Social information use for spatial decision in Zootoca vivipara

Abstract

Movements of individuals are conditioned by information acquisition coming from either personal or social sources. Yet, little is known about the processes used by individuals to make movement decisions when facing multiple sources of social information simultaneously. This study aimed to test experimentally how social information from multiple sources is used to make movement decisions, and whether a contrast in this information allows individuals to orientate in space. We used common lizards (Zootoca vivipara) in a replicated experimental setting: one focal individual received information from two other individuals coming from peripheral environments, before being given the opportunity to relocate in one or another of the peripheral environments. Our analyses revealed that the behavior of informants, their mothers morphology, as well as the quality of informants environment, affected movement decisions: the probability to relocate from the focal area increased when informants displayed traits associated with low resources (no food intake, poor maternal condition) or high competition (high activity). The physical condition of individuals also mediated the use of social information about food intake, with a match between resource availability in informants and personal condition. Conversely, spatial orientation was not affected by the contrast of phenotype between informants nor by spatial variability in resource availability. This study highlights that multiple social information sources can be used for movement decisions, likely because these information sources reflect the quality of the surrounding environment (e.g., competition level or resources availability). It also emphasizes that social information use for movement is conditioned by individual phenotype.