Based On The Morphological Characteristics Of The Locust And AFLP Marker Genome Scanning, The Adaptive Mechanism Of The Locust To The Environment Was Explored

The bamboo locust Ceracris kiangsu Tsai is unique in China and has been a forestry pest for a long time.Our previous study have revealed that there is high gene flow and high heterozygosity among different C.kiangsu populations,on this basis we try to explore whether there is population differentiation among the distribution range and which evolutionary pressure acts on the outliers.Therefore,in this paper we try to investigate the morphology and genetic adaptive mechanism of C.kiangsu.The main contents are as follows:(1)We measured 12 morphological characteristics in the 22 populations of 428 individuals,the principle component analysis further identified the head width and wing length are two key landmarks.We find that the three landmarks(body length,head width and wing length)increase with latitude,which conforms to the Bergmann's rule.(2)We also investigate the sexual size dimorphism in C.kiangsu and find that female individuals are significantly larger than male individuals and SSD index decreases with latitude,which conforms to Rensch's rule.(3)C.kiangsu has the behavior of aggregation.In this paper we used numerical analysis method to compare the morphometrics of gregarious and solitary phases.Two landmarks were significantly associated with flight and jump:forewing length and femur length.E/F(forewing length/femur length)ratio is affective in distinguish two ecotypes of C.kiangsu.E/F in gregarious ecotype population is 1.37,but 1.47-1.53 in solitary ecotype.Hence the E/F ratio does vary in two ecotypes,but F/C ratio has no differences in two ecotypes.(4)We conducted an amplified fragment length polymorphism(AFLP)genome scan in populations of C.kiangsu to search for candidate loci influenced by selection along an environmental gradient in southern China.We made a simulation analysis based on DFDIST and BayeScan.A total of 29 loci were detected in the genome of C.kiangsu with very high statistical supports,which is likely to be subjected to directional selection in local demes.Therefore,there may be differentiation among different populations of this species in China.(5)Based on the knowledge of outliers,we used a logistic regression analysis to explore the relationship of outlier and environmental variables.The results suggested that divergent selection arising from environmental variation has been driven by differences in temperature,precipitation,humidity and sunshine.Thus,these findings illustrate that divergent selection and potential local adaptation are indeed prevalent despites seemingly high levels of gene flow,and the results have important implications for our understanding of the interplay of evolutionary forces in general.