The Research On Degradation And Rejuvenation Of Exorista Civilis Adults(Diptera Tachinidae)

Exorista civilis Rondani(Diptera Tachinidae), as a plurivorous parasitic natural enemy insect, is the dominating natural enemy for the mature larvae of Mythimna separata Walker, thus playing an important role in controlling its population density. Currently, it has been reported about the biological and diapause storage characteristics of E. civilis, but nothing about the indoor propagation has been studied. Under this premise, a systematic research on E. civilis was carried out to reveal its flying ability, degradation index, rejuvenation technology as well as the change patterns of energy substances between generations. Detailed results are as below: 1. The flight ability of adult E. civilis.It shows that different aged adult E. Civilis have different flying abilities.1 day-old E. Civilis has a certain but weak flying ability which grows gradually and reaches at the greatest flight capabilities at 5 day-old and then decline to the lowest at the 9th day, even lower than that of the 3rd day ones. For female and male adults, the accumulated maximum flight distance is1.47 km and 0.55 km, and the total maximum flight duration is 1.32 h and 0.27 h within 8 successive hours, while the average speed is1.83 m/s and1.52 m/s, respectively. The flight ability of female E. Civilis is slightly but not significantly stronger than the male ones(p>0.05). Besides, it shows the flight ability of E. Civilis declines gradually through generations. In addition, there are certain differences between the individuals of population, of which the maximum total flight duration is 2.24 h within 8 successive hours, while the largest accumulative flight distance is 3.62 km and the maximum speed is 9.34 m/s. It suggests that the 5th day of E. Civilis should be the "active" period to search for the host with its greatest flight capability. While this ability declines gradually through generations. 2、The degradation law of E. civilis reared with alternative host M. separata Walker.The index of vitality and fertility of E. Civilis decrease after several generations, the egg amount was reduced by 44.9% from 1 to 9 generation, and average emergence quantity decreases from 135.5to 60.5, while the average developmental duration rises from 16.9 to 24.7, and shows worse the developmental uniformity having a wide range from 20 to 30 days. More importantly, the rate of successful parasitism decreases from 0.34 to 0.28. 3、 The rejuvenation technology of Exorista civili Rondani.Through different nutrition to rejuvenation of Exorista civilis Rondani, the result shows that the rejuvenation effect of 20% nutrient solution was better than the rejuvenation effect of 10% nutrient solution and the difference was significant, egg-laying quantity reached highest value according to 20% sucrose solution treatment, the average of egg-laying quantity was 350, 10% glucose solution got the lowest value, the average of egg-laying quantity was only 96.17, 20% sucrose solution treatment group was 3.6 times than 10% glucose solution treatment group; Emergence quantity of Exorista civilis Rondani reached highest value according to 20% sucrose solution treatment, the average of emergence quantity was 80.17, 10% glucose solution got the lowest value, the average of emergence quantity was only 24.83, 20% sucrose solution treatment group was 3.2 times than 10% glucose solution treatment group; there were no significant differences between the treatment group about the development period, but species had great differences between individuals, developmental duration between21-26, the developmental uniformity decreased; There were no significant differences between the treatment group about the successful parasitism rate and sex ratio, sex ratio between1.26-1.28 and successful parasitism rate between0.26~0.28.The results showed that the amount of egg-laying and emergence quantity was the biggest on horizontal 100 cm groups by dynamics and rejuvenation, the average amount of egg-laying was 290.17, the average quantity of emergence was79, as well as, having significant differences with other treatment groups. The amount of egg-laying and emergence quantity of vertical 100 cm groups was the biggest, the average amount of egg-laying was 323.17, the average quantity of emergence was88.5.The sex ratio and development duration had no significant differences between the every processing, sex ratio was between 1.23 to 1.27, average of development duration was 23 days.The weight of Exorista civilis adults which reared by using different host had significant differences, the weight of Exorista civilis adults that emergenced from Mythimna separata was 0.013, the weight of Exorista civilis adults that emergenced from Loxostege sticticalis was 0.033; the development duration of Exorista civilis adults that emergence from Mythimna separata prolong 5.8 day than Loxostege sticticalis; the average of egg-laying quantity of Exorista civilis adults which emergenced from Loxostege sticticalis was higher than Mythimna separata, the average of egg-laying quantity was 307.14;the successful parasitic rate of Loxostege sticticalis was 0.185, significantly lower than the successful parasitic success rate of Mythimna separata. 4、The change patterns of energy substances between different generationsAs for water content, there are no significant differences between different generations. While within same generations the water content of female adults is lower than that of the male ones. The total fat content of E. civilis increased with the generations, for both the male and female ones. And the female have higher fat content than the male ones. There are no significant difference for the content of glycerol of the female ones between different generations, but having a wide range from 11.9519 μ/mg to17.6149 μ/mg within same generations. While for the male ones, the content of glycerol grows gradually through generations from 9.5326 μ/mg to 19.7108 μ/mg; There are no significant differences of total sugar content between generations, and the content of total sugar content of female was 15.961 μ/mg~16.6835μ/mg while that of male ones is 15.2563 μ/mg~16.707 μ/mg.