Friday 20 June 2014

May 2014

After a good early start to the season, May was fairly slow-going for hoverflies. The highlight for me was seeing two Criorhina ranunculi in Scotland Wood. I first noticed one hovering close to the ground at the base of a large Douglas Fir. It had whitish hairs on the rear end. It kept settling briefly on a bramble leaf, where I managed to photograph it, and then returning to hover close to the base of the tree. At one point, a second fly joined it and they briefly tussled in mid-air, dropping to the ground. Almost immediately the visitor flew off and I never saw it again. The visitor had yellow hair at the apex of the abdomen. This is a colour variant, mimicing the red-tailed bumblebees.
Criorhina ranunculi

A visit to Irthlinborough Lakes with the Northants Diptera Group at the beginning of the month produced the hoverflies Anasimyia transfuga and Platycheirus fulviventris in the damp areas adjacent to the lakes. Several craneflies were found, including Tricyphona immaculata, Erioconopa trivialis and Phylidorea ferruginea. The following week we visited Ramsden Corner for the first time. The weather was not promising and the flies were hard to find. Two long-palped craneflies were found: Tipula varipennis and T. vernalis.

We did not have a local field meeting the following weekend as most of the group joined the Dipterists Forum Spring Weekend in Dorset. The hot weather there meant that hoverflies were hard to find but we did manage to see Microdon myrmicae at the RSPB reserve at Arne. Unfortunately, no Microdon species have been recorded in Northants. This weekend coincided with the Bioblitz at Halse Copse, organised by the Northants Biodiversity Records Centre. I made a belated visit during the following week. The temperature had dropped somewhat but was still suitable for finding flies. I did not find anything unusual during my visit but managed to add a few records for the site. These included a male empid fly, Empis bicuspidata, which I have not seen before. There were several species of long-legged fly (Dolichopodidae), including Dolichopus ungulatus, D. plumipes, D. popularis, D. longitarsis, Argyra diaphana and Chrysotus gramineus.

The moth traps at Pitsford continue to provide a steady stream of flies in the by-catch. These inluded the tiny metallic green soldierfly, Microchrysa flavicornis.