Construction And Application Of Insect Migration Trajectory Simulation Model Flexpart-Insect

Simulating the migration trajectory of insect swarm is an important way to study the relationship between source and sink of migratory insects,and is significant for monitoring and early warning of migratory insects.Active flight behaviors of Insect largely affect its migratory trajectory and landing area.There is no professional insect migration trajectory simulation platform(model),and the current main insect migration trajectory model rarely incorporates the flight behaviors of insect in simulating migratory trajectory and in analyzing the relationship between the source and sink of the insect population.Based on the Lagrange particle platform FLEXPART,this research incorporated the main migratory flight behaviors of insect into FLEXPART,and developed a professional insect trajectory simulation platform,Flexpart-Insect.Then we applied Flexpart-Insect to analyze the migration of different migratory insects.The main results are as follows:Flexpart-Insect is divided into four modules:program controlling and meteorological data processing,population and behavior parameters setting and initialization,flight behavior and meteorological factor interaction,and output of trajectory of population and individuals.The program controlling and meteorological data processing module is based on the FLEXPART,which has advantages in stability,meteorological data calculation and particle trajectory simulation.The module of population and behavior parameters setting and initialization,incorporates the species,flight altitude,thickness of the aerial layer,number of individuals,airspeed of individuals,orientation angle,and the response threshold of insect to temperature,rainfall and vertical airflow.The module of flight behavior reaction to meteorological factors involves various response mechanisms of insects to photoperiod,rainfall,temperature and vertical airflow.The module of trajectory output can produce average track of polulation and individual landing locations.To adapt to different application scenarios,Flexpart-Insect has been developed into two patterns,easy(Flexpart-Insect-Easy)and research pattern(Flexpart-Insect-Research).Flexpart-Insect-Easy is mainly applicable to the flight behavior parameters that could be obtained directly.Flexpart-Insect-Easy was mainly used by incorperating radar monitoring data at present.Flexpart-Insect-Research is applicable to the situation when the migratory behavior parameters cannot be properly obtained.Utilizing Flexpart-Insect-Easy,sensitivity of main flight parameters of insect to migratory trajectory was analyzed.The results show that flight altitude and flight orientation could largely affect the migratory trajectory direction,while parameters affecting migration distance are flight duration,flight altitude and flight speed.Overall,flight duration and flight height are the leading parameters that affecting insect migration trajectories.The sensitivity analysis could provide theoretical support for obtaining more accurate data of flight parameters in the future.The trajectories of several major migratory pests were simulated by Flexpart-Insect.By integrating the migratory flight behavior information from radar monitoring data into Flexpart-Insect,the landing distribution patterns of the aerial swarm of insect were quantitatively demonstrated,and the effect of the insect flight behaviors to distribution of trajectory endpoints was analyzed.Brown planthopper,White-Backed planthopper and rice leaf roller are species with weak flying and orientating ability.Flexpart-Insect integrated flight height and density distribution(obtained by radar monitoring)of them,and simulated the trajectories of swarms flying at different heights.The distribution patterns of trajectory endpoints among different flight duration or re-emigrating times were compared.The meadow borer and the beet armyworm are species with high airspeed and strong orientation ability.Compared with the inert particles floating in the wind,the flying behavior of them significantly affect migratory trajectories in terms of direction and distance.Specially,the active flight behavior of beet armyworm could significantly increase the success rate of migration across the sea.To sum up,this research has developed a professional insect trajectory simulation model Flexpart-Insect,which integrates insect migratory flight parameters and can be applied to different application scenarios.In the future,with the gradual establishment of radar monitoring network on aerial ecosystem,it is possible to get regional airborne swarm data from radar sites.Combining the radar monitoring data with the insect trajectory simulation platform,the dynamic monitoring and early warning of a wide range of aerial ecosystems can be realized,and this could provide the decision-making basis for the monitoring of migratory pests and for the research on the diversity of the air ecosystem.