EFFECT OF TEMPERATURE ON LATE IMMATURE STAGES OF CULICOIDES-BREVITARSIS (DIPTERA, CERATOPOGONIDAE)

Fourth-instar larvae of the biting midge, Culicoides brevitarsis Kieffer, were reared to adult in agar medium at temperatures of 20, 26, 30.5, 33, 35.5, 38 and 40-degrees-C. Optimum (> 80%) survival to adult occurred from 26 to 33-degrees-C. Temperatures outside this range disrupted development. Above 35.5-degrees-C, all immatures died before completing development. Duration of development from fourth instar to adult was shortest at 30.5-degrees-C (4.3 d). The estimated duration of development from egg to adult at 26-33-degrees-C was 11-13 d. The increased mortality of immature stages at temperatures > 33-degrees-C may be significant in the reduction of adult populations during summer in inland areas of the northern Australian tropics, where mean monthly maxima exceed 35-degrees-C from October until February.