早竹林拉步甲成虫种群动态和对金针虫的捕食作用

The population dynamics of the carabid beetle Carabus lafossei and its role as a predator of wireworm in Phyllostachys praecox forest

【目的】为了明确3种不同类型早竹Phyllostachys praecox林地拉步甲Carabus lafossei成虫的种群动态和对金针虫的捕食作用。【方法】采用陷阱法诱捕步甲成虫,采用形态学结合DNA条码法进行物种鉴定;分析拉步甲数量与土壤化学性质和林下植被盖度之间的相关性;质量测定法计算拉步甲对竹林金针虫的捕食量。【结果】3种类型早竹林中共捕捉到拉步甲成虫188头,其中撂荒地136头,中等强度经营样地34头,高强度经营样地18头。早竹林拉步甲成虫在4-10月份均有分布,其中以4-5月份种群数量最大。拉步甲个体数量与林下植被盖度极显著的正相关,与全磷和水解性氮极显著性的负相关,与有效磷显著的负相关。捕食量分析表明,单头的最大捕食量为0.734 g,最小捕食量为0.390 g,平均捕食量为0.540g。【结论】早竹林拉步甲成虫的种群数量大、存活时间长,其种群数量在不同经营方式样地之间存在极显著差异;拉步甲能够捕食竹林金针虫,是竹林金针虫的捕食性天敌昆虫。

[Objectives] To elucidate the population dynamics of the carabid beetle Carabus lafossei and its importance as a natural predator of wireworm in Phyllostachys praecox forest under three different cultivation regimes. [Methods] Pitfall traps was used to survey adult carabid beetles which were identified by morphology and DNA barcode. The correlation between the number of adult C. lafossei, soil chemical properties and vegetation cover(eg: weeds and shrubs) in P. praecoxforest was determined. The level of predation of adult C. lafossei on wireworms was determined by the weighing method. [Results] A total of 188 adult C. lafossei were collected in P. praecox forest;136 in unmanaged, 34 in managed, and 18 in intensively managed forests. Adult C. lafossei were present from April to October and were most numerous in April and May. The number of adult C. lafossei was positively correlated with vegetation cover, and negatively correlated with total phosphorus and hydrolysable nitrogen and available phosphorus. The average wireworm biomass consumed by a single C. lafossei was 0.540 g(range: 0.390-0.734 g). [Conclusion] The population of the adult C. lafossei in P. praecox forest was large and persisted over seven months of the year. Abundance differed significantly between forests with different intensities of forest management. C. lafossei is an important natural enemy of wireworm in P. praecox forests.