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）可帮助植物与蚂蚁建立互利共生关系：植物为蚂蚁提供食物作为回报，蚂蚁则帮助植物抵御植食者。花外蜜腺在植物系统发育中广泛分布，且很可能独立演化自植食性昆虫造成的伤口——这类伤口后续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记录多为轶事性报道。 本研究针对40个物种的38000株树木展开调查，是首个针对这一被忽视的蚂蚁行为开展的定量生态学研究。研究发现，蚂蚁与植物伤口的互作现象十分普遍（占调查树木个体的0.5%），且在23个树种中均有发现。这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。不含花外蜜腺的壳斗科（Fagaceae）在该类互作中的占比显著偏高。针对壳斗科而言，伤口处的蚂蚁出现情况与该物种的叶片受损程度呈显著相关，这提示植物伤口或许能够吸引互利共生的蚂蚁，从而为“蚂蚁造访的伤口是蚂蚁-花外蜜腺共生关系演化前身”这一假说提供了支持。鉴于植食性伤口随处可见，伤口渗出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）热带林冠层中蚂蚁种群数量极为庞大的现象。