Diapause induction in Harbin population of Colaphellus bowringi

The effect of photoperiod,temperature and food on diapause induction in a Harbin population of Colaphellus bowringi Baly was investigated.There was no photoperiodic response,and at a constant temperature of 20-30℃ the diapause rate was 91.8%-100% at various photoperiods.Temperature had some influence on diapause induction;lower temperatures could promote diapause,but higher temperatures inhibited diapause in a few individuals.A thermoperiod of C12 ∶ T12 combined with a photoperiod of L12 ∶ D12 had no effect on diapause at a mean temperature of 25℃.The percentage of diapausing individuals was 89.5%-100% at 25℃ and 76.9%-100% at 28℃.Host-plants had a significant effect on diapause;the highest diapause rate was observed in individuals fed leaves of Raphanus sativus and the lowest in those fed leaves of Lepidum sativum.