Characteristics of Echolocation Calls and Summer Diet of Three Sympatric Insectivorous Bats Species

From June to September, 2005, we compared echolocation calls, the summer diet and morphologic features of three bats species (Myotis siligorensis, Rhinolophus pusillus and Taphozous melanopogon) captured in two caves around Guilin city, Guangxi province, China. We got the following results: (1) Echolocation calls of T. melanopogon are lower modulated frequency (FM), with dominant frequency (32.84±1.17)kHz, and multi-harmonics (usually with four harmonics). This species has the largest body size, highest ratio of wing length to wing width and highest wing loading. This species is adapted to fly fast and forage for larger insects in open area such as those in treetops and above farmland. (2) The echolocation calls of M. siligorensis are FM. Their dominant frequency (84.44±8.13)kHz is higher than T. melanopogon. They have smaller body size, lower ratio of wing length to wing width and lower wing loading which are adapted to fly slower but are more manoeuvrable and suited to forage for small insects. (3) The echolocation calls of R. pusillus are long FM-CF-FM and their dominant frequency (110.78±1.65)kHz is the highest among these three species. R. pusillus and M. siligorensis have similar morphology with similar flight ability and manoeuvrability therefore they forage in similar habitat. In conclusion, these bats species differ from each other obviously in echolocation calls and diets, which lead to their conspicuously partitioned niches.