Tuesday 10 January 2017

Emerging Knopper Gall Wasps and an Unofficial NYD Plant Hunt

In September, the Common Oaks nearby had been affected by knopper galls, and I have been fascinated by the peculiarity of these galls since.  In late December I collected 14 galls from under an oak and kept them at home.   The gall wasps (Andricus quercuscalicis)are now emerging, the first around 1st January, then one on each of 7th, 8th and 9th January, and one today.  Clearly this is earlier than would happen in the wild, as they have been kept at a temperature of 20℃, but it has meant a chance to look at the wasps.

Only the female affects Common Oaks; the sexual generation is restricted to Turkey Oaks.  These are close ups of the female.   The body length is around 4mm and the wing 5mm.




Another, smaller, insect has just emerged from the galls, but as it is only 2.5mm long then ID might be challenging.

BSBI's New Years Day Plant Hunt officially ended I think on day 4.  Surprised at how few species I found in and around Hook Norton, on the 5th I walked from Traitor's Ford up to Gallows Hill over to Sibford Gower and back to my starting point, a couple of miles north-west of the village.

Traitor's Ford might have got its name in the civil war - the battlefield at Edgehill is not far away, but it could also be a mispelling of 'Trader's Ford'.   (I am reliant on the local history society's webpages). The Ford crosses the River Stour which rises near Wiggington, east of Hook Norton.   We are on a significant watershed such that the Stour flows west, ending up in the Avon and Severn, whereas the springs and streams through the village and to the south flow east into the Cherwell and on to the Thames.

I wrote an almost new car engine off in the Fords some years ago.   The water was quite high, but the car in front got across without any issues.  So keeping the revs up I crossed the river.   Unfortunately the engine had a turbo, and the air inlet was under the engine  (unlike the rally version of the car where the air intake was above the engine).   With high revs it sucked up water at pace through the inlet and into the engine.  A deep intake of breath by the AA rescue man suggested expensive damage and he was right.

From Traitor's Ford the route followed a couple of green lanes to Sibford, and then back across pasture and arable, where mercifully the frozen ground made walking easier.  Great views but very few plants in flower, a total of only 7.   Surprisingly there were very few in Sibford village, a single primrose and autumn hawkbit but none of the weedy plants seen three days earlier in Hook Norton.
Ditchedge Lane

Path to Sibford Gower

Autumn Hawkbit

Traitor's Ford


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