Dominy Nathaniel J, Svenning Jens Christian, Li Wen Hsiung
Department of Ecology and Evolution, University of Chicago, 1101 East 57th Street, 60637, Chicago, IL, USA.
J Hum Evol. 2003 Jan;44(1):25-45. doi: 10.1016/s0047-2484(02)00167-7.
Primates are unique among eutherian mammals for possessing three types of retinal cone. Curiously, catarrhines, platyrrhines, and strepsirhines share this anatomy to different extents, and no hypothesis has hitherto accounted for this variability. Here we propose that the historical biogeography of figs and arborescent palms accounts for the global variation in primate color vision. Specifically, we suggest that primates invaded Paleogene forests characterized by figs and palms, the fruits of which played a keystone function. Primates not only relied on such resources, but also provided high-quality seed dispersal. In turn, figs and palms lost or simply did not evolve conspicuous coloration, as this conferred little advantage for attracting mammals. We suggest that the abundance and coloration of figs and palms offered a selective advantage to foraging groups with mixed capabilities for chromatic distinction. Climatic cooling at the end of the Eocene and into the Neogene resulted in widespread regional extinction or decimation of palms and (probably) figs. In regions where figs and palms became scarce, we suggest primates evolved routine trichromatic vision in order to exploit proteinaceous young leaves as a replacement resource. A survey of the hue and biogeography of extant figs and palms provides some empirical support. Where these resources are infrequent, primates are routinely trichromatic and consume young leaves during seasonal periods of fruit dearth. These results imply a link between the differential evolution of primate color vision and climatic changes during the Eocene-Oligocene transition.
灵长类动物在真兽亚纲哺乳动物中独一无二，因为它们拥有三种类型的视网膜视锥细胞。奇怪的是，狭鼻猿、阔鼻猿和原猴亚目在不同程度上都有这种解剖结构，迄今为止还没有假说来解释这种变异性。在这里，我们提出无花果和乔木状棕榈的历史生物地理学可以解释灵长类动物色觉的全球差异。具体来说，我们认为灵长类动物侵入了以无花果和棕榈为特征的古近纪森林，这些果实发挥了关键作用。灵长类动物不仅依赖这些资源，还提供了高质量的种子传播。反过来，无花果和棕榈失去了或根本没有进化出显眼的颜色，因为这对吸引哺乳动物几乎没有优势。我们认为，无花果和棕榈的丰富度和颜色为具有混合色觉辨别能力的觅食群体提供了选择优势。始新世末期到新近纪的气候变冷导致棕榈和（可能）无花果在广泛区域灭绝或数量大幅减少。在无花果和棕榈变得稀缺的地区，我们认为灵长类动物进化出了常规的三色视觉，以便将含蛋白质的幼叶作为替代资源加以利用。对现存无花果和棕榈的色调及生物地理学的调查提供了一些实证支持。在这些资源稀少的地方，灵长类动物通常是三色视觉，并且在果实缺乏的季节食用幼叶。这些结果暗示了灵长类动物色觉的差异进化与始新世 - 渐新世过渡期间气候变化之间的联系。
