Laboratory measures of boldness correlate to ecological niche in threespine stickleback

Research on among individual variation in behavior has increased rapidly in recent years. It is intuitively appealing that among individual variation in behavior has ecological consequences and among the most likely to be affected is trophic niche. Bold individuals, with the tendency to be explorative and risk tolerant, can be less likely to alter their foraging behavior across contexts and therefore forage more consistently. Stable isotopes are a useful tool to retrospectively estimate ecological niche and have been found to correlate to foraging behavior in the wild. It is now pressing to extent studies to further examine the ecological or evolutionary relevance of personality. We examined if common behavioral traits were correlated to ecological niche in the wild using a rapid behavioral assay and δ13C and δ15N stable isotopes from fin and muscle reflecting ecological niche for the previous weeks and months. We found that latency to explore, as a proxy for boldness, correlated to values of δ13C with bolder fish having lower δ13C values. Moreover, latency to explore also explained variation in the change in individual stable isotope niche over time. These results highlight the long-term ecological importance of among individual variation in behavior and are among the first to support a correlation of laboratory measures of behavior and ecological niche in the wild.