مقایسه ی اثر دمای ثابت و متغیر طی چندین نسل پرورش آزمایشگاهی بر توانایی ذخیره سازی زنبور Trichogramma brassicae

The Trichogramma genus parasitoids is known to be the most used natural enemies of pests, especially pest lepidopteran in the world. The success of these biological control factors depends not only on the time and amount of release, but also on the quality of these. In this study, the role of pre-storage and storage time of Trichogramma brassicae in two constant temperatures of 25 ° C and variable of 20 ° C and 30 ° C under laboratory conditions were compared. In this experiment, both of treatments were cultivated for 13 generations at each of these temperatures under a relative humidity of 75 ± 5 percent and an optical period of 16 hours of brightness and 8 hours of darkness, then both of treatments were induced to induce diapause under 20 ° C The light period was 14 hours of darkness and 10 hours of brightness. After the departure of the 14th-generation wasps, 50 famale wasps mating moths were fed 20% with honey water and 50 wasps per day were sterilized and Ephestia kuehniella was placed. Then, both temperature treatments were transferred to a temperature of 10 ° C and absolute darkness. In order to emergenced insects from each treatment, a population after two months and another population were transferred to a temperature of 25 ° C after 4 months. The results indicated that the exit rate in the variable temperature treatment after two months and four months was significantly higher than constant temperature treatment. Also, in both of treatments, storage duration significantly reduced the emergence rate of insects. In fact, a meaningful difference in the rate of emergence of variable temperature treatment was also influenced by maternal experience at the temperature of induction of diapause (20 ° C) and under the influence of inheritance that the mother of many generations had adapted to this temperature. These results show the importance of the development of the native generation in the induction and success of the diapause.