Seale D B, Wassersug R J
Department of Biology, The Pennsylvania State University, 16802, University Park, Pennsylvania, USA.
Department of Anatomy, University of Chicago, 60637, Chicago, Illinois, USA.
Oecologia. 1979 Jan;39(3):259-272. doi: 10.1007/BF00345438.
The tadpoles of two anuran species, Rana sylvatica and Xenopus laevis, were fed various concentrations of two algae, Anabaena sphaerica (large filaments) and Chlorella pyrenoidosa (small unicells). Filtering rates were measured indirectly with a Coulter Counter system; buccal pumping rates were observed directly.Experimental measurements of buccal volume (volume cleared with each pump stroke) agreed closely with independent predictions from a descriptive model based on tadpole morphology. The Xenopus larvae had a larger buccal volume than Rana larvae of comparable size.The R. sylvatica tadpoles demonstrated: a lower (threshold) and an upper limit on the food concentration for filtering and ingestion, a peak in filtering rate at an intermediate (critical) concentration, a probable higher filtering efficiency on larger particles, and an asymptotic relationship between ingestion rate and concentration.Tadpoles maintained a maximum ingestion rate over a wide concentration range (above the critical concentration for filtering) by species-specific patterns of adjustment in pumping rate and buccal volume. Maximum ingestion rates, expressed as volume (but not number) ingested per unit time, were similar for tadpoles fed both Anabaena and Chlorella.Several anatomical features may limit the maximum ingestion rate, the maximum filtering rate, the maximum particle size ingested, the maximum volume of food that can be removed without clogging the gill filters, and other components of tadpole feeding dynamics.Data on tadpole feeding may be used to evaluate general suspension feeding models.The behavior of Rana tadpoles at various algal concentration in the field was consistent with predictions from these experimental studies. sediments when concentrations fell near or below a "critical" concentration. These field observations indicate that laboratory experiments and morphological studies can predict certain aspects of tadpole feeding activities in the field.Three general conclusions concerning the feeding dynamics of tadpoles follow from the data and discussion just presented: (i) they are similar in several respects to those of invertebrate suspension feeders, (ii) they apparently are regulated as functions of biovolume not of particle number, (iii) they can be predicted, in part, from morphological measurements on the tadpole's buccal pump. In addition, these data on tadpole feeding may be used to evaluate general models of suspension feeding dynamics.
以两种蛙类物种——林蛙（Rana sylvatica）和非洲爪蟾（Xenopus laevis）的蝌蚪为实验对象，投喂不同浓度的两种藻类：球形鱼腥藻（Anabaena sphaerica，大型丝状藻）和蛋白核小球藻（Chlorella pyrenoidosa，小型单细胞藻）。利用库尔特计数器系统间接测量过滤速率；直接观察口腔泵吸速率。对口腔容积（每次泵吸清除的容积）的实验测量结果与基于蝌蚪形态学的描述性模型的独立预测结果高度吻合。非洲爪蟾幼体的口腔容积比同等大小的林蛙幼体更大。林蛙蝌蚪表现出：过滤和摄取食物浓度的下限（阈值）和上限，在中等（临界）浓度下过滤速率出现峰值，对较大颗粒可能具有更高的过滤效率，以及摄取速率与浓度之间的渐近关系。蝌蚪通过特定物种的泵吸速率和口腔容积调节模式，在较宽的浓度范围内（高于过滤的临界浓度）维持最大摄取速率。以单位时间摄取的容积（而非数量）表示的最大摄取速率，对于投喂球形鱼腥藻和蛋白核小球藻的蝌蚪而言相似。若干解剖学特征可能会限制最大摄取速率、最大过滤速率、摄取的最大颗粒大小、在不堵塞鳃滤器的情况下可清除的最大食物容积，以及蝌蚪摄食动态的其他组成部分。蝌蚪摄食的数据可用于评估一般的悬浮摄食模型。林蛙蝌蚪在野外不同藻类浓度下的行为与这些实验研究的预测结果一致。当浓度降至接近或低于“临界”浓度时，它们会摄食沉积物。这些野外观察结果表明，实验室实验和形态学研究可以预测蝌蚪在野外摄食活动的某些方面。根据上述数据和讨论得出关于蝌蚪摄食动态的三个一般性结论：（i）它们在若干方面与无脊椎动物悬浮摄食者相似；（ii）它们显然是根据生物体积而非颗粒数量进行调节的；（iii）它们可以部分地从蝌蚪口腔泵的形态学测量中预测出来。此外，这些关于蝌蚪摄食的数据可用于评估悬浮摄食动态的一般模型。
