Grand, T.C. Risk-taking by threespine stickleback (Gasterosteus aculeatus) pelvic phenotypes: does morphology predict behaviour?
The relationship between risk-taking behaviour and anti-predator morphology was studied in benthic threespine stickleback fish (Gasterosteus aculeatus) from Paxton and Priest Lakes on Texada Island, British Columbia, Canada. In general, Priest Lake benthics possess complete pelvic girdles and numerous lateral plates. In contrast, Paxton Lake benthics exhibit an apparent polymorphism in anti-predator morphology; some individuals possess complete pelvic girdles while others lack them entirely. Although phenotypes tended to differ in their willingness to risk exposure to a trout predator while foraging, the predicted positive relationship between risk-taking behaviour and anti-predator morphology was not observed. While 'girdled' Paxton individuals were more willing to forage in the vicinity of the predator than 'girdleless' Paxton individuals, the more heavily armoured Priest fish were intermediate in their risk-taking behaviour. These results suggest that the relationship between risk-taking behaviour and anti-predatory morphology may be influenced by differences between phenotypes in predation regime and life history.