Worth the reward? An experimental assessment of risk-taking behavior along a life history gradient

Life history theory predicts that species with faster life history strategies should be willing to risk their survival more to acquire resources than those with slower life history strategies. Foraging can be a risky behavior and animals generally face a tradeoff between food consumption and predation risk. We predicted that the degree to which animals invest in current versus future reproduction (i.e. life history strategy) would determine how they approach this tradeoff. We manipulated food abundance in wetlands to assess whether life history theory could explain risk taking among females of five duck species with respect to foraging. We found evidence consistent with our prediction based on life history theory; species with a faster life history strategy were willing to engage in riskier behavior, by feeding more intensively, for a greater food reward. Females from species with faster life history strategies devoted 25% more time to feeding when in high food density treatment plots versus control plots. The percentage of time that females from species with slower life history strategies devoted to feeding was not affected by food density. These findings contribute to our understanding of life history theory and represent a possible mechanism to explain differences in life history strategies among species.