DISSERTATION RESEARCH: Herbivore Pressure, Inga Chemistry, Toxicity and Defensive Ants: Comparison of two Tropical Communities

植物和以它们为食的动物构成了地球上50%的有机体，它们之间的相互作用对天然林的多样性和动态有着深远的影响。植物进化出了一系列惊人的化学防御系统来阻止食草动物，食草动物也用解毒机制进行了反击。这种相互选择被认为是热带森林物种多样性巨大的原因。然而，我们对影响植物有效防御的选择强度的机制知之甚少。这项研究将通过比较巴拿马和厄瓜多尔的地点，来检验分布广泛的新热带属Inga在防御化学上的差异。我们预测，在厄瓜多尔更多样化和非季节性的森林中，草食动物的数量将会更多，因此保护自己的植物的选择将会更多。在每个地点，我们将量化食草动物的压力、Inga的多样性和丰度、对非蛋白质氨基酸和类黄酮(Inga的主要化学防御类别)的投资、实验室试验中防御对草食动物的毒性以及对自然界树叶的损害率。尽管草食动物和植物的相互选择对化学防御的进化具有假定的重要性，但很少有研究在复杂的自然群落中解决这一问题。

Plants and the animals that eat them make up 50% of the organisms on earth and the interactions among them have profound implications for the diversity and dynamics of natural forests. Plants have evolved an astounding array of chemical defenses to deter herbivores, and herbivores have countered with detoxification mechanisms. This reciprocal selection is believed to be responsible for the great species diversity of tropical forests. However, we know little of the mechanisms shaping the strength of selection for effective plant defenses. This study will examine differences in the defensive chemistry of a widespread Neotropical genus, Inga, by comparing sites in Panama and Ecuador. We predict that herbivore abundance, and hence the selection for plants to defend themselves will be greater in the more diverse and non-seasonal forest in Ecuador. At each site we will quantify herbivore pressure, diversity and abundance of Inga, investments in non-protein amino acids and flavonoids (the main classes of chemical defenses in Inga), toxicity of defenses to herbivores in laboratory trials, and rates of damage to leaves in nature. Despite the presumed importance of reciprocal selection by herbivores and plants on the evolution of chemical defenses, very few studies have addressed this in complex natural communities.