| heal.abstract |
The effect of temperature on the development of immature stages of the predator Iphiseius degenerans (Berlese) was studied at 15, 20, 25, 27.5, 30, and 32.5°C with 60% RH and photoperiod of 16:8 (L:D) h when feeding on Tetranychus urticae. The data obtained were used for the estimation of the thermal requirements of this predator by a linear and nonlinear model (Lactin 2-model). Developmental thresholds that were estimated by the linear model for immature stages of egg, protonymph, and deutonymph were approximately the same and found to be 11.71, 10.11, and 11.28°C, respectively, whereas that of the larval stage was found to be lower (7°C). The Lactin-2 model was also applied, and lower values were estimated for all immature stages than those by the linear model. Biological characteristics and life table parameters of the predator were also studied at 15, 20, 25, 30, and 32.5°C. Preoviposition period was shortest at high temperatures of 30 and 32.5°C (1.18 and 1.08 d, respectively), whereas fecundity was highest at 30°C. Longevity of adults and mean generation time was longest at 15°C. The intrinsic rate of increase was highest at 25 and 30°C (0.22 and 0.23 d -1, respectively), whereas doubling time was found to be shortest at 30°C. The results show that this predator develops effectively at a broad range of temperatures. Moreover, it can increase at relatively high temperatures and is well adapted to the high temperatures that occur in Mediterranean region. © 2006 Entomological Society of America. |
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