Lab members

Rachel Vannette

Associate Professor 2021-current

Assistant Professor 2015-2021

Department of Entomology and Nematology, University of California, Davis

Postdoc 2011-2015 Stanford University, Department of Biology, Life Sciences Research Fellow

Ph.D., University of Michigan, Ann Arbor, Department of Ecology and Evolutionary Biology, 2011

B.S. Biology, Calvin College, 2006


UC Davis Chancellor’s Fellow 2023-2027

NSF CAREER Awardee 2019-2024

Hellman Fellow 2019

Life Sciences Research Fellow 2012-2015

Google Scholar Site

Staff Research Associate

Jacob Cecala, Staff Research Associate 2024-current

UC Davis USDA Postdoctoral Fellow 2021-2023

Ph.D. University of California, Riverside 2021

M.S. California State Polytechnic University, Pomona 2015

B.S. California State Polytechnic University, Pomona 2012

Jake Cecala is a community ecologist interested in wild, native bee species and their interactions with cultivated plants in urban and agricultural areas. For his doctoral work, he investigated how commercial plant nurseries in California function as habitats for wild bees. As a member of the Vannette lab, Jake is studying how insecticides and drought interact to affect floral microbial communities and crop pollination. His Google Scholar page.

Graduate students

Gillian Bergmann, PhD student in the Ecology Graduate Group (NSF Graduate Research Fellow, UC Davis Dean’s Distinguished Graduate Fellow)

co-advised by Johan Leveau

twitter/instagram: @ingrid_blv426


Gillian is an ecologist interested in seed microbial community assembly. As an undergraduate at Oregon State University (OSU), she characterized the fungal communities of Douglas-fir seeds from throughout the Pacific Northwest and New Zealand. She went on to work as a lab technician at OSU, characterizing the wood fungal communities of Populus trichocarpa and assisting on various projects in the greenhouse and the field. As a PhD student at UC Davis, Gillian is investigating the spatial and temporal processes involved in microbial transmission from flowers to seeds. Her long-term goal is to apply a metacommunity framework to studying seed microbial community assembly across scales, with interests in plant-pollinator-microbe interactions and consequences for young plant health. Outside of science, she enjoys riding and racing her bike, baking, traveling, and spending time with her husband and cat.

Shawn Christensen, PhD Candidate in the Microbiology Graduate Group

Email: smchristensen ‘at’ ucdavis ‘dot’ edu

Twitter: @pollenmicrobes

Shawn is an evolutionary biologist turned microbiologist, broadly interested in microbial interactions/symbioses with plant-pollinator systems, weird evolutionary traits, and crosswords. They obtained a BS from University of Wisconsin-Madison in Evolutionary Biology, where they did research on reducing ecological impacts of phosphorus runoff, ethnobotany and domestication traits in Brassica rapa, botanical field excursions of all kinds, and the evolution of chemical sets in the early origins of life. In the Vannette lab, Shawn is currently studying nectar-dwelling Acinetobacter and other nectar microbes and their potential influences on pollen for nutrient procurement, as well as the metabolomics of solitary bee pollen provisions.


Lexie Martin, PhD Candidate in the Entomology Graduate group

Email: lexmartin ‘at’ ucdavis ‘dot’ edu


Lexie is an entomology PhD candidate interested in the impact of microbes on bee health. She received a BS in Biology (focus evolution, ecology, and behavior) and a BSA in Chemistry from the University of Texas at Austin. As an undergraduate, she investigated the spatial distribution of bacteria within the guts of bumblebees and the gut microbiota of the Mexican honey wasp. In the Vannette Lab, she studies how microbes acquired socially and environmentally affect the health of bumblebees and blue orchard bees.




Danielle Rutkowski, PhD Candidate in the Entomology Graduate Group

Email: dmrutkowski ‘at’ ucdavis ‘dot’ edu

Co-advised with Rick Karban

Danielle is an entomology PhD student interested in the relationships between bees and microbes. She completed her bachelor’s degree at Cornell University, where she studied how the relationship between mycorrhizal fungi and their host plants impacts insect herbivores. At UC Davis, she studies how bumble bees interact with the microbes, particularly fungi, in their environment, and how these relationships impact bee health.

Dino Sbardellati, PhD Student in the Microbiology Graduate Group

email: dlsbardellati ‘at’ ucdavis ‘dot’ edu

Dino is a microbiologist interested in understanding how microbial ecology shapes macroscale ecology. He received a BA in biology from Sonoma State University and an MS in Bacteriology from the University of Wisconsin Madison. Dino has worked on projects exploring how reintroduced Tule elk modulate terrestrial arthropod populations, how antibiotic treatment impacts gut microbial communities in Passalid beetles, and how diet effects bovine rumen microbial communities. In the Vannette lab, Dino’s work deals with studying the bacteriophage (viruses which target bacteria) communities associated with the bumble bee gut and how phages shape gut microbial communities. In his spare time Dino enjoys catching, pinning, and drawing insects, cooking pizza, and making art.


Leta Landucci, Jr. Specialist

Leta is a biochemist inspired by chemical ecology, broadly interested in exploring chemically mediated plant-insect-microbe interactions. Leta obtained a BS from the University of Wisconsin-Madison in Biochemistry, where she studied poplar acyltransferase enzymes involved in the biosynthesis of the crucial plant polymer, suberin. She also did research on the dynamic between physical and chemical plant traits and Japanese beetle herbivore behavior. As a member of the Vannette lab, Leta is studying how the production of peroxides secreted by nectarin proteins in floral nectar shapes microbial growth in nectar. She also aims to understand how this chemistry varies across plant species and influences pollinator-plant-microbe interactions. Leta was a NSF Postbaccalaureate Research Trainee in the lab from Sept 2022-Sept 2023.


Undergraduates in the lab

Helen Noroian: Helen is working with Lexie and Rachel on projects related to bee-microbe interactions and microbial community assembly in nectar.

Amy Hazemoto: Amy is working with Danielle on projects related to bee-microbial interactions and fungicide effects on bee-associated yeasts.


Lab photos:

March 2022 lab hike at Stebbins Cold Canyon with Gillian, Jake C, Shawn, Becca, Lexie, Danielle, Dino, Jake F and Rachel
partial Vannette lab 2019: Jeselle-Ann Laxa, Ivan Munkres, Maddie Handy, Isabelle Maalouf, Danielle Rutkowski, Rachel Vannette, Rachel Dutch, Marshall McMunn, Amber Crowley-Gall, Honey Pathak


some of us are coordinated 🙂

Partial lab group, summer 2018

(L to R: Allie Igwe, Ash Zemenick, Robert Schaeffer, Rachel Vannette, Honey Pathak and Imade Ojo)


Lab photo, Summer 2016

(L to R: Tim Rei, Chela Owens, Rachel Vannette, Ariana Nagainis, Megan Morris, Griffin Hall and Allie Igwe)


Youngest (honorary) lab members:

Sterling Vannette (2013-present) and Corwin Vannette (2017-present)



Previous affiliates

Jacob Francis, Postdoctoral researcher 2020-2023

B.S:  University of North Carolina at Asheville,  Ph.D. :University of Nevada Reno

In the Vannette lab Jake explored the intersection of plant, pollinator, and microbial ecology with a focus on how floral traits mediate these interactions. Jake is currently an Assistant Professor at Florida Atlantic University. 

Amber Crowley-Gall, USDA Postdoctoral Fellow  2019-2023; 2023-current Assistant Professor at Iowa State University

Amber is a chemical ecologist with an interest in understanding the role of sensory systems in insect host choice. Her work at UC Davis focused on microbial competition dynamics involving orchard pathogens and mVOC effects on insect behavior.


Marshall McMunn, NSF Postdoctoral Fellow; 2018-2020; USDA Postdoctoral Fellow 2020-2022

Marshall studied turtle ants and sunflower microbes (among other things) during his postdoctoral studies in the Vannette lab. He applied his statistical and coding expertise at the California Department of Justice and is now an Assistant Professor of Teaching at UC Davis.


Tobias Mueller, Junior specialist (2019-2021).

2021-current: Graduate student at Cornell Entomology, recipient of NSF GRFP




Alexandria Igwe,  PhD  Microbiology Graduate Group (2020)A. Igwe

2015-2020: PhD student in the Microbiology Graduate Group

2020-current: NSF Postdoctoral Fellow with Michelle Afkhami at the University of Miami, Assistant Professor at Virginia Tech



Megan Morris,  JDPE student from Liz Dinsdale’s lab at San Diego State University Vannette lab 2015-2016

2018-2020: Postdoc at Stanford University

2020-2023: Postdoc at Lawrence Berkeley National Lab



IMG_3242Griffin Hall, junior specialist  2015-2017

Bachelor’s degree, UC Davis, 2015

Coffee + travel blog



Robert Schaeffer, USDA ELI Postdoctoral Fellow 2016-2018

Assistant Professor at Utah State University

co-advised by R. Vannette, D. Crowder, N. Williams and T. Fukami



Ivan Munkres, junior specialist 2018-2019

Bachelor’s degree UC Davis 2018

2021-current, Graduate student at College of William and Mary



Casie Lee, 2017 STAR (Students Training in Advanced Research) Program student.

UC Davis School of Veterinary Medicine, DVM Candidate, Class of 2020, co-advised with Lisa Tell. Current:

Rachel Dutch, Master’s student in Avian Sciences, co-advised by Lisa Tell.






Madeline Handy

Madeline (Maddie) Handy joined the Vannette Lab as part of the Research Scholars Program in Insect Biology. In the Vannette lab, Maddie’s research focused on the Carpenter bee microbiome. She is now pursuing a master’s in public health. Current:





Previous undergraduate researchers in the Vannette lab:

Ariana Nagainis (Spring 2016-Fall 2016)

Chela Owens (Spring 2016)

Tim Rei (2016-2017)

Wendy Melendez (2016-2017)

Cody Kiniry (2017-2018)

Anthony Chan (2017-2018)

John Duque (2017-2018)

Isabelle Maalouf (2017-2019)

Honey Pathak (2017-2019)

Eliza Litsey (2018-2019)

Garrett Keating (2018-2020)

Dani Virdier (2019)

Jeselle-Ann Laxa (2019-2020)

Gigi Melone (2020)

Robert Montoya (summer 2021, EEREC REU)

Michael Yu (summer 2021, EEREC REU)

Douglas Perry (2020-2021)

Kt Lynch: (2021-2023)

Anoushka Basu: (2022-2023)

Sriram Srinivas: (2022-2023)


High School Student Affiliates

Almas Khan (2018-2019)