Lima Albertina P, Moreira Gloria
Dept. de Ecologia, INPA, CP 478, 69011-970, Manaus, AM, Brasil.
Oecologia. 1993 Mar;95(1):93-102. doi: 10.1007/BF00649512.
The feeding niche ofColostethus stepheni changes during ontogeny. Small individuals eat small arthropods, principally mites and collembolans, and larger frogs eat bigger prey of other types. The shift in prey types is not a passive effect of selection for bigger prey. There is a strong relationship between electivity for prey types and frog size, independent of electivity for prey size. Four indices of general activity during foraging (number of movements, velocity, total area utilized and time spent moving), which are associated with electivity for prey types in adult frogs and lizards, did not predict the ontogenetic change in the diet ofC. stepheni. Apparently, the behavioral changes that cause the ontogenetic change inC. stepheni are more subtle than shifts in general activity during foraging. Studies of niche partitioning in communities of anurans that do not take into consideration ontogenetic changes in diet and seasonal changes in the size structures of populations present a partial and possibly erroneous picture of the potential interactions among species.
斯蒂芬姬蛙（Colostethus stepheni）的取食生态位在个体发育过程中会发生变化。幼体吃小型节肢动物，主要是螨类和弹尾虫，而较大的蛙类则捕食其他类型的更大猎物。猎物类型的转变并非对更大猎物进行选择的被动结果。猎物类型的选择性与蛙类大小之间存在很强的关系，与猎物大小的选择性无关。觅食期间的四种一般活动指标（移动次数、速度、利用的总面积和移动时间），这些指标与成年蛙类和蜥蜴对猎物类型的选择性有关，但并不能预测斯蒂芬姬蛙饮食的个体发育变化。显然，导致斯蒂芬姬蛙个体发育变化的行为变化比觅食期间一般活动的变化更为微妙。在未考虑饮食个体发育变化和种群大小结构季节性变化的情况下，对无尾目群落生态位划分的研究呈现出物种间潜在相互作用的部分且可能错误的图景。
