Dominance and diet are unrelated within a population of invasive crayfish

Laboratory behavioral experiments are an important tool in ecology and evolution, but whether these behaviors reflect the field function of organisms is not always clear. Directly connecting laboratory behaviors to field interactions would increase understanding of a variety of organisms. A recent study proposed using stable isotopes to link laboratory behaviors to field function of individuals, but failed to find any such links within a population of the invasive rusty crayfish Faxonius rusticus (Girard, 1852). Here, we assessed whether methodological decisions around tissue analyzed for stable isotopes, laboratory acclimation time, and timing of primary consumer collection may have affected the result, hypothesizing that more dominant crayfish would have higher trophic positions and tissue with faster turnover rates may exhibit a stronger association between laboratory behavior and recent field function. We tested this relationship using F. rusticus individuals from a single population, and related laboratory dominance to stable isotope-derived trophic position using linear regression. We failed to find a relationship between dominance and trophic position, regardless of our different methodologies. Future studies should consider alternative behaviors that may better relate to function in the field and also investigate whether laboratory behavior and field function are related between, rather than within, populations or species.