Laterality in the Damaraland Mole-Rat: Insights from a Eusocial Mammal

SIMPLE SUMMARY: Side biases observed in behavior are thought to reflect underlying asymmetric brain function or hemispheric specialization. These asymmetries occur at the individual and population level, although population-level laterality normally is only evident in social species. In a previous study, we found both individual- and population-level laterality in a solitary mole rat species. Here, we assessed laterality in a eusocial mole rat species, the Damaraland mole rat, Fukomys damarensis, using turning biases. All individuals combined demonstrated left-turning biases, which was also significant at the population level. Wild-caught animals were more strongly lateralized, but lacked the population-level left-turning bias that was observed in captive mole rats. This emphasizes the importance of context and animal handling when measuring and interpreting behavioral asymmetries. ABSTRACT: Lateralization is the functional control of certain behaviors in the brain being processed by either the left or right hemisphere. Behavioral asymmetries can occur at an individual and population level, although population-level lateralization is less common amongst solitary species, whereas social species can benefit more from aligning and coordinating their activities. We assessed laterality (individual and population) through turning biases in the eusocial Damaraland mole rat, Fukomys damarensis. We considered factors such as breeding status (queen or subordinate), environment (wild-caught or captive), sex (male or female), colony and body mass. All individuals together demonstrated significant left-turning biases, which was also significant at the population level. Wild-caught animals were more strongly lateralized, had a wider spread over a laterality index and lacked the population-level left-turning bias as compared to captive mole rats. Subordinate animals were more lateralized than queens, demonstrating social status differences in turning biases for social mole rats. This emphasizes the importance of animal handling and context when measuring and interpreting behavioral asymmetries.