November 29th

A bright, frosty morning promised a few flies if I could find a sheltered sunny spot. I walked round Cold Oak Copse on the Compton Estate with other members of the "Wild Bunch".  A few small flies were darting about in the sun but I had only taken my small folding net and failed to catch any. I did manage to poot a couple of flies from tree trunks. Mike Killerby was more successful. He was beating shrubs to dislodge harvestmen and several flies dropped out, which he passed on to me. I have pinned them but only just started identifying them. Three picture-winged flies turned out to be one female Tephritis leontodontis and two male Tephritis formosa. A small cranefly with spotted wings and yellowish femora, each bearing three dark rings, was the very common Limonia nubeculosa. A pointed-wing fly was the usual Lonchoptera lutea. I still have some fungus gnats, a stilt fly and some calypterates to sort out. That was a reasonably productive morning.

When I arrived home I noticed some winter gnats dancing in the air over my garden. I managed to net three and will tackle them later. (30/11/2012 - they are male Trichocera saltator).

Now that I know beating over a white tray is effective for winter flies, I hope to get a decent list for December, weather permitting.

30/11/2012 update on unidentified flies mentioned above. The "stilt fly" was not a stilt fly but a small long-legged Empid - Tachypeza nubila. The fungus gnats were Mycetophila britannica and Bolitophila pseudohybrida. Two of the calypterates were Anthomyids and I have not retained them!

December Flies

I have just been browsing the latest issue of Dipterists Digest, number 19/2. In it Pete Boardman, from the Field Studies Council Preston Montford Centre has written an article on records of flies in December in Shropshire. He had examined the Shropshire records and found that there were none since 1945. In December 2011 he set out to record flies to see how many species were about and counted 31 species and one that is causing some identification problems. I won't go into details but I was impressed by the number.

This made me wonder what the Northants position is. I have checked the records held by me and the Northants Biodiversity Records Centre and we start in a better position than Shropshire did, although we have a way to go to reach 31 species. Here is a brief summary. Only four record sets have been made in December since 1990. The most impressive list was of 9 species at Collyweston Quarry made by Pete Kirby. The other three species were single records made by me (2) in 2011 and an anonymous record of 1 species in 2001. This gives a grand total of 12 species recorded in December since 1990!

The species are:
Stratiomyidae:
     Pachygaster atra
Phoridae:
     Megaselia serrata
Syrphidae:
     Pipizella viduata
Tephtritidae:
     Chaetostomella cylindrica
     Rhagoletis alternata
     Terellia colon
     Urophora cardui
     Urophora jaceana 
Sciomyzidae:
     Pherbellia dubia
     Coremacera marginata
Muscidae:
     Eudasyphora cyanicolor
     Polietes lardarius (the only species we have in common with the Shropshire list!) 
 
It is not surprising that there are several Tephritid flies on the list as many of these overwinter as adults. They tend to stay hidden in dense foliage unless there is a particularly warm spell. Sweeping coarse herbs, especially the plants that they breed in, may turn up some more. I was surprised that so few Muscids were recorded, but I suppose this is down to there not being many people who want to, or can, identify these bristly beasties. Looking under loose bark or in dark corners indoors may reveal a few.

So if you are fed up with pre-Christmas shopping or need to have some post-Christmas exercise, how about trying to improve the list?

Mid November 2012

A walk around Castle Ashby on Thursday produced plenty of Autumn colour and some spectacular fungi. Beech trees were particularly notable for both. However I did not find many flies. Whilst trying to photograph some fungi in the roots of a beech, I noticed a couple of very small flies running over the bark. I managed to collect one in a pooter but the other disappeared into a crack in the bark. With a bit of twig I managed to coax it out and pooted it up. One was fairly dark and the other yellowish. Under the microscope, the yellow one was easily keyed out to Lonchoptera lutea, a pointed-wing fly. The darker species was also a Lonchoptera but proved tricky. Eventually I concluded it too was L. lutea, largely by eliminating the other six British species.

On a walk near Maidwell on Saturday several hogweed plants were in flower in the road verge. They all had several common yellow dungflies, Scathophaga stercoraria, on them. These flies can be found all over Britain and in every month of the year, making them one of our most commonest flies.

Pete Sharp collected some hoof fungi, Fomes fomentarius, last week in Overstone Wood.  They showed some frass underneath, suggesting that larvae were living in them. He gave me three specimens to see if I could rear anything from them. Two are in my cold greenhouse and one in my study. I am checking them daily to see what emerges. Watch this space......

Invasive Fruit Fly

Hot on the heels of the Ash Dieback disease comes another threat to UK plants in the form of a small Asian fruit fly. Drosophila suzukii  oviposits into ripening fruit, including commercially important soft fruits and apples, pears and tomatoes.  The larvae then eat the developing fruit, which rot and drop. This obviously has potentially huge economic implications. The fly has already affected other countries such as the USA,  Canada and Italy. In its first year of detection in California it caused £300 million of damage to the fruit industry. It is not only a threat to commercial crops but also breeds readily in wild blackberries, making it virtually impossible to eradicate. This means that the only protection currently available is regular pesticide spraying.

It is easy to identify the adult fly as it is a typical Drosophila shape, about 2-3 mm long, yellowish brown in colour with darker bands at the hind edge of the tergites. The eyes are a bright ruby red and the wings have a subapical black spot. The Dipterists Forum will be publishing more information and encouraging members to look out for it and report it. In the meantime if you want to see what it looks like, here is a link

http://www.agf.gov.bc.ca/cropprot/swd_identification.pdf

VC32 Diptera Group Newsletter

As the field season is pretty well over, I am trying to catch up with identification of flies that I put aside earlier in the year when the lure of fieldwork was greater than my capacity to process the catch. I am also starting to receive records from other group members and would like to get them all processed early in the new year. I then hope to produce the next newsletter in January. Any articles or photos for the newsletter or indeed this blog are most welcome.

I have added a tab to the blog that will take you to the group's newsletters. I have only added the latest, number 12, as there is not an easy process to move the newsletter onto the blog - you have to cut and paste the text, then insert the photos and then edit the text for headers, spacing etc.. I shall, however, add future newsletters.

I am looking forward to the Dipterists Forum Members Day and AGM at Bristol Museum on 24th November, not least because our own Jolyon Alderman will be giving a talk, entitled "Off the beaten track: a season of swarm chasing".  The Dipterists Forum website has more details.
www.dipteristsforum.org.uk