DISSERTATION RESEARCH: The Importance of Plant Ontogeny for Tri-trophic Interactions

University Of Colorado At Boulder, Boulder CO

Investigators

Abstract

Herbivore damage is one of the greatest sources of mortality in plant populations. As a consequence, plants have evolved a wide array of defenses to protect themselves from being eaten. However, the production of plant defenses is costly. Plants are constrained in how they can allocate their resources throughout plant development (i.e. ontogeny) to various essential functions, including defense. While recent studies have demonstrated that plant ontogeny can affect the expression of numerous traits relevant to herbivores, such as nutritional content and physical and chemical defenses, less attention has been given to investigating potential indirect effects of this variation on consumer species. The aim of this project is to assess how variation in plant traits, such as nutritional value, size, and chemical and physical defenses, throughout the ontogeny of a host-plant (Plantago lanceolata), can modify its interactions with a specialist herbivore (Buckeye butterfly, Junonia coenia) and predators of that herbivore. The investigators will conduct three greenhouse and field experiments examining where butterflies choose to lay their eggs, caterpillar performance and caterpillar predation risk at four host plant developmental stages. This research will document potential ecological and evolutionary consequences of temporal variation in plant traits on plant-herbivore-predator dynamics. This knowledge is important for both agricultural systems and conservation biology. Being able to predict herbivore host selection, performance, and predation risk on different host plant developmental stages will help to improve pest management strategies for crops, as well as to develop better eradication plans for invasive plant species. Several undergraduates will be trained in ecological research methods in this study, and the researchers will conduct public outreach to K-12 students and teachers through established relationships with University of Colorado educational programs.