oak acorns chemically distorted by the eggs of a parasitic gall wasp the normally smooth green acorn warped into a similar

abnormal acorn andricus animal black botanical bug closeup cup damage disease distortion environment flora gall galls green growth hymenoptera infected inquiline insect invasive knopper leaf life macro natural nature nut oak parasite parasitised pedunculate plant quercus quercuscalicis robur seed species spring stem sticky still tree wasp wild wildlife woodland yellow yellowishgreen