ABSTRACT Dingle & Baker IBN 96-25653 Fitness Consequences and Individual Strategies of Natal Dispersion Although movement behavior profoundly influences the persistence and genetic structure of populations, and the spread of favorable mutations, invading species, and parasites, it has been studied less than other behaviors and life history traits. Animals must balance costs of movement with potential benefits, and their strategies may be affected both by genetic and ecological factors, and the algorithms used to evaluate habitat. Dispersal in the desert isopod, Hemilepistus reaumuri will be studied. The simplicity and manipulability of this semelparous isopod s life cycle make it uniquely suited for study of movement. The costs of dispersal in the field, as well as habitat selection and learning will be measured. These measurements will be integrated in a dynamic model of natal dispersal to understand how dispersal costs and habitat quality affect dispersal strategies and decisions, and how decisions can change with time and individual condition. Dispersal costs will be measured in terms of a) survival as a function of distance or time dispersed, b) time lost to growth or mate attraction, and c) condition in terms of lost energy or water and its effect on survival and lifetime reproductive success. Comparisons of the success of naturally chosen breeding burrow sites and experimentally imposed random sites will be made; the effects of past experiences of habitat quality and its variability on selectivity and dispersal distance will also be examined.
