitled to join BENHS events and receive discounts on their publications.

Tachinid Recording Scheme

The scheme has completely redesigned its web site and I can highly recommend taking a look. It includes links to the central European key and the latest name changes since Belshaw's RES key was published. There also good species accounts and distribution maps.

Publication News

I understand that Stubbs and Falk's "British Hoverflies" is to be reprinted rather than a new edition being produced. They should be available for the AES exhibition. There is the intention to publish a supplement to this edition to take into account the recent British additions. I believe this should be available around the end of the year.

Ball and Morris's WildGuide to Hoverflies should also be available by the end of the year.

Stubbs and Drake's "British Soldierflies and Their Allies" second edition is due later this year.

And Finally...

If anyone has any photos, interesting records or articles for the newsletter please send them to me by end December for the next edition. And thanks for the contributions to this one.

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