Tuesday, 30 May 2017

Buttercups and Oak Apples

Getting back to our local environment, we have enjoyed some fine, warm - if not hot - weather recently. This has brought out the flowers around Shipley Park. In the fields, Buttercups have begun to carpet the green.
This field, discovered as we peered through the trees along what we know as the 'Donkey Walk', looked particularly golden.
A little closer to home, the Buttercups were joined by stands of Cow Parsley along the old railway embankment beside Pewit Carr.
Wherever they are, Buttercups always give great value, especially when the sun shines on them, making them glow with a golden-yellow sheen.
Gall wasps create some fantastic and strange growths on the Oak trees of Britain. Normally around these parts, we can see spangle galls, marble galls, cherry galls and artichoke galls. This year however, we have noticed a large number of Oak Apples growing on the new shoots of our local Oaks.
These galls are quite large, being up to 2 inches across and indeed look like small apples hanging from the tree. The insect which causes these however, is far smaller. Biorhiza pallida is no more than a quarter of an inch long. Having hatched in the winter, female wasps climb up the Oak trees in spring, lay their eggs in the forming buds, injecting a venom into the bud at the same time. This venom, causes the bud to swell hugely as the developing larvae inside, secrete substances which make the gall grow even larger, thus protecting the grubs. There may be up to 30 developing grubs inside each gall.
Males and female emerge from different galls after two or three months and mate. Females then descend to the ground and lay their eggs in the roots of the Oak, forming more galls on those roots, which in turn, hatch out into more, wingless females which climb the trunk in spring, starting the cycle all over again. Brilliant!
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