The Role of Zingiberales Shared Evolutionary History and Leaf Traits in Structuring Rolled-leaf Beetle Assemblages in a Tropical Forest

Understanding how local assemblages of plants and animals are structured is a central challenge for evolutionary ecology. Tropical assemblages are high in species numbers and in variety of ecological interactions, providing unique multispecies biological systems to test ecological and evolutionary hypotheses about community assembly. The objective of this dissertation was to understand the role of Zingiberales shared evolutionary history and plant traits for structuring the rolled-leaf beetle (Cephaloleia and Chelobasis, Chrysomelidae) assemblage in a lowland wet forest (La Selva Biological Station) of Costa Rica. In chapter I studied the evolution of physical, nutritional, and chemical leaf traits, how leaf traits relate to each other, and how leaf traits and phylogenetic relatedness structure rolled-leaf beetles assemblages. I found that most chemical traits, few physical traits, and almost no nutritional traits are constrained by plant phylogeny. Physical and chemical traits were positively correlated with each other. Lastly, I found that Zingiberales shared evolutionary history, and physical and chemical traits structure rolled-leaf beetle assemblages at the study site. Non-native Zingiberales species have been introduced to La Selva surrounding areas. Subsequent to these introductions, some rolled-leaf beetle species have expanded their diets to these exotic hosts. In chapter II, I studied the role of Zingiberales shared evolutionary history and leaf traits driving these novel host expansions. I found that beetles feed on exotic hosts that are more closely related and more similar in their physical and chemical traits to their native hosts than to their non-native hosts. In chapter III, I studied the role of ecological and architectural traits structuring rolled-leaf beetle assemblages as measured by beetle species richness, abundance, and diversity. I found that leaf width, as a surrogate for leaf size, positively affects beetle species richness, abundance, and diversity. Also, leaf width structures the entire assemblage of rolled-leaf beetles. Lastly, in Chapter IV I present a natural history note on a predation event of a rolled-leaf beetle (Cephaloleia kressi, Chrysomelidae) by a staphylinid rove beetle (Phanolinus sp., Staphylinidae). This dissertation highlights the importance of shared evolutionary history and leaf traits for structuring a local herbivore assemblage in a tropical forest