- Author: Kathy Keatley Garvey
Rukowski, who studies with community ecologists Rachel Vannette, associate professor and vice chair of the UC Davis Department of Entomology and Nematology, and distinguished professor Rick Karban, will present her exit seminar on "Identity and Functions of Symbiotic Fungi Associated with Social Bees" on Monday, May 20.
Her hour-long seminar starts at 4:10 p.m. in Room 122 of Briggs Hall. It also will be on Zoom. The Zoom link:
https://ucdavis.zoom.us/j/9 5882849672.
"Social bees interact with diverse microbial communities that reside in flowers, in their nests, and within their guts," Rutkowski says in her abstract. "Fungi are common inhabitants of these environments, but despite their prevalence, little is known about their interactions with bees and their impacts on bee health. In my thesis, I identified common fungal associates of social bees and investigated their effects on bumble bee health, specifically focusing on their roles in bee response to fungicide, bee nutrition, and protection from pathogens."
"I identified several yeast groups frequently associated with social bees, including the genera Starmerella and Zygosaccharomyces," she relates. "Addition of these yeasts to bee diets improved survival and reproduction, and for one species, helped bees recover from negative effects of fungicide exposure. However, a follow-up study determined that these benefits to bee health are inconsistent and unrelated to bee nutrition. Rather, benefits of these yeasts instead may be mediated through pathogen suppression, as Starmerella yeasts are able to inhibit the growth of multiple fungal pathogens of bees. These results highlight the important impacts of these currently understudied microbes on bumble bee health, with implications for conservation of these pollinators."
In her 2021 ESA presentation, she drew attention to fungicide applications that are linked to declining bumble bee populations. She wrote in her abstract: "Native bees including bumble bees are important pollinators but face threats from multiple sources, including agrochemical application. Declining bumble bee populations have been linked to fungicide application, which could directly affect the fungi often found in the stored food and GI tract of healthy bumble bees. Here, we test the hypothesis that fungicides impact bee health by disrupting bumble bee -fungi interactions. Using two species, Bombus vosnesenskii and B. impatiens, we test the interactive effect of the fungicide propiconazole and fungal supplementation on the survival, reproduction, and microbiome composition of microcolonies (queenless colonies). We found that both bee species benefitted from fungi, but were differentially affected by fungicides. In B. vosnesenskii, fungicide exposure decreased survival while fungal supplementation mitigated fungicide effects. For B. impatiens, fungicide application had no effect, but fungal supplementation improved survival and offspring production. Fungicides altered fungal microbiome composition in both species, and reduced fungal abundance in B. vosnesenskii microcolonies, but not in B. impatiens, where instead fungal addition actually decreased fungal abundance. Our results highlight species-specific differences in both response to fungicides and the nature of fungal associations with bees, and caution the use of results obtained using one species to predict the responses of other species. These results suggest that fungicides can alter bee- fungi interactions with consequences for bee survival and reproduction, and suggest that exploring the mechanisms of such interactions, including interactions within bee-associated fungal communities, may offer insights into bumble bee biology and bumble bee conservation strategies."
Her many activities include:
- A 2023 graduate of The Bee Course, a 10-day workshop on bee collection and identification at the Southwestern Research Station in Portal, AZ.
- Co-chair of the department's entomological activities, 2022 UC Davis Picnic Day, with forensic entomologist Robert Kimsey.
- As a member of the UC Davis graduate student group, Equity in Science, Technology, Engineering, Math, and Entrepreneurship (ESTEME), she helped plan activities and lessons for middle school students in the Davis area.
- Former secretary and vice president of the UC Davis Entomology Graduate Student Association.
- Mentored prospective graduate students from groups underrepresented in STEM through a month-long program, and provided application advice and feedback on application materials.
Rutkowski holds a bachelor of science degree from Cornell University in entomology and biological sciences, with a concentration in ecology and evolutionary biology. She graduated in May 2018 summa cum laude with distinction in research.
At Cornell, Rutkowski did independent research with Professor Jennifer Thaler, carrying out an independent honor's thesis research project on ecological interactions between insect herbivores, plants, and arbuscular mycorrhizal fungi. Rutkowski also worked with Thaler on numerous other projects, studying interactions between potato plants, Colorado potato beetles, and their predators, as well as projects studying the interactions between arbuscular mycorrhizal fungi, tomato plants, and insect herbivores. She also worked with Professor Richard Lindroth at the University of Wisconsin, Madison, investigating how genotype and environmental conditions interact to affect the growth, defense and insect community of aspen trees.
Rutkowsk is the lead author or co-author in a number of publications:
- Rutkowski, D., Weston, M., Vannette, R.L. (2023) Bees just wanna have fungi: A review of bee associations with non-pathogenic fungi. FEMS Microbiology Ecology 99(8) https://doi.org/10.1093/femsec/fiad077
- Karban, R., Rutkowski, D., Murray, N. (2023) Flowers that self?shade reduce heat stress and pollen limitation. American Journal of Botany 110(2) https://doi.org/10.1002/ajb2.16109
- Pepi, A., Pan, V., Rutkowski, D., Mase, V., Karban, R. (2022) Influence of delayed density and ultraviolet radiation on caterpillar baculovirus infection and mortality. Journal of Animal Ecology 91(11):2192-2202 https://doi.org/10.1111/1365-2656.13803
- Rutkowski, D., Litsey, E., Maalouf, I, Vannette, R.L. (2022) Bee-associated fungi mediate effects of fungicides on bumble bees. Ecological Entomology 47(3):411-422 https://doi.org/10.1111/een.13126
- Mola, J.M., Stuligross, C., Page, M.L., Rutkowski, D., Williams, N.M. Impact of “non-lethal” tarsal clipping on bumble bees (Bombus vosnesenskii) may depend on queen stage and worker size. Journal of Insect Conservation 25, 195–201 (2021). https://doi.org/10.1007/s10841-021-00297-9
The UC Davis Department of Entomology and Nematology seminars are coordinated Brian Johnson, associate professor. For any technical issues with Zoom, contact him at brnjohnson@ucdavis.edu. The full list of spring seminars is here.
- Author: Kathy Keatley Garvey
Free and family friendly, the open house takes place from 1 to 4 p.m. in Room 1124 of the Academic Surge Building, 455 Crocker Lane, UC Davis campus.
"It should be a great event!” said Tabatha Yang, education and outreach coordinator. “There is a lot of interest in bees this time of year. The format will be tabling with direct conversations with visitors.” The event is free and family friendly. Parking is also free.
Among those participating will be the laboratory of community ecologist Rachel Vannette, associate professor and chair of the UC Davis Department of Entomology.
"At the Vannette Lab booth, you will be able to look into the life of a bee--both in terms of where they live and how they develop!" said doctoral candidate and researcher Lexie Martin. "A live bumble bee nest and solitary bee nests will be available, so you can peer inside a bee's house! Additionally, there will be live bee larvae to observe under a microscope and interactive displays on the bee life cycle."
Vannette describes her lab as "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."
Vannette's lab members participating at the open house will include:
Lexie Martin, doctoral candidate in the Entomology Graduate Group. She is interested in the impact of microbes on bee health
Dino Sbardellati, doctoral student in the Microbiology Graduate Group. He is a microbiologist interested in understanding how microbial ecology shapes macroscale ecology
Leta Landucci, a junior specialist and biochemist. She is inspired by chemical ecology, and broadly interested in exploring chemically mediated plant-insect-microbe interactions
Others scheduled to participate are Bohart Museum scientists and bee specialists Thomas Zavortink and Sandy Shanks; doctoral student Sofía Meléndez Cartagena of the Stacey Combes lab, Department of Neurobiology, Physiology and Behavior (she will focus on local bee diversity); Chancellor's Fellow Santiago Ramirez, associate professor, Department of Evolution and Ecology, who studies orchid bees; doctoral student Peter Coggan of the Ramirez lab (Coggan studies the neurological and genetic basis of orchid bee courtship behavior and evolution); and Richard Martinez, entomology graduate student researcher in the lab of apiculturist Elina Niño,associate professor of Cooperative Extension, UC Davis Department of Entomology and Nematology.
Martinez says that the E.L Niño Lab booth will display an observation hive and offer honey tasting from a variety of floral sources. He will be sharing recent projects aimed at improving honey bee health via dietary supplements. He also plans to showcase beekeeping suits and hive tools.
UC Davis distinguished professor emerita Lynn Kimsey, who directed the Bohart Museum for 34 years, is also scheduled to participate. She is known as "wasp woman," but she did her dissertation on orchid bees in Panama.
The Bohart Museum houses a global collection of eight million insects, plus a live petting zoo, and a gift shop. Professor Jason Bond directs the museum as of Feb. 1, succeeding UC Davis distinguished professor emerita Lynn Kimsey, who served 34 years. Bond is the Evert and Marion Schlinger Endowed Chair of the Department of Entomology and Nematology, and the associate dean, UC Davis College of Agricultural and Environmental Sciences. He also serves as president-elect of the American Arachnological Society.
For more information, access the website at https://bohart.ucdavis.edu or contact bmuseum@ucdavis.edu.
- Author: Kathy Keatley Garvey
A member of the Microbiology Graduate Group and the laboratory of community ecologist Rachel Vannette, associate professor and vice chair of the UC Davis Department of Entomology andNematology, he will deliver the Merton Love seminar from 3 to 4:30 p.m., Friday, May 24 in Room 1230 of Walker Hall. The Zoom link:
https://ucdavis.zoom.us/j/99429777483.
The award memorializes Robert Merton Love (1909-1994), emeritus professor of agronomy and range science, who served on the UC Davis faculty from 1940-1976.
“Shawn's thesis work spans microbiology, ecology and evolutionary biology, combined with careful natural history, to document novel species interactions between hosts and microbial communities,” said Vannette, who nominated him for the award. “Each chapter has broad implications for the ecology and evolution of host-microbe interactions. Shawn's work has already reframed the conditions under insect-microbe interactions are thought to hold relevance and evolve. His research has highlighted the utility of natural history observations of microbes and sampling understudied life history stages (overwintering developing insects).”
“Overall, Shawn's dissertation is an example of how detailed observations combined with fearless experimental dissection of interesting phenotypes can yield novel descriptions of species interactions that change the field's perception of when and where microbial communities are important,” she said.
“Shawn's first chapter describes adaptations of a flower specialist bacteria to acquiring resources from pollen—a nutrient source specific to flowers,” Vannette said. “Our lab was interested in the ecology of the flower-dwelling bacteria Acinetobacter, but Shawn took a new look at this bacterium, examining its growth morphology in nectar and in association with pollen. He noticed that this bacterium co-localized with pollen and grew exponentially more in the presence of pollen. To explore this phenotype, he designed new media and assays (microwaving pollen) to determine that Acinetobacter benefits the most from live pollen via stimulating pollen to germinate (within minutes!), then digesting it. Shawn then designed a series of experiments to examine if this ability was unique to this bacterial clade or shared among many floral microbes (it seems to be specific to Acinetobacter).”
“He collected brood cells (nectar and pollen balls along with developing larvae) from these locations at multiple points through bee development and examined not only the bacteria and fungal community composition through insect development, but also examined changes in microbial abundance at each life stage,” Vannette said. “In contrast to my (and the literature's) predictions, Shawn showed that microbial abundance peaks during larval overwintering, when solitary bees and other holometabolous insects are predicted to have voided their microbial gut communities. Instead, healthy A. bomboides hosts the highest abundance of fungi and bacteria during the fall—a wet season where pathogen abundance is also highest.”
Christensen received accolades and widespread media coverage for the first chapter of his dissertation, “Nectar Bacteria Stimulate Pollen Germination and Bursting to Enhance Microbial Fitness,” published in July 2021 in Current Biology. His second thesis chapter on the microbes associated with Anthophora bomboides, has just been accepted for publication by the International Society of Microbial Ecology (ISME).
And more good news: Christensen is a" co-principal investigator on a newly awarded grant by JGI to sequence the genome of the yeast," Vannette said, "and explore its functional potential in renewable energy and is applying to continue to leverage this system's potential in antifungal chemistry and evolution of pathogen defense.”
Every time we see the nests of Anthophora bomboides stanfordiana on the sand cliffs at Bodega Head, we think of the scientists, including Shawn Christensen and Rachel Vannette, who study them. The late Robbin Thorp, UC Davis distinguished emeritus professor, UC Davis Department of Entomology and Nematology, researched them decades ago.
Check out PBS' Deep Look video, "This Bee Builds Sandcastles at the Beach," and you'll never go to Bodega Bay without thinking of these digger bees.
/span>- Author: Kathy Keatley Garvey
Get ready...it's happening...the annual World Bee Day...
Monday, May 20 is World Bee Day, as declared by the United Nations "to raise awareness of the importance of pollinators, the threats they face, and their contribution to sustainable development."
"The goal is to strengthen measures aimed at protecting bees and other pollinators, which would significantly contribute to solving problems related to the global food supply and eliminate hunger in developing countries," the website points out. "We all depend on pollinators and it is, therefore, crucial to monitor their decline and halt the loss of biodiversity."
Lately we've been noticing multiple species of bumble bees in our pollinator garden in Vacaville. One of them appears to be Bombus bifarius.
The bumbles we've seen over the years in our pollinator garden--B. californicus, B. melanopygus, B.vosnesenskii and B. bifarius--especially like Coreopsis, a genus of flowering plants in the aster family, Asteraceae. It's also called tickseed.
Now that's not a good name for such a showy flower!
- Author: Kathy Keatley Garvey
In the human world, we recognize Mother's Day as a special day to celebrate all mothers. It's a day that Anna Jarvis of Grafton, West Va., established on May 10, 1909 with a worship service at St. Andrew's Methodist Church, Grafton.
Lady beetles, aka ladybugs, are mothers, too. The female lays a batch of eggs, from 10 to 50, at one time, and can lay about 1000 eggs in her lifetime, scientists say.
Beneficial insects! Yes, but in their larval form they eat even more.
Mature lady beetles will feed on 20 to 25 aphids per day, but their late-stage larvae will consume 10 times that number, making them far more effective predators, according to Whitney Cranshaw, a professor and Extension entomologist with Colorado State University (now emeritus), in a July 2018 article in Phys.Org.
A salute to lady beetles and their larvae on Mother's Day!