The Research On The Acoustic Characteristic And The Related Nuclei Function Of The Hipposideros Armiger's Doppler Shift Compensation Behavior.

Great leaf-nosed bat(Hipposideros armiger)represents the most delicate echolocation system bat group which perform a particularly sophisticated laryngeal echolocation behavior called Doppler-shift compensation(DSC). We used the pendulum device to study Doppler-shifted compensation of Hipposideros armiger. The bats'echolocation calls were recorded by the Ultrasound Detector both under the rest condition and Doppler shift condition. Then we analyzed the calls with Avisoft software. Our results suggested that when H. armiger was approaching the target, it showed positive Doppler shift compensation:call frequency and the velocity (v) were positive correlated. Call frequency fell to minimum when the bats'relative velocity reached to maximum; likewise call frequency raised to the resting condition frequency when the relative velocity became zero. Negative Doppler shift compensation occurred when bats were far away from the target. Under negative Doppler shift compensation condition, we found call frequency and velocity were positive correlated as well, and moreover, call frequency raised to maximum again while the bats had their minus direction's maximal relative velocity. However, under this status, the elevated value was much lower than the depressed value under positive compensation at the same velocity. The frequency of occurrence of negative compensation was obviously less frequent than that under positive compensation condition. Therefore, we inferred that the two characteristics of the negative Doppler shift compensation mentioned above may be the coactions consequence of the bio-structural restriction and natural selection. The key factor of uncovering the secret of bats' echolocation lies in the integration and feedback mechanism of the auditory and vocalization system. The inferior colliculus is an important nuclei in the mammals' auditory pathway, it plays crucial role in the task of auditory information processing. FoxP2 gene is the only known gene so far that affect the development of vocal and language system. Therefore,we knocked-down FoxP2 expression in the IC of great leaf-nosed bat. The result indicated that the knock-down in IC did not affect the the amount of the compensation frequencies during DSC and had no effect on call frequencies when bat at rest. We inferred that the FoxP2 gene expressed in the IC of the great leaf-nosed bat may not involved in the integration and tuning of auditory information in the IC area, which suggested that IC is not either the intergration center of the auditoty and vocal system nor the control centor of the DSC behavior.