Life table and temperature-dependent development of Diadegma anurum (Hymenoptera: Ichneumonidae) on its host Plutella xylostella (Lepidoptera: Plutellidae)

Life table and temperature-dependent development of Diadegma anurum (Thomson) (Hymenoptera: Ichneumonidae) was studied on diamondback moth, Plutella xylostella L. (Lepidoptera: Plutellidae) reared on cabbage, Brassica oleracea L. variety capitata, and cauliflower, Brassica oleracea L. variety botrytis. The developmental periods of immature stages were recorded at five constant temperatures (15, 20, 25, 30, and 35 degrees C). The population of D. anurum and its host failed to survive at 35 degrees C. Mean total development time of D. anurum was not significantly different on two host plants except at 25 degrees C. The developmental zero (low temperature threshold) was estimated to be 7.0 and 6.9 degrees C, and the thermal constant was 282.3 and 277.7 DD on cabbage and cauliflower, respectively, using the linear model. Data were fitted to four nonlinear temperature-dependent models. Evaluation of the models was carried out based on the following criteria: fit to data, number and biological values of the fitted coefficients, and accuracy on the estimation of the thresholds. Consequently, the Briere-1 model was accepted and recommended for the description of temperature-dependent development of D. anurum. The life table parameters of D. anurum were also studied at 25 degrees C constant temperature. Its intrinsic rate of increase (rm) and mean generation time (T) were estimated to be 0.169 and 16.083 d on cabbage, respectively. The life table parameters of D. anurum can be used to develop the models of population dynamics and prediction.