Effect of temperature on reproduction, development, and phenotypic plasticity ofDrosophila suzukiiin Brazil

Temperature is a determining factor for the development and establishment potential of insect pests. The present study describes the impact of temperature (13, 18, 23, 25, 28, 30, and 33 degrees C) on the life cycle parameters and phenotypic plasticity of South American populations ofDrosophila suzukii(Matsumura) (Diptera: Drosophilidae) in the laboratory. Secondary objectives were to determine the lower thermal threshold and thermal constant to estimate the number of annual generations of the insect in small-fruit-producing regions in Brazil. The highest egg-to-adult survival was recorded at 23 and 25 degrees C. At 30 and 33 degrees C, no emergence ofD. suzukiiwas observed. The egg-to-adult development time was shortest at 25 and 28 degrees C (ca. 10 days). The net reproductive rate (R-0), and the intrinsic rate of population increase (r(m)) were highest at 23 and 25 degrees C. In contrast, temperatures of 13 and 28 degrees C generated largest and smallest body sizes, respectively, and caused reductions of 99 and 93% in R-0. The estimated lower thermal threshold was 7.8 degrees C for egg-to-adult survival. The estimated thermal constant was 185.8 degree days, and the estimated annual number of generations ofD. suzukiiranged from 17.1 in cold regions to 27.2 in warm regions. The results of the present study are important for understandingD. suzukiioccurrence in the field, contributing to more informed and precise pest management.