Climate change, especially temperature increase, would affect insect physiology, behavior, and development as well as species distribution and abundance, evidenced by changes in the number of generations a year, increasing survival rates in winter, and the earlier appearance of some insects. Hence, an investigation was undertaken to understand effect of elevated temperature on population dynamics of Brown Planthopper (BPH). Experiments were carried out in Temperature control chamber (TCC) with five different constant temperatures (28.0, 30.0, 32.0, 34.0 and 36.0°C). Age specific life table was constructed for Nilaparvata lugens at various temperature regimes and it revealed that BPH took as long as 44 days to complete the generation at 28.0°C and as short as 32 days at 36.0°C. The 50% mortality occurred on 20.1 days after incubation at 28.0°C, whereas it was observed as early as on 6.3 days at 36.0°C. Pre-oviposition period decreased considerably with increasing temperatures. Total number of eggs recorded was more (233) at 30.0°C and less (116) at 36.0°C. It was also noted that the 50% fecundity in BPH was recorded on 36th day after incubation at 28.0°C, whereas it was observed on 24.3 days itself when the BPH was reared at 36.0°C. The net reproductive rate of BPH was observed to be higher at lower temperature regimes. All the growth parameters were observed to decrease at 36°C, which reveals that the temperature increase above 34 °C is detrimental to the development of BPH.
Keywords: Global warming, temperature, life table, population growth, population dynamics.
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