Have you ever considered them as important vectors of floral microbes?
Well, they are!
Community ecologist Ash Zemenick, formerly in the graduate student program of the UC Davis Department of Entomology and Nematology, will present an exit seminar, "Do Flower Visitors Network with Floral Microbes?" from 4:10 to 5 p.m., Wednesday, Nov. 8 in 122 Briggs Hall, UC Davis campus.
"Flowers are colonized by diverse microbial communities that can influence plant and pollinator health and mediate plant-pollinate interactions," says Zemenick, now a National Science Foundation postdoctoral fellow in the Weber lab at Michigan State University. "Because flower-visiting insects and hummingbirds can harbor high densities of microbial cells, flower visitors are thought to be important vectors of floral microbes. Although floral microbe community assembly is dependent, in part, on dispersal by flower visitors, floral microbe community assembly has yet to be fully considered in the context of the rich network of plant-flower visitor interactions with which they are linked."
The Zemenick dissertation involved "using an historic flower visitor dataset, field experiments and construction of a plant-flower visitor-microbe network to demonstrate the importance of flower visitor identity and interaction in mediating floral microbe community assembly and structure at both local and regional scales."
"With the help of four motivated undergraduates and many gracious entomologists, I built a tripartite plant-flower visitor-floral microbe network. Data was collected from 20 co-flowering plant species over a short phenological timespan in a high elevation wet meadow located in the Tahoe National Forest."
"Questions I (set about) answering with this dataset included: do plants occupy similar positions in both networks? Do plants with similar visitors have similar microbes? Which plants are hubs of floral microbe diversity? Can we determine whether dispersal (by visitor) or environmental filtering (by plant traits) is more important in structuring floral microbial communities?"
As a PhD candidate in the Rosenheim lab, Zemenick worked to "disentangle how the structure of plant-flower visitor interactions varies for different types of flower visitors, and the implications of varying structure for floral microbe communities."
Now, as a post doc in the Weber lab, "I will be studying how plant-mite interactions directly and indirectly influence leaf microbial communities and subsequent invasibility by pathogens. I will also be working on building a repository of introductory biology teaching material that humanizes the field of biology and biologists. It will include how biological research applies to current societal problems and highlight what it is like to be a biologist. The materials will be comprised of examples provided by biologists that self-identify as being part of underrepresented group(s) in STEM (e.g. in terms of race, ethnicity, gender, sex, sexuality, income, nationality, immigrant status, cognitive and physical ability, etc.)."
Overall, Zemenick enjoys studying ecological networks, community assembly, plants, insects, and microbes. "I also love to teach and help students get involved in research."
See more information on Zemenick's website, Inclusive Plant-Insect Microbial Ecology.
The UC Davis Department of Entomology and Nematology's fall quarter seminars, coordinated by Rachel Vannette, assistant professor, are held Wednesdays from 4:10 to 5 p.m. in 122 Briggs Hall. They are open to all interested persons. See seminar schedule.
The UC Davis Department of Entomology and Nematology has booked associate professor of biology Tim Linksvayer of the University of Pennsylvania for a seminar on “Genomic Signatures of Social Evolution in Social Insects" on Wednesday, Oct. 4.
The seminar, open to all interested persons, takes place from 4:10 to 5 p.m. in 122 Briggs Hall, Kleiber Hall Drive.
"Eusociality in ants, bees, wasps, and termites is a major evolutionary innovation, yet the genomic basis of sociality is largely unknown," Linksvayer says. "I will discuss recent and ongoing research in my lab focused on elucidating the genetic basis and evolution of social traits and social systems in ants and honey bees."
"We study the genetic and behavioral underpinnings of complex social systems in order to understand how these systems function and evolve," he says on his website. "We are especially interested in how social interactions affect genetic architecture and trait evolution."
Access his website and you'll see a pharaoh ant. "We use social insects, such as the pharaoh ant, as a study system because they are exemplar social systems and are also well-established models for research in social evolution, behavioral genetics, and collective behavior."
This is the second of the fall seminar series hosted by the department. The seminars began Sept. 27 and will conclude Dec. 6. Assistant professor Rachel Vannette is coordinating the seminars.
Oct. 11: (Cancelled as of Oct. 4) “Multitrophic Mediation of Plant Perception of Herbivores” by Gary Felton, Pennsylvania State University, who received his doctorate in entomology from UC Davis
Oct. 18: Exit seminar by Leslie Saul-Gershenz, doctoral candidate, UC Davis Department of Entomology and Nematology
Oct. 25:"Ecoinformatics and the Curious Case of Katydids in California Citrus" by Bodil Cass, UC Davis
Nov. 1:“Mating Distruption of Glassy-Winged Sharpshooter by Playback of Natural Vibrational Signals in Vineyard Trellis” by Rodrigo Krugner of the U.S,. Department of Agriculture/Agricultural Research Service (USDA-ARS)
Nov. 8: Exit seminar by doctoral candidate/ecologist Ash Zemenick, UC Davis Department of Entomology and Nematology
Nov. 15: “Revelations from Phasmatodea Digestive Track Transcriptomics” by Matan Shelomi, National Taiwan University, who received his doctorate in entomology from the UC Davis Department of Entomology and Nematology
Nov. 22: Thanksgiving week; no seminar
Nov. 29; “Ant Social Parasites Repeatedly Evolved Reproduction Isolation from Their Hosts in Sympatry” by Christian Rabeling, Arizona State University
Dec. 6: “Root Knot Nematode and Associated Pathogen Resistance” by Phil Roberts, University of Riverside
The Department of Entomology and Nematology, chaired by professor and nematologist Steve Nadler, is world renowned for its quality research, education and public service. Globally, it is ranked No. 7 by The Times Higher Educational World University Rankings for its teaching, research, international outlook and industry outcome. Its facilities include the Bohart Museum of Entomology, Harry H. Laidlaw Jr. Honey Bee Research Facility, and its mosquito research program based at UC Davis and the Kearney Agricultural Research and Center in Parlier.
Faculty are globally recognized for their expertise in insect demography, systematics and evolutionary biology of ants, pollination and community ecology, integrated pest management, insect biochemistry, molecular biology, and the systematics and evolutionary biology of nematodes. The graduate program offers master's and doctoral degrees. The teaching and research faculty includes some 40 professional entomologists and nematologists.
They buzz toward a blossom, sip nectar, and then head for another blossom. Typical, right?
But there's much more going on than you think.
It's not just the nectar that she's scented.
UC Davis community ecologist Rachel Vannette has just published a paper in New Phytologist journal that shows nectar-living microbes release scents or volatile compounds, too, and can influence a pollinator's foraging preference.
The groundbreaking research shows that nectar-inhabiting species of bacteria and fungi “can influence pollinator preference through differential volatile production,” said Vannette, an assistant professor in the UC Davis Department of Entomology and Nematology.
“This extends our understanding of how microbial species can differentially influence plant phenotype and species interactions through a previously overlooked mechanism,” Vannette said. “It's a novel mechanism by which the presence and species composition of the microbiome can influence pollination.”
“Broadly, our results imply that the microbiome can contribute to plant volatile phenotype,” she said. “This has implications for many plant-insect interactions.”
Their paper, titled “Nectar-inhabiting Microorganisms Influence Nectar Volatile Composition and Attractiveness to a Generalist Pollinator,” may explain in part the previous documented extreme variation floral volatiles that Robert Junker of University of Salzburg, Austria, and his team found; New Phytologist published their work in March 2017.
In their study, the Vannette team researchers first examined field flowers for the presence of nectar-inhabiting microbes, and in collaboration with co-authors Caitlin Rering and John Beck of the U.S. Department of Agriculture's Agricultural Research Service (USDA-ARS), Gainesville, Fla, characterized the headspace of four common fungi and bacteria in a nectar analog. Next, they used an intricate setup to quantify the antennal and behavior responses of honey bees to the chemical compounds. Finally, when they examined the scent of flowers in the field, they found that flowers which contained high densities of microorganisms also contained volatile compounds likely produced by those microbes, suggesting that microbial scent production can be detected and used by pollinators.
Although microbes commonly inhabit floral nectar, microbial species differ in volatile profiles, they found. “Honey bees detected most of the microbial volatiles or scents that we tested,” Vannette said, “and they distinguished the solutions of yeasts or bacteria based on volatiles only.” This suggests that pollinators could choose among flowers based on the microbes that inhabit those flowers.
The yeast Metschnikowia reukaufii produced the most distinctive compounds (some shared with the fruity flavors in wine) and was the most attractive of all microbes compared. This yeast is commonly found in flower nectar and is thought to hitch a ride on pollinators to travel from one flower to the next. Its scent production may help it attract pollinators, which then help the yeast disperse among flowers.
The Harry H. Laidlaw Jr. Honey Bee Research Facility, UC Davis, provided the honey bees. More than 20 species of flowers--mostly natives--were used in the survey, including canyon delphinium or canyon larkspur (Delphinium nudicaule), sticky monkey flower (Mimulus aurantiacus), salvia (Lepechinia calycina) and purple Chinese houses (Collinsia heterophylla). The samplings were done in the spring and early summer, when the natives are at their peak.
Co-authors of the paper are Caitlin Rering, postdoctoral fellow at USDA-ARS, Gainesville, Fla.; John Beck researcher at USDA-ARS; Griffin Hall, junior specialist in the Vannette lab; and Mitch McCartney in UC Davis Department of Mechanical and Aerospace Engineering.
The USDA and USDA-ARS funded the research.
About Rachel Vannette: She joined the UC Davis Department of Entomology and Nematology in September of 2015 from Stanford University where she was a postdoctoral fellow.
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 below ground 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.
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./span>
Take the nectar of the sticky monkeyflower, Mimulus auranticus.
UC Davis community ecologist Rachel Vannette and colleague Tadashi Fukami of Stanford University decided to examine microbial communities inhabiting the nectar of the sticky monkeyflower at the Jasper Ridge Biological Preserve in California's Santa Cruz Mountains.
Their paper, "Dispersal Enchances Beta Diversity in Nectar Microbes," published in Ecology Letters, revealed that contrary to popular assumption, “increased dispersal among habitats can actually increase biodiversity rather than decrease it."
The flower, in the family Phrymacease, is a native shrub common in chaparral and coastal scrub habitats of California and Oregon. It is primarily pollinated by Anna's hummingbird. Other common pollinators include bumble bees, carpenter bees, and thrips.
Dispersal is considered a key driver of beta diversity, which is “the variation in species composition among local communities,” Vannette said.
They are the first to publish work showing that increased dispersal can increase biodiversity.
In their experiment, they reduced natural rates of dispersal by eliminating multiple modes of microbial dispersal. “Specifically we focused in nectar-inhabiting bacteria and yeasts that are dispersed among flowers by wind, insects and birds,” they said. “We imposed dispersal limitation on individual flowers and quantified microbial abundance, species composition and microbial effects on nectar chemistry.”
This work has direct implications for conservation of many organisms in addition to bacteria and yeast, suggesting that preserving routes of dispersal among habitat patches may be important in the maintenance of biodiversity. In contrast to previous work showing that dispersal can homogenize communities or make them more similar, the published work demonstrates that dispersal can in some cases generate communities that are more different from each other. The authors hypothesize that this could be driven by priority effects, where early arriving species change the species that can establish within that habitat.
More broadly, “Studying the role of microbes in the environment addresses one of the biggest mysteries in science,” Vannette says. In her current work, she and her lab are investigating how microbial communities form, change, and function in their interactions with insects and plants. They are also researching how microorganisms affect plant defense against herbivores and plant attraction to pollinators.
Vannette, a former postdoctoral fellow at Stanford, joined the UC Davis Department of Entomology and Nematology faculty as an assistant professor in 2015.
Vannette's research was funded by the Gordon and Betty Moore Foundation through the Life Sciences Research Fellowship. Stanford also funded the research through grants from the National Science Foundation, the Terman Fellowship, and the Department of Biology at Stanford University.
The event, open to the public, is set from 8 a.m. to 6 p.m. Saturday, May 7 in the UC Davis Conference Center on Alumni Lane. It will be hosted by the Honey and Pollination Center of the Robert Mondavi Institute for Wine and Food Science, and the UC Davis Department of Entomology and Nematology.
Keynoting the symposium will be Yves Le Conte, director, French National Bee Lab, Avignon, France; and Dennis vanEngelsdorp, assistant professor of entomology at the University of Maryland and project director for the Bee Informed Partnership.
Among the highlights:
9 a.m. Amina Harris, director of the Honey and Pollination Center, and Neal Williams, associate professor of the Department of Entomology and Nematology and the center's co-faculty director, will welcome the crowd and introduce the speakers.
9:15 a.m. Yves Le Conte will speak on "Honey Bees that Survive Varroa Mite in the World: What Can We Learn from the French Bees"
10:15: Rachel Vannette will discuss "How Microbial Communities in Floral Nectar Influence Pollinator Preference and Foraging"
11:15: Claire Kremen will cover "Rediversifying Intensive Agricultural Landscapes to Promote Native Pollinators."
1:30 p.m.: Dennis van Engelsdorp will speak on "Reducing Colony Losses: Does It Take a Village?"
2:15 p.m.: Lightning Round Talks: Six-minute presentations about many different programs in the world of beekeeping
3:30 p.m.: Brian Johnson will discuss "The Importance of Division of Labor for Understanding Colony Health."
4 p.m.: Quinn McFrederick will speak on "The Bee Microblome."
In addition, a graduate student poster display and competition will take place, with the winners announced at 4:30 p.m. First place is $1000; second, $750; third, $500, and fourth, $250. A closing reception follows at 4:45 in the Good Life Garden at the Robert Mondavi Institute for Wine and Food Science on Old Davis Road.
Harris promises a rewarding and educational symposium. Comments from last year's symposium included:
- "As a new beehive owner I thought the information presented was fascinating and presented in a very efficient manner. I loved every aspect of the presentations!"
- "Nice to get science, there is a lot of fuzzy thinking out there."
- "Thank you for a well-organized, thoroughly engaging and thought-provoking day."
The UC Davis Conference Center is located across from the Mondavi Center for the Performing Arts.