Research

General research themes:

1. How do microbes influence host phenotype? Study system: nectar ecology and microbiology

Yeasts and bacteria are common inhabitants of flowers, and attain high densities in floral nectar. I am interested how (and when) these microbes influence plants and pollinators, the mechanisms involved, and evolutionary ecology of these interactions. I am also interested in how nectar constituents influence pollinator foraging and health.

With John Beck at USDA-ARS, we are examining the influence of nectar-inhabiting microorganisms on pollinator preference through volatile organic compounds.

Apis mellifera foraging on experimental nectar

Apis mellifera foraging on artificial nectar

With the ABI 50A lab, we are also examining plant-pollinator-microbe interactions in Epilobium canum, the California fuschia.

 

2. Community ecology of plant-associated microbial communities:

What mechanisms shape the structure and function of microbial communities associated with plants? How do can we use assembly mechanisms to better understand function, including effects on insect herbivores and pollinators?

Projects:

How does dispersal affect the structure and function of bacterial and yeast communities in floral nectar of Mimulus aurantiacus? Collaboration with Tad Fukami

Mimulus aurantiacus flower exposed to pollinators

Mimulus aurantiacus flower exposed to pollinators

Ongoing project: How do ants influence microbial community structure and nectar characteristics in coffee agroecosystems? Collaboration with Stacy Philpott

Previous work: Above-belowground interactions and feedbacks between herbivores and plant-associated microbes (mycorrhizal fungi). Previous collaboration with Mark Hunter

Assessing the performance of a specialist caterpillar D. plexippus on Asclepias syriaca (milkweed) seedlings associated with mycorrhizal fungi.

Assessing the performance of the specialist caterpillar Danaus plexippus (monarch) on Asclepias syriaca (milkweed) seedlings associated with mycorrhizal fungi.

3. Influence of anthropogenic changes on plant-microbe (insect) interactions

Ongoing project: Influence of agricultural management strategies on rhizosphere microbial community structure and influence on plant defense, with Amelie Gaudin, Clare Casteel and Christian Nansen.   In this project, we examine if organic, conventional or mixed management influences soil health, plant performance, and insect preference and performance in processing tomato systems.

 

Past work:Fragmentation affects fungal community composition in the rhizosphere of  Meterosideros polymorpha 

Meterosideros polymorpha flowers

Meterosideros polymorpha flowers

Elevated CO2 changes plant-microbe-insect interactions

OFC_GCB