Echolocation calls of 10 Chinese rhinolophid species were recorded to investigate the relationship between morphology and echolocation signals. All horseshoe bats use FM-CF-FM calls. Rhinolophus rex calls at 23.7 kHz, the lowest frequency in this genus. Call frequency was not correlated with body mass (P=0.200, 9 species). Close negative relationships were found between call frequency and ear length (r=-0.942, P<0.001) and also between call frequency and forearm length (r=-0.696, P<0.05). Residual analysis was carried out to remove the influence of other morphological features. After calculating ear length, forearm length residuals were not significantly related to call frequency (r=-0.095, P=0.808). The significance of the correlation between ear length and call frequency was slightly lowered (r=-0.642, P=0.062) after “removing” the influence of forearm length. Ear length, therefore, was a better predictor of call frequency than forearm length [Acta Zoologica Sinica 49(1):128-133,2003].
When they are flying,Great evening bat ( Ia io ) produces short FM echolocation calls including three harmonics,of which the first one and the second one are stronger.As they fly,the first harmonic is modulated from 49 0 to 18 3 kHz,the second one is modulated from 80 0 to 35 6 kHz,and the third one from 87 2 to 56 7 kHz.The average duration of the calls is 3 7 ms.It was predicted that Great evening bat ( Ia io ) captures big insects in the open area among foliages according to the sound characteristic analysis of echolocation calls and the analysis comparing with the echolocation calls of other bats that perch in the same cave.
