Female-biased Dispersal of the Emei Moustache Toad (Leptobrachium boringii) under Local Resource Competition

Dispersal is an important area of ecological and evolutionary research.Although many studies have been conducted in mammals and birds,dispersal pattern in amphibians is still unclear.To verify dispersal patterns of amphibians,an endangered species the Emei Moustache Toad(Leptobrachium boringii)was selected.In this study,we analyzed six genetic parameters:inbreeding coefficient(F_(IS)),gene diversity(H_S),the mean of corrected assignment index(mAI_C),the variance of corrected assignment index(vAI_C),relatedness(r)for all three years together and each year separately based on eight highly polymorphic microsatellite loci.Data in totaled across years and each year for 581 individuals captured during 2013–2015 revealed a significant female-biased dispersal pattern.Significantly higher F_(IS) and H_S in females,and lower mAI_C and r for each year separately in females support that L.boringii displays femalebiased dispersal,although r for the total dataset and vAI_C tests did not show significant differences between the sexes.Female-biased dispersal patterns may be explained by the local resource competition hypothesis.

The sex ratio of wild Chinese alligators Alligator sinensis

The Chinese alligator Alligator sinensis is one of the most endangered crocodilian species, and typically exhibits temperature-dependent sex determination. It is extremely important to clarify the sex structure of Chinese alligators to implement recovery projects successfully. However, the sex ratio of wild Chinese alligators remains unknown. In this study, we collected 28 years of sex ratio data from Chinese alligators residing in the natural and artificial habitats of Changxing Nature Reserve, China, and examined the differences in the sex ratio dynamics between these two populations. We observed that the sex ratio of wild Chinese alligators is 1 male to 4.507 females, which was significantly lower compared to that of the captive population （1 to 2.040; P 〈 0.001）, and is significantly different to previously documented sex ratios for this species （all P 〈 0.01）. Furthermore, we documented an annually stable （P = 1.000） female-biased sex ratio for wild alligators at hatching [1 male to 4.747 females; 0.174 （0.167~）.182）], in contrast to a dramatically fluctuating sex ratio （P 〈 0.001） in captivity [1 male to 1.674 females; 0.374 （0.246-0.593）], showing a potential mechanism for adjusting the sex structure. Finally, we found that the hatchling sex ratios were similar to that of the population sex ratio （P = 0.748）, with little correlation to air temperature values in the 60-70 day incubation period during the breeding season （July and August; both P 〉 0.05）. Overall, this study indicates that the stabilized female-biased sex ratio of Changxing Chinese alligators might result from selection pressure caused by local mate competition and major inbreeding .