School of Biological Sciences, The University of Queensland, St Lucia, Qld, Australia.
Plant Biol (Stuttg). 2013 May;15(3):566-72. doi: 10.1111/j.1438-8677.2012.00700.x. Epub 2012 Nov 22.
Because most plants require pollinator visits for seed production, the ability of an introduced plant species to establish pollinator relationships in a new ecosystem may have a central role in determining its success or failure as an invader. We investigated the pollination ecology of three milkweed species - Asclepias curassavica, Gomphocarpus fruticosus and G. physocarpus - in their invaded range in southeast Queensland, Australia. The complex floral morphology of milkweeds has often been interpreted as a general trend towards specialised pollination requirements. Based on this interpretation, invasion by milkweeds contradicts the expectation than plant species with specialised pollination systems are less likely to become invasive that those with more generalised pollination requirements. However, observations of flower visitors in natural populations of the three study species revealed that their pollination systems are essentially specialised at the taxonomic level of the order, but generalised at the species level. Specifically, pollinators of the two Gomphocarpus species included various species of Hymenoptera (particularly vespid wasps), while pollinators of A. curassavica were primarily Lepidoptera (particularly nymphalid butterflies). Pollinators of all three species are rewarded with copious amounts of highly concentrated nectar. It is likely that successful invasion by these three milkweed species is attributable, at least in part, to their generalised pollinator requirements. The results of this study are discussed in terms of how data from the native range may be useful in predicting pollination success of species in a new environment.
由于大多数植物需要传粉者访问才能产生种子，因此引入的植物物种在新生态系统中建立传粉者关系的能力可能在决定其作为入侵物种的成功或失败方面起着核心作用。我们调查了三种乳草物种——Asclepias curassavica、Gomphocarpus fruticosus 和 G. physocarpus——在澳大利亚昆士兰州东南部被入侵地区的传粉生态学。乳草复杂的花形态常常被解释为对专门传粉需求的一般趋势。基于这种解释，乳草的入侵与植物物种具有专门化的传粉系统不太可能成为入侵物种的预期相矛盾，而那些具有更普遍化的传粉需求的物种。然而，对三种研究物种自然种群中访花者的观察表明，它们的传粉系统在分类学水平上基本上是专门化的，但在物种水平上是普遍化的。具体来说，两种 Gomphocarpus 物种的传粉者包括各种膜翅目（特别是黄蜂），而 A. curassavica 的传粉者主要是鳞翅目（特别是蛱蝶）。所有三种物种的传粉者都得到了大量高度集中的花蜜的奖励。这三种乳草物种的成功入侵至少部分归因于它们普遍的传粉需求。本研究的结果从如何利用原生境的数据来预测物种在新环境中的传粉成功方面进行了讨论。
