Andricus quercuscalicis is a gall wasp species inducing knopper galls.
Andricus quercuscalicis
Galls (upper left and right) formed on acorns on the branch of a pedunculate (or English) oak tree by the parthenogenetic generation Andricus quercuscalicis.
Knopper galls and acorn cup
Developing knopper galls
Gall wasps, also traditionally called gallflies, are hymenopterans of the family Cynipidae in the wasp superfamily Cynipoidea. Their common name comes from the galls they induce on plants for larval development. About 1,300 species of this generally very small creature are known worldwide, with about 360 species of 36 different genera in Europe and some 800 species in North America.
Gall wasp
Diastrophus nebulosus on a raspberry gall
Andricus fecundatrix parthenogenetic generation, oak artichoke gall
Andricus quercuscalicis parthenogenetic generation gall