宁夏中宁县麦蚜寄生蜂群落多样性及优势种种群动态

为了解西北干旱区麦田蚜虫寄生蜂的多样性及优势种的种群动态,采用棋盘式五点取样法对宁夏中宁县麦蚜寄生蜂群落组成进行调查与研究,分析其多样性、丰富度、均匀度及优势度指数等指标的变化,应用Gaussian函数对各指标进行拟合,并对寄生蜂优势种的个体发生量进行时间动态描述。结果显示,该地区共调查获得麦蚜寄生蜂标本919份,隶属4总科7科12属21种,其中初寄生蜂11种,重寄生蜂10种。燕麦蚜茧蜂Aphidius avenae为初寄生蜂优势种,6月2日个体数达到顶峰,6月8日骤降,6月23日趋于平缓;重寄生蜂优势种为蚜虫宽缘金小蜂Pachyneuron aphidis、宽肩阿莎金小蜂Asaphes suspensus和蚜茧蜂长背瘿蜂Alloxysta sp.,前二者个体数均在6月18日达到最大值,6月23日呈下降趋势,后者5月28日上升,6月2日达到顶峰,6月23日缓慢降至最低值。该地区5月初麦蚜初寄生蜂的多样性指数较大,重寄生蜂的多样性指数则在5月中旬开始上升,总群落多样性指数在6月上旬最高;Gaussian函数对寄生蜂群落多样性指数时间动态变化的模型拟合参数表明,复杂农业景观下的寄生蜂物种多样性发生期明显长于简单农业景观。

Community diversity and population dynamics of dominant parasitoids and hyperparasitoids of wheat aphids in Zhongning County, Ningxia

In order to investigate the community diversity of wheat aphid parasitoids and hyperparasitoids and the population dynamics of dominant species in the arid region of northwestern China, the community composition of wheat aphid parasitoids and hyperparasitoids was determined by using five-spot sampling method in Zhongning County, Ningxia. The community composition was also analyzed for the diversity index, evenness index, dominance index, and richness index. The temporal dynamics of the indexes was modeled with Gaussian function and the population numbers of dominant species were described. The totally 919 parasitoid specimens were collected from wheat fields, including 21 species in four superfamilies, seven families and 12 genera. There were 11 parasitoid species and ten hyperparasitoid species. The dominant parasitoid species was Aphidius avenaes, while the dominant hyperparasitoid species were Pachyneuron aphidis, Asaphes suspensus and Alloxysta sp. in the local parasitic wasp community. The population of A. avenae reached its peak on June 2, plummeted on June 8, and remained in steady state on June 23. P. aphidis and A. suspensus all peaked on June 18, but both showed a trend of decline after June 23. Alloxysta sp. began to rise on May 28, reached its peak on June 2, and then slowly decreased to the lowest level on June 23. The diversity index of the parasitoids was higher than that of hyperparasitoids in early May, but the diversity index of the hyperparasitoids began to increase after mid-May. The highest diversity index of the parasitoids and hyperparasitoids was observed in early June. The occurrence of aphid parasitoids and hyperparasitoids in the complex landscape was longer than in the simple landscape based on comparative analysis of Gaussian parameters of the diversity dynamics in different agricultural landscapes.