Wednesday 4 July 2012

Coed Fron Wyllt between the rain showers.

There were quite amazing collections of wild flowers in patches along the path, hedge woundwort, buttercup, herb robert, yellow pimpernel, red campion, St Johns wort, foxglove and speedwell all combine to create a fantastic collage of colour.

The occasional hoverfly can be found, and here is one of my absolute favourites, Helophilus pendulus! I do wonder why it was named pendulus. It is the only species of the genus that I have seen so far, is said to be the commonest, and I have usually found it fairly near water, as discussed in Stubbs and Falk. Sites include Broadview Gardens by the Elgar pond, Haysden Country Park by the River Medway, Dene Park with its occasional shady ponds, and now here in these woods just by the stream. S & F do say it wanders away from water a bit. Its larvae are usually found in the mud of ponds, farm drains, or soaking wet manure or sawdust. Within sight of this adult was a farm barn with cattle in it, so absolutely everything fits in this case!


The insect above is a male. In Helophilus both sexes have a gap between the eyes, while in the female the eyes diverge evenly, and in the male the rear half of the eyes are more or less parallel, and there is a clear division between the front and rear halves of the frons. I think I can see both these features and that should mean that this is a male!

The basal yellow section of the right rear tibia that is visible looks as though it extends roughly a little bit more than half way along the limb, and that should mean that it is H. pendulus as opposed to H. hybridus in which the yellow should extend less than one third of the way along. However there are some insects which are intermediate! Reassuringly the abdominal pattern also has a complete black band the full width of the rear of tergite two, splitting tergite two from three, fitting pendulus, while hybridus has the yellow side patches connecting across and linking tergites two and three.

Features which get the choice as far as the pendulus/hybridus pair include the black face stripe, the narrow yellow back edges to tergite two and particularly tergite three, and the male facial characteristics quoted above.



The right hand wing appears to have sustained some damage, and to have a kink cutting across the R4+5 loop, particularly visible in the upper of these two photos.

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