The Effect Of Temperature On Reproduction And Diapause Of Grapholitha Molesta (Busck)(Lepidoptera:Tortricidae).

Grapholitha molesta (Busck)(Lepidoptera:Tortricidae) is a worldwide pest and widely distributed in China. They can eat many kinds of Rosaceae plants and have serious harm to the quality and yield of fruit. Temperature plays an important role in the development of Grapholitha molesta (Busck). For example, the temperature has an effect on egg laying and diapause. This study discussed the relationship between temperature and reproduction and diapause in the following three aspects:The effect of a single hot event in adult stage on adult survival rate and reproduction; the diversification of diapause rate and the capacity of cold hardiness under different constant temperatures; the effect of elevate temperatures in summer and autumn on the induce of diapause. The results are as following:1Under global warming, extremely hot events are expected to increase in frequency in temperate regions. Extremely hot events usually involve a few hours at extreme high temperatures. They are unlikely to cause widespread mortality, however reproduction may be affected by them. In this study, we examined such stress effects in the Grapholitha molesta (Busck)(Lepidoptera:Tortricidae). We simulated a single hot day (maximum of38℃lasting for4h) increasingly experienced under field conditions. This event had no detrimental effects on immediate mortality、total fecundity and male longevity, but it makes female longevity, oviposition days and post-oviposition days longer. When the male or the female is tressed, total fertility declines, If both the male and the female are stressed, the total fertility is the lowest. The pre-oviposition days become longer When the females copula with stressed males.2The diapause rate and capacity to low temperature have significant difference under different constant temperatures. According to the study, we discuss the feasibility that the contents of biochemical small molecules, such as sugars and alcohol, can determine the depth of diapause. Under library conditions, we set four temperatures, they are16、20、24、28respectively. The results show that:1) High temperature (28℃) can inhibit the induction of short photoperiod on diapause;2) the Grapholitha molesta (Busck)(Lepidoptera:Tortricidae) has stronger resistance to the cold when at low temperature;3) the Grapholitha molesta (Busck)(Lepidoptera:Tortricidae) has deeper depth at low temperature;4) the content of biochemical small molecules decrease when the temperature raises.3Under global warming, the temperature in summer and autumn increase. To examine weather the diapause rate and other traits of Grapholitha molesta (Busck)(Lepidoptera:Tortricidae) will change, we simulate the temperature of September-October in Tangshan, He Bei Province and set5different fluctuating temperature gradients. The results show that:1) High fluctuating temperature gradients (26、28℃) can reduce diapause rate significantly;2) When fluctuating temperature gradient is22℃, the diapause larvaes are the heaviest;3) With the fluctuating temperature gradients increase, the Grapholitha molesta (Busck)(Lepidoptera:Tortricidae) has shorter off fruit time;4) When the fluctuating temperature gradient is26℃, the survival rate is the lowest.