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Variable levels of predation pressure are known to have significant impacts on the evolutionary ecology of different populations and can affect life-history traits, behavior, and morphology. To date, no studies have directly investigated the impact of predation pressure on cognitive ability. Here we use a system of replicate rivers, each with sites of high- and low-predation pressure, to investigate how this ecological variable affects learning ability in a tropical poeciliid, Brachyraphis episcopi. We used a spatial task to assess the cognitive ability of eight populations from four independent streams (four high- and four low- predation populations). The fish were required to locate a foraging patch in one of four compartments by utilizing spatial cues. Fish from areas of low-predation pressure had shorter foraging latencies, entered fewer compartments before discovering the reward patch and navigated more actively within the maze, than fish from high-predation sites. The difference in performance is discussed with reference to forage patch predictability, inter- and intraspecific foraging competition, geographic variation in predation pressure, boldness–shyness traits, and brain lateralization.


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