Prey availability influences the effect of boldness on reproductive success in a mammalian predator

Boldness is an important trait in wild populations and among-individual differences can link to individual fitness. The strength and direction of relationships between behavioral and life-history traits may however vary according to environmental conditions, where fluctuating selection acting on behavioral traits contributes to the maintenance of personality differences. We explored sources of variation in Arctic fox (Vulpes lagopus) boldness and investigated how temporal variation in the abundance of a main prey (lemmings) influences the relationship between fox boldness and reproductive success. We measured the behavioral reaction of individuals when escaping after handling, as an indicator of their boldness. We obtained 70 measurements from 42 individuals during two years of low lemming abundance and two years of high lemming abundance and assessed fox litter size as an indicator of reproductive success. First, individual characteristics (age, sex, mass) did not affect Arctic fox boldness, while individual identity generated variation in boldness. Next, we found that during years of low lemming density, individuals behaving boldly had more pups than those behaving less boldly, suggesting boldness may provide an advantage when lemmings are scarce by increasing hunting success or allowing access to alternative resources. However, all individuals tended to show high levels of boldness when lemming density was high, and all produced large litters. Temporal variation in the abundance of a main prey might therefore influence the relation between boldness and reproductive success of a predator, and if individuals consistently differ in their level of boldness, fluctuating selection could contribute to the maintenance of personality.The README file contains column descriptions. General information for the analyses is presented in the article.Funding provided by: Natural Sciences and Engineering Research Council of CanadaCrossref Funder Registry ID: http://dx.doi.org/10.13039/501100000038Award Number: Funding provided by: Canada Foundation for InnovationCrossref Funder Registry ID: http://dx.doi.org/10.13039/501100001805Award Number: Funding provided by: Canada Research ChairsCrossref Funder Registry ID: http://dx.doi.org/10.13039/501100001804Award Number: Funding provided by: Fonds de recherche du Québec – Nature et technologiesCrossref Funder Registry ID: http://dx.doi.org/10.13039/501100003151Award Number: Funding provided by: Polar Knowledge CanadaCrossref Funder Registry ID: http://dx.doi.org/10.13039/100012258Award Number: Funding provided by: Parks CanadaCrossref Funder Registry ID: http://dx.doi.org/10.13039/100014612Award Number: Funding provided by: Natural Resources CanadaCrossref Funder Registry ID: http://dx.doi.org/10.13039/501100000159Award Number: Funding provided by: Garfield Weston FoundationCrossref Funder Registry ID: http://dx.doi.org/10.13039/100013999Award Number