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）是一类为蚂蚁提供筑巢场所与食物来源，以此换取蚂蚁抵御植食性动物保护服务的植物。植物释放的信号可调控蚂蚁的巡逻行为，使其与植食风险发生概率相匹配。本研究比对了两对亲缘关系紧密的蚁-植物共生体系中的通信信号。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广泛存在的简单小分子。触角电位仪（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感知此类化合物。但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响应水杨酸甲酯（methyl salicylate）。本研究聚焦的两种共生体系所使用的信号均为‘低成本’（代谢消耗极低）信号，这与具有趋同利益的共生伙伴间通信信号演化的理论预测相符。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间的通信模式预期一致。而两对姊妹共生体系却使用了不同的信号，这一现象表明，尽管二者的通信适应性演化结果相似，但其背后的调控机制却存在差异。