Phenotypic plasticity, the possibility of a single genotype to produce different phenotypes depending on environmental circumstances, is observed frequently in nature. Environmental changes can have negative consequences on the fitness of individuals or on the population abundance that phenotypic plasticity can prevent. At the individual level one of the most widespread and well-documented changes in life history is a change in feeding strategy over an individual's lifetime. This important life history strategy can also be subject to phenotypic plasticity. Although individual life history strategy is increasingly taken into account in the study of population dynamics, it is still unclear how phenotypic plasticity in feeding strategy affects coexistence of different strategies in the population and the population itself. To investigate the question, we use a structured population model where growth and reproduction are physiological functions of body size.
Results/Conclusions
We show that coexistence between two different feeding strategies is generally limited and restricted to a small range of values where the profitabilities of both resources are roughly equal. If the profitability of one of the resources is higher than the other, the individuals specializing on this highly profitable resource solely contribute to the population persistence. The alternative feeding strategy acts as a life history dead end: juvenile individuals choosing this strategy do occur in the population but never make it to reproduction. If the diet choice is plastic, the range of resource profitability for which there is coexistence of the strategies broadens to some extent, but is still not substantial. Unlike what could be expected, the phenotypic plasticity doesn't enhance an efficient use of both resources to increase population size. Our results show that the main role of phenotypic plasticity in feeding strategy is to buffer negative consequences of resource variabilities on the population persistence.