Numerical study of dynamic noseleaf models in greater horseshoe bats, Rhinolophus ferrumequinum

Li Gao,Xin Ma,Zhiwei Zhang,Weikai He,Hongwang Lu,Jianxiong Feng,V Goussev,J Yin

doi:10.1051/matecconf/201928304007

Abstract

Echolocating greater horseshoe bats (Rhinolophus ferrumequinum) emit biosonar pulses through nostril. The nostrilis surrounded by sophisticated and delicate appendages, i.e. noseleaf. It is known that the static part of noseleaf can cause different effects on bat biosonar pulse. In addition, the dynmaic noseleaf was found to be able to shape their emission beam. For detailed investigation of the effects of dynamic lancet on the ultrasonic beam, a 3D noseleaf model was constructed using the micro CT scanning of the noseleaf samples, and a simple model was constructed digitally for comparison. The model consists of two parts, for which one is the triangle on the top and the other one is the rectangle at the bottom. Quantitative numerical investigation on the lancet dynamic effect on the ultrasonic beam was performed using finite element analysis for both models.

Highlights

Different species of bats have developed different echolocation strategy to adapt to their living environment
Horseshoe bat emits sonar through nostril rather than mouth, and it has developed complex noseleaf that can reflect the acoustic wave [3]
The deformation of anterior leaf is closely related to the biosonar pulse [6]

Summary

Introduction

Different species of bats have developed different echolocation strategy to adapt to their living environment. Lancet can manipulate the beamwidth and the beampattern shapes in sonar pulses [4] In horseshoe bats, it has been observed by the author and other researchers that while emitting biosonar pulses, the lancet of the noseleaf is conspicuously in non-rigid motion, in addition, the lancet motion shows time overlap with the biosonar pulse [4]. The goals of this research were to: 1) investigate the detailed influence that deformation of the lancet may have on the emitted biosonar pulses in the dynamic biosonar system using numerical method, providing fundamental data from biological properties for real mechanical application; 2) investigate the acoustical beampattern of a simple model that simulates the shape of the nose leaf, deepening. The results calculated from one simplified geometry and one scanned model is compared

Models and methods

Results

Discussions

Ethics Statement