著者

中山 祐一郎 郷原 匡史 浅井 元朗

出版者

日本雑草学会

雑誌

雑草研究 (ISSN:0372798X)

巻号頁・発行日

vol.67, no.1, pp.31-43, 2022 (Released:2022-04-28)

参考文献数

100

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日本各地の河川堤防や河川敷において,アブラナ属(Brassica)の植物が定着して優占し,春季に一斉に開花する群落が見られている。また近年,穀物輸入港の周辺の路傍で“外来ナタネ”の定着・自生が確認されている。日本では以前からアブラナ属の自生種に対する誤同定が多い状況が続いており,分布や生態に関する実態の正確な理解を妨げている。日本におけるアブラナ属,とくにアブラナとセイヨウアブラナ,カラシナの3種について概説し,その形態的・生態的な特徴を示した。さらに,2000年以降に出版された主要な帰化植物等の図鑑と,図や解説のある主要な地方植物誌におけるアブラナ属の掲載状況を検討した。主要な専門書(図鑑等)において,栽培種と認識されているアブラナが掲載されていない,あるいは誤りを含む記述がされており,それがアブラナをセイヨウアブラナとして誤同定され続けている主因と思われる。今後,アブラナ類の調査について,正確な種同定に基づいて再検討した上で,影響の再評価がなされるべきである。

著者

屈 達才 前田 泰生 郷原 匡史 中塚 硬三 北村 憲二

出版者

日本昆虫学会

雑誌

昆蟲.ニューシリーズ (ISSN:13438794)

巻号頁・発行日

vol.5, no.4, pp.121-141, 2002

参考文献数

42

被引用文献数

1

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Three species of astigmatid mites which infest mason bees, i.e., Chaetodactylus hirashimai, C. nipponicus and Tortonia sp., are known to occur in Japan. Two of them, C. nipponicus and T. sp. are sympatrically distributed in central and northern Japan. They are cleptoparasites of Osmia cornifrons, which is utilized as a pollinator of apples. The invasion/infestation patterns of these mites were studied through a survey conducted at 24 apple orchards in various localities during winter between 1999 and 2001. A population of O. cornifrons was reared in Sendai City, northern Japan, in spring of 1999 so as to analyse the synchronization between invasion/infestation of mites and nesting activity of host bees. As overwintering stages of C. nipponicus, phoretic and cyst-like deutonymphs were found together in the same cells, while 5 stages (larvae, protonymphs, tritonymphs, adults and phoretic deutonymph) were confirmed to hibernate in Tortonia sp. The cyst-like deutonymphs were absent in the latter species. In C. nipponicus, the percentage of phoretic deutonymphs was extremely high (up to 99.6% per host cell), while in T. sp. was lower (6.6% in total). The life type of these 2 mite species is regarded as phoretic- and dweller-like, respectively. The difference of their life types between 2 mite species are enable the partitive use of the pollen-mass stored in the same nests. The following features, regarding to the invasion/infestation patterns, were recognized. 1) Mostly, the first nests made in tubes were infested by both species of mites. The number of cells infested by C. nipponicus extended up to 9 cells, but usually the inner ones were apt to be infested. On the other hand, infested cells were found throughout nest tubes in T. sp.; 2) Distribution and numbers of dead cell contents in a nest by infestation of mites differed between 2 mite species. Only 1-3 cell contents were killed in C. nipponicus, and none killed in T. sp.; 3) Prior to feed on the stored pollen-mass, both species of mites killed hosts. However, they were able to kill hosts of which stages were from egg to early third instar larva. To kill host eggs, it was needed more than 50 adult mites. Those hosts that escaped from slaughter survived and formed normal cocoons; 4) Coinhabiting with C. nipponicus and T. sp. in the same host cell was less frequently occurred (7.1% in total). In these cells, the individual ratio of C. nipponicus was always higher than that of T. sp. The 5 overwintering stages, except phoretic deutonymph, in Tortonia sp. were not all in diapause. These stages began to develop into the next stages sooner, when new food was given under warm temperature. The phoretic deutonymphs of both mite species activated their development by clinging to host bee bodies in both mite species. The cyst-like deutonymphs of C. nipponicus developed into the tritonymphs when subjected them to the scent of host bees.