Research into specialization of phytophagous insects to their host plants has produced a wealth of fascinating ecological and evolutionary patterns, inspiring much theoretical and empirical work in the area of how host-associations mediate differentiation. Similarly, islands have served as laboratories for evolutionary studies because of their tendency to produce rapid diversification within colonists. To investigate processes occurring at the population-species interface within an island lineage of host-associated insects, we isolated and characterized 17 microsatellite loci from the endemic Hawaiian planthopper (Nesosydne chambersi: Hemiptera: Fulgoroidea: Delphacidae), from the Big Island. This species is a relatively widespread member of a large genus, and its pattern of host use has been strongly influenced by the dynamic nature of the Hawaiian island landscape. We present a preliminary analysis of the planthopper genotype data here, including diversification among vicariant planthopper populations and the influence of recent gene flow.

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