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The common spangle gall on the underside of leaves and the currant gall on the male catkins or occasionally the leaves, develop as chemically induced distortions on pedunculate oak (''Quercus robur''), or sessile oak (''Quercus petraea'') trees, caused by the cynipid wasp ''Neuroterus quercusbaccarum'' which has both agamic and bisexual generations. Previous names or synonyms for this species are ''Neuroterus baccarum'', ''N. lenticularis'', ''N. malpighii'', ''Cynips lenticularis'', ''C. quercus-baccarum'', ''Spathegaster baccarum, S. varius'', ''S. interruptor''. ==Galls== The spangle gall generation on the underside of the oak leaves are flat discs, with a distinct central elevation, slightly hairy, yellow-green at first and reddish later, attached by a short stalk. These galls are up to 6 mm in diameter, unilocular, unilarval with a whitish or yellow undersurface; they mature in September, detach and fall to the ground before the leaves themselves. The larva continue to develop in the fallen spangle and, protected by the leaf layer, they overwinter.〔 Any Spangle galls that remain attached to the leaves dry up and die.〔 The smooth surfaced currant gall generation appears in April and lay unfertilised eggs in the staminate catkins or occasionally the developing young leaves. The resulting spherical galls are around 4 mm in diameter, unilocular and unilarval, green at first, maturing through pink to red, therefore closely resembling redcurrants.〔 Several different spangle type galls are found on oak leaves so close inspection is required for proper identification.〔(【引用サイトリンク】title=Oak Common Spangle gall )〕 The suckers at the base of older trees are often more heavily infested than the mature tree foliage. This may be due to the poor flying abilities of ''N. quercusbaccarum'' or it may relate to the physiological age of the leaves. The spangle galls are sometimes misidentified as scale insects.〔(【引用サイトリンク】title=Oak galls )〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Neuroterus quercusbaccarum」の詳細全文を読む スポンサード リンク
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