Effects Of Grazing And Seasonal Rainfall On Grasshopper Eggs In Grassland

Climate change is a serious environmental problem facing human beings.unreasonable grazing is one of the factors that lead to climate change.Inner Mongolia grassland is one of the most important grassland ecosystem in China,and the type of locust is extremely rich.They are not only important primary consumers,but also an integral part of the material cycle and energy flow.In recent decades,the frequency of extreme weather in Inner Mongolia grassland has increased year by year.At the same time locust disaster outbreak in recent years,climate and grazing is two important reasons.And locust eggs are a necessary process of locusts throughout the life history.Therefore,the study of grazing and climate on the impact of locust eggs will play an important role in the prevention of future locust disaster.In this study,by setting the effect of cross-treatment of grazing and increased rainfall in different seasons on the microenvironment of locust eggs in a typical steppe of the Mao Deng ranch in Xilinhot.Observation of the egg development,embryo period,hatching rate and mortality changes in response of the early genus Dacehippus harbipes(F.-W.),the middle species of Asian locusts:Oedaleus asiaticus B.-Bienko and the late species of Chorthippus dubius(Zub.).By comparing and analyzing the suitability of three species of locust eggs under the conditions of grazing and increasing rainfall in different seasons.The results showed that the increase of rainfall in autumn was the main factor of the egg development period shortening and the early embryo period avancing of the early genus Dacehippus barbipes eggs.The increased rainfall in autumn and spring shorten the development period of the Dasyhippus barbipes eggs.4-5 days.and embryonic period was 25.9-26.5 period.No increased rainfall in different seasons and increased rainfall in spring made the egg development period longest,7-9 days.the embryonic period was 24.8-25.1 period.Compared with the non-grazing treatment.the developmental stages of the eggs were delayed by 1-2 days in grazing treatment.and the embryonic period decreased by 0.4-0.5.Hatching rate of the eggs were 60-75%under the conditions of no increasing rainfall or increasing in a quarter.and 50-65%under the conditions of increasing rainfall in two or three quarters.The increased rainfall in spring was the main factor of shortening the development period and advancing the embryonic period of the middle species of Asian locusts eggs.The development period of Asian oedaleus asiaticus B.-Bienko egg was the shortest under the conditions of increasing rainfall in spring,summer and autumn,4-5.7 days,the embryo period was 25.6-26.1.The development period of Asian oedaleus asiaticus B.-Bienko egg was the longest under the conditions of no increasing rainfall in various seasons and increasing rainfall in summer,7.3-9.1 days,the embryonic period was 25.2-25.4 period.Compared with non-grazing treatment,the development period of Asian oedaleus asiaticus B.-Bienko egg was delayed 2-3 days in grazing treatment,the embryonic period decreased by 0.2-0.4 period.Hatching rate of the Asian oedaleus asiaticus B.-Bienko eggs were 60-75%under the conditions of no increasing rainfall or increasing in a quarter,and 50-65%under the conditions of increasing rainfall in two or three quarters.The increaseed rainfall in summer was the main factor of shortening the development period and advancing the embryonic period of the late species of Chorthippus dubius eggs.The development period of Chorthippus dubius eggs were the shortest under the conditions of increasing rainfall in spring.summer and autumn,3.1-4.2days,the embryo period was 25.8-26.1.The development period of Chorthippus dubius eggs were the longest under the conditions of no increasing rainfall in various seasons and increasing rainfall in summer,8.0-9.2 days.the embryonic period was 24.2-25.2 period.Compared with non-grazing treatment,the development period of Chorthippus dubius eggs were delayed 1.1-2.3 days in grazing treatment,the embryonic period decreased by 0.8-1 period.Hatching rate of the Chorthippus dubius eggs were79-83%under the conditions of increasing rainfall in various seasons.Grazing and increasing rainfall in different seasons changed the microenvironment of the locust eggs,and the microenvironment of locust eggs changed more violently under the conditions of no increasing rainfall or increasing rainfall in a quarter.Mainly were:significant soil temperature increase and soil moisture reduction during the day.air temperature rise and air humidity reduction;significant soil temperature rise and humidity reduction,air temperature reduction and air humidity rise during the night.The microenvironment of the eggs changed relatively stable,the change of temperature and humidity of the air and the soil were not obvious.Grazing mainly affected the proportion of biomass of Leymus chinensis.Increased rainfall in different seasons had a significant effect on the growth trend of different plants.Increased rainfall in summer contributed to the growth of Leymus chinensis.Increased rainfall in spring or summer and autumn helped the growth of Kirschner wire;increased rainfall in spring and summer or summer and autumn contributed to the growth of other plants.