| Scutiger boulengeri belongs to the genus Scutiger,Megophryidae,Anura,Amphibia.It was named Leptobrachium boulengeri by Bedriaga in 1898.It was later revised to Scutiger boulengeri.Since its discovery,there are few related studies,and mainly focused on the adaptation mechanism and ecological niche of tadpole.Therefore,this study is mainly based on field investigation,and its population ecology research is carried out in Taizimountain National Nature Reserve in Gansu Province.In this paper,the characteristics of population quantity,adult sexual dimorphism,female fertility,and characteristics of microhabitat selection during breeding period were discussed to supplement the biological data of this species.It also provides basic ecological data for subsequent research and protection of this high-altitude cold-range amphibian.The main results are as follows:(1)In field investigations,113 adult Scutiger boulengeri were found,among which the average body length of males was 52.35±0.14 mm,and the average body length of females was 60.88±0.28 mm.Further research and analysis showed that the heterotypic index of Scutiger boulengeri was SDI=0.140,there are obvious sexual dimorphism,which can be explained by the fertility hypothesis.(2)There were differences in population number and density of Scutiger boulengeri.Among them,Donggou had the highest density(11.5/hm~2),followed by Yaoshuixia(11.3/hm~2)and Tiegou the least(3.5/hm~2).The largest number of adult Scutiger boulengeri were found in May(85),and the smallest number were found in June(28).At the same time,the average head length,body weight and plumpness of adult Scutiger boulengeri found in May were greater than those in June,and there was a significant difference in plumpness between males and females(F=11.237,P=0.037<0.05).The plumpness of females is higher than that of males,showed that there were some morphological differences between the sexes of the adult Scutiger boulengeri during the breeding period.It was found that the majority of Scutiger boulengeri are male,and the total male to female ratio was 1:2.6.(3)The breeding time of Scutiger boulengeri lasted from early May to early June.The mean inner diameter of egg clusters(n=27)was r=1.63±0.64 cm,and the mean outer diameter was R=7.13±0.94 cm.The average clutch size of egg clusters was 432±148(n=14).By analyzing female fertility,it is found that there is a positive correlation between egg production and head length and body mass.This result suggests tha females tend to increase their body size to cope with high-energy-consuming,high-risk,and high-investment reproductive behaviors in order to improve their reproductive output.(4)The analysis of the habitat preference coefficient showed that Scutiger boulengeri were more inclined to inhabit wetlands or meadows,with low water temperature,clear water,high surface humidity,and egg mass attachments.At the same time,the principal component analysis showed that Temperature factors,water source factors and environmental factors of spawning grounds are the main factors that affect the selection of suitable habitats during the breeding period of Scutiger boulengeri. |
