| In this study,the mitochondrial COI and COII genes were used to identify the two species on the basis of morphological identification of Reticulitermes labralis and R.chinensis.In addition,8 pairs of microsatellite markers were used to analyze the genetic diversity of 22 colonies of R.labralis in three cities of Xi'an,Yuncheng and Bengbu.Then determined genetic structure and type of colony for R.labralis to provide a genetic basis for its effective control.The results were as follows:(1)The R.labralis and R.chinensis both belonged to Planifrontotermes of Reticulitermes.The soldiers both had similarities in their head features.The frontal area were both slightly bigger,the color were both tawny,the labrum were both spear-shaped and pellucid,the shape of the upper jaw were slightly different,the number of antennal segment were also overlapped.The shape of pronotum was generally same,the number of central hair on pronotum were 10-16 in R.labralis and 10-12 in R.chinensis.In terms of morphological description aspect,the similarity between R.labralis and R.chinensis was very high.So it was difficult to distinguish R.labralis and R.chinensis.(2)The measurement range of all features of R.labralis and R.chinensis were analyzed,while the length range of labrum was almost the same.The width range of labrum,the length range of the left upper jaw,the length,width and narrowness range of the chin,the length,mid-length and width range of pronotum and the length range of hind-tibia all were covered with each other.In terms of the average value of measurement,although two species were different,the differences were little.(3)The mitochondrial COI gene was used to analyze the genetic distance of R.labralis and R.chinensis.Meanwhile,R.aculabialis and R.flaviceps which were easily distinguishable from these two species,were studied for comparison.The intraspecific genetic distance ranged from 0.000 to 0.038 in R.labralis.The intraspecific genetic distance ranged from 0.000 to 0.004 in R.chinensis.The interspecific genetic distance ranged from 0.006 to 0.038 between R.labralis and R.chinensis.The genetic distance range between R.labralis and R.aculabialis,R.chinensis and R.aculabialis were 0.042-0.052 and 0.038-0.046,respectively.The interspecific genetic distance range between R.labralis and R.flaviceps,R.chinensis and R.flaviceps were 0.046 to 0.055 and 0.051-0.054,respectively..It can be seen that the intraspecific genetic distance in R.labralis was larger than the interspecific genetic distance between R.labralis and R.chinensis.However,the interspecific genetic distance between R.labralis and other approximate species R.aculabialis and R.flaviceps which was larger than the intraspecific genetic distance range in R.labralis,indicating that the relationship between R.labralis and R.chinensis was very similar.(4)The mitochondrial COII gene was used to analyze the genetic distance of R.labralis and R.chinensis,The intraspecific genetic distance ranged from 0.000 to 0.033 in R.labralis.The intraspecific genetic distance ranged from 0.000 to 0.004 in R.chinensis.The interspecific genetic distance ranged from 0.006 to 0.036 between R.labralis and R.chinensis.The genetic distance range between R.labralis and R.aculabialis,R.chinensis and R.aculabialis were 0.046-0.050 and 0.043-0.047,respectively.The interspecific genetic distance range between R.labralis and R.flaviceps,R.chinensis and R.flaviceps were 0.061-0.063 and 0.065-0.068,respectively.The interspecific genetic distance of COII gene was similar to the interspecific genetic distance of COI gene.The intraspecific genetic distance range of COII gene in R.labralis was similar to the interspecific genetic distance range between R.labralis and R.chinensis.The interspecific genetic distance between R.labralis and R.chinensis was significantly less than R.labralis with R.aculabialis and R.flaviceps.Therefore,it was recommended to treat R.labralis and R.chinensis as a species.(5)Eight pairs of microsatellite primers were used to analyze the genetic diversity of R.labralis in 22 colonies in the city of Xi'an,Yuncheng and Bengbu.The average number of alleles in Xi'an was 2.760 ± 0.691,the average number of effective alleles was 1.938 ± 0.411,the observed heterozygosity ranged from 0.225 to 0.779,and the average observed heterozygosity was 0.504 ± 0.183.The expected heterozygosity ranged from 0.159 to 0.576 and the average expected heterozygosity was 0.400 ± 0.137.I was Shannon's information index,indicating the diversity of population.Its average value was 0.674 ± 0.242,indicating that the diversity of the whole population was moderately high,The average value of polymorphic locus ratio(PPL)at 8 loci was 86.46%,indicating that these 8 loci had high polymorphism in each colony in Xi'an.The average number of alleles per locus in Yuncheng was 2.333 ± 0.926,the average number of effective alleles was 2.025 ± 0.772,the observed heterozygosity ranged from 0.000 to 0.933 and the average observed heterozygosity was 0.544 ± 0.323,the expected heterozygosity ranged from 0.000 to 0.681,the average expected heterozygosity was 0.411 ± 0.242.The I average value was 0.661 ± 0.418,indicating that the diversity of the population was moderately high.The average value of polymorphic locus ratio(PPL)was 79.17%.Because of the low polymorphic loci,8 loci polymorphism was normal in each colony in Yuncheng.The average number of alleles in R.labralis in Bengbu was 2.589 ± 0.702,the average number of effective alleles was 1.929 ± 0.488,the observed heterozygosity ranged from 0.221 to 0.900,and the average observed heterozygosity was 0.552 ± 0.251,the expected heterozygosity ranged from 0.188 to 0.631,the average expected heterozygosity was 0.407 ± 0.151.The average value of I was 0.670 ± 0.269,indicating that the overall diversity of the population was moderately high,the average polymorphic locus ratio(PPL)at 8 loci was 83.93%,the overall polymorphism in Bengbu was better.(6)Analysis of the genetic structure of R.labralis,on the whole,the genetic differentiation of each colony in R.labralis was moderately high,and the gene flow index Nm was 0.355(<1),which indicated that the gene flow level among different colonies was moderately low.And the average value of FST was 0.443,indicating a moderately high degree of differentiation.By the software structure 2.2 analysis,it was also found that there was a high degree of genetic differentiation between different colonies and low gene flow among the colonies.With the increase of geographic distance,the degree of genetic differentiation among colonies increased significantly,indicating that genetic space structure of population was highly differentiated.(7)Analysis of the colony structure for R.labralis,we found that 4 of 12 colonies in Xi'an were simple families,5 colonies were extended family and 3 colonies were mixed family.In Yuncheng,3 colonies all belonged to the extended family.In Bengbu,4 colonies belonged to simple family,3 colonies belonged to extended family.In general,the number of simple family and extended family was moderately high.The possible reason was that all colonies were collected in cities,so the influence of urbanization and human factor was high.As a result,the possibility of colony fusion was relatively low,the colony structure was relatively simple.Mixed family colonies were collected in the field under natural condition,so they were lower affected by human activities.Termites had a strong ability to build nest and breed,so the possibility of fusion between different colonies was relatively high. |
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