Signals of predation-induced directional and disruptive selection in the threespine stickleback
Year: 2012
Type: article
Abstract: Background: Different predation regimes may exert divergent selection pressure on \nphenotypes and their associated genotypes. Threespine stickleback Gasterosteus aculeatus have \na suite of bony structures, which have been shown to be an effective defence against predation \nand have a well-known genetic basis. \nQuestion: Do different predator regimes induce different selective pressures on growth rates \nand defence phenotypes in threespine stickleback between different habitats across distinct age \nclasses? \nHypothesis: In the presence of predation-induced selection, we expect diverging \nmorphological responses between populations experiencing either low or high predation \npressure. \nStudy system: Threespine stickleback were sampled from two natural but recently established \npopulations in an invasive range. One site has a high density of fish and insect predators, while \nat the other site predation pressure is low. \nMethods: We inferred predator-induced selection on defence traits by comparing the \ndistribution of size classes, defence phenotypes, and an armour-related genotype between different \nage classes in a high and a low predation regime. \nResults: Under high predation, there are indications of directional selection for faster growth, \nwhereas lateral plate phenotypes and associated genotypes show indications for disruptive \nselection. Heterozygotes at the Eda-gene have a lower survival rate than either homozygote. \nNeither pattern is evident in the low predation regime. \nConclusion: Potential evolutionary responses to divergent predation pressures between sites \nare apparent in a recently established system.
Language: English
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W1607225207