Data from: The evolution of communication in two ant-plant mutualisms

Myrmecophytes are plants that provide nesting sites and food to ants that protect them against herbivores. Plant signals function to synchronize ant patrolling with the probability of herbivory. We compared the communication signals in two symbioses involving ant and plant pairs that are closely related. The two plants emitted the same volatile compounds upon damage. These compounds are simple molecules common in the plant kingdom. Electroantennography revealed that the two symbiotic ants, as well as several other ant species, were able to perceive these compounds. However, workers of one species responded only to hexanal, while those of the other species responded mostly to methyl salicylate. The two signals involved in the focal symbioses are ‘cheap’ (low metabolic cost), which is consistent with theoretical predictions for the evolution of signalling between partners with convergent interests. They are also not specific, which is expected between plants and broad-spectrum predators such as ants. The fact that different signals are used in the two sister symbioses suggests different mechanisms underlying similar adaptations in the evolution of communication.蚁栖植物（Myrmecophytes）是一类为蚂蚁提供栖息场所与食物来源的植物，而蚂蚁则会保护其免受植食性动物的侵害。植物信号的功能在于将蚂蚁的巡逻行为与植食风险发生的概率同步起来。本研究对两组亲缘关系密切的蚂蚁-植物共生体系中的通信信号进行了对比分析。两种受损植物会释放相同的挥发性化合物，这类化合物是植物界中常见的简单小分子。触角电图法（electroantennography）检测结果显示，这两种共生体系中的蚂蚁，以及其他数种蚂蚁，均能够感知这类化合物。然而，其中一种蚂蚁的工蚁仅对己醛（hexanal）产生响应，而另一种蚂蚁的工蚁则主要对水杨酸甲酯（methyl salicylate）做出反应。本研究聚焦的两类共生体系所使用的信号均为‘低成本’（代谢消耗极低）信号，这与互利伙伴间基于趋同利益演化出的通信信号的理论预测相符。同时这类信号也不具备特异性，这与植物与蚂蚁这类广谱捕食者之间的共生关系预期一致。两组姊妹共生体系中采用了不同的信号这一现象，表明在通信演化过程中，相似适应性背后可能存在着不同的作用机制。