Duchen Pablo, Renner Susanne S
Systematic Botany and Mycology, University of Munich (LMU), Menzinger Strasse 67, D-80638 Munich, Germany.
Am J Bot. 2010 Jul;97(7):1129-41. doi: 10.3732/ajb.0900385. Epub 2010 Jun 18.
The Cucurbitaceae genus Cayaponia comprises ∼60 species that occur from Uruguay to the southern United States and the Caribbean; C. africana occurs in West Africa and on Madagascar. Pollination is by bees or bats, raising the question of the evolutionary direction and frequency of pollinator shifts. Studies that investigated such shifts in other clades have suggested that bat pollination might be an evolutionary end point. •
Plastid and nuclear DNA sequences were obtained for 50 accessions representing 30 species of Cayaponia and close relatives, and analyses were carried out to test monophyly, infer divergence times, and reconstruct ancestral states for habitat preferences and pollination modes. •
The phylogeny shows that Cayaponia is monophyletic as long as Selysia (a genus with four species from Central and South America) is included. The required nomenclatural transfers are made in this paper. African and Madagascan accessions of C. africana form a clade that is part of a polytomy with Caribbean and South American species, and the inferred divergence time of 2-5 Ma implies a transoceanic dispersal event from the New World to Africa. The ancestral state reconstructions suggest that Cayaponia originated in tropical forests from where open savannas were reached several times and that bee pollination arose from bat pollination, roughly concomitant with the shifts from forests to savanna habitats. •
Cayaponia provides the first example of evolutionary transitions from bat to bee pollination as well as another instance of transoceanic dispersal from the New World to Africa.
南瓜科的卡亚波尼亚属包含约60个物种，分布于从乌拉圭到美国南部以及加勒比地区；非洲卡亚波尼亚分布于西非和马达加斯加。授粉由蜜蜂或蝙蝠完成，这引发了传粉者转变的进化方向和频率问题。对其他类群中此类转变的研究表明，蝙蝠授粉可能是一个进化终点。
获取了代表卡亚波尼亚属30个物种及近缘种的50份材料的质体和核DNA序列，并进行分析以检验单系性、推断分歧时间以及重建栖息地偏好和授粉模式的祖先状态。
系统发育显示，只要包含Selysia（一个来自中南美的有四个物种的属），卡亚波尼亚就是单系的。本文进行了所需的命名转移。非洲和马达加斯加的非洲卡亚波尼亚材料形成一个分支，是与加勒比和南美物种的多歧分支的一部分，推断的2 - 5百万年前的分歧时间意味着一次从新世界到非洲的跨洋扩散事件。祖先状态重建表明，卡亚波尼亚起源于热带森林，多次到达开阔的稀树草原，并且蜜蜂授粉起源于蝙蝠授粉，大致与从森林到稀树草原栖息地的转变同时发生。
卡亚波尼亚提供了从蝙蝠授粉到蜜蜂授粉进化转变的首个例子，以及另一个从新世界到非洲跨洋扩散的实例。
