Reproductive Biology Of Chrysoperla Sinica (Tjeder) Adults In The Process Of Diapause Development

The green lacewing, Chrysoperla sinica (Tjeder), is an important natural enemy attacking agricultural and forestry pests like aphids, mites and eggs, young larvae of lepidopterous insects, and a good biological control agent. This species overwinters as diapausing adults. This paper mainly dealt in details with the effect of temperature and photoperiods and nutrition on the fecundity of C. sinica in different diapausing periods. The main results were summarized as follows.1 The effect of wintering periods on the reproductive biology of Chrysoperla sinica (Tjeder) in the different diapausing periods.The reproductive biology of C. sinica adults in different overwintering periods were assessed under constant condition(s15L-9 D,RH=60~70%,T=22℃). The results showed that the trend of pre-oviposition period of adults increased from Nov to April, and decreased from Jun to April. The adults remained in maintenance phase in Jun, and the diapsuse intensity was the deepest, therefore the pre-oviposition was the longest. The pre-oviposition period of adults was the shortest in April, indicating the diapause has terminated. Egg production per female adults in Feb was significantly more than that of adults in Nov,Dec,Jun and March, but not than that of adults in April.The regression analysis showed that there was remarkably correlation between the pre-oviposition periods and the egg production (P<0.05), indicating that the relation between them was positive.2 The effect of temperature on the reproductive biology of Chrysoperla sinica (Tjeder) adults in the different diapausing periodsThe reproductive biology of overwintering adults of C. sinica, was measured in Nov,Jan and Mar at three constant temperature 18,22 and28℃. The results indicated that the higher the temperature, the ealier the diapause terminated, and that the pre-oviposition period, and oviposition period and the longevity decrease in the female adults as the temperature increase. When the diapause terminated, temperature is the most important factor regulated the development of the C. sinica. Temperature and overvintering period also have remarkable effects on the reproductive capacity of green lacewing ,The fecundity were the highest when the temperature was 22℃and the lowest was 18℃.3 The effect of photoperiod on the reproductive biology of Chrysoperla sinica (Tjeder) adults in the different diapausing periods.The reproductive biology of C. sinica adults in different overwintering periods were assessed at 22℃under three photoperiod 15L-9D,13.5L﹣10.5D and 12L-12L. The results indicated that photoperiod had no obvious effect on the oviposition period and the the longevity of female adults, but had obvious effects on pre-ovipositon and the egg production. Egg production of the adults under 15L-9D is much higher that of egg production under 13.5L﹣10.5D and 12L-12L. Therefore the most favorable photoperiod is around 15L-9D.4 The effect of nutrition on the reproductive biology of Chrysoperla sinica (Tjeder) in the different diapausing periods.The results indicated that the starvation can reduce the survival rate of the overwintering adult significantly, the pre-oviposition period prolonged and the egg production reduce if starvation for longer period. It had no significant effect on the longevity of female adults and oviposition period if the starvation was followed by feeding, the pre-oviposition period would not be affected significantly if the adults were provided with food, though the egg production was affected.The experimental diapausing adults expired if they were provided pure water only after their emergence, indicating that energy is needed during the diapausing period, sugar is an important energy material, and protein is one of the materials for the development of the reproductive system..