Biting kinematics do not differ between ecologically divergent populations of Trinidadian guppies

Abstract

AbstractPerformance, the ability to complete an ecologically relevant task, serves as a link between underlying morphology and the maximum functional capacity and fitness of an individual. Performance can vary within species due to environmental context and the trait of interest, but this is less understood compared with variation across species. Trinidadian guppy (Poecilia reticulata) populations are separated by waterfall barriers that result in repeated selection for predator avoidance in high predation environments and resource competition in low predation environments. An array of locally adapted traits results from these shifts, however, the role of these local adaptations in prey capture performance traits remains unclear. We examined biting kinematics in replicate populations of adult female guppies collected from natural high and low predation habitats. We expected that competition in low predation populations would drive performance differences compared with fish from high predation populations. Using high‐speed videos of fish feeding on an agar substrate, we did not find support for differences in jaw or approach kinematics between populations, suggesting a lack of local adaptation in our sample. To gain further insight, we examined four representative, whole‐body morphometric traits previously shown to be divergent in guppies. Again, differences were not discovered in our sample, which may indicate limitations in the use of shape traits. We suggest that female guppies are kinematic generalists and that selection on prey capture may act on traits other than performance, such as feeding behaviors (e.g., consumption rates, kinematic integration, and prey preference).