| Dispersal is defined as persistent movement for individual animals from its point of origin to the breeding place,which is an important part of animal life.In population,compared to the other gender,dispersal of one gender has larger quantity of individuals or more widely spread,this is sex-biased dispersal.Moreover,dispersal has a vital effect on distribution,age-structure,sex-structure,genetic structure,population dynamics,the survival and development.Furthermore,sex-biased dispersal has a promoting effect on genetic structure and environment adaptability for the small scale population,which has a profound effect on the research of population genetic structure and meta-population.The research of sex-biased dispersal,which mostly concentrates on birds and mammals,also includes amphibians,actinopterygian fishes,arthropods and partial reptiles.The typical monogamy birds typically display female sex-biased dispersal,whereas mammals mainly show male sex-biased dispersal.However,there is still no general sex-biased dispersal pattern in amphibians.In this research,we collected 581 samples of individuals' toes in three years from 2013 to 2015 through field monitoring of reproduction period.The sampling site is located at Badagongshan mountain in Hunan Province.Through screening of microsatellite primers in Leptohrachiu boringii,we analyzed the genetic diversity of population,explored the sex-biased dispersal pattern of the Emei moustache toad and explained the formation reasons.The results of this study were as follows:(1)The population of the Emei moustache toad based on microsatellite DNA had a high genetic diversity.The total number of allele genes was 71 based on eight microsatellite loci,and the average number of allele genes was 8.875.Partial probability value of observed heterozygosity was lower than expected heterozygosity,but the observed and expected heterozygosity were relatively high.The mean observed heterozygosity was 0.686.The mean expected heterozygosity was 0.718.Polymorphism information content ranged from 0.465 to 0.822 and the mean was 0.655.Hence,the population of the Emei moustache had a high genetic diversity.(2)The Emei moustache toad population showed female sex-biased dispersal.Based on the microsatellite data,we analyzed the five genetic parameters:relatedness(r:F=-0.0004,M=0.0038,P=0.2640),coefficient of inbreeding(Fis:F=0.0690,M=-0.0078,P=0.0010*),gene diversity(Hs:F=0.7162,M=0.7029,P=0.0150*),mean of corrected assignment index(mAIC:F=-0.3175,M=0.3657,P=0.0120*)and variance of corrected assignment index(vAIC:F=10.2302,M=8.7772,P=0.3600)through the FSTAT software,and further verified different populations' relatedness between the genders.The result was female sex-biased dispersal in L.boringii.(3)The evolution mechanism of female sex-biased dispersal in L.boringii.According to resource competition hypothesis,males tend to be philopatric and females tend to be dispersed because of the polygynous species in L.boringii.Furthermore,the males have territory,obtain good resources and know nearby regional environment well,which indicated that males tend to be philopatric and thus the females were more likely to dispersal.Therefore,the mechanism of female sex-biased dispersal pattern in L.boringii could be explained by resource competition hypothesis. |
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