University of Missouri - Saint Louis

The Graduate School

Announcement

An oral examination in defense of the dissertation for the degree

Doctor of Philosophy in Biology

Diego Salazar
B.S. in Biology, December 2001. Universidad de Costa Rica


Exploring the local and regional effects of plant diversity on plant-herbivore interactions.

 

Abstract

The study of biological diversity and its effects on ecosystem functioning and species interactions has always been a fundamental part of biology. The accelerating loss of species in conjunction with an increasing change in the natural environment has underlined the importance of biodiversity on the evolutionary and ecological dynamics of natural systems. In this dissertation I explore the effect of local and regional patterns of plant diversity in plant-herbivore interactions. Furthermore, this work goes beyond the classical concepts of taxonomical diversity and investigates the role of phylogenetic and chemical diversity on plant-herbivore interactions. To accomplish this work I have chosen as study system the Pantropical plant genus Piper (Piperaceae). In chapter one I explore the patterns of herbivore diversity along a latitudinal gradient by following to widely distributed Piper species from Mexico to Bolivia. Here I show how that changes in herbivore diversity along this latitudinal gradient are likely changing the nature and intensity of the evolutionary herbivore pressures experienced by plants. In chapter two I examine how non-random patterns of seed dispersal by bats are increasing local understory Piper diversity. Furthermore, I show how these changes in local diversity are also reducing Piper herbivore damage due to possible resource dilution effects. This represents the first evidence of a direct link between seed dispersal and plant herbivore interactions. In chapter three I explore the relationship between inter-specific chemical diversity and intra-specific chemical variation. Here I put forward the potential association between the number of dominant secondary compounds present in a particular Piper species and the relative ecological value that said compounds have for interactions between plants and their herbivores. Finally, in chapters four and five I use a metabolomic approach to investigate the role that Piper chemical diversity at the community has on species coexistence and community assembly. Here I show how natural Piper communities are more chemically diverse than expected by chance. This section also shows that Piper communities with higher chemical diversity have less herbivore damage. As a unit, this work provides strong evidence of the importance of taxonomical and chemical diversity for plant herbivore interaction.


 

Date: October 30th, 2013

Time: 12:30 a.m. to 1:30 p.m.

Place: Benton Hall B104

 

Defense of Dissertation Committee

 

Robert J. Marquis, Ph.D (Advisor)

Alejandra Jaramillo, Ph.D.

 

Elizabeth A. Kellogg, Ph.D.

Robert E. Ricklefs, Ph.D.