Influence of constant and variable temperatures on pupal development of the sheep bot fly (Oestrus ovis L.)

The paper presents the results obtained in experiments on the influence of constant and variable temperatures on the pupal development of the sheep bot fly Oestrus ovis L. The lower thermic threshold of pupal development was established (12.1 degrees C for males, 11.5 degrees C for females). The sum of the effective temperatures necessary for the completion of pupal development was calculated (242.9 +/- 3.0 degree/day for males, 278.8 +/- 3.8 degree/day for females). The long duration of the female development was noticed for the first time, this fact being explained by energy consumed for the maturing of sexual products. It was determined that pupal development of the sheep bot fly under variable temperatures within the limits of the temperature norms of the species is equal to the development under the respective mean temperature. Extreme high temperatures included in the amplitude inhibit the development. This proves the suitability of the calculated value of the heat sum for phenological prognoses.