Sunday 8 July 2012

To Meadows Pond on the Tower Walk

This is a short walk crossing to the South side of the village, around the Castle Gardens and along the shady path by the side of the Ha-Ha, and out by the pond created a few years ago in Meadows field just to the East of the River Bourne.

The brambles and roses along the path by the back of Castle Gardens yielded honeybees and Episyrphus balteatus - apparently ubiquitous in my limited experience. Along the shady walk sheltered by the leylandii cypresses along the side of Castle Gardens there were high flying small hoverflies that looked in silhouette like more Episyrphus. Here there are elder, brambles, ivy and nettles, with some wall lettuce and black horehound to be found. It's when this path opens out, unsheltered by the leylandii, and it runs between the maize field and the brambles rambling over the wall of the Ha-Ha, with brambles, roses, and hawkweeds, sow-thistles, hogweed, mallows, ragwort and cut-leaved geranium along a wide grassy path, that a greater diversity of insects can usually be found.

I did manage to spot a Syrphus on what I thought was a hawkbit. The difficulty of telling the Syrphus species apart with only photographs is very clear. It is very difficult to get a clear shot of the rear femora, and without specimens you can't get the confirmatory microscopic details. However this does look like either ribesii or vitripennis, according to the key and the other information in Stubbs and Falk. This was the only Syrphus I saw today, but I think there are probably quite a few individuals around, possibly of several different species.


I found an interesting Eristalis on the ragwort by the end of the maize nearest the Ha-Ha of the Castle Gardens, and in the end keyed it out as Eristalis arbustorum. It was quite small, the face was dusted white overall, there were white hairs on the side of the thorax below the wings, the tibiae were about half dark, half pale, the rear metatarsus was swollen - at least from some angles, the stigma was extended past the tip of the Sc vein, without any obvious wing shading as seen from directly above, even though I think this could be seen from the angle. I couldn't see any hairs, long or short, on the aristae of the antennae. This was a particularly dark individual, with no obvious orange patches on the tergites, but there are internet pictures of similarly coloured individuals, and it was agreed by Ian Andrews on ispot.






On the single hogweed plant out in flower, there were quite a few insects including 2-3 male and female Syritta pipiens. Although rather blurry photographs, enough could be seen of the overall shape, swollen rear thighs, leg colour patterns, tergite spotting and dusty thoracic sides to give me confidence in my identifications. On the hogweed there were also a lot of small dark beetles and black ants.




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