9623578 Larson Geographic structuring of a group of South American annual fishes which inhabit seasonally wet environments will be analyzed using variation in mitochondrial DNA sequences. Hypotheses that phenotypic variation is correlated with molecular genetic variation, and that local adaptation to extant environments explains distributional patterns of variation in life history traits will be tested. By studying the distribution of molecular genetic variation in a statistically rigorous manner, it will be possible to determine whether phenotypic differences among populations reflect historical events or current local adaptations. Research funded by this award should improve the understanding of factors responsible for survival in environments experiencing rapid, often stochastic fluctuations. Results will also have potentially broad applied significance. Under normal conditions, temporary bodies of water become a breeding ground for mosquitoes; thus killifish, due to their unique ability to survive complete desiccation of their habitat, have been lauded as the ideal mosquito control agents. By understanding which populations are most likely to succeed in a given habitat, it will be possible to maximize the benefits of killifish as successful mosquito control agents.
