In Cave Dwelling Bat Echolocation Sound Waves And Niche Differentiation

Echolocation system and flight are two characters which distinguish bats from other mammalians. Bats use echolocation calls to orient and detect targets. Bat's ability to locate enviroments and discriminate targets changes along with echolocation calls. Flight characters associate with morphologic features. With different wing shape, the velocity and maneuvorbility change evidently, and so do suitable foraging habitat and targets type. Bats those inhabit in the same habitat will present ecopartition in echolocation, morphology, diets and so on in order to avoid interspecies competition. Therefore, in the thesis, first descripe morphologic characters and analyse echolocation calls of five bat species, Myotis daubentonii, M. formosus, Murina leucogaster, M. ikonnikovi, Rhinolophus ferrumequinum in different of sex and states which includes flight, stationary, hanging and crawling; sencondly, study the difference of echolocation calls during flight, diets, morhpologic characters, foraging habitat, foraging strategy and action rules of the five bat species by contrast. At last, conclude that that niche separation of the bats are evident, what make bats coexist stably. Rhinolophus ferrumequinum is biggest in these 5 species(mess is about 20g), use CF echolocation calls, which is sensitive to wing-vibrated insects. It feeds mainly on big-medium insects of order Lepidoptera and Coleoptera, foraging in wide space and sparse-foliage forest by aerial feeding and gleaning. Other four species all use FM echolocation calls. Murina leucogaster and M. formosus are nearly the same in body size, the former's wave width is wondrously big. It feeds mainly on medium-small insects of order Lepidoptera and Diptera, foraging in complicated forest by aerial feeding. The latter's wave width is medium. It feeds mainly on medium-small insects of order Coleoptera and Lepidoptera, foraging in medium-complicated forest by aerial feeding or gleaning. M. daubentonii and M. ikonnikovi are the smallest ones in size. The former' wave width is medium. It feeds mainly on aquatic small insects of order Diptera and Trichoptera, foraging in 5-20cm above water surface and midium- complicated forest by trawling and aerial feeding. The latter's wave width is shortest, which have disadvantage to discriminate targets from enviroment. It feeds mainly on even smaller insects of order Lepidoptera and Diptera, foraging in wide space or sparse-foliage forest by aerial feeding. Vision is an important assistant means during foraging. These interspecies differences decrease interspecies competition, and ensure they can coexist in one cave steadily. At the same time, the result show that there is significant difference of echolocation calls in different states in all species, and only in M. daubentonii and M. ikonnikovi that there is significant difference in body size and echolocation calls betweed two sexes, but not in R. Ferrumequinum. The difference in calls and morphology is possibly the means of escaping interspecies sound jamming and ardent competition. While the difference of sound during flight indicate that bats may prefer to different foraging styles, foraging habitat, targets size and so on.