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.

动物个体应根据食物可获取状况动态调整采食策略。本研究采用DNA宏条形码（DNA metabarcoding）技术，为肯尼亚两个栖息地利用模式、社会地位及繁殖状态存在差异的象群家族构建了个体水平的采食时间序列数据集。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条独特植物序列。研究结果契合已有公认的生态学规律：大象在雨季更多采食草本植物，旱季则转向木本或其他植物类群。在从“放牧采食”（取食草本）到“浏览采食”（取食木本）的策略转换背后，粪便DNA宏条形码分析进一步揭示了个体间食物丰富度、群落组成及食物重叠度的季节动态变化。两个象群家族的大象在旱季均呈现出相对统一的采食食谱，但在雨季维持食谱一致性的程度存在显著差异。相较于占主导地位的"Royals（王室）"家族，处于从属地位的"Artists（艺术家）"家族在整个时间序列中的食谱一致性更强，且该一致性始终呈正向趋势。优势家族时间序列中更高的个体采食差异性，可能源于与幼崽抚育相关的营养需求分化，或是该家族个体拥有优先获取优质栖息地的权限。尽管经典生态学理论预测，在资源匮乏条件下，个体应通过特化采食不同食物以适配有限资源，但本研究数据表明，家族纽带或可促进采食食谱的一致性，并催生多样化的采食文化，这也直观反映了社会行为与营养获取之间的内在关联。