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Causes and consequences of resisting herbivory: How long-lived plants avoid damage from diverse short-lived insect herbivores
Author(s): Colin Orians1, Tara J Massad2, Phyllis Coley3
1. Tufts University 2. Oregon State University 3. The University of Utah
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Geometrid on Inga marginata.jpgDescription
Students will gain an understanding of the evolutionary and ecological importance of plant-insect interactions, plant defense strategies, how to measure herbivory, and the importance of promoting diversity and equal opportunities in science.
Students will explore a paper summarizing years of research on plant-insect interactions and plant defense. They will watch brief videos about measuring herbivory in the field. Students will summarize broad plant defense strategies, design a restoration experiment integrating concepts discussed about plant defenses in order to limit herbivore damage, and they will design broader impacts with the aim of learning to communicate science and promote diversity and equity in science.
This module deals with the two most diverse groups of higher organisms in the tropics as well as the ecology and evolution of their interactions as driven by the fascinating, but invisible realm of plant chemistry. The module promotes analytical skills, creative problem solving, and discussions of equity.
Overview
Over a quarter of the leaf material tropical trees produce is consumed by herbivores; in response plants have evolved a diversity of defense strategies that influence tri-trophic interactions, coexistence and the immense biodiversity of the tropics.
Plants and insect herbivores are the two most diverse groups of higher organisms, and understanding their interactions is key to understanding the richness of tropical forests. Herbivore pressures are intense in the tropics, and in response, plants have evolved an amazing diversity of defense strategies that involve: i) secondary metabolites, ii) foliar nutrients, iii) leaf toughness, iv) trichomes and other physical leaf traits, v) leaf phenology, and vi) a reliance on predators. So, despite its appearance, a tropical rainforest is not a salad bowl to herbivores.
In-depth, long-term research in a complex study system has allowed Dr. Lissy Coley and colleagues to decipher many components of plant defenses and plant-herbivore interactions more broadly. Focusing on Inga, a hyper-speciose Legume genus of canopy trees, they have carefully documented patterns of herbivory, diverse plant defense strategies, and elucidated evolutionary processes that promote tropical diversity. They have shown that rates of herbivory are high, that chemical, physical, and biotic defenses are all critical to survival, and that herbivores have resulted in a surprising diversity of defenses among closely related species. Moreover, their work has demonstrated that despite the rapid diversification of defenses and extreme levels of herbivore specialization, herbivores are forced to constantly evolve to utilize their host plants. The body of work Lissy and her team have produced (summarized in their 2018 paper that is the focus of this module) speaks to the value of long-term, collaborative research and has paved the way for new and exciting questions to be examined in the field of chemical ecology.
Learning Objectives:
Students will be able to:
- Describe patterns of herbivory in the tropics and explain the importance of herbivores as top-down selective pressures on plants.
- Compare different types of plant defense and discuss why defenses are so diverse within and between species.
- Design appropriate experimental approaches to understand plant-herbivore interactions.
- Recognize the value of collaborative research, training for young researchers in less developed countries, and outreach.
Support was provided by: A grant from the United States National Science Foundation (DBI-RCN-UBE 2120141).
Cite this work
Researchers should cite this work as follows:
- Orians, C., Massad, T. J., Coley, P. (2024). Causes and consequences of resisting herbivory: How long-lived plants avoid damage from diverse short-lived insect herbivores. OCELOTS, QUBES Educational Resources. doi:10.25334/CJ9T-GG65