36(4), 666-672, (1 August 2007)https://doi.org/10.1603/0046-225X(2007)36[666:IOCTOL]2.0.CO;2
KEYWORDS: population dynamics, developmental threshold, life table, age-specific survivorship
Laboratory clip-cage studies were conducted to quantify the temperature-dependent development, survivorship, and reproduction and to generate life history characteristics and population growth parameters of the cotton aphid, Aphis gossypii Glover, on phenologically standardized greenhouse-grown cottons at 10, 15, 20, 25, 30, and 35°C. The developmental thresholds were estimated to be 6.3, 6.7, 5.9, 5.9, and 6.3°C for first to fourth instars and for total nymphal development, respectively. The maximum rate of development were estimated to occur at 32.2, 30.8, 30.4, 30.0, and 30.2°C for first to fourth instars and for total nymphal development, respectively. Increased temperature resulted in more rapid decline in survivorship, which was particularly sharp at 35°C, dropping from 94 to 17% in 5 d. Number of days elapsed until first deposition of progeny increased progressively and sharply at temperatures 10 (26 d) to 15 (15 d) to 20°C (8 d) and stabilized at 5 d for 25, 30, and 35°C. Average lifetime fecundity of females rose from a low of 9.76 progeny at 10°C to a peak of 58.9 progeny at 30°C and declined sharply to 17.3 at 35°C. Finite rate of population growth was highest at 25°C and lowest at 10°C. Although stage-specific developmental maxima occurred between 30 and 32°C, a nonlinear regression model estimated 28.6°C to be the optimum temperature for overall cotton aphid development, reproduction, and population increase.