Collaborative Research: Plant Secondary Metabolites as Mediators of Trophic Interactions in a Tropical Forest Community.

Tulane University, New Orleans LA

Investigators

Abstract

Studying how soil quality, light availability, plant chemistry, and insect abundance interact is an important component of understanding how ecosystems function. The rain forest shrub, Piper cenocladum, and its associated insects have been useful for such studies. Piper cenocladum provides food and shelter for ants that protect it from insect herbivores, and it produces several toxins that increase with moderate increases in soil quality and light availability. Previous research with this system demonstrated that the ants controlled specialized insect herbivores, while the plant toxins deterred herbivory by insects with broader diets. Are these results unique to this unusual ant-plant mutualism or are these common phenomena that can happen in many rain forest understory plants? As one step towards exploring the generality of previous results, the proposed study will examine the effects of insects, soil, and light on a closely related plant species that has not evolved a mutualism with ants. The proposed collaboration between ecologists and chemists will allow for a thorough study examining the roles of insect predators versus plant toxins in controlling insect herbivores. Results from the work will provide valuable information for ecological theory and guidance for practical decisions in conservation biology and agriculture.