The shy, the digger and the adventurous: consistency and repeatability of personality traits in the social Lusitanian pine vole, Microtus lusitanicus

Abstract

In social species, the array of behavioral traits displayed by the different elements of the group can play a key role in the dynamics and fitness of the colony. This could help explain group organization, dispersion, and species’ sociality level. The Lusitanian pine vole, with its complex tunnel system and cooperative breeding strategy, is a perfect candidate to study personality in a social species. We formed laboratory-colonies with wild-caught individuals and their laboratory-reared offspring, and performed repeated behavioral tests of activity, exploration, and boldness. We identified one personality trait (Shyness) and two behavioral syndromes: the Active-Explorative-Bold Syndrome, characterizing individuals that are active, explorative, and bold aboveground; and the Explorative-Shy Syndrome, characterizing individuals not bold enough to venture out in the open often, but being quite explorative underground. Our results suggest that some individuals spend more time aboveground to forage for food and nest materials, while others may be more prone to stay underground, maintaining the burrows and taking care of offspring. By testing across different generations, we found that some traits were not consistent across life stages, indicating that behavioral changes occur during M. lusitanicus’ ontogeny. Lastly, we also found differences between wild-caught and lab-reared individuals, suggesting that captivity can lead to a loss of variation in personality traits in this species. Our results can contribute to a better understanding of the role of diverse personality types in populations of social species, of how personality structure can change across the lifespan and how environmental complexity can shape personality traits.