Monday, 3 July 2017

Borough Hill and Elderstubbs Farm

Today, Sunday, was the occasion of another meeting of NAPDT - the Northamptonshire and Peterborough Diptera Group. Five of us gathered and we visited two sites, both on the periphery of Daventry.
Borough Hill, our first venue, has received many visits from naturalists over the years so its fauna and flora are fairly well known, but certain groups of organisms, such as spiders, are still in need of recording.
I have expressed alarm over recent weeks about the apparently poor state of the butterflies and moths in this region but today, although they were not abundant, there were reasonable numbers of both to be seen. Skippers in particular were plentiful with the Small Skipper, Thymelicus sylvestris, present in large numbers. The specimen shown is a male, this being confirmed by the dark streak on the forewing.
Small Skippers were very common. A male feeds at red clover.
Borough Hill, Daventry. 2 July, 2017
The Essex Skipper, Thymelicus lineola, is very similar and was also present, being by no means confined to Essex. Its name is also confusing in another way, this species being on average slightly smaller than the Small Skipper. The underside of the tip to the antennae is black, just about visible in the second picture. It will be noted too that the dark streak is absent, this specimen being a female.
Essex Skipper? The black tip to the underside of the antennae is just about
visible. Borough Hill, Daventry. 2 July, 2017
Some day-flying moths can be very butterfly-like, particularly the Cinnabar, Tyria jacobaeae, one of which was noted, and the Five-spot Burnet, Zygaena trifolii. I accidentally netted one of these but it was happy to sit there for a while until I shook it off.
This Five-spot Burnet seemed reluctant to leave my sweep net.
Borough Hill, Daventry. 2 July, 2017
I was hoping to see a Six-spot Burnet but all those seen appeared to be 'Five-spots' including this mating pair. The sexes are easy to tell apart: the male has a smile on his face while the female is the one who keeps glancing at her watch.
Five-spot Burnets with the next generation in mind.
Borough Hill, Daventry. 2 July, 2017
Insects in general abounded including beetles and two-winged flies - diptera. This enormous order includes hoverflies, a family of insects to which our group would be paying particular attention. One species noted was Chrysotoxum verralli. This rather handsome wasp-mimic may be in decline so it was pleasing to be able to record this male.
A male hoverfly, Chrysotoxum verralli, soaks up the sun.
Borough Hill, Daventry. 2 July, 2017
In our sweep-nets we probably, collectively, caught thousands of insects but only a tiny percentage - probably well under 1% - was to be retained for checking out under a microscope so, with a handful of specimens, we gathered to drive to our second venue.
This was Elderstubbs Farm or, to be precise Elderstubbs Farm Pasture, a Local Wildlife Site (LWS) being sympathetically managed by the owner for the benefit of wildlife. It is more or less adjacent to Kentle Wood, a site to which I have made many visits. Would this LWS be much different?
The answer was a resounding Yes. Within minutes I had noted several Marbled White butterflies, Melanargia galathea which, despite its name, is not related to the Small White, nor the Large White, but is closely related to the Meadow Brown!
Near to the entrance were clumps of Yellow Toadflax, Linaria vulgaris, also known as Bunny Mouths and clearly related to snapdragons. The toadflaxes possess a long spur to the rear of the flowers; the snapdragons - Antirrhinum species - have none.
Yellow Toadflax near to the entrance of Elderstubbs Farm Pasture.
2 July, 2017
I moved on quickly, even though several insects were showing interest in the yellow flowers. The main field I now entered was waist deep in grasses, principally False Oat Grass, Arrhenatherum elatus. This was of little botanical interest but several spiders had constructed nursery webs among their stems. A wet flush - a point where water is seeping from the ground - marked the likely location of a spring-line, and a horsetail, probably Great Horsetail, Equisetum telmateia (my botany is a bit rusty) was present in large patches. It too bore many spider webs.
Horsetail dominated some of the wet areas. Elderstubbs Farm Pasture.
2 July, 2017
At the lower end of the field flowed a small stream, a tributary of the River Leam, lined with oak and various shrubs. Oak as a species supports an enormous number of invertebrates and I quickly spotted this Forest Bug, Pentatoma rufipes. This is quite a dark example but whatever the shade of colour it is one of our most handsome shieldbugs. The nymphs are rarely seen, being confined to the tops of trees, commonly oak. Craneflies and 'dollies' - members of the Dolichopodidae family - were among the insects present.
A dark form of the Forest Bug, Pentatoma rufipes.
 Elderstubbs Farm Pasture, near Daventry. 2 July, 2017
More time could have been productively spent at this site but we were now well into the afternoon and we decided to call it a day.

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