Collaborative Research: Prey Movement in Hazardous Environments: Studies in a Tropical Stream Fish System

North Carolina State University, Raleigh NC

Investigators

Abstract

Abstract Proposal Number DEB-0108439 James F. Gilliam North Carolina State University RUI: COLLABORATIVE RESEARCH: PREY MOVEMENT IN HAZARDOUS ENVIRONMENTS: STUDIES IN A TROPICAL STREAM FISH COMMUNITY The goal of this study is to explore the effects of two phenomena, predators and individual variation, on the dispersal of a tropical stream fish. Their effects on dispersal are unknown. The first question addresses whether increasing predator threat, with the addition of predatory fish species, slows dispersal rate of the prey species through threatened zones of a river (a previous study found that a predatory fish increased rather than suppressed prey movement). The second question evaluates if individual boldness in the tendency to explore beyond the home range contributes to dispersal rate within a population and if so, whether individual differences are inherited. Fieldwork will be done in natural streams in Trinidad that contain the prey species, but which differ in the number of predator species that they contain. Movement in each stream will be determined by mark-recapture procedures. Individual variation in boldness will be evaluated through behavioral assays, and its heritability assessed by rearing offspring of movers and non-movers. To directly determine whether individual variation in boldness contributes to dispersal rate in nature, a reciprocal transplant experiment will be done in two sister tributaries of a river in which movers in one tributary will be exchanged for stayers in the other. If boldness is an individual characteristic, the two streams should eventually contain populations that differ in rates of dispersal. The results of the proposed studies with fish are expected to open new avenues to understanding the factors that affect the dispersal in natural habitats of tropical rivers.