Anxiety and exploratory behavior in the African striped mouse, Rhabdomys, taxa are partially modified by the physical rearing environment

Abstract

The environment may modulate genetic influences on behavioral expression. We investigated whether the physical rearing environment modulates anxiety and exploratory behavior in four populations, representing three species, of the striped mouse Rhabdomys. One population originated from an arid, open habitat and the others from grassy, covered habitats, and two species occurred in sympatry. We raised captive individuals of all populations in treatments that simulated cover or no cover for two generations and investigated the behavior of resulting adults in an open‐field, light–dark and startle response tests. We expected that, when raised without cover, the arid population would be less anxious and more exploratory than grassland populations, but found the opposite in the open‐field test only. We also expected that all individuals would be anxious and less exploratory when raised under cover, which was the case for anxiety in a light–dark test, but individuals from the no cover treatment were more anxious in the open‐field test. Only one population × treatment interaction was detected in which the arid population was least exploratory. Therefore, the physical rearing environment had less of an influence than phylogeny on the development of anxiety and exploration in Rhabdomys.

Social recognition and short‐term memory in two taxa of striped mouse with differing social systems

“…Similarly, female degus huddled as frequently with stranger females as they did with familiar females although interactions with strangers were typically more agonistic(Insel et al, 2020). Differences in amicability between individuals of different Rhabdomys taxa suggest that the causal mechanism for social preference may differ in the genus.Personality experiments in non-social contexts have shown that R. pumilio is comparatively less anxious and bolder than R. d. chakae(Mackay & Pillay, 2021;Rymer & Pillay, 2012) which is partially modulated by rearing environment and a result of phylogenetic differences between taxa(Mackay & Pillay, 2019). We found that R. pumilio approached stimulus females faster and investigated them for longer than R. d. chakae, regardless of stimulus type.…”

“…Personality experiments in non‐social contexts have shown that R. pumilio is comparatively less anxious and bolder than R. d. chakae (Mackay & Pillay, 2021; Rymer & Pillay, 2012) which is partially modulated by rearing environment and a result of phylogenetic differences between taxa (Mackay & Pillay, 2019). We found that R. pumilio approached stimulus females faster and investigated them for longer than R. d. chakae , regardless of stimulus type.…”

Environmental correlates of exploratory behavior and anxiety in three African striped mouse (Rhabdomys) taxa occurring in different habitats and contexts.

“…The OF consisted of a glass tank (46 × 30 × 35 cm) with opaque sides. The tank floor was divided into nine equal squares using electrical tape, which did not impede movement of a mouse in the current or any of our previous studies (Mackay & Pillay, 2019; Rymer & Pillay, 2012; Rymer et al, 2008). A single mouse was placed in the center of the tank.…”