Abstract:
Over 125 million years of ant-plant interactions have culminated in one of the most intriguing evolutionary outcomes in life history. The myrmecophyte Duroia hirsuta (Rubiaceae) is known for its mutualistic association with the ant Myrmelachista schumanni and several other species, mainly Azteca, in the north-western Amazon. While both ants provide indirect defences to plants, only M. schumanni nests in plant domatia and has the unique behaviour of clearing the surroundings of its host tree from heterospecific plants, potentially increasing resource availability to its host. Using a 12-year survey, we asked how the continuous presence of either only M. schumanni or only Azteca spp. benefits the growth and defence traits of host trees. We found that the continuous presence of M. schumanni improved relative growth rates and leaf shearing resistance of Duroia better than trees with Azteca. However, leaf herbivory, dry matter content, trichome density, and secondary metabolite production were the same in all trees. Survival depended directly on ant association (> 94% of trees died when ants were absent). This study extends our understanding of the long-term effects of strict ant-plant mutualism on host plant traits in the field and reinforces the use of D. hirsuta-M. schumanni as a model system suitable for eco-co-evolutionary research on plant-animal interactions.
摘要:
超过1.25亿年的蚂蚁-植物相互作用最终导致了生活史上最有趣的进化结果之一。MyrmectrumDuroiahirsuta(Rubiaceae)以与蚂蚁Myrmelachistaschumanni和其他几种物种的相互联系而闻名,主要是阿兹台克,在亚马逊西北部。虽然两种蚂蚁都为植物提供间接防御,只有M.schumanni在植物domatia中筑巢,并且具有从杂种植物中清除寄主树周围的独特行为,可能会增加其主机的资源可用性。根据一项为期12年的调查,我们询问是否只有M.schumanni或只有Aztecaspp的连续存在。有利于寄主树的生长和防御特性。我们发现M.schumanni的持续存在比使用Azteca的树木更好地改善了Duroia的相对生长速率和叶片抗剪切性。然而,叶食草动物,干物质含量,毛状体密度,所有树木的次生代谢产物产量相同。生存直接取决于蚂蚁的结合(当没有蚂蚁时,>94%的树木死亡)。这项研究扩展了我们对严格的蚂蚁-植物共生对田间寄主植物性状的长期影响的理解,并加强了D.hirsuta-M.的使用。Schumanni作为适用于动植物相互作用的生态协同进化研究的模型系统。