Departamento Ecología Evolutiva, Instituto de Ecología, Universidad Nacional Autónoma México, Ciudad de México 04510, Mexico.
Departamento de Botánica, Instituto de Biología, Universidad Nacional Autónoma México, Ciudad de México 04510, Mexico.
Mol Phylogenet Evol. 2019 Apr;133:176-188. doi: 10.1016/j.ympev.2019.01.004. Epub 2019 Jan 11.
The genus Agave sensu lato contains ca. 211 described species, many of which are considered keystone species because of their ecological dominance and the quantity of resources they provide with their massive, nectar-rich inflorescences. The large diversity of Agave species has been hypothesized as being related to their reproductive strategy (predominantly monocarpic) and diverse pollinators (e.g., bats, hummingbirds, hawkmoths). In particular, Agave species provide resources that a few genera of nectar feeding bats from the subfamily Glosophaginae are dependent upon. To explore a possible coevolutionary relationship between Agave and the bat species that pollinate them, we calibrated molecular phylogenies of both groups and looked for a correlation in their dates of divergence. One coding and two non-coding regions of the chloroplast genome were sequenced from 49 species of the Agavoideae (Asparagaceae), and the mitochondrial gene Cyt-b and nuclear coding gene RAG2 were either sequenced or obtained from gene bank for 120 Phyllostomid bats. Results from the analyses indicate that Agave sensu lato is a young genus (estimated crown age 2.7-8.5/stem age 4.6-12.3 Ma), with an increasing diversification rate, and the highest speciation rate among Agavoideae's clades. The origin of the Glossophaginae bats (stem age 20.3-23.5 Ma) occurred prior to the stem age of Agave sensu lato, while the origin of the current pollinators of Agave species, members of the genera Glossophaga, Leptonycteris, Anoura, Choeronyscus, Musonycteris and Choeronycteris, was estimated to be around 6.3-16.2 Ma, overlapping with the stem age of Agave sensu lato, supporting the hypothesis of diffuse coevolution.
广义龙舌兰属（Agave sensu lato）包含约 211 个已描述的物种，其中许多物种因其生态优势和大量花蜜丰富的花序提供的资源而被认为是关键物种。龙舌兰属物种的多样性被假设与它们的生殖策略（主要是单性结实）和多样化的传粉者（如蝙蝠、蜂鸟、天蛾）有关。特别是，龙舌兰属物种为少数几种以花蜜为食的蝙蝠提供了资源，这些蝙蝠属于食蜜蝠亚科（Glosophaginae）。为了探索龙舌兰属和为其授粉的蝙蝠物种之间可能存在的共同进化关系，我们对这两个群体的分子系统发育进行了校准，并寻找它们分歧日期的相关性。我们从龙舌兰科（Agavaceae）的 49 种拟兰亚科（Agavoideae）中测序了叶绿体基因组的一个编码区和两个非编码区，并且为 120 种 Phyllostomid 蝙蝠测序或从基因库中获取了线粒体基因 Cyt-b 和核编码基因 RAG2。分析结果表明，广义龙舌兰属是一个年轻的属（估计冠年龄 2.7-8.5/茎年龄 4.6-12.3 Ma），具有不断增加的多样化率，并且是拟兰亚科中分化速率最高的属。食蜜蝠亚科（Glossophaginae）的起源（茎年龄 20.3-23.5 Ma）发生在广义龙舌兰属的茎年龄之前，而目前龙舌兰属物种的传粉者，包括 Glossophaga、Leptonycteris、Anoura、Choeronyscus、Musonycteris 和 Choeronycteris 属的成员，起源于约 6.3-16.2 Ma，与广义龙舌兰属的茎年龄重叠，支持了扩散共同进化的假说。
