The two-year research, led by Ola Lundin, a former postdoctoral fellow in the Neal Williams lab, UC Davis Department of Entomology and Nematology and published in the Journal of Applied Ecology, details what plants proved most attractive to honey bees, wild bees and other pollinators, as well as what drew such natural enemies as predators and parasitic wasps.
The research, “Identifying Native Plants for Coordinated Habitat Management of Arthropod Pollinators, Herbivores and Natural Enemies,” is co-authored by Williams, professor of entomology and a Chancellor's Fellow at UC Davis; and project specialist Kimiora Ward of the Williams lab.
“I hope this study can inform selection of plants that support pollinators and natural enemies without enhancing potential pests,” said Lundin, first-author of the paper and now a postdoctoral fellow in the Department of Ecology, Swedish University of Agricultural Sciences, Uppsala.
“Planting wildflowers is a key strategy promoted nationally to support wild and managed bees,” said Williams. “Successful adoption of these plantings in agricultural landscapes will require that they not only support pollinators but that they also avoid supporting too many pests. Plant selection going forward will need to balance multiple goals of pollinators pest management and other functions. This research is a first step on the path to identifying plants that will meet these goals."
The three scientists, who conceived the ideas and developed the methodology for the research project, established 43 plant species in a garden experiment on the grounds of the Harry H. Laidlaw Jr. Honey Bee Research Facility at UC Davis. They selected plant species that were drought-tolerant; native to California (except for buckwheat, Fagopyrum esculentum, known to attract natural enemies and widely used in conservation biological control); and, as a group, covered a range of flowering periods throughout the season.
“For early season bloom, Great Valley phacelia (Phacelia ciliata) was a real winner in terms of being attractive for both wild bees and honey bees,” Lundin said. “Elegant Clarkia (Clarkia unguiculata) flowers in late spring and was the clearly most attractive plant for honey bees across the dataset. The related Fort Miller Clarkia (C. williamsonii) was also quite attractive for honey bees and had the added benefit that a lot of minute pirate bugs visited the flowers.”
Lundin said that common yarrow (Achillea millefolium) “attracted “attracted the highest numbers of parasitic wasps but also many herbivores, including Lygus bugs.”
“In general a lot of parasitic wasps were found on Asteraceae species (the daisy family) and this was a somewhat surprising result considering that they have narrow corollas, and for parasitic wasps relatively deep corollas that can restrict their direct access to nectar. Under the very dry conditions in late summer, Great Valley gumplant (Grindelia camporum) and Vinegarweed (Trichostema lanceolatum) both performed well and attracted high numbers of wild bees.”
The team found that across plant species, herbivore, predator and parasitic wasp abundances were “positively correlated,” and “honey bee abundance correlated negatively to herbivore abundance.”
The take-home message is that “if you're a gardener or other type of land manager, what you'd likely prefer would be a mix of some of the most promising plant species taking into account their individual attractiveness for these arthropod groups, plus several more factors including costs for seed when planting larger areas,” Lundin said.
“Plant choice can also depend on how you weigh the importance of each arthropod group and whether you are interested in spring, summer or season-long bloom,” Lundin added. Those are some of the questions that the Williams lab plans to explore in future projects.
Williams praised the “uniquely capable team that came together.”
“Ola is an emerging leader in considering integrated management of pests and pollinators and Kimiora is a known expert in developing regionally-relevant plant materials to support pollinators,” Williams said. “They and some talented UC Davis undergraduates--notably Katherine Borchardt and Anna Britzman--compiled a tremendously useful study.”
The overall aim of the study “was to identify California native plants, and more generally plant traits, suitable for coordinated habitat management of arthropod pollinators, herbivores and natural enemies and promote integrated ecosystem services in agricultural landscapes,” the researchers wrote.
More specifically, they asked:
- Which native plants among our candidate set attract the highest abundances of wild bees, honeybees, herbivores, predators, and parasitic wasps,
- If the total abundances of arthropods within these functional groups across plant speacies are related to the peak flowering week, floral area, or flower type of the focal plant species, and
- If the total abundances of arthropods within these functional groups are correlated to each other across plant species.
“A first critical step for design and implementation of multifunctional plantings that promote beneficial arthropods while controlling insect pests is to identify suitable plant species to use,” the authors wrote in their abstract. “We aimed to identify California native plants and, more generally, plant traits suitable for the coordinated management of pollinators (wild bees and honey bees), insect herbivores and arthropod natural enemies (predators and parasitic wasps).”
At the time, the Laidlaw grounds included nearly 50 bee colonies: some 20 to 40 honey bee colonies, and eight managed research colonies of the yellow-faced bumble bee, Bombus vosnesenkii.
The project received funding from the USDA Resources Conservation Service, USDA Agricultural Marketing Service, USDA National Institute of Food and Agriculture and a Swedish foundation for scientific research, the Carl Tryggers Stiftelse for Vetenskaplig Forskning.
The conference, themed “Multidimensional Solutions to Current and Future Threats to Pollinator Health,” will cover a wide range of topics in pollinator research: from genomics to ecology and their application to land use and management; to breeding of managed bees; and to monitoring of global pollinator populations. Topics discussed will include recent research advances in the biology and health of pollinators, and their policy implications.
Keynote speakers are Christina Grozinger, distinguished professor of entomology and director of the Center for Pollinator Research, Pennsylvania State University, (the research center launched the annual pollinator conferences in 2012) and Lynn Dicks, Natural Environment Research Council (NERC) Research Fellow, School of Biological Sciences, University of East Anglia, England.
Grozinger studies health and social behavior in bees and is developing comprehensive approaches to improving pollinator health and reduce declines. Lynn Dicks, an internationally respected scientist, studies bee ecology and conservation. She received the 2017 John Spedan Lewis Medal for contributions to insect conservation.
Other speakers include:
- Claudio Gratton, professor, Department of Entomology, University of Wisconsin-Madison
- Quinn McFrederick, assistant professor, Department of Entomology, UC Riverside
- Scott McArt, assistant professor, Department of Entomology, Cornell University
- Maj Rundlöf, International Career Grant Fellow, Department of Biology, Lund University, Sweden
- Juliette Osborne, professor and chair, Applied Ecology, University of Exeter, England
- Maggie Douglas, assistant professor, Environmental Studies, Dickinson College
The UC Davis Honey and Pollination Center, directed by Amina Harris, is playing a major role in the international conference. The center's events manager, Elizabeth Luu, is serving as the conference coordinator. For more information on the conference, access the UC Davis Honey and Pollination website at https://honey.ucdavis.edu/pollinatorconference2019 and sign up for the newsletter for up-to-date information.
DAVIS--Pollination ecologist and Chancellor's Fellow Neal Williams, professor of entomology, UC Davis Department of Entomology and Nematology, has been named one of the Highly Cited Researchers in the 2018 list just released by Clarivate Analytics.
Williams is one of only 19 UC Davis researchers so honored and one of 10 from the College of Agricultural and Environmental Sciences.
Williams focuses his research on the ecology and evolution of bees and other pollinator insects and their interactions with flowering plants. His work is particularly timely given concern over the global decline in bees and other pollinators.
The company, based in Philadelphia, honors exceptional scientists and social scientists who have demonstrated significant influence by publishing multiple papers that rank in the top 1 percent by citations in a particular field and year, over a 10-year period.
“This is a wonderful testament to the incredible breadth of expertise at UC Davis and the associated global impact,” said Prasant Mohapatra, UC Davis vice chancellor for research, in a UC Davis news story. “I would like to congratulate each of the named investigators and their teams on such an inspiring accomplishment.”
Williams joined the UC Davis Department of Entomology (now Department of Entomology and Nematology) in 2009 from the Bryn Mawr (Pa.) College. He holds a bachelor's degree from the University of Wisconsin, Madison, and a doctorate from the State University of New York, Stony Brook.
He was named a Chancellor's Fellow in 2015, a five-year program that granted him $25,000 to support his research, teaching and public service activities. The program, established in 2000 to honor the achievements of outstanding faculty members early in their careers, is funded in part by the Davis Chancellor's Club and the Annual Fund of UC Davis.
Clarivate Analytics' services focus largely on analytics, including scientific and academic research, patent analytics, regulatory standards, trademark protection, pharmaceutical and biotechnology intelligence, domain brand protection and intellectual property management. The services include Web of Science, and EndNote.
UC Davis researchers on the 2018 list are:
- Jay Belsky, Human Ecology, College of Agricultural and Environmental Sciences
- Eduardo Blumwald, Plant Sciences, College of Agricultural and Environmental Sciences
- Siobhan M. Brady, Plant Biology, College of Biological Sciences
- Cameron S. Carter, Psychiatry and Behavioral Sciences, School of Medicine
- Douglas R. Cook, Plant Pathology, College of Agricultural and Environmental Sciences
- Alan Crozier, Nutrition, College of Agricultural and Environmental Sciences
- Shuguang Cui, Electrical and Computer Engineering, College of Engineering
- Kathryn G. Dewey, Nutrition, College of Agricultural and Environmental Sciences
- Jorge Dubcovsky, Plant Sciences, College of Agricultural and Environmental Sciences
- Irva Hertz-Picciotto, Public Health Sciences, School of Medicine
- Robert J. Hijmans, Environmental Science and Policy, College of Agricultural and Environmental Sciences
- Theodore C. Hsiao, Land, Air and Water Resources, College of Agricultural and Environmental Sciences
- David A. Mills, Food Science and Technology, College of Agricultural and Environmental Sciences
- Sally Ozonoff, Psychiatry and Behavioral Sciences, School of Medicine
- Sally J. Rogers, Psychiatry and Behavioral Sciences, School of Medicine
- Andrew Sih, Environmental Science and Policy, College of Agricultural and Environmental Sciences
- Neal M. Williams, Entomology and Nematology, College of Agricultural and Environmental Sciences
- Heike Wulff, Pharmacology, School of Medicine
- Qi Zhang, Environmental Toxicology, College of Agricultural and Environmental Sciences
Page, a pollination ecologist, was one of 69 awardees selected from more than 3600 applicants. Her fellowship is funded by the Department of Defense.
“The fellowship is well deserved,” said Williams, her major professor and a pollination ecologist and a UC Davis Chancellor's Fellow. “Maureen is a talented researcher, who shows a real passion for her research that is combined with a highly analytical meticulous approach.”
Of her project, Williams said: “Her work melds careful field sampling with advanced analysis, including computational optimization modeling. It will move existing research to a new level by exploring the nutritional basis of competitive interactions among pollinators. The project builds from a solid foundation but his highly innovative. Its results should be of tremendous value to the scientific community, but are also highly relevant for decision making to promote sustainable food systems for California and beyond.”
Page received her bachelor's degree in biology, cum laude, from Scripps College, Claremont, Calif., in 2016, and then enrolled in the UC Davis entomology graduate program, with a career goal of becoming a professor and principal investigator.
“I became interested in UC Davis because I was interested in working in Neal's lab,” she related. “After my sophomore year of college, I participated in National Science Foundation's Research Experiences for Undergraduates (NSF REU) with the Chicago Botanic Gardens. One of the professors I was working with, Jennifer Ison, told me that my research interests aligned well with the work coming out of Neal's lab and I quickly realized she was right.”
“I even bookmarked the Williams lab webpage so I could check for recent papers!” Page said. “Neal is an even better advisor than I could have hoped for and I feel very grateful to be a part of UC Davis Department of Entomology and Nematology.”
Her dissertation research focuses on using plant-pollinator interaction networks to (1) assess the impact of honey bee introductions on native plant pollination and (2) optimize wildflower plantings to simultaneously support honey bee health and diverse native bee communities.
“I've always loved flowers and I think my love of bees grew out of my academic interest in pollination ecology and a desire to apply my talents towards research that would benefit farmers and pollinator conservation efforts,” said Page, a native of San Francisco but who grew up in Ashland, Ore.
As a volunteer researcher for Southern Oregon University, she worked on a watershed project in the Klamath-Siskiyou Wildlands Center, and was named the City of Ashland's Conservationist of the Year in April 2012. The city honored her at its Earth Day celebration.
Keenly interested in bee research, Page received a 2013 Scripps Environmental Research Grant to establish a solitary bee monitoring program at the Bernard Field Station in Claremont. She created a reference collection and species list of bee diversity at the field station, gaining experience collecting, pinning and identifying bee specimens. She presented her findings at the Scripps Undergraduate Research Symposium. Page later worked on a project categorizing pollen deposition by the yellow-faced bumble bee, Bombus vosnesenkii to California figwort, Scrophularia california.
What fascinates her about bees? “Tough question!” said Page, who is the first entomologist in her family. “Bees are so very interesting for so many different reasons! I'm particularly fascinated by the relationship between bees and flowers--with bees acting as pollinators and flowers offering bees important pollen and nectar resources. I think the biggest misconception is that all bees are honey bees. In fact, there are more than 20,000 species in the world, only 7 of which are considered honey bees!”
An average day?
“My field season has started, so on an ‘average day' I'm at one of my lab's wildflower plantings by 7 a.m. and driving home with coolers of bees and flowers around 7 p.m.,” Page said. “The most fun part of my fieldwork is using something called a ‘mobile bouquet' to measure single-visit pollen deposition by different pollinator taxa to different plant taxa.”
Page was awarded a grant from the Davis Botanical Society earlier this year, and won second place in the graduate students' poster competition at the 2018 UC Davis Bee Symposium for her poster, “Impacts of Honey Abundance on the Pollination of Eschscholzia californica. Last year she received a Northern California Botanists' Grant and a Davis Botanical Society Grant.
Eager to reach youth about the importance of pollinators, Page began volunteering in 2016 for the Center for Land-Based Learning, mentoring students from Sacramento High School, and engaging them in hands-on conservation science at Say Hay Farms, a 20-acre family farm in Yolo County. She has taught students at her Davis area field site about the benefits of providing wildflower habitat for pollinators.
The UC Davis doctoral student has also presented lectures at the Hoes' Down Harvest Festival, Yolo County, on “Pollinators on the Farm” and led a kids' bug hunt. She presented an invited lecture on “Beneficial Insects in Home Gardens” to the El Dorado Master Gardeners, part of the UC Cooperative Extension program, and volunteered at their other activities.
Page serves as secretary of the UC Davis Entomology Graduate Student Association. In her leisure time, she enjoys “baking, rock climbing, learning new things, and sketching--mostly-flowers, bees, and sometimes butterflies.”
The researchers, led by Rachael Winfree of Rutgers University, New Brunswick, N.J. set out to answer the question “How many species do we need for crop pollination?”
They identified more than 100 species of wild bees pollinating watermelon, cranberry and blueberry crops on a total of 48 farms in New Jersey and Pennsylvania--the mid-Atlantic region of the United States.
The answer: “Not nearly enough bees are available for crop pollination,” Winfree said.
“We found that maintaining ecosystem services in nature requires many species, including relatively rare ones,” said Winfree, professor of ecology, evolution and natural resources. The publication, “Species Turnover Promotes the Importance of Bee Diversity for Crop Pollination at Regional Scales,” appears in the section, Ecology.
The ecologists first counted pollen grains of different bee species to measure bee pollination, tallied the number of bees and the different species pollinating the crops, and then figured out the minimum set of bee species that could meet various pollination needs. Finally, they plotted the cumulative number of bee species needed against the number of sites.
“So how many species do we need to ensure reliable crop pollination?” he asked. “The answer to this question helps us manage our agricultural and natural lands. Past studies suggest that often just a few bee species can do the job for any one site.”
The study, among the first of its kind, “reveals that when we look across multiple farm sites in a region, we need many more species than experimental studies have suggested in the past,” Williams said. “At one farm, pollination might rely on a handful of species, but across 40-50 farms in a region we need 10 times that number. This is because the most important species change from one place to another. “
So how many bee species are important to ensure crop pollination?
“More than we thought!” Williams said. “Working to promote bee diversity across regions is important for maintaining pollination and secure food systems.” The researchers counted 100 species of wild bees.
Winfree said previous experiments completed in the lab didn't answer the question: “How many bees do we really need?”
“When you have five (ish) bee species you get enough pollination,” she said “But there are only so many species you can even fit in an experiment. What we wanted to know is, how many bees do real farmers need to pollinate actual farms across an entire state?”
“Any one farm might need only a few species, but different bee species pollinate the different farms, so to pollinate all 50 (ish) farms we needed about 10 times as many species as are needed in smaller scale experiments,” Winfree said. “More than half of the 100 (ish) bee species we saw in the study were needed at some farm for some crop.”
Winfree, reiterating that “we need more bees than we thought,” said the issue is “important because many scientists are concerned that bees are in trouble. There is limited information on how most bee species are doing, but some of the species we do know about are declining. This work shows that preserving lots of bee species is important for food security.”
Other co-authors of the study are James Reilly of Rutgers; Ignasi Bartomeus of Rutgers but based at a biological station in Seville, Spain; Daniel Cariveau of Rutgers and the University of Minnesota; and Jason Gibbs of the University of Manitoba, Winnipeg, Canada.
A grant from the National Institute of Food and Agriculture (NIFA) of the U.S. Department of Agriculture funded the data collection research. Winfree conceived the study, oversaw the data collection, led the conceptual development and wrote the manuscript. Williams contributed to the conceptual development and manuscript preparation.