Friday, 5 April 2013

Early April 2013

I have been away in Sri Lanka for a couple of weeks and coming back to snow was a bit of a shock. It is still too cold for much insect activity but there are a few things to report.

Firstly, the Cranefly Identification Workshop, run by John Kramer at Pitsford Water's Holcot Lodge went well with 11 attendees. John gave a well illustrated introductory talk to the cranefly families before we got stuck in to the keys, using John's reference collection. It was also an opportunity for John to get some feedback on these draft keys so they can be revised for publication. Updates will be posted on the Dipterists Forum website from time to time.

Secondly, Roger Morris and Stuart Ball's new WildGuide to British Hoverflies arrived through the post. I am very impressed. The photos illustrating key identification features are generally first class. I am sure it will convert many people into identifying hoverflies. There is much detail in the well-illustrated text that will be valuable not only to beginners but to experienced dipterists as well. It is particularly good at helping with field identification.  It does not replace Stubbs and Falk's British Hoverflies, which is much more comprehensive, but it does complement it very well.

On the subject of Hoverflies, the Wildlife Trust for Beds, Cambs and Northants will be continuing its Hoverwatch monitoring work at Old Sulehay this year. If anyone is interested then do get in touch with me or Henry Stanier at the Trust's Cambourne office. We are also looking out for people who would like to set up a constant effort hoverfly monitoring site on any of the Trust's reserves. This is basically the same as the "Big Hoverfly Watch", described by Roger Morris in the Bulletin of the Dipterists Forum. The only difference is that for the Trust sites is that we want a visit in July as well as May and June. The same survey can be used for both projects. In preparation for the Hoverwatch and constant effort projects I shall be running a one day workshop at Ring Haw field centre on April 27th.. If anyone is interested in attending please contact me or Henry Stanier.

I have not found any flies of interest locally, but Mike Killeby has been beating dead leaves and branches of pines on our forays on the Compton Estate. He has passed the flies on to me for identification. The most interesting were 3 picture-winged flies found Denton Wood on 14th March. These keyed out to Tephritis matricariae. A number of these gall-forming flies over-winter as adults and emerge in the Spring to lay their eggs on the developing host plants.

Yesterday Mike gave me a window gnat, which keys out to be a male Sylvicola cinctus. This is probably the most common member of the genus, although many books illustrate what is claimed to be Sylvicola fenestralis. This latter species is not common and has been misidentified in a number of publications. Indeed my attention was drawn to it by Jon Cole when I listed S. fenestralis in one of the newsletters. He sent me a paper showing the differences in genitalia. I have re-examined my specimens using this paper and they have all proven to be S. cinctus. I urge anyone who thinks they have S. fenestralis to double check. For females it is necessary to exert the genitalia a little. With dried specimens this means relaxing. I put the specimen in a jar with some damp tissue in the bottom, the specimen should not be in contact with the damp paper. Left tightly sealed overnight, the specimen was quite flexible and I was able to work on it without bits shattering all over the place.

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