The relative effects of history, dispersal and ecology on the community structure of island systems of arboreal day geckos in the genus Phelsuma will be investigated. Restriction enzyme analysis of mtDNA will be used to distinguish between these effects. First, phylogeny of the genus will be compared with biogeography and physical history. Second, maternal inheritance patterns of mtDNA will be used to identify genotypes on recently emerged islands and determine whether these genotypes evolved in situ or represent dispersal events. This will provide a lower estimate of colonization rate. Third, maternal inheritance patterns of mtDNA will again be exploited to reconstruct the colonization history of the granitic Seychelles by P. sundbergi and P. astriata. This information will be used to determine the influences founder effects and ecological interactions have had in producing observed body size patterns. Preliminary results indicate that the Seychelles were originally "colonized" by two distantly related ancestors. The colonist leading to P. astriata was a close relative to P. lineata; the colonist leading to P. sundbergi was close relative to P. madagascariensis and P. abbotti. Further work will include basic ecological studies, ecological comparisons with Anolis radiation, and phylogenetic comparisons with other taxa.
