Morphology And Function Of Flight Muscle Mitochondria During Swarming In The Termite Reticulitermes Chinensis

The duration of swarming is short and alate will dealate at the time when they land,and then will mate and nest.Therefore,swarming is a key behavior contributing to the reproduction of termites and holds a critical position in life history of termites.Current studies about swarming have mainly focused on climatological and biological characteristies of this behavior.However,the energy metabolism of swarming in termites remains largely unknown.In this thesis,we want to know mechanism of energy metabolism of swarning through investigating morphology and function of flight muscle mitochondria during swarming in termites,which provides theoretical basis for studying mechanism of energy supply and gives a new way for exploiting inhibitors of swarming in termites.The termite Reticulitermes chinensis Snyder is a major tree-killing and fiber-harming pest.Since the size of R.chinensis colony is very small,alates are easier to be produced.This study used R.chinensis to analyze flight muscle mitochondria and isolated mitochondria morphological dynamics,flight muscle mitochondria ?-GPDH pathway and Complex I pathway oxidative phosphorylation among three stages of the process of swarming:1d before swarming(from gathering around the flight holes to flight),flight duration,and Id after flight(dealate).Furthermore,we tested complex enzyme activity in respiratory electron-transport chain of flight muscle mitochondria,production of Reactive Oxygen Species(ROS)in flight muscle mitochondria,and energy charge production of aerobic metabolites in flight muscle mitochondria of this three stages.The results are as follows:Morphological change of flight muscle mitochondria among the different swarming stagesOne day and four days after R.chinensis swarming,myofibril of flight muscle begin to degrade,but there are no significant changes in the shapes of mitochondria;on the contrary,numbers of mitochondria had fragmented among the isolated mitochondria,in the duration of swarming and one day after swarming.Furthermore,the degree of fragmentation is distinct in the later period.These results demonstrated that the flight muscle mitochondria were influenced by the degradation of flight muscle,and the isolated mitochondria obviously change in their morphology.Comparison of the oxidative phosphorylation in ?-GPDH pathway and complex I pathway in the flight muscle mitochondria among the three swarming stagesThe RCR(respiratory control center)of a-GPDH pathway reduced significantly in the flight muscle mitochondria of R.chinensis during swarming and one day after swarming(p<0.05).Moreover,the respiration rate of state 3(mitochondrial respiration rate at abundance of ADP)and state 4(mitochondrial respiration rate at the lack of ADP)increased significantly one day after swarming(p<0.05),and P:O ratio significantly reduced in swarming duration and one day after swarning(p<0.05).In the complex I pathway,RCR reduced significantly one day after swarming(p<0.05),and the respiration rate of state 3 was the highest one day before swarming,reduced at flying and lowest one day after swarming,all difference was significant(p<0.05).These results indicate that the function of oxidative phosphorylation in mitochondria became weak at swarming and one day after swarming.Comparison of reactive oxygen species(ROS)production in the flight muscle mitochondria among the three swarming stagesMore ROS were generated significantly in the duration of swarming than one day before and one day after swarming in the flight muscle mitochondria of R.chinensis(p<0.05).This result suggests that the activity of mitochondria decreased in the period of swarning for the sake of production of ROS which is detrimental to the work of mitochondria.Comparison of complex enzyme activity in the electron transfer chain in the flight muscle mitochondria among three swarming stagesAll the activity of a-glycerol phosphate dehydrogenase(a-GPDH),a-GPDH+cytochrome c oxidoreductase(Complex ?),succinate dehydrogenase(Complex ?),Complex ?+Complex ?,NADH dehydrogenase(Complex ?)+Complex ? and cytochrome c oxidases(Complex IV)are more higher from one day after swarming than those from one day before swarming and at swarming(p<0.05).The possible reasons for the above results are that R.chinensis dealates need to provide enough energy for later tandem-running,pairing and nesting through increasing the enzyme activity alter the reduction of mitochondrial function.Comparison of the contents of aerobic respiration metabolism in the flight muscle mitochondria among the three swarming stagesThe contents of ATP and ADP,and energy charge are higher significantly from one day before swarming than those from one day after it and duration of it(p<0.05),but the condition of AMP is on the contrary with ADP and ATP(p<0.05).These results suggested that termites need more energy one day before swarming than the two late swarming stages.In summary,our results showed that flight muscle mass is more complete,the activity of mitochondria is higher and the function energy metabolism is strongest one day before swarming.However,the activity of mitochondria decreased due to the increasing of reactive oxygen species at swarming.One day after swarming,the flight muscle degraded and the activity of mitochondria decreased.