Dataset S7 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.

动物个体应依据食物可获得性调整自身饮食构成。本研究采用DNA宏条形码（DNA metabarcoding）技术，为肯尼亚两个象群的大象构建了个体水平的饮食时间序列，这两个象群在栖息地利用、社会地位与繁殖状态上均存在差异。本研究共检测到至少367种可作为食物的植物类群，单份粪便样本中最多可检出137条独特的植物序列。研究结果与已被广泛证实的规律相符：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。在从“食草”到“啃食”的策略转换中，饮食DNA分析还揭示了个体间食物丰富度、食物组成以及饮食重叠度的季节性变化。两个象群的大象在旱季均会形成相对统一的饮食结构，但在雨季维持饮食一致性的程度存在差异。相较于优势象群“Royals”，从属象群“Artists”在其整个饮食时间序列中的饮食一致性更强，且一致性始终保持正向。优势象群“Royals”的饮食时间序列中个体差异更为显著，这可能反映了与幼崽抚育相关的营养需求分化，或是该象群拥有优先获取偏好栖息地的权限。尽管理论预测在资源匮乏条件下，个体应专一采食不同食物，但本研究数据显示，家族纽带或许能促进饮食一致性，并催生多样化的摄食文化，这也反映了社会行为与营养之间的关联。