[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.