Data from: Ants at plant wounds – a little-known trophic interaction with evolutionary implications for ant-plant interactions

Extrafloral nectaries (EFNs) allow plants to engage in mutualisms with ants preventing herbivory in exchange for food. EFNs occur scattered through the plant phylogeny and likely evolved independently from herbivore-created wounds subsequently visited by ants collecting leaked sap. Records of wound-feeding ants are, however, anecdotal. By surveying 38,000 trees from 40 species, we conduct the first quantitative ecological study of this overlooked behavior. Ant-wound interactions were widespread (0.5% of tree individuals) and occurred on 23 tree species. Interaction networks were opportunistic, closely resembling ant-EFNs networks. Fagaceae, a family lacking EFNs, were strongly overrepresented. For Fagaceae, ant occurrence at wounds correlated with species-level leaf damage, potentially indicating that wounds may attract mutualistic ants, supporting the hypothesis of ant-tended wounds as precursors of ant-EFNs mutualisms. Given the commonness of herbivore wounds, wound sap as steadily available food source might furthermore help to explain the overwhelming abundance of ants in (sub)tropical forest canopies.花外蜜腺（Extrafloral nectaries, EFNs）使植物能够与蚂蚁建立互利共生关系，通过提供食物换取蚂蚁帮助抵御植食者。花外蜜腺在植物系统发育谱系中广泛分布，且很可能独立起源于植食动物造成的伤口——这类伤口随后会被采集渗漏汁液的蚂蚁造访。不过，目前关于取食伤口汁液的蚂蚁的相关记录仅为零散的轶事性报道。本研究通过调查40个物种的38000棵树木，完成了针对这一被忽视行为的首次定量生态学研究。蚂蚁与树木伤口的互作现象十分普遍（占调查树木个体的0.5%），并在23个树种中被观测到。此类互作网络具有机会主义特征，与蚂蚁-花外蜜腺互作网络高度相似。不具备花外蜜腺的壳斗科（Fagaceae）在此类互作中占比显著偏高。针对壳斗科而言，伤口处的蚂蚁出现情况与物种水平的叶片损伤程度呈显著相关，这或许表明伤口能够吸引互利共生的蚂蚁，从而支持“蚂蚁趋附的伤口是花外蜜腺互利共生演化前体”的假说。鉴于植食动物造成的伤口十分常见，伤口渗漏的汁液作为稳定可获取的食物来源，或许还能进一步解释（亚）热带森林冠层中蚂蚁种群数量极为丰富的现象。