Temporal variation in feeding morphology and size-structured population dynamics in fishes
Hjelm, Joakim; Johansson, Frank
Considerable variation in morphology associated with resource use is a classic example of local adaptation to the environment. We demonstrate that a temporal change in feeding morphology might occur within a population. In a 5-year natural field experiment, we estimated gill raker morphology, resource density and population dynamics of the roach and its competitor, the perch. Despite a variation in density of zooplankton resources and perch across years, no change in roach density was observed. However, gill raker morphology in roach covaried with size structure of the zooplankton resource across years. A laboratory experiment confirmed that gill raker morphology has a great effect on roach foraging efficiency on zooplankton and that there is a functional trade-off with regard to zooplankton foraging. We suggest that the response in gill raker structure is an adaptation to deal with the rapid population dynamics of zooplankton, which are in turn mediated by changes in the size structure of the competing perch.
feeding morphology; phenotypic plasticity; size structure; functional trade-off; population dynamics
Proceedings of the Royal Society B: Biological Sciences
2003, Volym: 270, nummer: 1522, sidor: 1407-1412
Utgivare: ROYAL SOC
Permanent länk till denna sida (URI)