Geographical Distribution, Spread Pathway And Biological Control Techniques Of Predatory Mites Of Tribolium Castaneum (Herbst) (Coleoptera:Tenebrionidae) In China

Tribolium castaneum?Herbst?,red flour beetle,is one of the main economically important stored grain insect pests in China,which has spreaded to most provinces from the southeast coast during about 60 years.However,there are few researches of prevention and control of red flour beetle in China.In this dissertation,the geographic distribution,spread pathway,and biological control of predatory mites of T.castaneum in China had been studied in order to prevent and control its further spread.It is significant to the theory and practice of invasion management which can provide scientific evidence and decision support to the organizations of stored grain protection and plant quarantine.Firstly,the geographical distribution of T.castaneum in China was studied and confirmed using integrated methods of manual and trapping collection,morphological and molecular identification.Secondly,the population genetic structure,invasion origin and spread pathway of red flour beetle in China was studied and revealed based on sequencing and analysis of mtDNA COI gene.Finally,through the introduction and assimilation of related techniques from Czech Republic,this research investigated and identified the common species of predatory mites in the stored grain region of medium-high temperature in China,then studied and developed the biological control techniques of predatory mites which could be used to control T.castaneum.The results and concludions are as following.?1?T.castaneum had distributed at least 23 provinces of China,however without collections in Tibet,Qinghai,and Gansu provinces in this research.According to the results of the survey in 56 grain storages of 23 provinces,the adults of T.castaneum were collected in 32 storages of 19 provinces.The red flour beetle had not been collected in 4 storages of Tibet,3 storages of Qinghai,and 2 storages of Gansu.Three of 5 grain storages in Heilongjiang and 2 of 7 storages of Jilin had the a few collections of red flour beetle.Tibet and Qinghai were suggested to regulate T.castaneum as provincial quarantine pest and prevent its introduction.?2?In China,the genetic structure of T.castaneum population is differentiated in regions at various temperatures and diffused from south to north.Based on sequence analysis of 393 T.castaneum specimens of 24 geographic populations in 13 provinces of China,24 geographic populations of T.castaneum are combined with grain storage ecological regions.According to the temperature and humidity,the grain storage regions are divided into 4 regions,namely A hot and humid grain storage region,B subtropical grain storage region,C warm temperate grain storage ecological region and D warm temperate dry grain storage ecological region,among which the genetic structure of 24 T.castaneum populations is significantly differentiated though the difference is minor.The haplotype diversity?Hd?of 24 geographic populations decreases gradually from south to north.There exists significant negative correlation between haplotype diversity?Hd?and latitude?r=-0.505,p= 0.012,p<0.05?.It is speculated that T.castaneum initially invades in the southeastern coastal area of China and is diffused from south to north.?3?The biological control techniques of predatory mites on T.castaneum introduced from Czech Republic and further developed in this research had prospect of application.Cheyletus eruditus Schrank and C.malaccensis Oudemans were the common species of predatory mites in the stored grain region of medium-high temperature in China and usually appeared with some common stored insect pests such as T.castaneum.Both of C.eruditus and C.malaccensis preferked to prey upon the 1^st and 2^nd instar larvae of T.castaneum.For the predation ability of eggs and 1^st,2^nd and 3^th instar larvae of T.castaneum,C.malaccensis was better than C.eruditus.Although single C.malaccensis presented stonger predation ability than single C.eruditus,the parthenogenetic C.eruditus had more advantages of population control of T.castaneum due to its rapid population growth.