- Author: Kathy Keatley Garvey
“I am interested in understanding and predicting how microbial communities influence interactions between plants and insects,” she said. “In the Vannette lab (in Briggs Hall), we use tools and concepts from microbial ecology, chemical ecology, and community ecology to better understand the ecology and evolution of interactions among plants, microbes and insects."
A native of Hudsonville, Mich., Vannette received her bachelor of science degree in biology with honors at Calvin College, Grand Rapids, Mich., and her doctorate in ecology and evolutionary biology from the University of Michigan, in 2011. Her dissertation was entitled “Whose Phenotype Is It Anyway? The Complex Role of Species Interactions and Resource Availability in Determining the Expression of Plant Defense Phenotype and Community Consequences.”
In her PhD research, she examined how variation in nutrient availability and plant associations with mycorrhizal fungi belowground influenced defense chemistry in milkweed plants and the performance of a specialist herbivore (Danaus plexippus). She found that resource-based tradeoffs can in part explain plant allocation to antiherbivore defense and mycorrhizal fungi. This work also describes that plant genotypes vary in their investment in defense and associations with belowground fungi.
As a Stanford University postdoctoral fellow, funded by a life sciences research fellowship, Vannette examined the community ecology of plant-associated microorganisms. Using diverse systems, she studied the assembly of microbial communities, microbial response to anthropogenic changes like habitat fragmentation, and microbial effects on plant-pollinator interactions.
- Community ecology of plant-associated microbial communities. She explored what mechanisms shape the structure and function of microbial communities associated with plants, and how to assemble mechanisms to better understand functions, including the effects on insect herbivores and pollinators. She also researched how ants influence microbial community structure and nectar characteristics in coffee agroecosystems.
- Nectar ecology. Knowing that yeasts and bacteria are common inhabitants of flowers, and attain high densities in floral nectar, she researched how these microbes influence plants and pollinators, the mechanisms involved, and evolutionary ecology of these interactions. She also studied how nectar constituents influence pollinator foraging and health.
- Influence of anthropogenic changes on plant-microbe (insect) interactions. She researched how fragmentation affects fungal community composition in the rhizosphere of Meterosideros polymorpha, a species of flowering evergreen tree in the myrtle family. She also studied elevated carbon dioxide changes plant-microbe-insect interactions, and researched the effects of mycorrhizal fungi on plant defense and plant-herbivore interactions.
The National Wildlife Research Foundation featured Vannette's research on monarchs and milkweed in its March 11, 2013 piece on “Catering to Butterfly Royalty." The article, by author Doreen Cubie, focused on Vannette's research as a graduate student at the University of Michigan. Vannette and advisor Mark Hunter studied five common species of milkweeds, the host plant for monarchs. They found that climate change may disrupt the chemistry of milkweeds, and encouraged gardeners to help the monarchs by planting more of these critical host plants.
Vannette and Hunter grew the plants in open-air chambers, “exposing them to elevated amounts of carbon dioxide designed to mimic Earth's atmosphere in the future,” wrote Cubie. “Although most of the plants grew slightly larger, the composition of plant leaves changed dramatically. Most of the milkweed families decreased their production of toxins, some by as much as 50 percent. The extra carbon dioxide exposure toughened the leaves, a problem for the caterpillars.
Last March Vannette was an invited speaker on the ecology and evolution of the microbiome at the University of Michigan Early Career Scientists' symposium in Ann Arbor, Mich.
Among her recent publications:
- Co-author of “Plant-Derived Variation in the Composition of Aphid Honeydew and its Effects on Colonies of Aphid-Tending Ants,” published in November 2014 in the journal Ecology and Evolution.
- Lead author of “Genetic Variation in Plant Below-Ground Response to Elevated CO2 and Two Herbivore Species,” published in July 2014 in Plant Soil.
- Co-author of “Honey Bees Avoid Nectar Colonized by Three Bacterial Species, but not by a Yeast Species, Isolated from the Bee Gut,” published in a January 2014 edition of PLOS ONE.
- Lead author of “Historical Contingency in Species Interactions: Towards Niche-Based Predictions,” published November 2013 in Ecology Letters. (Recommended by the Faculty of 1000)
- Author: Kathy Keatley Garvey
His seminar will be recorded for later viewing on UCTV.
"Ecologists have long recognized that species interactions change over time, due to temporal variation in abiotic environments and in the abundance and relative life stages of interacting species," Yang says. "Despite - or perhaps because of - the ubiquitous role of time in structuring species interactions, other aspects of community complexity have often been emphasized ahead of temporal complexity. However, a growing emphasis on understanding how phenology, ontogeny, stage-structure and transient event-driven dynamics affect species interactions may signal the re-emergence of a 'temporally explicit' perspective in community ecology. A temporally explicit view of community ecology aims to understand how species interactions change over time, and the consequences of shifts in this timing."
In his talk he will suggest "how a temporally explicit view of species interactions could build upon the ubiquitous and implicit consideration of time that is already fundamental to ecology. If we step away from common simplifying assumptions about the constancy of community structure and process, what new questions emerge? This introduction to the session will attempt to identify some common themes that are emerging from a temporally explicit perspective in ecology, illustrated with examples from recent studies in multiple systems."
Yang said the key emerging themes of this synthesis are
- In systems where multiple dynamic processes operate on different timescales, it is important to consider sequential (as opposed to strictly alternative) hypotheses;
- The study of species interactions should consider both phenology and ontogeny, especially when stage-structured interactions occur throughout life histories;
- Biotic and abiotic constraints on species interactions can define windows of opportunity in time, where quantitative shifts in the timing of key events (such as physical disturbances or resource pulses) can qualitatively alter life history outcomes;
- A temporally explicit perspective seeks to explain the mechanisms of historical contingency in community assembly; and
- The continued development of a temporally explicit perspective in ecology is important for understanding how real-world species interactions are coordinated in time, and the potential implications of disrupting this coordination.
Yang's research interests include community ecology, species interactions, temporal variation, extreme events in nature, and the integration of ontogeny and phenology. Last year received a prestigious National Science Foundation Early Career Development Award of $600,000. He was one of four young UC Davis faculty members selected for the award. Yang is studying the importance of timing in interactions between plants, animals and their environment, specifically studying the monarch butterfly and milkweed. Species interactions change with the seasons and with different life stages, and climate change may disrupt these interactions, for example, if caterpillars emerge before food sources are available.
Yang earned his bachelor's degree (ecology and evolution) from Cornell University in 1999 and his doctorate from UC Davis in 2006, studying with entomology professor and ecologist Rick Karban. Yang conducted postdoctoral research at UC Santa Barbara before returning to UC Davis as a faculty member in 2009. While at UC Santa Barbara, he served as a UC President's Postdoctoral Fellow in the Department of Ecology, Evolution and Marine Biology.