Effect of temperature on the development and predatory potential of Exochomus nigripennis (Erichson) (Col.: Coccinellidae) fed on Gossyparia spuria (Modeer) (Hem.: Eriococcidae)

In this study, the effect of four temperatures (23,27, 31, and 35 °C) were evaluated on the development and predatory potential of Exochomus nigripennis (Erichson) (Col.: Coccinellidae) fed on Gossyparia spuria (Modeer) (Hem.: Eriococcidae) under laboratory conditions (60 ± 5% RH, and a photoperiod of 16:8 (L:D) h). The longest developmental time of total immature stages was at 23 °C (49.0 days) and the shortest was at 35 °C (22.5 days). Also, the mortality of immature stages significantly decreased as the temperature was increased from 23 to 31 °C, and then increased at 35 °C. The larvae reared at 31 and 35 °C consumed more prey than those reared at the other rearing temperatures. In contrast, larvae reared at 23 °C ate less prey than those reared at the others. Adults who came from larvae reared at 31 °C were heavier than those reared at the other temperatures. Based on the linear model, the low-temperature threshold for egg incubation, total larval stage and pupal stage was 10.54, 13.91 and 8.34 °C, respectively. In this model, the amounts of thermal requirement for egg incubation, total larval stage and pupal stage was 90.09, 270.27 and 101.01 °C, respectively. The nonlinear estimates were higher than the linear estimates. Overall, the results of the development of immature stages together to the predation rate and the adult weight would have led to the conclusion that 31 °C was favorable to E. nigripennis . Also, our findings support this hypothesis that the development of ectothermic animals like insects is closely linked to environmental temperature.