同水塘分布两种无尾两栖类蝌蚪的竞争策略

实验室条件下,通过活动性水平,变态时的体重、增长率和完成变态所需时间考察同水塘分布的中华蟾蜍(Bufo gargarizans)和高原林蛙蝌蚪(Rana kukunoris)的竞争策略。实验按照2×3因子设计,即:食物资源2个水平(高、低),组合方式3个水平(10只中华蟾蜍蝌蚪,记为B组;5只中华蟾蜍蝌蚪和5只高原林蛙蝌蚪,记为BR组;10只高原林蛙蝌蚪,记为R组)。中华蟾蜍蝌蚪的活动性在食物水平低时显著低于食物水平高时,而高原林蛙蝌蚪的活动性在不同食物水平下无显著差异;食物水平低时,混合组的高原林蛙蝌蚪变态时体重和体重增长率都显著高于R组,而混合组中华蟾蜍蝌蚪与B组相比无显著差异;在不同处理组中,食物水平低时混合组中华蟾蜍蝌蚪幼体期最短。这些结果表明:中华蟾蜍蝌蚪在不同食物资源条件下所选择的生存策略可能不同,即食物资源充足时,增加活动性获取更多食物;食物资源有限时,降低活动性且提前完成变态;与中华蟾蜍蝌蚪相比,在食物资源有限时高原林蛙蝌蚪获取食物能力更强。

Competitive Strategies of Two Species of Co-occuring Tadpoles(in English)

We examined the competitive ability of larval toads(Bufo gargarizans)and frogs(Rana kukunoris)which co-occur in natural pools in the Jiuzhaigou Nature Reserve.We measured the activity level,growth rate,mass at metamorphosis and larval period in a laboratory experiment.Tadpoles of B.gargarizans were significantly more active when food was abundant than scarce,while there was no significant difference in the activity of R.kukunoris tadpoles at different food levels.At low food availability,mass at metamorphosis and growth rate of R.kukunoris were significantly increased in the presence of B.gargarizans,whereas the presence of R.kukunoris had no significant effect on the mass and growth rate of B.gargarizans.In all treatments,the larval period of B.gargarizans at low food availability was the shortest.These results suggest that B.gargarizans can adapt to different food levels by changing their activity rate.At high food level,B.gargarizans increased activity to gain more food.At low food level,B.gargarizans decreased activity and achieved early metamorphosis.However,when food resources were limited,R.kukunoris could gain more food than B.gargarizans.