Monday, 6 June 2016

Cwmdu

After a tip off from Paul Tabor who had found the hoverfly Anasymia contracta (new for valley) in a tiny area of Bulrush in Cwmdu, I decided to go and have a look (twitching hoverflies, whatever next). The area itself was little more than a puddle and there were at least 2 pairs mating and 3 singles there. Blaencaerau has 4 areas much bigger than this, so I'll be keeping an eye out up there as things seem to come out 14 days later in Caerau than at the lower end of the valley. They were difficult to photograph and very skittish, but I managed a few shots.

 Small area of Bulrush at Cwmdu
 Anasymia contracta on Buttercup - T2 on abdomen is clearly longer than wide
 pair mating
Also came across this lone small Sphegina on the bog well away from the wooded area. It has noticeably yellow humeri [hairs] around the thorax, but the experts don't like doing these from photos. So I netted it and checked under 30x magnification, that it wasn't a Sphegina sibirica [which are much larger] by checking the chitinous bridge behind the coxae which was complete. This feature can only be seen under high magnification. That leaves 3 species, verecunda can be ruled out on wing venation and it has dark humeri. clunipes can be ruled out as it too has dark humeri. The yellow humeri around the thorax confirms this is Sphegina elegans, although the photo is not enough to prove this.

2 comments:

Paul Tabor said...

well done Martyn i think i can safely say that where there is bulrush even in small amounts we should be able to find A.contracta among it

Paul Parsons said...

Good twitch!