2013

TF0820 : Lots of galls

taken 11 years ago, near to Bourne, Lincolnshire, England

Lots of galls
Lots of galls
Oak trees pay host to a wide variety of infecting insects, many of which are cynipid wasps, which have a strange double reproductive cycle - female-only wasps reproduce by parthenogenesis, and lay eggs of a normal male/female generation who mate and in turn generate the next asexual females.

The two large green galls are probably the Cherry gall caused by the asexual female phase of a gall wasp 'Cynips quercusfolii'. I was taught that you only ever get one per leaf, but that seems to have changed in recent years. There is a Pea gall, but it is smaller and smoother. These will turn red toward Autumn, hence the 'Cherry' name.

The brown scales are Spangle galls, possibly the best known oak leaf gall. These are home to the asexual phase of 'Neuroterus quercusbaccarum'. The spangles fall off in Autumn (oaks notoriously keep their leaves late) and form a valuable food for birds. Those that do survive winter in the leaf litter will emerge, mate, and lay eggs on male catkins that form bright red galls up to 5mm in diameter!

The lilac-coloured galls on the same leaf might be Schenck's gall - the bisexual generation of 'Neuroterus albipes'. The galls of 'Neuroterus quercusbaccarum' and 'Neuroterus albipes' are both highly variable, and this colour is unusual for both.

On the leaf behind the toroidal galls are another common oak infestation, the Silk-Button Spangle Galls caused by the asexual cycle of the gall wasp 'Neuroterus numismalis'.

Creative Commons Licence [Some Rights Reserved]   © Copyright Bob Harvey and licensed for reuse under this Creative Commons Licence.
Geographical Context: Wild Animals, Plants and Mushrooms Tree: English Oak Image Buckets ?: Life Closeup other tags: Galls Click a tag, to view other nearby images.
This photo is linked from: Automatic Clusters: · Tree [652] · Year [287] · Leaves [287] · Oak [243] Other Photos: · Lots more galls · Oak Cherry Galls ·
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TF0820, 3472 images   (more nearby 🔍)
Photographer
Bob Harvey   (more nearby)
Date Taken
Sunday, 18 August, 2013   (more nearby)
Submitted
Monday, 19 August, 2013
Subject Location
OSGB36: geotagged! TF 0829 2048 [10m precision]
WGS84: 52:46.2639N 0:23.7779W
Camera Location
OSGB36: geotagged! TF 0829 2048
View Direction
Northwest (about 315 degrees)
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Image classification(about): Supplemental image
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