Dataset S6 from Foraging history of individual elephants using DNA metabarcoding

Individual animals should adjust diets according to food availability. We used DNA metabarcoding to construct individual-level dietary timeseries for elephants from two family groups in Kenya varying in habitat use, social position and reproductive status. We detected at least 367 dietary plant taxa, with up to 137 unique plant sequences in one fecal sample. Results matched well-established trends: elephants tended to eat more grass when it rained and other plants when dry. Nested within these switches from ‘grazing’ to ‘browsing’ strategies, dietary DNA revealed seasonal shifts in food richness, composition and overlap between individuals. Elephants of both families converged on relatively cohesive diets in dry seasons but varied in their maintenance of cohesion during wet seasons. Dietary cohesion throughout the timeseries of the subdominant ‘Artists’ family was stronger and more consistently positive compared to the dominant ‘Royals’ family. The greater degree of individuality within the dominant family's timeseries could reflect more divergent nutritional requirements associated with calf-dependency and/or priority access to preferred habitats. Whereas theory predicts that individuals should specialize on different foods under resource scarcity, our data suggest family bonds may promote cohesion and foster the emergence of diverse feeding cultures reflecting links between social behaviour and nutrition.

个体动物应根据食物可获取情况调整日粮。我们采用DNA宏条形码（DNA metabarcoding）技术，为肯尼亚两个象群的个体构建了个体水平的日粮时间序列，这两个象群在栖息地利用、社会地位和繁殖状态上均存在差异。本次研究共检测到至少367种采食植物类群，单份粪便样本中最多可检出137条独特的植物序列。研究结果与已确立的采食规律高度吻合：大象在雨季会更多采食草本植物，旱季则转向其他植物类群。在这种从‘牧食’到‘啃食’采食策略的转变背后，日粮DNA分析揭示了个体间食物丰富度、组成及重叠度的季节变化。两个象群的大象在旱季均呈现出相对统一的日粮结构，但在雨季维持这种采食一致性的能力存在差异。相较于占主导地位的‘皇家’象群，处于从属地位的‘艺术家’象群在整个时间序列中的采食一致性更强，且这种一致性始终保持正向水平。占主导地位的‘皇家’象群时间序列中呈现出更高的个体差异性，这可能反映了幼崽依赖以及/或优先获取偏好栖息地所带来的营养需求分化。尽管理论预测在资源匮乏条件下，个体应特化采食不同食物，但本研究数据表明，家族纽带或可促进采食一致性，并催生多样化的采食文化，这反映了社会行为与营养之间的内在关联。