Lardner Björn
Department of Animal Ecology, Ecology Building, S-223 62 Lund, Sweden e-mail:
Oecologia. 1998 Nov;117(1-2):119-126. doi: 10.1007/s004420050639.
Tadpoles of Rana arvalis originating from seven island populations were tested for responses to non-lethal predator presence. In general, tadpole growth was reduced and the relative tail depth was increased at predator presence. There was no effect of predator presence on the predicted size at metamorphosis. The differentiation rate, translating as length of the larval period, was lower at predator presence, but this seems to be merely an effect of the reduced growth. Although populations differed with respect to growth, relative tail length, relative tail depth, differentiation rate and predicted size at metamorphosis, no obvious differences were found in their responses to predator presence. Data on predator occurrences in the source ponds show that tadpoles originating from ponds with a high predation pressure have a higher differentiation rate, i.e. they will metamorphose at an earlier date than those from "safe" ponds (if raised under the same conditions). Moreover, they are also predicted to metamorphose at a smaller size, which is in accordance with theoretical models. Despite the fact that populations differed in growth, no correlation was found between growth and predation risk in the source ponds.
对源自七个岛屿种群的林蛙蝌蚪进行了测试，以观察它们对非致命捕食者存在的反应。总体而言，在有捕食者存在的情况下，蝌蚪的生长减缓，相对尾深增加。捕食者的存在对变态时的预测体型没有影响。在有捕食者存在的情况下，作为幼虫期长度的分化率较低，但这似乎仅仅是生长减缓的结果。尽管不同种群在生长、相对尾长、相对尾深、分化率和变态时的预测体型方面存在差异，但在它们对捕食者存在的反应中未发现明显差异。源池塘中捕食者出现的数据表明，来自捕食压力高的池塘的蝌蚪具有更高的分化率，即与来自“安全”池塘的蝌蚪相比（如果在相同条件下饲养），它们会更早变态。此外，预计它们变态时的体型也较小，这与理论模型一致。尽管不同种群在生长方面存在差异，但在源池塘中未发现生长与捕食风险之间存在相关性。
