MODELING THE EFFECT OF TEMPERATURE ON THE LONGEVITY OF THE GRAIN APHID, SITOBION-AVENAE (F) (HOM, APHIDIDAE)

Adult S. avenae were reared under constant temperatures of 12, 16, 20, 22.5 and 28.5 degrees C and under periodically fluctuating temperatur es of 10-15 and 15-20 degrees C for 14 h light and 10 h dark per day r espectively. The aphid's longevities were distributed unimodally under constant conditions and bimodally in the case of fluctuating temperat ure regimes. An accelerated life model was set up to model the observe d temperature dependency. The results obtained from the experiments wi th constant temperatures were used to estimate the parameters of this model. The results obtained from the experiments with the fluctuating temperatures were used to validate the accelerated life model. Althoug h the accelerated life model used in this study was originally develop ed to simulate the effect of temperature on unimodally distributed lif e times, it was also appropriate to simulate the effect of temperature on bimodally distributed life times, according to tests involving est imates of the biological parameter intrinsic growth rate r. Using resa mpling methods the mean value as well as the 95% confidence limits of this parameter can be calculated from either the model predictions or the experimental data.