Boldness and behavioral syndromes in the bluegill sunfish, Lepomis macrochirus

Abstract

In recent years, evidence for interindividual variation in “personality” within animal populations has been accumulating. Personality is defined as consistency in an individual's behavioral responses over time and/or across situations. One personality trait that has potentially far-reaching implications for behavioral ecology, and may provide insight into the mechanisms by which consistent behavioral correlations arise, is that of boldness. Boldness is defined as the tendency of an individual to take risks and be exploratory in novel contexts. Using the framework of behavioral syndromes, we tested for individual differences in boldness in the laboratory among field-caught juvenile bluegill sunfish (Lepomis macrochirus) within and across the contexts of exploratory behavior, activity, and risk taking (e.g., antipredator) behavior. After such testing, individuals were tagged and returned to their lake of origin as part of a mark–recapture study testing for the repeatability of individual differences in boldness. Here, we report strong and consistent individual differences in boldness within and across all 3 behavioral contexts. Additionally, we observed that at least some boldness behaviors were repeatable after a 1–3 month recapture period. This study provides novel evidence for a boldness syndrome in sunfish, as well as insight into how behavioral types (e.g., shy/bold) may evolve and be maintained in natural populations.