叹气沟河优势摇蚊种群动态、周年生产量及营养基础

Population dynamics,annual production,and trophic basis of dominant chironomids in Tanqigou Stream.

2006年4月—2007年3月对清江流域二级河流叹气沟河大型底栖动物群落中摇蚊优势种进行了为期1周年的调查。结果表明:主要优势摇蚊斑特突摇蚊(Thienemanimyia lentiginosa)、波特真开氏摇蚊(Eukiefferiella potthasti)和拟长跗摇蚊(Paratanytarsus parthenogeneticu)的生活史均为1年2代;拟长跗摇蚊、斑特突摇蚊的种群密度6月、9月和翌年月出现峰值,波特真开氏摇蚊则在5月和翌年1月出现峰值;采用龄期频率法(instar-frequency method)测算的周年生产量(湿质量)和生产量(P)/生物量(B)分别为斑特突摇蚊17.44g·m-2、3.4,波特真开氏摇蚊1.66g·m-2、2.3,拟长跗摇蚊3.3g·m-2、6.4;3种摇蚊的生产量在时间动态上重叠程度较大,主要发生在春季;通过对3种摇蚊的前肠内含物分析,测算了各类食物的比例及其对生产量的贡献率,结果表明,无形态碎屑为主要食物类型,占前肠内含物的73.27%～86.89%,而斑特突摇蚊生产量则主要来源于动物性食物的贡献率(51.64%)。

An investigation on the population dynamics, annual production, and trophic basis of dominant chironomids in the macrozoobenthos community in a second order river （Tanqigou Stream） of Qingjiang River Basin was conducted from April 2006 to March 2007. The results showed that all of the three dominant chironomids Thienemanimyia lentiginosa, Eukiefferiella potthasti and Paratanytarsus parthenogeneticus developed two generations per year. The population density of P. parthenogeneticus and T. lentiginosa reached the peaks in June, September and next January, while that of E. potthasti attained the peaks in May and next January. The annual production （in wet mass） and its ratio to biomass of the three chironomids estimated by instarfrequency method were 17.44 g·m^-2 and 3.4 for T. lentiginosa, 1.66 g·m^-2 and 2. 3 for E. potthasti, and 3.3 g·m^-2 and 6. 4 for P. parthenogeneticus, respectively. The temporal overlap of the production among the three chironomids was relatively large in spring. The proportions of various food types and their contribution to the production were estimated by foregut content anal- ysis, showing that amorphous detritus was the most important food type, accounting for 73.27% - 86. 89% of the foregut content of E. potthasti and P. parthenogeneticus, while animal material contributed 51.64% to the production of T. lentiginosa.