Differentiation And Stability Of Female Genital Morphology In Gambusia Affinis Along Climatic Gradient

Western mosquitofish(Gambusia affinis),originally from North America.Due to like eating mosquitos larvae and adaptability is strong,the mosquitofish has been introduced throughout the world to control anophelism.The western mosquito fish has been listed as one of the world's 100 most invasive species because of its impact on native species.Introduced to mainland China in 1924,mosquito fish has spread to most of southern China over the past century.In the vast hinterland of southern China,the climate and geographical conditions are obviously different.In the process of transmission and diffusion,mosquitofish will undergo certain differentiation in genetic physiology and morphology to adapt to complex climatic and geographical differences.The differentiation of the apparent morphology is the easiest to observe,and the morphological function of the organism corresponds to the physiological function.The differentiation of the phenotypes is the easiest to observe,and the morphological function of the organism corresponds to its physiological function.Although the appearance of female reproductive organs is simple,small structural changes can have a big impact on the mating process.Therefore,this study explored the morphological diversity of the reproductive organs of mature female western mosquitofish in several regional populations in China.To explore the influence of climatic and geographical differences on the morphological structure of female reproductive organs and the main mechanism of the formation of genital differences.Further study on the origin of morphological and structural differentiation of female genital(phenotypic plasticity and rapid evolution).The samples in this study were from seven geographic populations of western mosquitfish across 13 latitudes and 17 longitudes of the Chinese mainland.Morphological analysis was performed on the reproductive organs of female fish and homogenous garden experiment was conducted on the western mosquitofish in three places,which explore the source of morphological differentiationThe results are as follows:(1)the morphology of female genital of western mosquitofish is different along the climate gradient in China: the area of urogenital apertural and ap.papilla in inland areas is larger;The size of the urogenital apertural in southern inland and northern coastal areas(namely along the Yangtze river)is relatively large,while the size of the urogenital apertural in southern coastal areas(south China coast)is relatively small,indicating that the population in this area is relatively dense.(2)the results of the homogenous garden experiment show: Compared with female fish raised in the laboratory,the female fish caught in the wild have a larger opening size,and the difference between the two is large,so the urogenital ap.opening area has a strong phenotypic plasticity.Compared with the second generation female fish raised in the laboratory,the parental female fish caught in the wild have little difference in the urogenital apertural area and the apertural papilla area,which all have strong genetic stability.In summary,the research results show that ecological differences such as climatic and geographical factors play an important role in the population diffusion of mosquitofish,which supports the ecology hypothesis.The results of this study confirmed the formation mechanism of the morphological characteristics of female reproductive organs.The results provide evidences and clues for the microevolution mechanism of moequtiofish populations,and enable us to have a more comprehensive understanding of the adaptation of the invasive mosquitofish populations to the environmental changes of the invasive site.