三种共栖蝙蝠的回声定位信号特征及其夏季食性的比较

2005年6至9月,对桂林市郊区两个山洞中高颅鼠耳蝠(Myotissiligorensis)、菲菊头蝠(Rhinolo-phuspusillus)和黑髯墓蝠(Taphozousmelanopogon)的回声定位叫声特征和食性进行分析,并结合其形态特征与野外观察,推断其捕食生境和捕食策略。研究结果发现:黑髯墓蝠体型最大,声音特征属短调频型多谐波,一般为4个谐波,能量主要集中在第二谐波上,主频率为(32·84±1·17)kHz,选择鞘翅目和双翅目昆虫为主要食物;高颅鼠耳蝠(长调频型)和菲菊头蝠(长恒频-调频型),体型都较小,主频率分别是(84·44±8·13)kHz和(110·78±1·65)kHz,以双翅目昆虫为主要食物;而菲菊头蝠则以鞘翅目和双翅目昆虫为主要食物。上述结果证明,高颅鼠耳蝠、菲菊头蝠和黑髯墓蝠在声音和食物组成等方面出现了明显分化。

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.