Influence of rising temperature on population growth parameters of Helicoverpa armigera (Lepidoptera: Noctuidae)

Temperature-dependent life table studies were performed to evaluate the direct effects of rising temperatures (۲۰, ۲۲.۵, ۲۵, ۳۰, ۳۵, ۳۷.۵, and ۴۰ °C ± ۰.۵) on Helicoverpa armigera (Hübner) (Lep: Noctuidae). The results indicated that H. armigera could successfully survive and reproduce at all temperatures tested except at ۳۷.۵ and ۴۰ °C (at ۳۷.۵ °C, no adults emerged, and at ۴۰ °C, no eggs hatched). However, a significant difference was observed among the mean life table parameters of H. armigera at survived temperatures. The constant temperatures of ۲۲.۵ and ۲۵ °C were considered the optimum degree of eggs laid by females of H. armigera.  The intrinsic rate of rise (r) at the specified temperatures ranged from ۰.۰۸۰ day−۱ at ۳۵ °C to ۰.۱۴۵ day−۱ at ۲۲.۵ °C. In addition, the value of the net reproductive rate (R۰) of H. armigera at the different temperatures tested varied from ۹.۲۲ offspring at ۳۵ °C to ۵۰۱.۰۱ offspring at ۲۲.۵ °C. Furthermore, the values of the gross reproductive rate (GRR) were significantly different at the tested temperatures, and the lowest and highest values of this parameter were obtained at ۳۵ °C (۴۲.۱۸ offspring) and ۲۲.۵ °C (۱۰۵۶.۴۴ offspring), respectively. Immature mortality increased with increasing temperature. The results obtained in the present study may provide insight into predicting population dynamics and the efficacy of the subsequent management programs for this pest.

کلیدواژه ها:

Constant temperatures ، Cotton bollworm ، Helicoverpa armigera ، Life table parameters