Effect of temperature and photoperiod on hatching of eggs of Tokunagayusurika akamusi (Tokunaga) (Diptera : Chironomidae)

The hatching time of eggs of Tokunagayusurika akamusi (Tokunaga) decreased significantly when temperature was increased from 5degreesC to 25degreesC; eggs fail to hatch at 30degreesC. The percentage of T akamusi eggs that developed into normal larva also was negatively correlated with temperature. The hatching time decreased with lengthened photoperiod.

滇池摇蚊科幼虫和水丝蚓属的生物学特性分析

报道了昆明滇池摇蚊科幼虫Chironomidae、水丝蚓属Limnodrilus的分类特征、生态学特点 ,分析了滇池摇蚊科幼虫、水丝蚓属优势种的变化及与滇池水质的关系 ;首次对其食性进行了分析并对其摄食量进行了估算 ,研究结果表明 :1kg摇蚊幼虫每天可消耗鲜藻 0 0 94kg ;1kg水蚯蚓每天可消耗鲜藻 0 0 89kg ;讨论了摇蚊幼虫、水丝蚓在昆明滇池综合治理中起到的控藻作用 ,为滇池的综合治理提供了基础资料。

莲窄摇蚊幼虫对莲的为害和防治

<正> 绝大多数摇蚊幼虫生活在各种类型的水体里,其中湖泊、池塘和河流的底部尤多。摇蚊科(Chironomidae,属双翅目)的幼虫因个体数量众多而闻名,为经济鱼类的主要天然饵料,并可用于水体的生物监测和湖泊类型的分类等。但幼虫营巢或泥底穴居,也造成对经济作物的为害。已有为害稻秧的报道。部分种类由于潜居在高等水生植物的叶片内,造成对宿主的为害。莲窄摇蚊Stenochironomus nelumbus(Tokunaga & Kuroda)对莲Nelumbo nuciferaGaertn.的荷叶为害尤为典型。

Seasonal changes, life cycle, and production of a psychrophilic chironomid (Propsilocerus akamusi) in a Chinese Lake

Seasonal changes, life cycle, and production of a psychrophilic Chironomidae species, Propsilacerus akamusi (Tokunage), were studied in eutrophic Lake Donghu. The P akamusi population was characterized by a single annual reproduction period during late November to December, and the larval growth mainly occurred in winter. Most of P akamusi were univoltine, while some of them came to emergence in two years or more. The average density and biomass were 318.9 ind./m(2) and 0.57 g dry weight /m(2) during January 1998 to June 2000, respectively, but these values did not include any summer measurement,; since the larvae aestivated in the deep sediment layer and could not be sampled routinely in summer. The annual production of P akamusi was 2.73g dry weight/m(2), and the corresponding production/biomass ratio was 4.60.

Impact of eutrophication on biodiversity of the macrozoobenthos community in a Chinese shallow lake

Comparative studies on community structure and biodiversity of macrozoobenthos were carried out in three lake areas with different states of eutrophication (mesotrophic, eutrophic and hypereutrophic) in a shallow subtropic lake (Lake Donghu) in the middle basin of the Yangtze River of China. Thirty-three taxa (including six Mollusca, five Oligochaeta, 15 Chironomidae and seven other zoobenthos) were found during February 1998 to April 1999. The results show that the more eutrophic the lake water, the lower the macrozoobenthos species diversity (measured as species number, diversity index, and K-dominant curves). Abundance of the oligochaete Limnodrilus hoffmeisteri was positively correlated with the degree of eutrophication, which was due mainly to its ability to tolerate low dissolved oxygen. The chironomid Tanypus chinensis also thrived in the hypereutrophic environment; however, it was less endurable to eutrophication than L. hoffmeisteri.