Effect of short-term heat stress on demographic parameters of the Diamondback moth, Plutella xylostella L Lepidoptera: Plutellidae larva

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عنوان دوره: سومین کنگره بین المللی حشره شناسی ایران
نویسندگان
1Agricultural Entomology Research Dept., Iranian Research Institute of Plant Protection, AREEO, Tehran, Iran,
2Department of Entomology, Faculty of Agriculture, Tarbiat Modares University, Tehran, Iran
چکیده
The diamondback moth (DBM), Plutella xylostella (L.) (Lepidoptera: Plutellidae), is a serious and economically important pest of cruciferous crops in the world. Temperature and relative humidity are among the most important abiotic factors affecting the biology of DBM. Some researchers have shown that extreme temperature and humidity conditions are environmental stresses that can result in DBM death if they persist. In this research, the effect of short-term heat stress on larval stage was studied on demographic parameters of P. xylostella at laboratory condition. Diamondback moth larvae were exposed to 30, 35 and 40°C for duration of 2, 4, 6 and 8 h and then returned to normal temperature condition (25 °C). The larvae maintained at 25°C were used as control. Daily fertility, preimaginal development time and mortality were analyzed according to Jackknife method and with SPSS and MINITAB statistical software. The results showed that P. xylostella larvae were successfully developed to adulthood at short-term (2, 4, 6 and 8 h) heat stresses. The highest and the lowest net reproduction rate (R0) was obtained at 30 °C (61.68 ± 4.08 female / female / generation) for 8 h and (17.76 ± 2.57 female / female / generation) for 6 h, respectively. The generation time (T) was longest at 40 °C for 2 h (18.40 ± 0.33 days). The intrinsic rate of increase (r) ranged from 0.16 ± 0.007 day-1 at 30 °C for 6 h to 0.25 ± 0.005 day-1 at 30 °C for 8 h with significant difference. The results showed that the climate change and high temperature play an important role in changes in the biological characteristics of DBM; however, the pest adapted to environmental changes and maintained its optimum fitness.
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