FACTORS AFFECTING THE DISTRIBUTION OF BOT FLIES (DIPTERA, OESTRIDAE) ON ISLANDS IN LAKE BARKLEY, KENTUCKY AND TENNESSEE

The present study analyzes the effect of six abiotic and eight biotic variables on the presence of Cuterebra on islands in Lake Barkley in K entucky and Tennessee. Abiotic factors were: area, length, distance to mainland, distance to nearest island, elevation, and last inundation. Biotic factors were: tree species diversity (sd), shrub sd, vine sd, and herbaceous sd, percent herbaceous cover, percent tree cover, mamma l species, and small mammal sd. A Cuterebra, presumably C. fontinella fontinella (Clark), infested white-footed mice on two islands and hous e mice on one island. Six other small mammal species were not infested . There was no significant difference between prevalence and sex of ho st. No correlation between the presence of Cuterebra and biotic or abi otic factors was found (P > 0.05). The presence of house mice did not determine the presence of Cuterebra on islands. Factors associated wit h island biogeography did not appear to play a role in determining the presence of Cuterebra. Only the presence of white-footed mice was rel ated functionally to the presence of Cuterebra on islands (R(2) = 0.85 ; P < 0.05). Although other small mammals may be found on islands, the occurrence and prevalence of C. fontinella on islands was primarily l imited by the presence of white-footed mice regardless of other abioti c or biotic factors.