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

Abstract

Species or populations are locally adapted to the environments they occupy because of different selection pressures. Our study considers behavioral differences in rodents originating from environments with different levels of overhead cover. We investigated exploratory behavior and anxiety in 4 populations of the African striped mouse Rhabdomys, in South Africa, from different environments: R. pumilio from a semi-desert; R. bechuanae and R. d. dilectus, which were sympatric in the central grasslands; and another allopatric R. d. dilectus occurred in the northern grasslands. We tested all individuals in 5 standard laboratory tests: light-dark, startle response, open field and novel object tests, and the plus maze. In a principle components analysis, R. pumilio and the central grassland R. dilectus grouped together, and R. bechuanae and the allopatric R. dilectus grouped together, but there was some overlap between populations. Univariate analyses showed population-level differences in exploration and anxiety. R. pumilio and the central R. d. dilectus were more exploratory and less anxious than R. bechuanae and the allopatric R. d. dilectus. The behavior of R. pumilio (more exploratory and less anxious) reflects the open environments it occupies in nature, whereas the allopatric R. d. dilectus and R. bechuanae were less exploratory and more anxious reflecting the closed habitats they occupy. The similarity between R. pumilio and the central R. d. dilectus cannot be explained by habitat and might be related to the effects of coexistence between central grassland R. d. dilectus and R. bechuanae, which may potentially alter the behavior of one or both species. (PsycInfo Database Record (c) 2021 APA, all rights reserved).