Abstract: To clarify the effects of different temperatures and parental reproductive ages on the offspring color morph differentiation, the newly-born first-instar nymphs of the red and green pea aphid (Acyrthosiphon pisum) on the 2^nd, 7^th, and 12^th parental reproductive age from F₀-F₅ were continuously raised for five generations at three temperatures (15, 22, and 26 ℃). Results showed that temperature and parental reproductive age had a significant effect on the offspring color morph differentiation. Red color morph A. pisum tended to produce green color morph offsprings at 15 ℃, while green color morph A. pisum tended to produce red color morph offsprings at 26 ℃. The proportion of non-parental color morph offspring produced by red and green parents at 22 ℃ was significantly lower than that at 15  and 26 ℃ (P<0.05). Furthermore, different parental reproductive age also had a certain effect on the offspring color morph differentiation. The parental reproductive age affected the proportion of color differentiation and the time of color differentiation in the offsprings of pea aphid (P<0.05), indicating that the onset of color differentiation in the offsprings of red and green pea aphid was related to different parental reproductive ages at the same temperature.

Key words: temperature, parental reproductive age, pea aphid, generation, color morph differentiation.