Neuroscience Institute and Department of Biology, Georgia State University, P.O. Box 5030, Atlanta, GA 30302-5030, USA.
Integr Comp Biol. 2011 Nov;51(5):771-80. doi: 10.1093/icb/icr063. Epub 2011 Jun 24.
Chemicals are a frequent means whereby organisms defend themselves against predators, competitors, parasites, microbes, and other potentially harmful organisms. Much progress has been made in understanding how a phylogenetic diversity of organisms living in a variety of environments uses chemical defenses. Chief among these advances is determining the molecular identity of defensive chemicals and the roles they play in shaping interactions between individuals. Some progress has been made in deciphering the molecular, cellular, and systems level mechanisms underlying these interactions, as well as how these interactions can lead to structuring of communities and even ecosystems. The neuroecological approach unifies practices and principles from these diverse disciplines and at all scales as it attempts to explain in a single conceptual framework the abundances of organisms and the distributions of species within natural habitats. This article explores the neuroecology of chemical defenses with a focus on aquatic organisms and environments. We review the concept of molecules of keystone significance, including examples of how saxitoxin and tetrodotoxin can shape the organization and dynamics of marine and riparian communities, respectively. We also describe the current status and future directions of a topic of interest to our research group-the use of ink by marine molluscs, especially sea hares, in their defense. We describe a diversity of molecules and mechanisms mediating the protective effects of sea hares' ink, including use as chemical defenses against predators and as alarm cues toward conspecifics, and postulate that some defensive molecules may function as molecules of keystone significance. Finally, we propose future directions for studying the neuroecology of the chemical defenses of sea hares and their molluscan relatives, the cephalopods.
化学物质是生物防御捕食者、竞争者、寄生虫、微生物和其他潜在有害生物的常用手段。在理解生活在各种环境中的生物如何利用化学防御方面已经取得了很大进展。其中最重要的进展是确定防御性化学物质的分子身份以及它们在塑造个体之间相互作用中所扮演的角色。在破译这些相互作用的分子、细胞和系统水平机制，以及这些相互作用如何导致群落甚至生态系统的结构方面，也取得了一些进展。神经生态学方法将来自这些不同学科的实践和原则统一起来，并在所有尺度上进行统一，因为它试图在一个单一的概念框架内解释生物的丰度以及物种在自然栖息地中的分布。本文探讨了化学防御的神经生态学，重点是水生生物和环境。我们回顾了关键分子的概念，包括石房蛤毒素和河豚毒素如何分别塑造海洋和河岸社区的组织和动态的例子。我们还描述了我们研究小组关注的一个主题的现状和未来方向——海洋软体动物，尤其是海兔，在其防御中使用墨汁。我们描述了介导海兔墨汁保护作用的多种分子和机制，包括作为防御捕食者的化学防御和作为同类警报信号，并且假设一些防御性分子可能作为关键分子发挥作用。最后，我们提出了未来研究海兔及其软体动物亲属（头足类动物）化学防御的神经生态学的方向。
