同地共栖三种鼠耳蝠食性差异及其生态位分化

2005年9—11月在贵州省安龙县笃山乡暗河村,分析了共栖同一山洞3种鼠耳蝠的形态特征和食性。在体型上,华南水鼠耳蝠体重为(4.46±0.53)g,前臂长为(34.63±1.45)mm;毛腿鼠耳蝠体重为(5.15±1.76)g,前臂长为(35.20±1.07)mm;西南鼠耳蝠体重为(10.94±0.87)g,前臂长为(45.21±1.15)mm。3种鼠耳蝠的体重两两之间差异显著,西南鼠耳蝠与另外2种鼠耳蝠的前臂长相比两两之间差异显著。在食物组成上,华南水鼠耳蝠主要捕食近水面活动的双翅目及其幼虫,体积百分比和频次百分比分别为79.7%和100%;毛腿鼠耳蝠主要捕食双翅目和小型鞘翅目,体积百分比分别占59.6%和28.8%,频次百分比分别为91.3%和80.1%;西南鼠耳蝠的食物组成主要为近地面或在地表活动的鞘翅目步甲科和埋葬虫科昆虫,体积百分比和频次百分比分别为80.8%和100%;3种鼠耳蝠食物组成存在显著差异。结果表明,同地共栖3种鼠耳蝠除了形态结构上出现差异,食物组成也存在明显的差异。据此,推测3种鼠耳蝠可能采取不同的捕食生境和捕食策略,从而导致捕食生态位分离,避免出现激烈竞争,使得3种近缘鼠耳蝠能够同地共栖。

Dietary differences and niche partitioning in three sympatric Myotis species

The morphology and diet characteristics of three Myotis species roosting in the same cave were studied in Anlong County, Guizhou from September to November 2005. The three mouse-eared bats were the Chinese water myotis (Myotis laniger) "body mass: (4.46±0.53) g, forearm: (34.63±1.45 mm)", fringed long-footed myotis (Myotis fimbriatus) "body mass: (5.15±1.76) g, forearm: (35.20±1.07) mm" and szechwan myotis (Myotis altarium) "body mass: (10.94±0.87) g, forearm: (45.21±1.15) mm". There were significant differences in the body masses of the three species. The forearm length of M. altarium was significantly longer than the other two species. M. laniger preyed mostly on dipsters and their larvae (79.7% in volume and 100% in frequency, Diptera). M. fimbriatus preyed mostly on dipsters and small beetles (59.6% and 91.3%, Diptera; 28.8% and 80.1%, Coleoptera). The prey of M. altarium was mostly ground-dwelling beetles (80.8% and 100%, Carabidae and Silphidae, Coleoptera). These dietary examinations indicate that the three species are highly adapted to different foraging habitats. Our work suggests that the spatial differences in foraging niches and trophic resource partitioning represent the major mechanism behind the levels of co-existence seen in this particular bat community.