Wednesday, 9 September 2015

Some Gall

The onset of autumn always brings to our attention, a large number of galls around the countryside. Most of the galls are to be seen on the leaves and twigs of the various Oak trees. Among the most attractive - if a gall can be described as attractive - are the Cherry Galls.
Found on the underside of the oak leaves, these spherical growths are produced by the larvae of a tiny gall wasp which goes by the name of Cynips quercusfolii. Starting off green, the gall 'ripens' and flushes red as the grub inside matures, before turning brown as the leaves die and fall in late autumn.
The grub itself will remain inside the gall even when the leaf has fallen, emerging as an adult during the winter. This generation of wasp is asexual, but will nevertheless lay eggs on the tree trunk and unopened Oak buds the following spring. These will develop into the next, sexual generation of gall wasps which will lay more eggs on the Oak, producing the next season's Cherry Galls. And so the cycle starts all over again.
But for now, we can just enjoy the colourful little 'marbles' on the oak leaves before they all drop in a few weeks time.
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