Influence of temperature on the development and reproduction of Metaphycus parasaissetia, an adult parasitoid of Parasaissetia nigra

Key Words：Parasaissetia nigra, Metaphycus parasaissetiae, temperature, development, reproduction

Abstract：       Under constant temperatures of 18℃, 21℃, 24℃, 27℃, 30℃, 33℃ and 36℃, the development and reproduction Metaphycus parasaissetiae Zhang and Huang, a parasitic wasp on Parasaissetia nigra （Nietner）, were studied. The developmental threshold and effective accumulated temperature of the wasp were 13.10 ℃ and 215.00 degreeday, respectively. Developmental duration of the wasp decreased with the increasing temperature, and the expected equation of developmental duration (N) against temperature (T) was N =［215.00 ± 44.32］/［T-(13.10 ± 3.24)］. The relationship between developmental rate (V) and temperature (T) was fitted to the sigmoid curve: V =-e ^{(1.33 + 37.3 / T).}It can be estimated that the wasp can finish 18 generations yearly in Hainan. The parasitic rate of the parasitoid on the pest fluctuated from 13.33% to 20.00% under the setting temperature, and reached the highest value (20.00%) at 30℃. The proportion of female wasps reached the highest (70.3%) at 27℃. With the increasing temperature, adult wasps tended to emerge concentratively, and more wasps eclosed earlier with a shortened duration of eclosion. The umber of eggs laid by each female reached the highest at 30℃, averagely 25.7 per female. The longevity of female wasps decreased with the increasing temperature, and the longevity could be significantly prolonged with the supplement of honey water. The suitable temperature range was from 27℃ to 30℃ for the development and reproduction of the parasitoid, and the optimal temperature was 30℃.