Abstract
Life table studies are essential tools for understanding population dynamics. The life table parameters of Aphis gossypii Glover (Hemiptera: Aphididae) feeding on the host plant, Hibiscus syriacus L. were studied under laboratory (25±1°C and relative humidity of 65±5% and a photoperiod of 16L : 8D h) and field conditions (23-43°C, and relative humidity of 27-95%). The data were analysed using the age-stage, two-sex life table theory. The life table studies were started with 50 and 40 nymphs in laboratory and field conditions, respectively. Under laboratory conditions, A. gossypii reared on H. syriacus had a higher survival rate, fecundity, and longevity than those reared under field conditions. When reared under field conditions, A. gossypii had a longer nymphal developmental time, shorter adult longevity, and lower fecundity than those reared under laboratory conditions. The intrinsic rate of increase (r), net reproductive rate (R0), and the finite rate of increase (λ) under laboratory conditions, were higher than those obtained under field conditions. Nevertheless, there were no significant differences in the mean generation time T (days) between field and laboratory conditions. In the present study, the results clearly showed that life table parameters of A. gossypii were significantly different under field and laboratory conditions. These results could help us to understand the A. gossypii population dynamics under field conditions. The results could also help us make better management decisions for economically important crops
INFLUENCE OF ENVIRONMENTAL FACTORS ON THE POPULATION DYNAMICS OF CHILLI THRIPS, Scirtothrips dorsalis (HOOD) AND APHID, Aphis gossypii (GLOVER)
