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科学网—Current Biology：长花距非洲兰花的传粉者转移机制

花匠小妙招
2024-12-12 15:51

Food Reward Chemistry Explains a Novel Pollinator Shift and Vestigialization of Long Floral Spurs in an Orchid

第一作者：Miguel Castañeda-Zárate

第一单位：南非夸祖鲁·纳塔尔大学

通讯作者：Timotheüs van der Niet

Abstract

背景回顾：During the evolutionary history of flowering plants, transitions between pollinator groups (pollinator shifts) have been frequent, and contributed to the spectacular radiation of angiosperms.

提出问题：Although the evolution of floral traits during pollinator shifts has been studied in real time under controlled laboratory conditions, it is challenging to study in nature and therefore poorly understood.

主要研究：Using a comparative, multidisciplinary approach, we dissect the evolution of floral traits during a pollinator shift in the long-spurred African orchid Satyrium longicauda.

结果1-传粉者转变：Phylogenetic analysis and ecological experiments revealed a shift from moth- to oil-collecting bee pollination.

结果2-转变原因：Remarkably, flowers of the bee-pollinated form are similar in morphology, color, and overall volatile chemistry to those of moth-pollinated forms, but differ in having spurs that are mostly devoid of nectar, and have an elevated presence of the oil-derived compound diacetin, which oil-collecting bees use as a cue for oil presence.

结果3-长花距作用：Experiments demonstrated that long spurs are critical for pollination of a moth-pollinated form, but are not needed for pollination of the bee-pollinated form.

研究结论：We conclude that the pollinator shift in Satyrium was mediated by a switch in chemistry of the pollinator reward. The ancestral presence of diacetin might have served as a pre-adaptation for bee pollination, whereas the current mismatch between flower morphology and bees is due to the retention of vestigial floral spurs.

研究意义：These results elucidate the sequence of floral evolution in the early stages of pollinator shifts and help to explain the assembly of suites of co-varying traits through pre-adaptation and vestigialization.

摘要

在有花植物的演化历史中，传粉群体之间的转变，即传粉者转变发生比较频繁，作用于被子植物的辐射扩张。尽管前期已经在实验室条件下对传粉者转变过程中花性状的演化进行了实时的研究，但是自然条件下的研究仍然是一个挑战，因而这方面的认知比较匮乏。基于一个比较、多学科的方法，作者解析了长距非洲兰花中传粉者转变过程中花性状的演化。系统发育分析和生态试验显示长距非洲兰花的传粉者从蛾类转变为了采油的蜂类。有趣的是，蜂类授粉的花在形态、颜色以及总体的挥发性化合物与蛾类授粉的花朵整体相似，不同之处仅在于其花距大多没有花蜜，反而油脂类化合物二乙酸甘油酯的含量有所增加，该物质是采油蜂判断花中是否存在油脂的关键信号物质。进一步的试验显示长距对于蛾类传粉方式的授粉至关重要，但对于蜂类传粉方式的授粉却不是必要的。因此，作者认为长距非洲兰花中传粉者的转变是由于植物中提供给传粉者的“奖励性”化合物的变化所导致的。二乙酸甘油酯的古老存在可能是蜂类授粉的的预适应，而现在蜂类与花形态的不匹配是由于退化花距的残留。本文的结果阐述了一个早期传粉者转变过程中的花演化进程，有助于我们进一步理解植物通过预适应和退化性状进行共变异性状的组配。

通讯作者

**Timotheüs van der Niet**

个人简介：

荷兰瓦赫宁根大学，硕士；

瑞士苏黎世大学，博士。

研究方向：

授粉者对于植物物种形成和多样性的影响。

doi: 10.1016/j.cub.2020.10.024

Journal: Current Biology

Published date: Nov 05, 2020

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链接地址：https://blog.sciencenet.cn/blog-3158122-1258299.html

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