Thermal Effects on the Population Parameters and Growth ofAcyrthosiphon pisum(Harris) (Hemiptera: Aphididae)

The pea aphidAcyrthosiphon pisum(Harris) (Hemiptera: Aphididae) is a cosmopolitan and polyphagous species. An evaluation ofA. pisum's demographic parameters and growth was carried out after rearing aphids on faba bean plants (Vicia faba) under five different temperature conditions (10 degrees C, 15 degrees C, 20 degrees C, 25 degrees C and 30 degrees C). We analyzed the raw life history data, including developmental time, survival, longevity and reproduction, using an age-stage, two-sex life table to consider variable developmental rates among individuals. The population fluctuation ofA. pisumdetermined the stage-specific population structure and potential population growth under different temperature conditions.A. pisumindividuals developed successfully from nymphs to adults at all temperatures in this study. The developmental rate ofA. pisumincreased as the temperature increased. Our results indicated thatA. pisumshowed a higher pre-adult mortality, lower total fecundity and a negative intrinsic rate of increase at 30 degrees C. The highest intrinsic rate of increase (0.30) and finite rate of increase (1.35) were observed at 25 degrees C. Comparisons of population parameters and their analytical methods between differentA. pisumpopulations from other geographic areas are also discussed.