Population Dynamics And Monitoring Forecasting Techniques Of Dendrolimus Houi Lajonquiere And D.kikuchii Matsumura

The Dendrolimus houi Lajonquière and the D.kikuchii Matsumura are deemed as the major pests in the forest.Additionally,these two kinds of species,as the congeneric related species,are jointly occuring in numerous places.Through analyzing the indoor emergence regulations,imagoes' oviposition options,larval niche and the larval foraging taxis of two types of pests,the differences between the D.houi Lajonquière and the D.kikuchii Matsumura in the bio-ecological aspects are anatomized and discussed.The differentiation and the overlapping condition of two types of pests for drawing on the resource of the host,and whether these two types of pests are adaptive to the host they prefer are delved into.The differences between two types of pests in the bioecological features are explored.These research efforts shall be conducive to the understanding of the dynamic variation mechanism of each type of pest population in the places where these two types of pests are jointly occurring.Here are the following results: 1.Occurrence Regularity of Two Types of Pests and Monitoring ModelThe first generation imagoes of D.houi Lajonquière and the D.kikuchii Matsumura of the year are trapped through adopting the sex pheromone.As the result indicates,the imagine occurrences of two types of pests are basically the same.The imagoes are basically occurred in the first ten-day period of Jun.and died away after the middle of Jul.The emergences of two types of pests are peaking in the last ten-day period of Jun.or in the beginning of Jul.The cocoons of the second generation of D.houi Lajonquière and the D.kikuchii Matsumura of the year are acquired in the field and placed indoor for observing the condition of emergence.As the result indicates,the D.kikuchii Matsumura shall be 5d earlier than D.houi Lajonquière for the initiation of emergence.The emergency rhythm of D.houi Lajonquière bespeaks the single apex,with the peak of emergence mainly concentrated in the first half of Oct.The emergency rhythm of D.kikuchii Matsumura bespeaks the bimodal pattern,with two peaks of emergence,respectively as the first and middle ten-day periods of Oct.Based on the trapping data of the first generation imagoes of two types of pests,population density of the second generation larvae of two types of pests are respectively collected.Through adopting the curve estimation,the fitting prediction model of the imago's and the second generation larva's population density of D.houi Lajonquière and the fitting prediction model of the imago's and the second generation larva's population density of D.kikuchii Matsumura are respectively acquired.2.Analysis of NicheD.houi Lajonquiè's and the D.kikuchii Matsumura's utilizations of space and time resources are anatomized on the basis of the niche theory.The mechanism of competition and connection between larva populations of D.houi Lajonquière and the D.kikuchii Matsumura is quantitatively described.As the result indicates,the niche widths of larvae of D.houi Lajonquière and the D.kikuchii Matsumura in the aging stage are respectively 0.6423 and 0.5299,bespeaking the space resource utilization of D.houi Lajonquière is more wide.As the pests are growing,the competition coefficient of two types of pests is constantly growing,bespeaking that two types of pests shall be more sever in seizing the nutritional resource as the pupal stage is coming.In view of the time niche of two types of pests,the niche of D.houi Lajonquière is 0.9143 in width,a data slightly over that of D.kikuchii Matsumura,0.8912.In view of the overlapping niche,the D.kikuchii Matsumura's shall be higher than that of D.houi Lajonquière,bespeaking that among the hazardous period of D.kikuchii Matsumura,D.houi Lajonquière is also jeopardizing the forest.Comprehensively,either D.houi Lajonquière or D.kikuchii Matsumura shall maintain the relatively stable population quantity in the certain period,without the outbreak or peak in their hazardous periods.Accordingly these two types of pests shall constantly and greatly jeopardize the forest in their hazardous period.Furthermore,it is spoken that the population development of D.houi Lajonquière and D.kikuchii Matsumura is less affected in the experiment area.3.Analysis of Host Preference of Two Types PestThe average accumulated egg amount,accumulated egg proportion and the larva quantity on different types of pine needle are selected as the evaluation indexes as to analyze the imagoes' oviposition option and larval foraging option of D.houi Lajonquière and D.kikuchii Matsumura on their hosts,Pinus kesiya var.langbianensis,P.armandii,P.tabulaeformis and P.bungeana.As the result indicates,the percentages of imagoes' average accumulated egg of D.houi Lajonquière on P.kesiya var.langbianensis,P.armandii,P.tabulaeformis and P.bungeana are respectively as 46.98%,26.10%,22.73%,4.19%,and those of D.kikuchii Matsumura are 48.22%,23.55%,15.80%,12.44%.Within 36 h of observation,the foraging taxis on larva of D.houi Lajonquière and D.kikuchii Matsumura on 4 types of pines are discrepant with each other,and the imagoes' oviposition option taxis are also different from each other.