Data from: The phenotypic determinants of diet variation between divergent lineages of threespine stickleback

<p><span>Lineages with independent evolutionary histories often differ in both their morphology and</span> <span>diet. Experimental work has improved our understanding of the links between the biomechanics of morphological traits and foraging performance (trait-utility). However, because the expression of foraging-relevant traits and their utility can be highly context-specific, it is often unclear how dietary divergence arises from evolved phenotypic differences. Here, we explore the phenotypic causes of dietary divergence between two genetically and phenotypically divergent lineages of threespine stickleback (Gasterosteus aculeatus) with independent evolutionary histories of freshwater colonization and adaptation. First, using individuals from a line-cross breeding design, we conducted 150 common-garden foraging trials with a community of multiple prey species and performed morphological and behavioural analyses to test for prey-specific trait-utility. Second, we tested if the traits that explain variation in foraging performance among all individuals could also explain the dietary divergence between the lineages. Overall, we found evidence for the utility of several foraging traits, but these traits did not explain the observed dietary divergence between the lineages in common garden. This work suggests that evolved dietary divergence results not only from differences in morphology but also from divergence in behaviours that underlie prey capture success in species-rich prey communities.</span></p>