Welcome to the Vannette lab


The Vannette lab is a team of entomologists, microbiologists, chemical ecologists, and community ecologists trying to understand how microbial communities affect plants and insects (sometimes other organisms too). We often study microbial communities in flowers, on insects or in soil. We rely on natural history observations, and use techniques from chemical ecology, microbial ecology and community ecology.  In some cases, we study applied problems  with an immediate application including pathogen control or how to support pollinators. Other questions may not have an immediate application but are nonetheless grounded in theory and will contribute to basic knowledge and conservation (e.g. how can dispersal differences among organisms affect patterns of abundance or biodiversity?).

Lab news


July 2024: It’s a busy summer! We just returned from our lab retreat at Point Reyes, are hosting undergraduate summer interns, and much of the lab is heading to Beneficial Microbes. Recently submitted manuscripts include “Seasonal assembly of nectar microbial communities across angiosperm plant species: assessing contributions of climate and plant traits” led by Jake Cecala and Rachel and “Targeted Viromes and Total Metagenomes Capture Distinct Components of Bee Gut Phage Communities” led by Dino Sbardellati.

May 24 2024: Paper led by Shawn Christensen describing the bacterial and fungal communities of Anthophora bomboides, a solitary bee, is now accepted to the ISME Journal and published ONLINE

May 2024: Two exit seminars scheduled! Danielle Rutkowski’s exit seminar is on Monday May 20 at 4:10 pm in Briggs 122 or via Zoom: https://ucdavis.zoom.us/j/95882849672.  Shawn Christensen’s exit seminar and Merton Love seminar (for excellence in PhD research) is Friday, May 24th at 3:00-4:30PM in Walker Hall Room 1230 or via zoom.

April 2024: The lab participates in many outreach events: We hosted a table at UC Davis Picnic Day focused on native and solitary bees and the microbes they acquire from flowers. Rachel also talks about bees at the Tahoe Environmental Research Center’s lecture series.

March 2024: Lexie Martin receives a Wildlife Health Center Fellowship to support her work on Osmia bee microbiomes. Thanks to Phil and Karen Drayer for your support of this work!

March 2024: Jake Cecala’s paper describing effects of neonicotinoid pesticides on nectar microbes is accepted to Environmental Microbiology. Congrats Jake!

February 2024: Rachel visits Manaaki Whenua Landcare Research and gives a talk at the Pollination Symposium. Thanks Manpreet Dhami for the invitation and amazing visit!

December 2023: FEMS Microbiology Ecology names Danielle’s review of bee-fungal interactions as Editor’s choice!

November 2023: Danielle, Shawn, Dino, Lexie and Jake F head to EntSoc 2023! And Lexie and Shawn both won student awards for best talks in their section this year. Congrats you two!

November 2023: Paper on Anthophora bomboides microbiomes led by Shawn Christensen, now on bioRxiv:https://doi.org/10.1101/2023.11.02.565352

October 2023: Jake’s paper on comparing dispersal and host filtering of plant microbiomes now out in New Phytologist!

September 2023: Rachel and Lexie present at the Orchard Bee Association meeting on work related to Osmia lignaria and Osmia ribifloris.

June 2023: Danielle and Lexie present at the Pollinator Health Conference at Penn State, and Rachel presents at the Hitchcock Center for Chemical Ecology meeting put on by the Jeffrey Lab at University of Nevada Reno.

May 2023: Jake Francis, Dino and Lexie present at the Yosemite Symbiosis workshop

May 2023: Two graduate students in the lab are awarded competitive fellowships! Lexie Martin was awarded the National Science Foundation GRFP and Dino Sbardellati was awarded a USDA Predoctoral Fellowship. Congrats!

April 2023: Vannette Lab hosts a booth focusing on native bees, flowers and microbes at UC Davis Picnic Day 2023

February 2023: Jake Cecala presents at The Pesticide Stewardship Alliance meeting

February 2023: Rachel and Leta attend the Gordon Conference on Plant Herbivore Interactions in Ventura, CA. Rachel helps out as discussion leader for session on “Microbial mediation of plant-herbivore interactions”

January 2023: Jake Francis presents work from his recently submitted preprint at the AmNat meeting in Asilomar and wins an award for the best Postdoc Talk!

November 2022: Many lab members visit Vancouver for the EntSoc meeting. Danielle, Lexie,  Shawn and Rachel present current work and Danielle wins the President’s prize for best talk (for a second time)!!

August 29, 2022: Rachel gives a seminar for the GEMS institute. Thanks for the invitation Irene!

August 2022: Sad to see him go, but Marshall accepts a job at the California DOJ. Best wishes!

July 2022: It’s conference season! Many members of the Vannette lab are headed to the Beneficial Microbes conference , and Rachel presents at Phyllosphere 2022.

July 2022: Rachel named a finalist for the Falling Walls Foundation Science Breakthrough prize, in the Life Sciences division.

June 2022: Marshall McMunn’s paper on Cephalotes ant microbiome changes with temperature is published in FEMS Microbiology Ecology. Congrats Marshall and coauthors!

May 2022: We celebrate many accomplishments this spring!

  • Lexie passed her Entomology Area Exam
  • Lexie and Danielle received Jastro awards to support their research
  • High school student Genna (mentored by Amber Crowley-Gall) presented her results
  • Leta Landucci (previous Ralph Lab member) was awarded an NSF REPS fellowship to join the Vannette lab in the fall
  • Doug Perry (mentored by Marshall McMunn) will join the Hansen Lab at UCR
  • Undergraduate Kt Lynch (mentored by Jake Francis) was awarded the Northern California Botanists scholarship to support her work on flower/seed
  • microbes this summer! Congrats all!!

May 2022: Jacob Francis attends the Yosemite Symbiosis Workshop to present his work on microbial communities in flowers.

April 2022: Jake Cecala co-organized and presented at a session of the Pacific Branch of the Entomological Society of America on “Plant-Pollinator Interactions in a Changing World”

April 2022:Rachel gives a seminar for the SEE Seminar series in the Department of Biological Sciences at Louisiana State University. Thanks to Jiaqi Tan for the invitation!

Feb 2022: Rachel gives a talk at the University of Oregon Institute of Ecology and Evolution. Thanks to Lauren for the invitation!

December 2021: Danielle is awarded a USDA Predoctoral Fellowship to study bumble bee-yeast interactions. Congrats Danielle!!!

December 2021: Insect Ecology and Vannette lab chooses some favorite papers from this past year: 2021 papers of the year

September 2021: Rachel gives a talk as the Hagedorn speaker for the Entomology and Insect Science Graduate Interdisciplinary Program at the University of Arizona. Thanks graduate students for the invitation!

July 2021: The complete special issue on plant-pollinator-microbe interactions in Current Opinions in Insect Science, co-organized by Rachel and Robert Junker, is now complete and online, including our editorial. Check it out!

June 2021: Jacob Francis is awarded an NSF PRFB to study secondary metabolites in nectar, and their consequences for microbes and pollinators. We are excited to continue work with him! Congrats Jake F!

June 2021: Jacob Cecala, a recent grad from the Wilson Rankin lab at UCR, is awarded a USDA NIFA Postdoctoral Fellowship to study effects of water availability and pesticide use on bees and bee-microbe associations. We are excited for him to join the lab in the fall. Congrats Jake C!

June 2021: The quarter ends and field work is in full swing! Various projects are in full force by Shawn and Marshall at Stebbins Cold Canyon Reserve, by Shawn, Rachel and collaborators at Bodega Bay Marine Reserve, and we’re gearing up for work in the Sierra, including at Sagehen Creek Field Station in work led by Jake Francis.

May 2021: Shawn is awarded a NRS research fellowship for work at Stebbins Cold Canyon Reserve. Congrats Shawn!

March 2021: Rachel gives an invited (virtual) seminar at the Max Planck Institute for Chemical Ecology. Thanks for the invitation Jonathan Gershenzon!

March 2021: Rachel gives an invited (virtual) seminar at the University of Cinncinati. Thanks for the invitation Stephanie Rollman and lab!

February 2021: Rachel gives and invited (virtual) seminar at the University of Pittsburgh. Thanks for the invitation Tia-Lynn Ashman and lab!

January 2021: Insect Ecology group at UC Davis chooses favorite papers of 2020 or go to the archives for our picks from 2019, 2018, or 2016

January 2021: New preprints posted: 1) Shawn’s work finding that Acinetobacter germinates (and eats) pollen, and two agricultural flower microbiome papers: 2) management effects  microbiome composition in almond flowers  and 3) management and landscape composition affect  microbiome of pear flowers

Fall 2020: Danielle Rutkowski and Shawn Christensen both pass the QE and advance to candidacy. Congrats you two.

10/30/20 Rachel gives an invited (virtual) seminar to the University of Colorado Denver. Thanks for the invitation Sara Branco!

10/16/20 Rachel gives an invited (virtual) seminar for the Microbiology group at Autonomous University of Querétaro. Excellent discussion. Thanks for the invitation, Etzel Garrido Espinosa!

9/20 New papers from the lab discussing nectar microbiome, its effects on plants and pollinators, and traits that promote dispersal of microbes have been published online.

8/31/20 Jacob Francis joins the lab as a Postdoctoral Fellow, to work on nectar chemistry and pollination. Welcome Jake!

8/28/20 Allie Igwe officially defends and turns in her dissertation. Congrats Dr. Igwe!

6/20: Amber Crowley-Gall and Marshall McMunn receive USDA NIFA Postdoctoral Fellowships to begin independent projects in the lab. Congrats to both Amber and Marshall! Amber will work on Erwinia, volatile cues and pollinator preference. Marshall will work on sunflowers and microbial effects on nectar quality via trait plasticity.

4/20: Allie Igwe is awarded a prestigious NSF Postdoctoral Fellowship to work on soil microbial communities and develop novel online tools to increase interest in ecology. Congrats Allie!

2/10/20: Rachel participated as a lecturer in the Chemical Communication Winterschool in Ede, Netherlands. It was a great experience with excellent students, organizers and co-lecturers.

1/10/20:  Paper on microbial community assembly and function in nectar published in FEMS Microbiology Ecology with first author Megan Morris, lab alum who recently started new job at LBL. 

12/11/19: Lab members participate in the annual “Favorite papers of 2019, insect ecology edition

10/19: Lab hires Tobias Mueller as new Junior specialist. Welcome Tobias!

7/17/19: Vannette lab attends the International Pollinator Conference! Check out Danielle’s poster on bumble bees and yeasts; Megan’s poster on bacteria and pollen, and Rachel (V) talks about hummingbird gut microbes.

7/10/19: The National Science Foundation funds Rachel’s CAREER grant on “Nectar chemistry and ecological and evolutionary tradeoffs in plant adaptation to microbes and pollinators”.  We are excited to investigate why plant species vary in microbial growth in flowers, and its causes and consequences

6/23/19: Rachel moderates and speaks in ASM Microbe session on Rules and Randomness in microbial community assembly

6/10/19: Rachel returns from a fun and productive ISCE meeting in Atlanta.


Looking for old news? You’ll have to check the archives


Department of Entomology and Nematology

43 Briggs Hall (Basement)

Davis, CA 95616

rlvannette at ucdavis dot edu

Office phone: 530-752-3379

Lab phone: 530-752-4317

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