Free-ranging bats combine three different cognitive processes for roost localization

Abstract

Animals have evolved different cognitive processes to localize crucial resources that are difficult to find. Relevant cognitive processes such as associative learning and spatial memory have commonly been studied in a foraging related context under controlled laboratory conditions. However, in natural environments, animals can use multiple cognitive processes to localize resources. In this field study, we used a pairwise choice experiment and automatic roost monitoring to assess how individually marked, free-ranging Bechstein's bats belonging to two different colonies use associative learning, spatial memory and social information when localizing suitable day roosts. To our knowledge, this study tests for the first time how associative learning, spatial memory and social information are used in the process of roost localization in bats under the natural conditions. We show that, when searching for new roosts, bats used associative learning to discriminate between suitable and unsuitable roosts. For re-localizing previously occupied roosts, bats used spatial memory rather than associative learning. Moreover, bats significantly improved the localization of suitable unfamiliar roosts and tended to increase their accuracy to re-localize previously occupied day roosts using social information. Our field experiments suggest that Bechstein's bats make hierarchical use of different cognitive processes when localizing day roosts. More generally, our study underlines that evaluating different cues under natural conditions is fundamental to understanding how natural selection has shaped the cognitive processes used for localizing resources.

No evidence for memory retention of a learned association between a cue and roost quality after hibernation in free‐ranging bats

“…We glued a hemisphere to the box's lid, either with a radius of 40 or 50 mm to signal suitable and unsuitable boxes, respectively. The ability of bats to discriminate hollow hemispheres of different sizes according to their echo‐acoustic characteristics has previously been demonstrated in a foraging and roost selection context (Hernandez‐Montero et al.,; Simon, Holderied, & Helversen, 2006 in press).…”

“…Our experimental setup followed the protocol of Hernandez‐Montero et al., (in press). We tested for memory retention of a learned association using a pairwise choice experiment of roosts with different suitability associated with an external echo‐reflective cue.…”

“…We assessed associative learning and its memory retention by analyzing each bat's visiting pattern of experimental boxes. The data from 2016 are a subset of the data collected for another study by Hernandez‐Montero et al., (in press). The data from 2017 were newly collected for this study.…”

“…The data from 2017 were newly collected for this study. Data processing was in accordance to Hernandez‐Montero et al., (in press). To avoid pseudo‐replication, we considered only the first record of each bat at a given box in the night as a visit (night is defined from 19:00 to 7:00).…”

Do bats use scent cues from guano and urine to find roosts?

“…Roost choice by bats involves multiple sensory cues (Hernández-Montero et al, 2020;Kerth, 2008;Ruczyński & Kalko, 2007;Ruczyński et al, 2009), and there are several reasons why we might expect roost-finding bats to use scent-based social cues alongside other social cues. First, bats use scent in other contexts, such as social recognition, foraging, and mate selection (Bloss et al, 2002;Bouchard, 2001;Chaverri et al, 2018;De Fanis & Jones, 1995;Theis et al, 2016).…”