['Abiotic and biotic factors in a local habitat may strongly impact the community residing within, but spatially structured metacommunities are also influenced by regional factors such as immigration and colonization. We used three years of monthly treehole census data to evaluate the relative influence of local and regional factors on our study system.', 'Every species responded to at least one of three local environmental factors measured: water volume, leaf litter mass, and presence of a top predator. Several species were affected by water volume, and a non-exclusive group of species were influenced by leaf litter mass. Relative abundance of Aedes triseriatus was higher in treeholes with higher volumes of water, and relative abundances of three out of six other species were lower in treeholes with higher volumes of water. Leaf litter mass positively affected densities of Aedes triseriatus and relative abundance of several dipteran species. The density of the top predator, Toxorhynchites rutilus, affected the relative abundance of the two most common species, A. triseriatus and Culicoides guttipennis. Treeholes with T. rutilus had an average of two more species than treeholes without T. rutilus. We found little evidence of synchrony between pairs of treeholes, either spatially or temporally. There were high levels of spatial and temporal turnover, and spatial turnover increased with distance between patches.'] Do local and regional factors influence the structure of treehole metacommunities?