Saturday 2 June 2012

Glocaenog

Monty and I took to the Forestry Commission track through Glocaenog forest for a "middle of the day" walk today, after a nice bit of shopping for Nain in Ruthin.

The trees were mainly Sitka Spruce, Picea sitchensis, with this year's growth of foliage just popping out of the bud scales and shedding them as joined cupules of scales all over the ground and undergrowth.


There were spots of quite nice habitat in between the trees, including patches of more open areas, and this decrepit rotten standing trunk, so valuable for insects and woodpeckers.


The trackside was well furnished with plants wherever the trees did not completely shade out the track, and this was dominated by Herb Robert, Geranium robertianum, and Creeping Buttercup, Ranunculus repens in flower, with lots of shoots of Willowherb, Epilobium, growing in between them and due to flower later in the season.



There were large numbers of what I think is the small hoverfly Melanostoma scalare all along the track on the buttercup and also to a lesser extent on the Herb Robert and the Ribwort  Plantain flowers. Notice the obviously pale halteres, which can even look green in some individuals. The first three photos are females with the characteristic pattern of yellow triangles on T3 and T4 behind the yellow spots on T2 on the top of the abdomen, generally dusted face with a protruding knob and dark patch above the antennae, yellowish antennae, glossy black thorax and scutellum, with pale front and mid legs with some darker shading on the rear legs. The last comment is typical of insects in its complexity, looked at from the inside the dark shading perhaps starts half way down the tibiae, looked at from the outside it is just the tarsi that are dark, at least in this picture.

In this photo this female has a fairly swollen abdomen, with the top plates (tergites) well separated from the bottom plates (sternites), only connected by the extendible membranous sides. This may well be because she is carrying a lot of eggs. The internal organs can be seen fairly clearly through the membrane. The yellow patches on the tergites clearly reach the edges. All individual insects photographed seemed to be in a very similar state.




The picture below is probably one of the best I got of one of these females. They move quite delicately from one resting spot to another, often on the flowers, feeding gently off the pollen or nectar:


This I am pretty sure is a male of the same species, with its characteristically elongated narrow abdomen. There were far fewer of these.


There was also a stubby very black hoverfly (I think!), but again with pale halteres! This male should go to ispot for further work, but I am guessing Cheilosia at the moment (confirmed almost instantly by Ophrys on ispot)! There appears to be a small pale patch on the pleura (?) just forward of the pale halteres. The thorax is both very black glossy and fuzzily long-hairy. The face appears to have a dark double bump, somewhat unusual. The legas are clearly dark, unlike most Cheilosia.


Other plants of interest included the occasional Wood Avens or Herb Bennet, Geum urbanum, a member of the Rose family.


Other plants in flower seen alongside the path were Dandelion, Cats Ear, Field Buttercup, Birds-foot Trefoil and Garlic Mustard and different grasses, although I didn't get any photos of these I am afraid. However I did manage to photograph the flowers of a bilberry, of which there were several patches intermingled with heather, possibly on more established banks or maybe more acid areas.


There were also some really great shuttlecock clumps of fern:


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