Shin-ichi Akimoto
Article first published online: 13 JAN 2014
DOI: 10.1002/ece3.949
Abstract
To evaluate the impact of fallout from the Fukushima Daiichi Nuclear Power Plant accident on organisms, this study compared the morphology and viability of gall-forming aphids between the Fukushima population and control populations from noncontaminated areas. This study, in particular, focused on the morphology of first-instar gall formers derived from the first sexual reproduction after the accident. Of 164 first instars from Tetraneura sorini galls collected 32 km from Fukushima Daiichi in spring 2012, 13.2% exhibited morphological abnormalities, including four conspicuously malformed individuals (2.4%). In contrast, in seven control areas, first instars with abnormal morphology accounted for 0.0–5.1% (on average, 3.8%). The proportions of abnormalities and mortality were significantly higher in Fukushima than in the control areas. Similarly, of 134 first instars from T. nigriabdominalis galls, 5.9% exhibited morphological abnormalities, with one highly malformed individual. However, of 543 second-generation larvae produced in T. sorini galls, only 0.37% had abnormalities, suggesting that abnormalities found in the first generation were not inherited by the next generation. Although investigation is limited to one study site, this result suggests that radioactive contamination had deleterious effects on embryogenesis in eggs deposited on the bark surface, but a negligible influence on the second generation produced in closed galls. Furthermore, analysis of both species samples collected in spring 2013 indicated that the viability and healthiness of the aphids were significantly improved compared to those in the 2012 samples. Thus, the results of this study suggest the possibility that a reduced level of radiation and/or selection for radiation tolerance may have led to the improved viability and healthiness of the Fukushima population.
http://onlinelibrary.wiley.com/doi/10.1002/ece3.949/full
研究成果のポイント
・福島県の高線量地域で，虫こぶを作るワタムシ（アブラムシの仲間）の２種に，2012 年には高頻度
の死亡と形態異常を検出。
・しかし，2013 年には，２種類とも健全な個体の割合が前年より増加し，集団の回復の兆しを把握した。
研究成果の概要
福島第一原発事故による放射性降下物が野生生物にどのような影響を及ぼすかは，一般市民も研究
者も強い関心を示しているものの，ほとんど実態が明らかにされていません。本研究では，福島県川
俣町の高線量地域で，虫こぶ（図３）を作るワタムシ（アブラムシの仲間）の２種に，2012 年には高
頻度の死亡と形態異常を検出しました。原因として，放射性降下物の影響が強く疑われました。しか
し，2013 年には，影響を受けた集団がすでに回復しつつある兆しを把握できました。チェルノブイリ
事故の悪影響に関する報告は数多くありますが，原発事故後の集団の回復を示唆した結果は初めて得
られたものです。
論文発表の概要
研究論文名：Morphological abnormalities in gall-forming aphids in a radiation-contaminated
area near Fukushima Daiichi: selective impact of fallout?（福島第一原子力発電所近隣の高線
量汚染地域での虫こぶ形成アブラムシにおける形態異常：降下物による選択的なインパクトによるも
のか？）
著者：秋元 信一（北海道大学大学院農学研究院昆虫体系学研究室）
公表雑誌：Ecology and Evolution, Volume 4, Issue 4, pages 355–369,2014
(http://onlinelibrary.wiley.com/doi/10.1002/ece3.949/full) オープンアクセス
公表日：米国東部時間 2014 年 1 月 13 日
