Adaptations in the echolocation behavior of fruit-eating bats when orienting under challenging conditions

Abstract

statement 24When echolocating under demanding conditions e.g. noisy, narrow space, or cluttered environments, 25 frugivorous bats adapt their call pattern by increasing the call rate within biosonar groups. 26 Abstract 27For orientation, echolocating bats emit biosonar calls and use echoes arising from call reflections. 28They often pattern their calls into groups which increases the rate of sensory feedback over time. 29Insectivorous bats emit call groups at a higher rate when orienting in cluttered compared to uncluttered 30 environments. Frugivorous bats increase the rate of call group emission when they echolocate in noisy 31 environments. Here, calls emitted by conspecifics potentially interfere with the bat's biosonar signals 32 and complicate the echolocation behavior. To minimize the information loss followed by signal 33 interference, bats may profit from a temporally increased sensory acquisition rate, as it is the case for 34 the call groups. In frugivorous bats, it remains unclear if call group emission represents an exclusive 35 adaptation to avoid interference by signals from other bats or if it represents an adaptation that allows 36to orient under demanding environmental conditions. Here, we compared the emission pattern of the 37 frugivorous bat Carollia perspicillata when the bats were flying in noisy versus silent, narrow versus 38 wide or cluttered versus non-cluttered corridors. According to our results, the bats emitted larger call 39 groups and they increased the call rate within the call groups when navigating in narrow, cluttered, or 40 noisy environments. Thus, call group emission represents an adaptive behavior when the bats orient in 41 complex environments. 42 43 orientation 45 259 260 Amichai, E., Blumrosen, G. and Yovel, Y. (2015). Calling louder and longer: how bats use 261 biosonar under severe acoustic interference from other bats.