Explaining leptokurtic movement distributions: intrapopulation variation in boldness and exploration.

Leptokurtic distributions of movement distances observed in field-release studies, in which some individuals move long distances while most remain at or near their release point, are a common feature of mobile animals. However, because leptokurtosis is predicted to be transient in homogeneous populations, persistent leptokurtosis suggests a population heterogeneity. We found evidence for a heterogeneity that may generate persistent leptokurtosis. We tested individuals of the Trinidad killifish Rivulus hartii for boldness in a tank test and released them back into their native stream. Boldness in the tank test predicted distance moved in the field releases, even after effects of size and sex were removed. Further, data from a 19-mo mark-recapture study showed that individual growth correlated positively with movement in a predator-threatened river zone where the Rivulus population is spatially fragmented and dispersal is likely to be a hazardous activity. In contrast, no such correlation existed in a predator-absent zone where the population is unfragmented. These results show that a behavioral trait, not discernible from body size or sex, contributes to dispersal and that a component of fitness of surviving "dispersers" is elevated above that of "stayers," a fundamental assumption or prediction of many models of the evolution of dispersal through hazardous habitat.

Characterization of 32 novel microsatellite loci for population and mating system studies using Campostoma anomalum (central stoneroller).

The central stoneroller (Campostoma anomalum) is an abundant, widespread and sexually dimorphic stream minnow that is a useful model for mating system studies as well as a sentinel species for understanding population-level processes for fishes in headwater communities. We developed one genomic library enriched for dinucleotide repeats and isolated 48 putative, novel microsatellite loci. Of those, we present 32 polymorphic and independent microsatellite markers with 3 to 16 alleles per locus and heterozygosity ranging from 0.23 to 0.95. Hence, these markers will be useful for future behavioural, ecological and evolutionary studies using C. anomalum.

Twenty-three microsatellite DNA loci for population genetic studies and parentage assignment in orangethroat darter, Etheostoma spectabile.

The genus Etheostoma is a species-rich and ecologically important group of fishes in North America. The orangethroat darter (Etheostoma spectabile) is widely distributed and abundant in headwater streams throughout the central Midwest, and is an excellent model for ecological and mating system studies. We developed 23 novel, polymorphic, and independent microsatellite loci for E. spectabile. We found from two to 14 alleles per locus, and observed heterozygosities ranged from 0.39 to 1.0. These markers, in combination with others isolated from Etheostoma taxa, will be useful for ecological and evolutionary studies in the genus.