27th October 2011

Overnight rain didn't deter the moths from flying. The trap held 2 Satellites, a November Moth, 5 Chestnuts, 2 Yellow-line Quakers and a Red-green Carpet.

Someone commented the other day about what looked like "lentils" all over the path to the Terrace. They are indeed quite noticeable. The clue to what they are lie in the tree that overhangs the path at this point - an Oak. The "lentils" are in fact plant galls - called Spangle Galls. A tiny gall wasp about 1mm long lays an egg in the oak leaf cuticle. A chemical in the wasp's ovipositor causes a gall to form and inside that the larva develops. So many galls can occur that the leaf is totally covered. Come the autumn, these galls fall to the floor with the larva still inside. The wasp larva overwinters to emerge as an adult in the spring. Because each gall contains a grub, they are a useful food source for birds, particularly Wood Pigeons and thrushes.
Spangle Galls beneath an Oak tree

No comments:

Post a Comment