Department of Ecology, Leuphana University, 21335 Lüneburg, Germany.
Proc Biol Sci. 2013 May 8;280(1762):20130680. doi: 10.1098/rspb.2013.0680. Print 2013 Jul 7.
Chemical compounds are highly important in the ecology of animals. In social insects, compounds on the body surface represent a particularly interesting trait, because they comprise different compound classes that are involved in different functions, such as communication, recognition and protection, all of which can be differentially affected by evolutionary processes. Here, we investigate the widely unknown and possibly antagonistic influence of phylogenetic and environmental factors on the composition of the cuticular chemistry of tropical stingless bees. We chose stingless bees because some species are unique in expressing not only self-produced compounds, but also compounds that are taken up from the environment. By relating the cuticular chemistry of 40 bee species from all over the world to their molecular phylogeny and geographical occurrence, we found that distribution patterns of different groups of compounds were differentially affected by genetic relatedness and biogeography. The ability to acquire environmental compounds was, for example, highly correlated with the bees' phylogeny and predominated in evolutionarily derived species. Owing to the presence of environmentally derived compounds, those species further expressed a higher chemical and thus functional diversity. In Old World species, chemical similarity of both environmentally derived and self-produced compounds was particularly high among sympatric species, even when they were less related to each other than to allopatric species, revealing a strong environmental effect even on largely genetically determined compounds. Thus, our findings do not only reveal an unexpectedly strong influence of the environment on the cuticular chemistry of stingless bees, but also demonstrate that even within one morphological trait (an insect's cuticular profile), different components (compound classes) can be differentially affected by different drivers (relatedness and biogeography), depending on the functional context.
化学物质在动物生态学中非常重要。在社会性昆虫中，体表化合物是一个特别有趣的特征，因为它们包含不同的化合物类别，涉及不同的功能，如通讯、识别和保护，所有这些功能都可能受到进化过程的不同影响。在这里，我们研究了广泛未知的、可能对立的进化和环境因素对热带无刺蜜蜂体表化学物质组成的影响。我们选择无刺蜜蜂是因为一些物种不仅表达自身产生的化合物，还表达从环境中摄取的化合物，这在无刺蜜蜂中是独特的。通过将来自世界各地的 40 种蜜蜂的体表化学物质与其分子系统发育和地理分布联系起来，我们发现不同化合物群体的分布模式受到遗传亲缘关系和生物地理学的不同影响。例如，获取环境化合物的能力与蜜蜂的进化史高度相关，在进化上更为先进的物种中占主导地位。由于存在环境衍生的化合物，这些物种进一步表现出更高的化学和功能多样性。在旧世界的物种中，无论是环境衍生化合物还是自身产生的化合物，在同域物种之间的化学相似性都特别高，即使它们彼此之间的亲缘关系不如异域物种，这表明即使对主要由遗传决定的化合物，环境的影响也很强。因此，我们的研究结果不仅揭示了环境对无刺蜜蜂体表化学物质的出乎意料的强烈影响，还表明即使在一个形态特征（昆虫的体表轮廓）中，不同的成分（化合物类别）也可能受到不同驱动因素（亲缘关系和生物地理学）的不同影响，这取决于功能背景。
