BIOLOGICAL AND LIFE TABLE PARAMETERS OF Stethorus gilvifrons (Muls.) (Coleoptera: Coccinellidae) REARED ON Tetranychus urticae Koch.

Developmental time and rate of immature stages, growth index, survival percentage, longevity, fecundity, and life table parameters of Stethorus gilvifrons (Muls.) when reared on Tetranychus urticae Koch were studied at three constant temperatures (20, 25, and 30℃). There were significant variations in total developmental time of immature stages of the predator (male and female) among the three tested temperatures when the predator was reared on T. urticae. Growth index and developmental rate of S. gilvifrons males and females were higher at 30℃ than 20 and 25℃ when reared on the tetranychid mite. There were significant differences in pre-oviposition period among the three tested temperatures. In addition, there were significant variations among inter-oviposition, oviposition, and total longevity when the predator was reared at the three tested temperatures. Male longevity was significantly shorter at 30℃ than at 20 and 25℃ when fed on T. urticae. Fecundity rate was significantly higher at 30℃ than at 20 and 25℃ when fed on T. urticae. The mean generation time (T) and doubling time (DT) were shorter at 30℃ than at 20 and 25℃ which fed on T. urticae at 30 ℃. Generally, the value of gross reproductive rate (GRR), the net reproduction rate (Ro), the intrinsic rate of increase (rm), the finite rate of increase (λ) were higher at 30℃ than at 20℃ and 25℃.