Study On The Flight-to-light Rhythm And Flight Orientation Behaviorof Migratoryrice Planthoppers

Rice planthopper is the most importantagricultural pest,especiallyforits spreading ofvirus disease which canseriouslyaffect the rice production.In the nature,lots of migratory insects have shownactive orientationduringlong-distance flight,which could be affected by many factorsremaining to be explored.To know and master the law of migratory orientation may help to clarifythe migratory path and the landing site,providing scientific basis for accurate prediction.The knowledge onmigratory population dynamics of rice planthoppers and theirmigratory characteristics could also provide scientific basis of theiroccurrence as well as of the monitoring and early warningfor the epidemic of virus they transmit.With the twoself-developed devices of "Hourly automatic lighttrapping device"(Granted patent:ZL 2011 2 0265335.8)and "Simulation device for tracking flight orientationof small insects"(Granted patent:ZL 2014 2 0642817.4),we conducted the study on the flight-to-light rhythm and flight orientation behavior of migratory rice planthopper,respectively.Specific results are as follows:1.Research on the flight-to-light rhythmof migratory rice planthopper.With the hourly automatic light trapping device from 2012 to 2015,we carried on systemic study on flight-to-light rhythmof migratory rice planthopperfrom year 2012 to 2015.Our work indicated that,(?)the trapped number of transiting population of brown planthopper and white-backed planthopper showsevident interannual difference;(?)the trapped number ofmigratory populations of small brown planthoppershowsno interannual difference,and the trapping peak periods werefrom early june to late june(when it is the harvesting time for wheat),trapped individuals of small brown planthopperweremainly emigrantpopulation;(?)In 2013,the percentages for hourly automatic light trappingof white-backed planthopper during the super peak days and normal dayshighlight the flight-to-lightrhythm as dawn peak pattern,and the white-backed planthopper show adusk peak pattern offlight-to-light rhythmduring the peak days.In 2015,the percentages for hourly automatic light trappingof white-backed planthopper during the peak daysshow a dusk peak pattern of flight-to-light rhythm.Given the above,in addition to the environmental factors,the immigration and emigration of migratory rice planthopper may alsoaffected by the behavioural circadian rhythm.2.Research on flightorientation of migratory rice planthopper.With thesimulation device for tracking flight orientationof small insects,the flight orientaion bahevor of brown planthopper has been studied.We defined the center of rotation as the coordinatescenter,the north direction as the Y axis,the east direction as the Xaxis.The flight orientation experiment on brown planthopper was conducted with eastern directionas a starting point as,overlooking counterclockwise direction aspositive direction of angles(0°?angle range<360°).By calculating,the average orientation angle of brown planthopperwas 92.35± 29.960.Our work preliminary confirmed the feasibility of simulation device for tracking flight orientation of small insectsbeing applied in research on flight orientation of rice planthoppers.In the following work,we will continue focusing on theimprovement of the self-developed device,andfurther explore the flight orientation mechanisms of rice planthoppers.