SPATIAL-DISTRIBUTION OF HOVERING MALE TABANUS-NIGROVITTATUS (DIPTERA,TABANIDAE)

Male Tabanus nigrovittatus Macquart hover as a premating strategy in t he early morning over Atlantic coastal salt marshes. These males are d istributed with peak densities near mosquito ditches and with fewer ho vering males farther from the ditch. Multivariate analysis indicated t hat male density or the distance between individuals is an important f actor in structuring hovering male spatial distribution. When compared with previously published data, male densities match peak emergence o f females. T. nigrovittatus numbers are lowest directly adjacent to mo squito ditches, where Tabanus conterminus (Walker) tends to hover, sug gesting that spatial separation may contribute to reproductive isolati on in these two sibling species.