Studies On The Life History Traits Associated With Reproduction Of Scutiger Boulengeri From The Tibetan Plateau

In this paper,the life history traits associated with reproduction of scutiger boulengeri were studied.S.boulengeri are mainly distributed in 3300-5100 m above sea level,is one of Anura distribution of the highest in China,widely distributed in our country in Qinghai,Gansu,Tibet,Sichuan and other places,abroad in Nepal.So far,the related researches of S.boulengeri mainly focus on the background investigation and the cold-adaptation of tadpoles,but less on the life history traits associated with reproduction.It is of great significance to understand the life history of amphibians,to grasp the relevant characteristics of their life history and to protect species and to reveal the evolutionary mechanism of species.This paper focuses on the early embryonic development?partial?,number of eggs,spawning mode,age structure of the population,dimorphism and geographical variation of testicular size of the toad.The research results show that:1.The shape of the eggs of the S.boulengeri was annular,with the average size of the outer ring R=6.71±1.03 cm,and the average size of the inner ring R=1.3±0.78 cm?n=29?.The average number of eggs was 352±194?n=10?,and most of the eggs were located at the bottom of rocks in the stream,generally 4.91±1.77 cm from the bottom of the stream.The stream is generally 6.64±2.00 cm deep.2.The age structure of the population was studied by using SkeLetochronology method.The results showed that the average ages of males was 8.2±1.8 years?n=63?,and the range of ages was 5¹3 years.The mean age of female was 9.5±2.0 years?n=26?,and the range of ages was 6¹5 years.3.The body size of S.boulengeri was significantly dimorphic.Mean body size was significantly different between males and females,with females being larger than males in SVL?males,52.6±3.7 mm,n=25;females,62.7±6.5 mm,n=12;t=6.0,df=35,P<0.001?.The results of GLMs revealed that the seven hindlimb muscles?triceps femoris,biceps femoris,semimembranosus,adductor longus,gracilis major,gracilis minor and gastrocnemius?and the total muscle mass differed significantly between the sexes when the influence of SVL was controlled.When controlling for the influence of body size,three hindlimb muscles?triceps femoris,semimembranosus,plantaris longus?and the total muscle mass differed significantly between the amplectant and non-amplectant males.4.Testis size is associated with the intensity of male-male competition for mating and thus may be treated as an indicator of male reproductive investment.The adjusted means of testis size?left,right and overall weights of testes?significantly differed among altitudes when the influence of SVL,body weight and age were controlled(left testis weight:F_2,35=10.95,P<0.001;right testis weight:F_2,35=3.93,P=0.029;overall testis weight:F_2,35=8.96,P=0.001).Testis weight was positively correlated with body weight,but not with body length and age.