Data from: Predator life history and prey ontogeny limit natural selection on the major armour gene, Eda, in threespine stickleback

Natural selection shapes the evolution of antipredator traits in prey.
However, selection in the wild depends on ecological context, including
features of predator and prey populations, making field studies of
selection critical to understanding how predators shape selection on prey
defenses. Threespine stickleback (Gasterosteus aculeatus) is a classic
system to study the effects of predators on the natural selection of prey.
In lakes and rivers, fish predators have been shown to impose selection
against low plated adult stickleback phenotypes and genotypes. We directly
measured selection by predatory salmonids on the Ectodysplasin-A (Eda)
gene in estuary stickleback from California. Despite previous studies
showing a positive correlation between predator presence and frequency of
the Eda ‘complete’ allele in estuary populations, we found that Eda ‘low’
genotypes were not significantly more frequent in salmonid predator diets.
Further, we found no evidence of changes in Eda genotype frequencies
across generations that would suggest directional selection driven by
predators. Prior selection studies have examined the effects of large
resident trout on adult stickleback. In contrast, predators in this study
were juvenile anadromous salmonids, which only ate juvenile stickleback
whose plate phenotypes had not fully developed. Thus, in this case,
predator life history and stickleback ontogeny may preclude strong
selection on stickleback armor. Our results underscore the importance of
selection studies in the wild for understanding the context-dependent
nature of selection in natural populations.