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 (greater than 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 greater than 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.