Silk Button Spangle Galls

Silk Button Spangle Galls are caused by the asexual generation of the gall wasp Neuroterus numismalis. Certain small solitary wasps lay their eggs in leaves, and this stimulates the leaf to grow an abnormal swelling in which the larvae develop. The shape and size of the swellings is characteristic of the particular species of wasp in a single species of tree. In this case, the galls are formed only in oak leaves.

This is 1 of 28 species of Hymenoptera (bees and wasps) and of 172 insect species recorded at Charlton Down Nature Area so far.

Useful Books and Links

Britain’s Plant Galls – a photographic guide, Michael Chinery, Wild Guides, British Plant Gall Society, 2011, ISBN 978-190365743-0

https://en.wikipedia.org/wiki/Neuroterus_numismalis

https://www.dorsetnature.co.uk/pages-gall/g-74.html