Investigation of acoustic navigation strategy of bats based on spatial learning by a mathematical model

Abstract

Echolocating bats achieve minimal design ultrasonic sensing using one transmitter and two receivers. We have previously found that the bats adaptively change avoidance routes and number and direction of broadcasts as they learn obstacle space by repeatedly flight. In this research, we propose a mathematical model that represents changes in flight path and pulse emission during spatial learning of bats based on these behavioral data. Specifically, by using the psychological effect of alertness to obstacles as a parameter, we confirmed that a simple mathematical model can express the changes in acoustic navigation as the bats learn the space. Furthermore, we flied the bats in spaces where either acoustically clear (chain trains) or poorly permeability obstacles (acrylic boards) were placed in the same layout. As a result, differences in flight speed and pulse direction were found between those two conditions. By comparing the simulation result from mathematical model with behavioral results, we discuss psychological effects on unknown and known space due to differences in acoustic permeability and utilization of spatial memory during navigation. [Work supported by JSPS KAKENHI Grant Nos. JP18H03786 and JP16H06542 and JST PESTO Grant No. JPMJPR14D8.]