- Author: Kathy Keatley Garvey
The article, “Vehicle Pollution Is Associated with Elevated Insect Damage to Street Trees,” is published in the Journal of Applied Ecology. It received the Editor's Choice Award.
“This research reveals strong effects of vehicle pollution on insect damage to trees,” said Meineke, who conceived the idea for the project, funded by the department. “Trees next to highways are exposed to multiple stressors, including urban heat, pollution, and insects, all of which affect one another and tree health. Our research strongly suggests planting trees that are less susceptible to herbivory near highways.”
Her team included her colleague, UC Davis distinguished professor Richard “Rick” Karban, who co-wrote the manuscript, and junior specialist David Eng, then of the Meineke lab. The study targeted vehicle pollution in the Sacramento Valley “and adds to a now growing chorus of studies demonstrating the scientific value of intra-urban gradients of particular variables (heat, pollution, surrounding vegetation),” they wrote.
They suspect that “vehicle pollution depresses defensive pathways within trees and reduces the concentrations of key compounds that protect against herbivore damage.”
The researchers demonstrated that leaf damage to a native oak species (Quercus lobata), known as the valley oak,” is “substantially elevated on trees exposed to vehicle emissions.”
“Together, our studies demonstrate that the heterogeneity in vehicle emissions across cities may explain highly variable patterns of insect herbivory on street trees,” they wrote. “Our results also indicate that trees next to highways are particularly vulnerable to multiple stressors, including insect damage. To combat these effects, urban foresters may consider installing trees that are less susceptible to insect herbivory along heavily traveled roadways.”
The valley oak is a deciduous, long-lived tree that can reach up to 98 feet in height and live up to 600 years. It is known to tolerate wildfires.
“Past studies hint at the potential role of vehicle pollution as a driver of leaf nutritional quality for chewing herbivores. At one site in the United Kingdom, trees within 100 meters of motorways were much more likely to be severely defoliated than trees at further distances. Elevated herbivory was attributed to elevated nitrogen dioxide (NO2) along highways.” Another study in the Los Angeles Basin, showed that “herbivore communities on oak trees at more polluted natural areas tended to be more dominated by chewing herbivores compared to less polluted natural areas.”
The UC Davis researchers wrote that their results “demonstrate that highly polluted, highway-adjacent habitats are associated with shifts in plant-insect interactions and that this topic may be ripe for future research into how roadside environments may affect insect conservation and plant performance in cities.”
Their study highlights the importance of planting decisions along major roadways. “The concept of ‘right tree, right place' has long stated that tree selection should be aimed at maximizing the performance in urban areas,” they wrote. “Quercus lobata and other species that are highly susceptible to herbivores may provide ecosystem services sub-optimally along highways, and may have shorter lifespans due to chronic damage promoted by on-road pollution trees.”
“Identifying tree species that are robust to pollution, and resistant to insects that may benefit from pollution, could be a novel consideration in planting decisions. This consideration may become even more important as many cities become drier and hotter, and insect herbivores have disproportionate impacts on tree growth. Because city-owned trees are planted and cannot themselves evolve in response to climate change, we may be required to develop new cultivars to promote robust trees along roadways.”
- Author: Kathy Keatley Garvey
The Labudio is located in Room 128 of the Environmental Horticulture Building, 200 Arboretum Drive, UC Davis.
The public is invited. "Please bring a t-shirt if you'd like to screen print one of our designs on it, too," they said. "Kids can make shirts, too. The event will be indoor/outdoor, so please dress accordingly." No reservations are necessary.
"The students were each assigned an insect species in decline or moving about the planet and becoming invasive in new habitats," said Meineke, an urban landscape entomologist and assistant professor. "The insects students were assigned are among those most impacted by humans, and students were given an opportunity to re-envision how people might interact more gently and intentionally with insects, our small, yet consequential co-inhabitants."
"We are so proud of how the students interacted with this topic," Meineke said. "They were charged with researching their insects and turning that research into designs that could be screen printed on watercolor paper, ceramic tiles to be installed in Briggs 122, and fabric. Their designs are nothing short of spectacular!"
UC Davis distinguished professor Diane Ullman, an artist and entomologist, "helped immensely," said Meineke, adding that she wasn't "an official co-teacher but she essentially acted as one."
Meineke was recently named one of the 12 UC Davis recipients of the prestigious Hellman Fellowships, an annual program supporting the research of early-career faculty. Her project, “Assessing Preservation of Chemical Compounds in Pressed Plants," focuses on whether herbarium specimens collected over hundreds of years harbor chemical compounds that reveal mechanisms responsible for changing insect-plant interactions.
Meineke was among the scholars and artists who helped spearhead the newly created Harvard Museum of Natural History's “In Search of Thoreau's Flowers: An Exploration of Change and Loss," hailed as an examination of the natural world and climate change at the intersections of science, art and history. She helped launch the project in 2017 when she was a postdoctoral fellow at the Harvard University Herbaria. The 648 plant specimens that Henry David Thoreau donated to the museum form the foundation of the exhibit. It opened to the public May 14.
A native of Greenville, N.C., Meineke joined the UC Davis Department of Entomology and Nematology on March 1, 2020, from the Harvard University Herbaria. As a National Science Foundation postdoctoral fellow, she studied how urbanization and climate change have affected plant-insect relationships worldwide over the past 100-plus years.
She received her bachelor of science degree in environmental science, with a minor in biology, in 2008 from the University of North Carolina, Chapel Hill. She obtained her doctorate in entomology in 2016 from North Carolina State University.
Professor Ullman, a celebrated teacher, artist and researcher, is the 2014 recipient of the Entomological Society of America (ESA) National Excellence in Teaching Award and the UC Davis Academic Senate's 2022 Distinguished Teaching Award for undergraduate teaching. She is a fellow of both the American Association for the Advancement of Science (2014) and the ESA (2011).
When she was singled out for the UC Davis Academic Senate Award, her nominators praised her as providing "superb teaching and mentoring for many years, not only in the Department of Entomology and Nematology but as a leader in the Science and Society program. She has brought art-science fusion alive in innovative ways. Her nominees and students rave about her deep dedication, care, and knowledge in all teaching interactions, as well as her overall commitment to student success. One student nominee summed it up: "My experience in her course last spring was one that lifted my spirits, enriched my education, and strengthened my love for art and science during a time when it was difficult to feel positive about anything.”
Ullman's research encompasses insect/virus/plant interactions and development of management strategies for insect-transmitted plant pathogens. She has worked with many insect vector species (thrips, aphids, whiteflies, leafhoppers, mealybugs) and the plant pathogens they transmit, including viruses, phytoplasma and bacteria.
One of her latest art projects--with colleagues, UC Davis students and community members--is the Sonoran Dreams Art Project in the Garden Apartments of the University Retirement Community, Davis. Handmade ceramic tiles depicting the flora, fauna and symbols of the Sonoran Desert surround the elevator.
Ullman received her bachelor of science degree in horticulture from the University of Arizona and her doctorate in entomology from UC Davis in 1985. She joined the UC Davis faculty in 1991 after serving as an associate professor of entomology at the University of Hawaii. Her credentials include: chair of the UC Davis Department of Entomology, 2004-2005; associate dean for undergraduate academic programs for the College of Agricultural and Environmental Sciences, 2005 to 2014; and co-founder and co-director of the UC Davis Art/Science Fusion Program, launched in September 2006.
- Author: Kathy Keatley Garvey
This was Rutkowski's second consecutive President's Prize.
Doctoral candidate Lindsey Mack and doctoral student Adelaine “Addie” Abrams scored second-place for their research presentations in the highly competitive program.
Their topics ranged from bumble bees (Rutkowski) and ants (Griebenow) to mosquitoes (Mack) and thrips and aphids (Abrams).
At the Entomological Society of America (ESA) annual meetings, students are offered the opportunity to present their research and win prizes. They can compete in 10-minute papers (oral), posters, or infographics. The President's Prize winners receive a one-year paid membership in ESA, a $75 cash prize, and a certificate. Second-winners score a one-year free membership in ESA and a certificate.
Danielle Rutkowski
Danielle Rutkowski, who studies with community ecologists Rachel Vannette, associate professor, and distinguished professor Richard “Rick” Karban, spoke on “The Mechanism Behind Beneficial Effects of Bee-Associated Fungi on Bumble Bee Health,” at her presentation in the category, Graduate School Plant-Insect Ecosytems: Pollinators.
Her abstract: "Bees often interact with fungi, including at flowers and within bee nests. We have previously found that supplementing bumble bee colonies with these bee-associated fungi improves bee survival and increases reproductive output, but the mechanisms behind these effects are unclear. This research aimed to determine the mechanisms underlying positive impacts of fungal supplementation in the bumble bee, Bombus impatiens. We tested two hypotheses regarding possible nutritional benefits provided by bee-associated fungi. These included the role of fungi as a direct food source to bees, and the production of nutritionally important metabolites by fungi. To test these mechanisms, we created microcolonies bumble bees and exposed each microcolony to one of four treatment groups. These four treatments were created based on the presence of fungal cells and the presence of fungal metabolites. We found that bee survival and reproduction were unaffected by treatment, with trends of decreased survival and reproduction when fungi were present. This contradicts previous results we've found using this bumble bee species, where fungi had a positive impact. It is possible that this disparity in results is due to differences in pathogen pressure between the two experiments, as bees in the first experiment were exposed to large amounts of pathogen through provided pollen, including Ascosphaera and Aspergillus. This pollen was sterilized for subsequent experiments, reducing pathogen load. Therefore, it is possible that bee-associated fungi benefit bees through pathogen inhibition, and future work exploring this hypothesis is necessary to fully understand the role of these fungi in bumble bee health."
Zach Griebenow, who studies with major professor and ant specialist Phil Ward, (Griebenow also captained the UC Davis Entomology Games Team in its national championship win at the Entomology Games or Bug Bowl) explained “Systematic Revision of the Obscure Ant Subfamily Leptanillinae (Hymenoptera: Formicidae), Reciprocally Informed by Phylogenomic Inference and Morphological Data.” His category: Graduate School Systematics, Evolution and Biodiversity: Evolution 1.
His abstract: "Ants belonging to the subfamily Leptanillinae (Hymenoptera: Formicidae) are sister to nearly all other extant ants. Miniscule and subterranean, little is known of their behavior. Contrary to the collecting bias observed in most ants, male leptanilline specimens are acquired more easily than workers or queens. The sexes are almost never collected in association, and many subclades within the Leptanillinae are known from male specimens only. Our comprehension of evolutionary relationships among the Leptanillinae is further obstructed by oft-bizarre derivation in male phenotypes that are too disparate for phylogeny to be intuited from morphology alone. These restrictions plague our understanding of the Leptanillinae with probable taxonomic redundancy. My thesis aims at leptanilline taxonomy that reflects phylogeny, inferred from both genotype and phenotype, and integrates morphological data from both sexes. Here I present the results of (1) phylogenomic inference from ultra-conserved elements (UCEs), compensating for potential systematic biases in these data, representing 63 terminals; and (2) Bayesian total-evidence inferences from a handful of loci, jointly with discrete male morphological characters coded in binary non-additive or multistate fashion. Notably, these analyses identify worker specimens belonging to the genera Noonilla and Yavnella, which were heretofore known only from males. Given such discoveries across the Leptanillinae, the number of valid leptanilline genera is reduced from seven to three in order to create a genus-level classification that upholds monophyly along with diagnostic utility."
Mack, who studies with medical entomologist-geneticist Geoffrey Attardo, assistant professor, covered “Three Dimensional Analysis of Vitellogenesis in Aedes aegypi Using Synchrotron X-Ray MicroCT” in the category, Graduate School Physiology, Biochemistry and Toxicology: Physiology.
Her abstract: "Traditional methods of viewing the internal anatomy of insects require some degree of tissue manipulation and/or destruction. Using synchrotron-based x-ray phase contrast microCT (pcMicroCT) avoids this issue and has the capability to produce high contrast, three dimensional images. Our lab is using this technique to study the morphological changes occurring in the mosquito Aedes aegypti during its reproductive cycle. Ae. aegypti is the primary global arbovirus vector, present on all continents except Antarctica. Their ability to spread these viruses is tightly linked with their ability to reproduce, as the production of eggs in this species is initiated by blood feeding. Amazingly, this species produces a full cohort of eggs (typically 50-100) in just 3 days' time following a blood meal. This rapid development represents dramatic shifts in physiological processes that result in massive volumetric changes to internal anatomy over time. To explore these changes thoroughly, a time course of microCT scans were completed over the vitellogenic period. This dataset provides a virtual representation of the volumetric, conformational, and positional changes occurring in tissues important for reproduction across the vitellogenic period. This dataset provides the field of vector biology with a detailed three-dimensional internal atlas of the processes of vitellogenesis in Ae. aegypti."
Abrams, who studies with Extension agricultural entomologist and assistant professor Ian Grettenberger (she is a member of the Horticulture and Agronomy Graduate Group), titled her research, “Hitting the Mark: Precision Pesticide Applications for the Control of Aphids in California Lettuce" in the category, Graduate School Physiology, Biochemistry and Toxicology: Integrated Pest Management.
Her abstract: "Commercial lettuce production in California's central coast represents 70 percent of the production in the United States. Recent discoveries of some chemistries in ground and surface water in the Salinas valley region have placed the insecticidal chemistries used by the industry at risk of increased regulation. Automated thinner-sprayers use plant-detection sensors to apply chemical sprays directly to individual lettuce plants, so that the same amount of product to plants as a standard broadcast sprayer while potentially reducing the amount of pesticide applied per acre by up to 90 percent. Field experiments testing this technology for the control of western flower thrips (Frankliniella occidentalis) and aphids, lettuce-currant aphid (Nasovonia ribisnigri) and others, were conducted to compare the efficacy of automated sprays to a conventional broadcast application system. Experiments were conducted in conventionally managed organic romaine lettuce fields using a complete randomized block design. Prior to and at regular intervals after treatment, heads were sampled from experimental and control plots to assess pest pressure. Results from this experiment validate the use of the automated sprayers to apply insecticides for the control of aphid and thrips pests in lettuce and will be discussed in the context of developing best-use-practices for this technology."
The 7000-member ESA, founded in 1889, is the largest organization in the world serving the professional and scientific needs of entomologists and individuals in related disciplines. Its members, affiliated with educational institutions, health agencies, private industry, and government, are researchers, teachers, extension service personnel, administrators, marketing representatives, research technicians, consultants, students, pest management professionals, and hobbyists.
(See all of student competition winners on ESA site)
- Author: Kathy Keatley Garvey
Unlike honey bees, carpenter bees do not live in hives, they have no queen and they do not produce honey.
The work, published in the journal Molecular Ecology, focused on two species of carpenter bees, the Valley carpenter bee or Xylocopa sonorina, and the mountain carpenter bee, Xylocopa tabaniformis, from multiple geographic sites in their range, said corresponding author and community ecologist Rachel Vannette, an associate professor in the UC Davis Department of Entomology and Nematology.
The research suggests that “sociality may not be the main driver of microbiome structure in bees as is often assumed,” Vannette said.
Co-first author Madeline Handy, an undergraduate student and research intern in the Vannette laboratory and a member of the Research Scholars Program in Insect Biology (RSPIB), originated the research. Co-first author and microbiologist Dino Sbardellati of the Vannette lab and a graduate student in the UC Davis Microbiology Graduate Group, contributed bioinformatics and statistical analysis.
The researchers sequenced the microbial communities “using technology that produces longer reads from microbial DNA and allows us to get a better picture of the microbes that are found in the crop and gut, as well as their relatedness to each other,” Vannette said.
The significance of the research? “Social bees have a gut microbiome that's a model for human gut microbiomes—microbes contribute to digestion in the gut, affect host immunity and physiology in both bees and humans,” Vannette said. “But a key question is how do these types of microbiomes form and what maintains them? Social interactions has been posed as a major driver but this study suggests that advanced sociality is not required for the maintenance of this type of microbiome. Second, we show that long-read amplicon sequencing can be used in novel ways to generate hypotheses about how microbes are transmitted and maintained within insects.”
Next Steps. The next steps? “We would love to know what are these bacteria doing and if they are beneficial to bees. Our lab is excited to explore how bacterial and fungal communities in bee GI tract, stored food and other insect life stages like larvae or pupae may contribute to bee nutrition and health.”
The six-member team also included co-authors Michael Yu, UCLA Department of Ecology and Evolutionary Biology; Nicholas Saleh, Department of Entomology and Nematology Fort Lauderdale Research and Education Center, University of Florida, Davie; and Madeleine M. Ostwald, School of Life Sciences, Arizona State University, Tempe.
Their paper is titled “Incipiently Social Carpenter Bees (Xylocopa) Host Distinctive Gut Bacterial Communities and Display Geographical Structure as Revealed by Full-Length PacBio 16S rRNA Sequencing.”
Abstract:
“The gut microbiota of bees affects nutrition, immunity and host fitness, yet the roles of diet, sociality and geographical variation in determining microbiome structure, including variant-level diversity and relatedness, remain poorly understood. Here, we use full-length 16S rRNA amplicon sequencing to compare the crop and gut microbiomes of two incipiently social carpenter bee species, Xylocopa sonorina and Xylocopa tabaniformis, from multiple geographical sites within each species' range. We found that Xylocopa species share a set of core taxa consisting of Bombilactobacillus, Bombiscardovia and Lactobacillus, found in >95% of all individual bees sampled, and Gilliamella and Apibacter were also detected in the gut of both species with high frequency. The crop bacterial community of X. sonorina comprised nearly entirely Apilactobacillus with occasionally abundant nectar bacteria. Despite sharing core taxa, Xylocopa species' microbiomes were distinguished by multiple bacterial lineages, including species-specific variants of core taxa. The use of long-read amplicons revealed otherwise cryptic species and population-level differentiation in core microbiome members, which was masked when a shorter fragment of the 16S rRNA (V4) was considered. Of the core taxa, Bombilactobacillus and Bombiscardovia exhibited differentiation in amplicon sequence variants among bee populations, but this was lacking in Lactobacillus, suggesting that some bacterial genera in the gut may be structured by different processes. We conclude that these Xylocopa species host a distinctive microbiome, similar to that of previously characterized social corbiculate apids, which suggests that further investigation to understand the evolution of the bee microbiome and its drivers is warranted.”
Handy, who is pursuing her master's degree in public health, says her interest is “in all things microbiome, but I'm particularly interested in women's health and nutrition when it comes to the microbes living in our bodies.”
Sbardellati is interested in understanding how microbial ecology shapes macroscale ecology. In the Vannette lab, he studies bacteriophage (viruses which target bacteria) communities associated with the bumble bee gut and how phages shape gut microbial communities.
The Vannette lab is a team of entomologists, microbiologists, chemical ecologists, and community ecologists trying to understand how microbial communities affect plants and insects, and sometimes other organisms as well.
- Author: Kathy Keatley Garvey
The UC Davis Entomology Games Team edged out Alabama's Auburn University 75 to 70 to win the national championship at the Entomological Society of America's Entomology Games, waged Tuesday night, Nov. 15 at the ESA meeting in Vancouver, British Columbia.
This is the fourth national championship for UC Davis since 2015.
The 2022 UC Davis team was comprised of four doctoral candidates from the Department of Entomology and Nematology: Zachary Griebenow of the Phil Ward lab, captain; Jill Oberski of the Ward laboratory; Erin “Taylor” Kelly of the Geoffrey Attardo lab; and Madison “Madi” Hendrick of the Ian Grettenberger lab.
"The 2022 Entomology Games were once again a highlight of the ESA Annual Meeting for students in entomology from all over the country," said Games Committee chair Meredith Spence Beaulieu, university program manager of Global One Health Academy, North Carolina State University. "My fellow members of the Entomology Games Committee and I congratulate the University of California, Davis, team on their victory, and we commend all the teams and students who participated this year."
The highly anticipated event is a lively question-and-answer, college bowl-style competition on entomological facts played between university-sponsored student teams. The question categories are biological control, behavior and ecology, economic and applied entomology, medical, urban and veterinary entomology, morphology and physiology, biochemistry and toxicology, systematics and evolution integrated pest management and insect/plant interactions.
Among the questions (paraphrased) asked at the Entomology Games:
- The principal blood sugar of insects is a disaccharide called what? Answer: Trehalose.
- All Neuroptera pupate within shelters spun from silk produced by what anatomical structure? Answer: Malpighian tubules
- In 1973 Dr. David Gibby of the Washington State University Extension Center started a program to meet the demand for urban horticulture and gardening advice, which has since expanded to all 50 states and 8 Canadian provinces. What is the name of this program? Answer: The Master Gardeners' Program
In the finals, the Auburn team was comprised of Dan Aurell, Chelsia Smith and Dylan Brown. In the preliminary round, Alan Jeon also competed with them.
The student-quiz event, launched in 1982, was formerly known as the Linnaean Games but the ESA Board of Directors changed the name in July of 2020 to "Entomology Games." Students compete first at an ESA branch level, with each branch sponsoring the winning team and runner-up at the nationals. UC Davis won the championship at the Pacific Branch in April. UC Riverside placed second.
The ESA meeting, themed "Entomology as Inspiration: Insects Through Art, Science and Culture," opened Nov. 13 and continues through Nov. 16. It is a joint meeting with the Entomological Society of Canada and the Entomological Society of British Columbia.
The Entomology Games championship match video will be posted soon on ESA's YouTube channel. The full bank of questions will be loaded on this site. The previous UC Davis championships:
- 2018: The University of California team (UC Davis/UC Berkeley) defeated Texas A&M. Members of the UC Team: captain Ralph Washington Jr., then a UC Berkeley graduate student with a bachelor's degree in entomology from UC Davis; doctoral students Brendon Boudinot, Jill Oberski and Zachary Griebenow of the Phil Ward lab, and doctoral student Emily Bick of the Christian Nansen lab.
- 2016: UC Davis defeated the University of Georgia. Members of the UC Davis team: captain Ralph Washington Jr., Brendon Boudinot and Emily Bick.
- 2015: UC Davis defeated the University of Florida. Members of the UC Davis team: captain Ralph Washington Jr., and members Brendon Boudinot, Jessica Gillung and Ziad Khouri.
Founded in 1889 and located in Annapolis, Md., the 7000-member ESA is the world's largest entomological organization. It is affiliated with educational institutions, health agencies, private industry and government. Members are researchers, teachers, extension service personnel, administrators, marketing representatives, research technicians, consultants, students, pest management professionals, and hobbyists. The 2022 president is evolutionary biologist Jessica Ware, associate curator of invertebrate zoology at the American Museum of Natural History, New York.
Resources:
- Listen to the 2018 Entomology Games (won by the University of California team, comprised of three UC Davis graduate students and one UC Berkeley students who is a UC Davis alumnus), posted on YouTube (audio only, no video)
- Watch the 2016 National Linnaean Games Championship Round (won by UC Davis), posted on YouTube
- Watch the 2015 National Linnaean Games Championship Round (won by UC Davis), posted on YouTube
