Pollinators aren't just bees, butterflies, beetles and bats.
They're also birds, like hummingbirds.
Ornithologists tell us that hummingbirds can easily eat their weight in a day, feasting on carbohydrates (nectar from blossoms and sugar water from feeders) and protein (insects and spiders).
The hummingbird menu includes such insects as ants, aphids, fruit flies, gnats, weevils, beetles, mites and mosquitoes. They also raid spider webs to grab a quick spider meal and any hapless insects trapped there.
We were thinking of insects and pollinators today (this blog focuses on insects and the entomologists who study them) after reading a UC Davis research paper published in the Proceedings of the Royal Society B that tested sugar water in hummingbird feeders.
Fact is, sugar water in hummingbird feeders can contain high densities of microbial cells but “very few of the bacteria or fungi identified have been reported to be associated with avian disease,” says community ecologist and co-author Rachel Vannette of the UC Davis Department of Entomology and Nematology.
The research is one of the first to explore the microbial communities that dwell in sugar water from feeders and compare them to those found in flower nectar and samples from live hummingbirds.
“The potential for sugar water from hummingbird feeders to act as a vector for avian pathogens--or even zoonotic pathogens--is unknown,” said Vannette, an assistant professor in the UC Davis Department of Entomology and Nematology. “Our study is one of the first to address this public concern. Although we found high densities of both bacteria and fungi in sugar water samples from feeders, very few of the species of bacteria or fungi found have been reported to cause disease in hummingbirds.”
“So although birds definitely vector bacteria and fungi to feeders, based on the results from this study, the majority of microbes growing in feeders do not likely pose significant health hazards to birds or humans,” Vannette said. “However, a tiny fraction of those microbes has been associated with disease, so we encourage everyone who provides feeders for hummingbirds to clean their feeders on a regular basis and to avoid areas where human food is prepared.”
The paper, “Microbial Communities in Hummingbird Feeders Are Distinct from Floral Nectar and Influenced by Bird Visitation,” is the work of first author Casie Lee, a UC Davis School of Veterinary Medicine student; Professor Lee Tell of the UC Davis School of Veterinary Medicine's Department of Medicine and Epidemiology; Tiffany Hilfer, an undergraduate student and Global Disease Biology major; and Vannette.
Lee, mentored by Vannette and Tell, led the field experiment and performed bird observations and laboratory work during a summer project funded by the Students Training in Advanced Research (STAR) and Merial Veterinary Scholars Programs.
The researchers also compared the microbes in the feeders to those in floral nectar and found they differed in microbial composition.
“Birds, feeder sugar water, and flowers hosted distinct bacterial and fungal communities,” they wrote in their abstract. “Floral nectar and feeder sugar water hosted remarkably different bacterial communities; Proteobacteria comprised over 80% of nectar bacteria, but feeder sugar water contained relatively high abundance of Firmicutes and Actinobacteria, as well as Proteobacteria. Hummingbird feces hosted both bacterial taxa commonly found in other bird taxa and novel genera including Zymobacter (Proteobacteria) and Ascomycete fungi.”
The UC Davis scientists conducted their research at a private residence in Winters, attracting two hummingbird species, Calypteanna (Anna's Hummingbird) and Archilochus alexandri (Black-chinned Hummingbird) to drop net feeder traps. They mixed bottled water with conventional white granulated sugar (one part sugar and four parts water).
See more information--and photos--on their research on the UC Davis Department of Entomology website.
But back to insects and the hummingbirds that eat them. Entomologist Doug Tallamy of the University of Delaware says that "hummingbirds like and need nectar but 80 percent of their diet is insects and spiders."
Wildbirds on Line says: "I frequently put overripe bananas of my fruit feeder to attract tiny fruit flies, which in turn attract the hummers. The hummingbirds eat every fly and return in a few hours to feast on the next batch of fruit flies that discover the overripe fruit. What an easy way to observe hummers eating insects!"
Now that's an idea! Fruit flies for the hummers!
Vannette, who researches pollinator microbiomes, titled her innovative project “Characterizing the Structure and Function of Pollinator Microbiomes." She investigates the communities of bacteria and fungi in flowers and pollinators, including bees and hummingbirds. “Our work to date suggests that microbes in flowers are common and influence pollinator behavior,” she says.
The Hellman funding will allow her to link microbial communities in flowers with their influence on pollinators by examining microbial modification of nectar and pollen chemistry, and examine how microbial effects vary among plant and pollinator species, and with environmental variation.
We remember the groundbreaking research published by Vannette and her colleagues last year in the New Phytologist journal. Their paper, titled “Nectar-inhabiting Microorganisms Influence Nectar Volatile Composition and Attractiveness to a Generalist Pollinator,” showed that nectar-living microbes release scents or volatile compounds that can influence a pollinator's foraging preference.
Nectar-inhabiting species of bacteria and fungi “can influence pollinator preference through differential volatile production,' Vannette related last September. “This extends our understanding of how microbial species can differentially influence plant phenotype and species interactions through a previously overlooked mechanism. 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. This has implications for many plant-insect interactions.”
The 11 Hellman Fellows will receive a total of $244,000 in grants for research in a wide range of disciplines. Since 2008, UC Davis has received nearly $3 million in Hellman grants, awarded to 136 early-career faculty members. The Hellman Fund provides grant monies to early career faculty on all 10 UC campuses, as well as to four private institutions.
Vannette joined the UC Davis Department of Entomology and Nematology in 2015 after serving as a postdoctoral fellow at Stanford University's biology department, where she was a Gordon and Betty Moore Foundation Postdoctoral Fellow from 2011 to 2015 and examined the role of nectar chemistry in community assembly of yeasts and plant-pollinator interactions.
She received her bachelor of science degree, summa cum laude, in 2006 from Calvin College, Grand Rapids, Mich., and her doctorate from the University of Michigan's Department of Ecology and Evolutionary Biology, Ann Arbor, in 2011. Her thesis: “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.”
We look forward to hearing more about this exciting research!
The department launched the seminars Wednesday, Jan. 10 with epidemiologist Amy Morrison of Iquitos, Peru, discussing dengue.
The seminars will continue through March 14. All will take place on Wednesdays from 4:10 to 5 p.m. in 122 Briggs Hall, Kleiber Hall Drive.
Next up: UC Davis alumnus Fiona Goggin, a member of the entomology faculty, University of Arkansas, will present a seminar on “Molecular and Phenomic Approaches to Study Plant Defenses Against Insects and Nematodes” from 4:10 to 5 p.m., Wednesday, Jan. 17 in 122 Briggs Hall.
Goggin, who received her doctorate from UC Davis and her bachelor's degree from Cornell University, focuses her research program on plant defenses against herbivory, with emphasis on mechanisms of resistance against vascular feeders such as aphids and root-knot nematodes.
The list of speakers:
Jan. 17: Fiona Goggin, professor of entomology, University of Arkansas and a UC Davis alumnus. Topic: “Molecular and Phenomic Approaches to Study Plant Defenses against Insects and Nematodes."
Jan. 24: David Gonthier, postdoctoral fellow, Clare Kremen lab, UC Berkeley. Topic: to be announced. His primary research objective is to understand the importance of biodiversity across natural and managed ecosystems.
Jan. 31: Amanda Hodson, UC Davis postdoctoral fellow and assistant professional researcher with Louise Jackson's Soil Ecology Lab, UC Davis. Topic: "Molecular Detection and Integrated Management of Plant Parasitic Nematodes." Her research interests include soil ecology, integrated pest management and ecological intensification of agricultural systems.
Feb. 7: Marm Kilpatrick, assistant professor, Department of Ecology and Evolutionary Biology, UC Santa Cruz. Topic: to be announced. He studies ecology of infectious diseases and population biology. His research "unites theory and empirical work to address basic and applied questions on the ecology of infectious diseases as well as population biology, evolution, climate, behavior, genetics, and conservation."
Feb. 21: Kerry Mauck, assistant professor of entomology, UC Riverside. Topic: to be announced. She studies insect vector behavior, plant-pathogen interactions, chemical ecology, and integrated disease management.
Feb. 28: Candidates for nematology position. (Pending)
March 3: John Tooker, associate professor of entomology and Extension specialist, Department of Entomology, Pennsylvania State. Topic: to be announced. His areas of expertise include insect ecology, plant-insect interactions, conservation biological control, chemical ecology and gall insects.
March 7: Alvaro Acosta-Serrano, senior lecturer, Liverpool School of Tropical Medicine. Topic: to be announced. His research focuses on fundamental aspects of the biology of kinetoplastid parasites and their vectors, and on developing molecular tools to control and prevent parasite transmission in disease-endemic areas.
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.