Cumulative effect of temperature on the growth, development and reproduction of red pea aphid (Acyrthosiphon pisum Harris) among different generations

To determine the cumulative effect of temperatures on the growth, development and reproduction of red pea aphid (Acyrthosiphon pisum), and further provide scientific theory for using ecological treatment on pea aphid, we studied the life tables of 3 continuous generations of red pea aphid through indoor observation under five temperature regimes (12 ℃, 17 ℃, 22 ℃, 25 ℃ and 28 ℃). Results showed that the nymph stage of F₂ generation shortened by 16.0% and 6.8% compared with F₀ and F₁ generations at 12 ℃. There was no significant difference among three generations at 22 ℃ and 25 ℃. Respectively, F₂ generation time reduced by 10.5% and 12.4% compared with F₀ and F1 at 12 ℃. There was no significant difference among three filial generations at 17 ℃, 22 ℃ and 25 ℃. The average reproduction of F₂ generation was significantly lower than those of F₀ and F1 at 12 ℃. Also, offspring fertility obviously declined in continuous high temperature of 25 ℃. The average reproduction of F1 and F2 decreased by 49.3% and 50.9% respectively compared with F₀. Also the fecundities of both F₁ and F₂ aphids were not significantly different compared with thatF₀ at 22 ℃. Continuous feeding of red pea aphid and the related gained weight were affected by the minimum at 12 ℃ and 25 ℃ among all treatments, and there was no significant difference in weight among three generations. The weight of F₁ generation was significantly higher than those of F₀ and F₂ generations at 22 ℃, furthermore, the body weight growth rate apparently increased with the number of generations at 12 ℃. With increasing generations, under 12 ℃ and 25 ℃, net reproductive rate (R₀) and generation time (T) of red pea aphid respectively declined and shortened. The intrinsic increase rate (r_{mλ) of F1 and F2 generations increased significantly compared with F0 under 25 ℃. This showed that in continuous low temperature or high temperature stress, offspring fertility of red pea aphid declined. However, developmental duration shortened and with no significant changes in body weight. The intrinsic increase rate (rm) and finite increase rate (λ) increased, showing a strong adaptive capacity to the environment. This was one of the reasons for the rise of filial population of red pea aphid.}