The Migration Distance Of Brown Planthopper On Different Time Scales

Hundreds of millions of insects migrate over long distances each year to adapt to seasonal changes in resources and habitats.The migration distance of insects directly reflects the spatial distribution of insect population and determines the growth potential of insect population.The amount of insect migration in different areas tends to decrease with the increase of distance,but due to the influence of habitat quality,population density constraints,and other factors.The "effective migration distance" of the population(that is,the distance with a larger population size)may not be the region with the largest number of landed insects.In this study,brown planthopper(BPH,Nilaparvata lugens(Stal))was taken as an example.In order to determine the "effective migration distance" of BPH population,the paper analyzes the spatial distribution of single day migration,total migration during peak migration,the number of colonization population,and the migration distances of BPH population on different time scales were compared.BPH is a kind of rice pest with long distance migratory habit,whose migration is seasonal.And it gradually moves northward from the breeding area,from mid to late April with the southwestern airflow.The process of northward migration reached the end of Huaibei growing region in early August,and the whole process was larger across space and time scale.This article is based on the fourth times(June 10th-July 10th),fifth(July 11th-August 10th)times mainly northward movements,through the analysis of the data of light lure of BPH from 2006 to 2015 in more than 50 sites in the south growing region of China,studying the immigration peak period of the light trapping changes in population in different regions,defining the larger amount of migration area and the land law;through the analysis from the mid to late June to the the mid to late August,different regions of three field populations of BPH in primary growth multiple is calculated,finally defining a clear population area with larger quantities.The main research results are as follows:Time scale 1:the migration distance of BPH population in single dayThe General Addictive model(GAM)was used to evaluate the single migration distance of BPH in southern rice region by analyzing the distribution of daily light trap population at different migration distances.The results showed that the logarithmic values of BPH trapping volume were negatively correlated with distance during the fourth northward migration,but in the slope of Nanling region was 2 degrees(spatial resolution:30'×30')and the westward direction,there is a large amount of descending insects;then during the fifth northward migration period,there was also a negative linear relationship between the logarithmic value and the distance,but the degree was less.In the hilly area of the Yangtze River,the slope of the belt is 3 degrees(spatial resolution of slope data:30'×30'),the southwest windward slope has a large number of descending insects.Time scale 2:the migration distance of BPH population in peak periodGeneralized linear mixed model(GLMMM)was used to analyze the distribution of light trapping population at different migration distances and to evaluate the migration distance of BPH population on the time scale of "1 month".The results showed that during the fourth period of northward migration,the accumulative light trap of BPH decreased exponentially within the range of 0-800km from NanNing,including eastern GuangXi,HuNan and southern Jiangxi,but there was no significant difference in the number of insects within the range larger than 800km in different regions.During the fifth northward migration,The cumulative quantities of light trapping decreased exponentially in the range of 0-600km from Guilin,which included most areas of Hunan and Jiangxi,but the amount of insect was not different from that of 600km in different regions.Time scale 3:the migration distance of BPH colonization populationsThe population growth times of three generations of BPH were calculated.The migration distance of BPH population after successful colonization was evaluated,which is the migration distance on the time scale of "one generation" by analyzing the distribution of field population at different migration distances at each site.The results showed that there was no obvious regular relationship between the population growth multiple and distance.Finally,the field population large area is in the northeast of Jiangxi and the southern Anhui because of the decreased habitat suitability caused by the rice harvest,the intraspecific competition caused by the population in the field,the rice cultivation system and so on.Although there was a large number of insects in the area near the starting point.The purpose of this study is to evaluate the migration distance of insect population on different time scales.From a short time scale(such as single migration time scale),the number and distance of migratory population decreased exponentially.The effective distance of population migration is "effective distance" from the starting point 1000km,considering the habitat suitability(the population density,abundant food and so on).This study can not only help to understand the relationship between population diffusion and distance,ecological adaptability and evolutionary significance of insect migration,but also provide theoretical basis for predicting the development of migratory insect population and achieving effective population management.