著者

末永 斂 劉 維徳 繆 建吾 徐 薇

出版者

長崎大学熱帯医学研究所

雑誌

熱帯医学 (ISSN:03855643)

巻号頁・発行日

vol.24, no.4, pp.p229-234, 1982-12

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アカイエカの産卵活動の季節的推移が1981年8月から1982年7月までの1年間にわたり上海市内の復興公園で調べられた.容量約10lの水がめに水をはり,少量の麩を入れてイエカ用の産卵容器とし,これを公園の一角の人家に隣接した木蔭に設置した.この水がめを毎朝点検し,水表面に産み落されているすべての卵塊を採集して卵塊別に小容器に収容し,27℃の恒温室内で2~3日間放置してそれらの孵化状況を調べた.その結果次のことが明らかになった.アカイエカの産卵活動は平均最高気温が30℃を越す夏の間はむしろ低調である.年間を通じて2つの活動の山があり,最盛期は8月下旬から9月上旬にかけてみられ,もう一つの山は7月上旬頃にみられる.11月下旬から翌年4月上旬までの最高平均気温が10℃以下を示す寒い期間は産卵活動がみられない.1982年春最初の卵塊は5月上旬の最高平均気温が23.9℃,最低平均気温が15.0℃のときに採集された.この蚊の活動の消長は年により,地理的,気候的及び環境的条件によって異なると思われるが,上海におけるアカイエカの産卵活動の季節的推移の型は日本におけるこの蚊の成虫の季節的消長の型に似ているようである.The seasonal change in the oviposition activity of Culex pipiens pollens was observed at Fuxing Gongyuan (Renaissance Park), Shanghai for one year from August, 1981 through July 1982. An earthen jar of about 10 litters in size and containing wheat bran solution was set up as an ovi-trap for house mosquitoes in a corner of the park. All egg rafts of Culex pipiens complex, which were deposited on the water surface in the jar, were picked up every morning and examined for hatching in the laboratory. From the results of the survey, the oviposition activity of Cx. p. pollens in Shanghai seems to be rather low during the summer when the maximum temperatures are over about 30 C. Two clear peaks of the activity were observed; higher peak was in late August through early September and lower one was in early July. No egg rafts were found from late November, 1981 to late April, next year, when the maximum temperatures were below about 10C. The first egg rafts in 1982 were collected in the begining of May when the temperatures were 23.9C (Mean Max.) and 15.0C (Mean Min.). Although the seasonal distribution of activity seems to be different every year by climatic and environmental conditions, the pattern of seasonal change in the oviposition activity of Cx. p. pallens in Shanghai is similar to the pattern of seasonal distribution in adults of this mosquito in Japan.