拖网式食鱼蝠——大足鼠耳蝠的形态、回声定位声波及捕食策略

Morphological features, echolocation calls and foraging strategy in the trawling piscivorous bat: Rickett's big-footed bat Myotis ricketti

大足鼠耳蝠(Myotisricketti)是中国特有蝙蝠,其回声定位声波和捕食策略国内外均无报道,对大足鼠耳蝠该方面的研究报导是国内首次。大足鼠耳蝠体型较大,具有强大的后足,足上有强而有力的弯曲的爪,尾膜和距很长。大足鼠耳蝠回声定位声波为FM(调频)型,一般具有1～2个谐波,主频率较低(37.78±1.04kHz),调频带较宽(第一谐波频带宽为42.02±6.98kHz,第二谐波频带宽为25.79±7.89kHz),声脉冲时间较长(2.91±0.54ms),声脉冲间隔时间变化较大(32.30±15.10ms),能率环较高(11.27±5.84%);野外观察发现,大足鼠耳蝠主要在低水面上空飞行,利用大足从水面捕食猎物(拖网式捕食),猎物主要由鱼类组成。即分析和讨论了大足鼠耳蝠形态特征、回声定位特征和捕食策略的相互适应性。

The Rickett's bigfooted bat (Myotis ricketti) is an endemic bat species in China, and the research about its echolocation call and its foraging strategy has not been reported in China or abroad. So the study about the Rickett's bigfooted bat in this article is the first report in China. The Rickett's bigfooted bat has quite big body, has strong and large feet, and its feet have strong and crooked claws, its tail membrane and its astragalus are quite long. The bigfooted bat emits FM (frequency modulated) echolocation with 1 to 2 harmonics, its dominant frequency is low (3778±104 kHz). The band width of modulated frequency is wide (the band width of first harmonics is 4202±698 kHz, and the band width of second harmonics is 2579±789 kHz). The pulse duration (2.91±054 ms) of the bigfooted bat's echolocation is long relative to other Myotis bats, and the interval between pulses has relatively large variability (3230±1510 ms), and its dutycycle is quite high (1127%±584 %). The Rickett's bigfooted bat mainly flied close to the water surface of pond, and they hunt for preys from water surface by their large feet (trawling) according to wild investigation. And its food mainly consisted of small fishes. We analyzed and discussed the adaptability between the bigfooted bat's morphological features, its echolocation characteristics and its foraging strategy in this article. 