Common Spangle Galls

These are not the Spangles I knew as a child!

Neuroterus quercusbaccarum is a tiny gall wasp that causes these Common Spangle Galls on the underside of oak leaves in Autumn. The galls drop off, female gall wasps emerge and lay their eggs in oak buds. The grubs then cause the formation of Currant Galls (they look like unripe blackcurrants) on young leaves and catkins during late Spring. Male and female wasps then emerge from the currant galls and mate. Eggs are then laid on oak leaves and when they hatch, new Spangle Galls form around them.