Wild bats briefly decouple sound production from wingbeats to increase sensory flow during prey captures

Abstract

Summary Active sensing animals such as echolocating bats produce the energy with which they probe their environment. The intense echolocation calls of bats are energetically expensive, but their cost can be reduced by synchronizing the exhalations needed to vocalize to wingbeats. Here, we use sound-and-movement recording tags to investigate how wild bats balance efficient sound production with information needs during foraging and navigation. We show that wild bats prioritize energy efficiency over sensory flow when periodic snapshots of the acoustic scene are sufficient during travel and search. Rapid calls during tracking and interception of close prey are decoupled from the wingbeat but are weaker and comprise <2% of all calls during a night of hunting. The limited use of fast sonar sampling provides bats with high information update rates during critical hunting moments but adds little to their overall costs of sound production despite the inefficiency of decoupling calls from wingbeats.

Correction: Echolocating Daubenton's bats are resilient to broadband, ultrasonic masking noise during active target approaches

“…5). We speculate that the bats perhaps were not able to maintain the same high SL across a whole approach because of the decoupling of call emission and wingbeats at close ranges that seemingly dictates lower SL at higher wingbeat frequencies (Stidsholt et al, 2021). In that light, our findings imply that echo information redundancy via higher biosonar sampling rates when closing on a target is more important to the bat than improving ENRs in noise.…”

Pregnancy-related sensory deficits might impair foraging in echolocating bats

“…S1). We also compared the wingbeat rate of the two groups, since bats are known to adjust emission timing to their wingbeat in order to conserve energy [ 27 , 28 ], but found no significant difference ( P = 0.5, mixed-effect GLM with BMI as the fixed effect and bat ID and trial number as random effects, n = 10). The distribution of the IPIs between the groups indicates that the pregnant bats emitted calls once every wingbeat or every other wingbeat more frequently than the post-lactating bats (Additional file 2 : Fig.…”

Daubenton’s bats maintain stereotypical echolocation behaviour and a lombard response during target interception in light

“…To test our second hypothesis, we examined how bats used decreased call intervals and increased buzz durations in different light and noise conditions. As a result of the coupling between call production and wingbeat cycle in bats [ 51 , 52 ], we found bimodal CI distributions. To identify individual peaks in CI data, we performed k- means clustering on all non-buzz calls using the function kmeans() with 4 clusters.…”