Andricus inflator

Like many oak gall wasps, there are two generations per cycle, with one sexual and one asexual, each creating different galls. In spring, the sexual gall is a swelling at the tip of the twig which can be up to 15 mm across. The interior cavitity is long and narrow and at the bottom is an egg-shaped inner gall, containing the larval gall wasp. Old galls persist and can have new shoots growing from them. They are green at first, later becoming the same colour as the twig. The wasps emerge in the summer and after mating, females from the sexual gall lay their eggs on a bud, especially on buds sprouting straight from the trunk. The resulting asexual gall is a small, green, egg-shaped swelling up to 6 mm across and is surrounded by bud scales. Each gall contains a single larva {according to Chinery) or more (according to Plant Parasites of Europe), can be found from September to November and, as it matures, turns brown, falling to the ground in late autumn. …