Testing the high-tannin hypothesis with scatter-hoarding rodents: experimental and field evidence
Testing the high-tannin hypothesis with scatter-hoarding rodents: experimental and field evidence
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DOI：
10.1016/j.anbehav.2007.08.017
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发表时间：
2008-04
期刊：
影响因子：
2.5
通讯作者：
Zhishu Xiao;Gang Chang;Zhibin Zhang
中科院分区：
文献类型：
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作者：
Zhishu Xiao;Gang Chang;Zhibin Zhang
通过实验(关在笼子里，每天几小时)和实地(自由放养，几个月)的研究，我们测试了高单宁的假说，即囤积动物更喜欢立即吃更多低单宁的食物，但囤积更多的高单宁食物供以后消费。我们研究了两种常见的老鼠(爱德华的长尾老鼠Leopoldamys edwardsi和板栗鼠Niviventer fulvescens)和两种坚果物种(亨利的板栗和软木橡木，栓皮栎)，它们的单宁水平不同(0.6%对11.7%)，但其他特征相似。基于高单宁假设，我们预测(1)两种大鼠都会立即吃更多的低单宁栓皮栎坚果，但更少高单宁的栓皮栎坚果；(2)在收获给定的坚果后，它们更愿意囤积更多的栓皮栎坚果，更少的C.henryi坚果。第一个预测在我们的研究中得到了坚定的支持：在所有条件下，两种老鼠都吃了比栓皮栎更多的坚果。然而，第二个预测只在持续了几个月的实地研究中得到支持，而不是在半自然围栏中进行的实验(只有1天)。我们发现，与低单宁的栓皮坚果相比，高单宁的栓皮坚果被囤积并在田间作为幼苗存活的可能性要高得多。我们的结论是，这里使用的实验条件不太可能导致受试动物的自然取食偏好，高单宁假设得到支持，特别是在野外环境中。
With a combination of both experimental (caged, hours/daily) and field (free-ranging, several months) studies, we tested the high-tannin hypothesis that hoarding animals prefer to eat more low-tannin food items immediately but hoard more high-tannin items for later consumption. We studied two common rat species (Edward's long-tailed rat, Leopoldamys edwardsi; and chestnut rat, Niviventer fulvescens) and two nut species (Henry's chestnut, Castanea henryi; and cork oak, Quercus variabilis) that show varying tannin levels (0.6% versus 11.7%) but are similar in other traits. Based on the high-tannin hypothesis, we predicted that (1) both rat species would eat more low-tannin C. henryi nuts instantly but fewer high-tannin Q. variabilis nuts and (2) after harvesting a given nut, they would prefer to hoard more Q. variabilis nuts and fewer C. henryi nuts. The first prediction was firmly supported in our study: both rat species ate more C. henryi nuts than Q. variabilis nuts under all conditions. However, the second prediction was supported only in the field study, which lasted over several months, in contrast to the experiments conducted in seminatural enclosures (only 1 day). We found that high-tannin Q. variabilis nuts, in contrast to low-tannin C. henryi nuts, had a significantly higher probability of being hoarded and surviving as seedlings in the field. We conclude that experimental conditions used here are less likely to result in natural feeding preferences of tested animals and the high-tannin hypothesis is supported especially in the field setting.