Kunz Britta Kerstin, Linsenmair Karl Eduard
Department of Animal Ecology and Tropical Biology, Theodor-Boveri Institute of Biosciences, University of Wuerzburg, Am Hubland, 97074 Wuerzburg, Germany.
Primates. 2008 Oct;49(4):239-45. doi: 10.1007/s10329-008-0101-6. Epub 2008 Sep 9.
Seed size is an important plant fitness trait that can influence several steps between fruiting and the establishment of a plant's offspring. Seed size varies considerably within many plant species, yet the relevance of the trait for intra-specific fruit choice by primates has received little attention. Primates may select certain seed sizes within a species for a number of reasons, e.g. to decrease indigestible seed load or increase pulp intake per fruit. Olive baboons (Papio anubis, Cercopithecidae) are known to select seed size in unripe and mature pods of Parkia biglobosa (Mimosaceae) differentially, so that pods with small seeds, and an intermediate seed number, contribute most to dispersal by baboons. We tested whether olive baboons likewise select for smaller ripe seeds within each of nine additional fruit species whose fruit pulp baboons commonly consume, and for larger seeds in one species in which baboons feed on the seeds. Species differed in fruit type and seed number per fruit. For five of these species, baboons dispersed seeds that were significantly smaller than seeds extracted manually from randomly collected fresh fruits. In contrast, for three species, baboons swallowed seeds that were significantly longer and/or wider than seeds from fresh fruits. In two species, sizes of ingested seeds and seeds from fresh fruits did not differ significantly. Baboons frequently spat out seeds of Drypetes floribunda (Euphorbiaceae) but not those of other plant species having seeds of equal size. Oral processing of D. floribunda seeds depended on seed size: seeds that were spat out were significantly larger and swallowed seeds smaller, than seeds from randomly collected fresh fruits. We argue that seed size selection in baboons is influenced, among other traits, by the amount of pulp rewarded per fruit relative to seed load, which is likely to vary with fruit and seed shape.
种子大小是一项重要的植物适合度性状，它会影响从结果到植物子代建立之间的多个环节。许多植物物种的种子大小差异很大，但该性状对于灵长类动物种内果实选择的相关性却很少受到关注。灵长类动物可能会出于多种原因在一个物种内选择特定的种子大小，例如减少难消化的种子量或增加每个果实的果肉摄入量。已知橄榄狒狒（东非狒狒，猕猴科）会在不同程度上选择非洲球花豆（含羞草科）未成熟和成熟豆荚中的种子大小，因此种子小且种子数量中等的豆荚对狒狒传播的贡献最大。我们测试了橄榄狒狒是否同样会在狒狒通常食用其果肉的另外九种果实物种中选择较小的成熟种子，以及在狒狒以种子为食的一个物种中选择较大的种子。这些物种在果实类型和每个果实的种子数量上存在差异。对于其中五个物种，狒狒传播的种子明显小于从随机收集的新鲜果实中手动提取的种子。相比之下，对于三个物种，狒狒吞下的种子明显比新鲜果实中的种子更长和/或更宽。在两个物种中，摄入种子的大小与新鲜果实种子的大小没有显著差异。狒狒经常吐出多花核果木（大戟科）的种子，但不会吐出其他具有相同大小种子的植物物种的种子。对多花核果木种子的口腔处理取决于种子大小：吐出的种子明显比从随机收集的新鲜果实中取出的种子更大，而吞下的种子更小。我们认为，除其他性状外，狒狒对种子大小的选择受每个果实相对于种子量所获得的果肉量的影响，而果肉量可能会因果实和种子形状而异。
