西藏齿突蟾蝌蚪的发育和群体年龄结构研究

西藏齿突蟾是一种冷域性两栖动物,其蝌蚪和幼蟾大多群集在海拔2100—2400米的山区溪流或草丛中。6—7月初孵出蝌蚪,冰下越冬,经五年发育成幼蟾。由5月份所得蝌蚪的群体年龄结构统计,一和二龄蝌蚪占79％,三年以上个体明显减少,五龄变态幼蟾仅占2％。四龄个体的死率最高,仅有32％的四龄蝌蚪变成五龄幼蟾。

ON THE DEVELOPMENT AND POPULATION AGE STRUCTURE OF SCUT1GER BOULENGERI TADPOLES

Scutiger boulengeri is a species of amphibian living in low temperature environment. The development and population ecology of its tadpoles have not been reported up to now. From 1981 to 1987, the authors systematically researched the habitat feature, population density, development and life table of Scutiger boulengeri tadpoles. The results were summarized as follows:1. Most of the tadpoles and larvae of Scutiger boulengeri clustered in brook or grass glade located in the mountain areas in which the elevation was from 2100 to 2400 meters. The tadpoles hatched from spawns in early July. They often clustered in the shallow water at the midday of summer and lived under ice in winter.2. By observing the tadpoles of Scutiger boulengeri raised in room and analysing annual rings of vertebrae, it was researched that the age of different individuals in nature and the development feature of every age-group. It was first affirmed that it needed five years to develop from hatching to becoming a larva in Scutiger boulengeri.3. From the quantity of different aged tadpoles captured in Xinglong mountain areas, Gansu Province in May, the population age structure was counted. The quantity of one-year-old and two-year-old tadpoles was 79% of the total, and that of tadpoles above three-year-old reduced obviously. The fiveyaer-old larvae was only 2% of the total in quantity.4. According to the static life table of tadpoles, it was suggested that the mortality of the Scutiger boulengeri tadpoles increased with the processing of age. The mortality of four-year-old tadpoles was the highest. Only 32% of four-year-old tadpoles developed to the five-year-old larvae.