The UC Davis Department of Entomology and Nematology's seminar on Wednesday, Feb. 26 will feature six “Faculty Flash Talks” on topics ranging from honey bees to tsetse flies to digger bees to trapdoor spiders to fruit flies.

The seminar, set from 4:10 to 5 p.m. in 122 Briggs Hall, will include Joanna Chiu, Jason Bond, Geoffrey Attardo, Rachel  Vannette, Julia Fine, and Arathi Seshadri.

Associate professor Joanna Chiu, vice chair of the department, will present “results from a project in which we study the mechanisms by which insects sense environmental changes (temperature and photoperiod) to regulate their seasonal physiology. Our lab has identified a protein that can track seasonal changes in temperature and photoperiod to promote winter physiology. Without this protein, insects don't know winter is coming!”

Her laboratory research interests include molecular genetics of animal behavior, Circadian rhythm biology, and posttranslational regulation of proteins.

Capsule information:

Jason Bond, Schlinger Chair in Insect Systematics, is a global expert on spiders. His research interests include systematics, taxonomy, and evolution of terrestrial arthropods with an emphasis on arachnids and myriapods. "We employ molecular, morphological, and ecological approaches to study questions related to evolutionary diversification at multiple hierarchical levels (populations – higher taxa)," he says. (See recent grant.)

Geoffrey Attardo, a medical entomologist/geneticist, focuses his research on insect disease vectors, insect reproduction, vector/parasite interactions, reproductive physiology, male seminal secretions, symbiosis, lactation, nutrition, lipid metabolism, transcriptional regulation, comparative genomics, transcriptomics, proteomics and metabolomics. His research on tsetse flies was recently featured on KQED's Deep Look (see news story on Deep Look). (See news story on landmark research.)

Rachel Vannette, community ecologist and assistant professor who coordinates the department's seminars, says: "All plants are colonized by microorganisms that influence plant traits and interactions with other species, including insects that consume or pollinate plants. I am interested in the basic and applied aspects of microbial contributions to the interaction between plants and insects. I also use these systems to answer basic ecological questions, such as what mechanisms influence plant biodiversity and trait evolution." (See recent research)

Arathi Seshadri and Julia Fine, who recently joined the USDA-ARS lab on Bee Biology Road, UC Davis, aim to improve honey bee survival and beekeeping sustainability in California and nationwide. They collaborate with federal, university, non-governmental and industry partners. (See news story on opening of the facility.) 

Seshadri, a pollination biologist with expertise in honey bee behavior and plant reproductive strategies, is working with beekeepers and farmer stakeholders to develop projects aimed at finding solutions to the ongoing pollination challenges. Also trained as an evolutionary biologist, she has applied principles of plant-pollinator mutualism, specifically the impact of phytochemicals in pollen and nectar on honey bee health and colony performance. Her contributions to pollinator conservation include enhancing the sustainability of all pollinators, including native bees on farms and urban areas. She also has expertise in agroecosystem-based approaches and citizen science programs to promote pollinator diversity and abundance.

Fine, an entomologist with expertise in insect toxicology, honey bee physiology, reproduction and development, focuses her research on identifying how stressors impact honey bee behavior, health and fecundity. She uses both established and novel laboratory techniques. Her previous projects involved investigating how agrochemical and viral stressors interact to affect the development and survival of honey bee brood and how nutritional stress affects honey bee queen fecundity. In engaging with beekeepers and growers, Fine is researching how realistic biotic and abiotic stressors affect honey bee reproduction, longevity and pollination services, and she is identifying techniques and strategies to overcome these effects.

The seminar is open to all interested persons. For more information, contact Vannette at rlvannette@ucdavis.edu.

Evolutionary biologist and entomologist Corrie Moreau specializes in ants. (Photo by Roberto Keller-Perez)

They draw the attention of curious kids--some poke them with a stick, stomp on them, or race their bicycles over them. Some peer into the holes, trying to see the insects inside.

When Corrie Moreau was a young girl, she no doubt was one of the kids who peered inside.

She's now a noted evolutionary biologist and entomologist  (specialty myrmecology, the study of ants).

Moreau will present a UC Davis Department of Entomology and Nematology seminar,  "Piecing Together the Puzzle to Understand the Evolution of the Ants: Macroevolution to Microbiomes"  from 4:10 to 5 p.m., Wednesday, Jan. 15 in 122 Briggs Hall, Kleiber Hall Drive.

Moreau is the Moser Professor of Biosystematics and Biodiversity, Departments of Entomology and Ecology and Evolutionary Biology at Cornell, University, Ithaca, N.Y. and the curator of the Cornell University Insect Collection.

"Moreau and colleagues were the first to establish the origin of the ants at 140 million years ago using molecular sequence data (40 million years older than previous estimates), and that the diversification of the ants coincided with the rise of the flowering plants (angiosperms)," according to an entry in Wikipedia. "In addition, Moreau and Charles D. Bell showed that the tropics have been and continue to be important for the evolution of the ants. Moreau and colleagues have demonstrated the importance of gut-associated bacteria in the evolutionary and ecological success of ants through targeted bacterial and microbiome sequencing, including showing that bacterial gut symbionts are tightly linked with the evolution of herbivory in ants."

Her honors are many and widespread. In 2018 she was elected a fellow of the American Association for the Advancement of Science. Also in 2018, she was featured in National Geographic as a "Woman of Impact." In 2015, she was included in "15 Brilliant Women Bridging the Gender Gap in Science."

A native of New Orleans, Moreau holds degrees (bachelor and master's)  from San Francisco State University and a doctorate in biology from Harvard University (2007). At Harvard, she studied with major professors E. O. Wilson and Naomi Pierce. Wilson featured her in his 2013 book, Letter to a Young Scientist.

"There was no bravado in Corrie, no trace of overweening pride, no pretension,"  Wilson wrote. "The story of Corrie Saux Moreau's ambitious undertaking is one I feel especially important to bring to you. It suggests that courage in science born of self-confidence (without arrogance!), a willingness to take a risk but with resilience, a lack of fear of authority, a set of mind that prepares you to take a new direction if thwarted, are of great value – win or lose."

Moreau will cover a lot of ground in her UC Davis talk. "To fully understand the macro evolutionary factors that have promoted the diversification and persistence of biological diversity, varied tools and disciplines must be integrated," she says in her abstract. "By combining data from several fields, including molecular phylogenetics/phylogenomics, comparative genomics, biogeographic range reconstruction, stable isotyope analyses, and microbial community sequencing to study the evolutionary history of the insects, we are beginning to understand the drivers of speciation and the interconnectedness of life. Comparative phylogenetic analysis reveals the interconnectedness of ants and plants and that ants diversified after the rise of the angiosperms. Comparative genomics has permitted the exploration of the role of symbiosis on genome evolution and behavioral gene evolution demonstrating that Red Queen dynamics are at play in obligate mutualisms..."

"Microbial contributions to ants are not limited to diet enrichment," she says, "and we find evidence for their role in cuticle formation. These multiple lines of evidence are illuminating a more complete picture of ant evolution and providing novel insights into the role that symbiosis plays to promote biological diversity."

UC Davis graduate student Marshall McMunn of the Phil Ward lab is the host. Community ecologist Rachel Vannette, assistant professor (rlvannette@ucdavis.edu), coordinates the weekly seminars. See seminar schedule.

Steve Nadler, professor and chair of the UC Davis Department of Entomology and Nematology, and professor Sharon Lawler with their empty containers. (Photo by Kathy Keatley Garvey)

Sounds like a great story, right?

Make that great cookies.

They weren't there to present their research on nematodes, aquatic insects or pollinators. They were there to enjoy some camaraderie at the UC Davis Department of Entomology and Nematology's holiday party, and...drum roll...they won the top prizes in the cookie contest.

• Best chocolate cookie: Aquatic entomologist Sharon Lawler, professor, UC Davis Department of Entomology and Nematology, for her recipe, "Dirty Drunk Snowballs"
• Best non-chocolate cookie: Nematologist Steve Nadler, professor and chair, UC Davis Department of Entomology and Nematology, for his Internet-modified recipe, "Cranberry Orange Cookies"
• Best decorated cookie: Community ecologist Rachel Vannette, assistant professor, UC Davis Department of Entomology and Nematology, for her "Stamped Citrus Shortbread" recipe from the New York Times

William Tuck, academic personnel specialist in the Phoenix Cluster, which serves the Department of Entomology and Nematology and the Department of Plant Pathology, coordinated the event and awarded $25 Amazon gift cards to the winners.

The proof of the pudding? Empty containers.

Want to make the recipes? They shared!

Dirty Drunk Snowballs
By Sharon Lawler

Ingredients:

1 box Trader Joe's Mini Dark Chocolate Mint Stars 
1/4 cup dark rum (white rum or bourbon will also work)
1/4 cup confectioner's sugar

Method:

Grind up the cookies in a food processor or blender until pretty fine but with some texture left. Stir enough dark rum so that the crumbs hold together well, but stop before it gets soggy. Let the mix sit for 15 minutes or so. Sift the confectioner's sugar into a bowl. Roll the mix into small balls, and then roll them in the confectioner's sugar.

Cranberry Orange Cookies 
By Steve Nadler
Internet-modified recipe

Ingredients:

1 cup unsalted butter, softened
1 cup granular white sugar
1/2 cup brown sugar (packed)
1 egg
1-1/2 teaspoons grated orange zest
5 tablespoons orange juice
2-1/2 cups all-purpose flour
1/2 teaspoon baking soda
1/2 teaspoon salt
2 cups orange-flavored dried cranberries (Trader Joe's)
1-1/2 cups confectioner's sugar

 Method:

1. Use a food processor to chop the dried cranberries
2. Preheat oven to 375 degrees F.
3. In a large bowl, blend together the butter, white granular sugar, and brown sugar until smooth.
4. Whisk the egg in a small bowl, then mix into the large bowl.
5. Add 1 teaspoon of orange zest and 2 tablespoons of orange juice into the large bowl and mix.
6. In a separate bowl, mix together the flour, baking soda, and salt.
7. Stir the flour mixture from step 6 into the large bowl.
8. Mix in the chopped cranberries, working to distribute them evenly.
9. Drop cookie dough mixture (rounded tablespoon) on ungreased cookie sheets. Space them 2 inches apart.
10. Bake for about 12 minutes in the preheated oven (375 F). The edges will begin to turn golden brown when ready.
11. Remove cookies from sheets and cool on wire racks.
12. In bowl, mix 1/2 teaspoon orange zest, 3 tablespoons of orange juice, and the confectioner's sugar until smooth. Brush on the tops of the cooled cookies. Let dry.

Rachel Vannette, community ecologist and assistant professor (Photo by Kathy Keatley Garvey)

For the Cookies

• 2 cups/255 grams all-purpose flour, plus more as needed
• ⅓ cup/45 grams cornstarch
• ½ teaspoon kosher salt
• 1 cup/225 grams unsalted butter (2 sticks), softened
• ½ cup/100 grams granulated sugar
• 1 orange (preferably tangelo)
• 1 lemon
• ½ teaspoon vanilla extract
• ½ teaspoon lemon extract
• ¾ cup/75 grams sifted confectioners' sugar
• 1 tablespoon melted butter
• 1 tablespoon fresh orange juice, plus more as needed

For the Glaze:

• 3/4 cup/75 grams sifted confectioners' sugar
• 1 tablespoon melted butter
• 1 tablespoon fresh orange juice, plus more as needed

Preparation

1. Prepare the cookies: Add flour, cornstarch and salt to a medium bowl, and whisk to combine. Set aside.
2. Combine butter and granulated sugar in the bowl of a stand mixer fitted with the paddle attachment. Zest half the orange and half the lemon directly into the bowl. Reserve the lemon and orange for the glaze. Cream the butter mixture on medium-high speed until light and fluffy, 2 to 3 minutes. Add vanilla and lemon extracts and beat on medium speed until well combined, scraping the bowl a few times as needed.
3. Add the flour mixture to the butter mixture and beat on low speed just until combined. Scrape the bowl and fold a few times to make sure everything is well combined. Wrap dough in plastic wrap, flatten into a disk, and chill until firm, at least 1 hour, and up to 3 days.
4. Heat oven to 350 degrees. Cut dough in half and let one piece warm up for 30 minutes if it has chilled longer than an hour. Return the other half to the refrigerator. Portion the dough into pieces roughly the size of walnuts (a scant 2 tablespoons/about 35 grams), then roll each piece into a ball between your hands. One at a time, dip a ball of dough into flour and set on work surface. If dough balls soften too much, return them to the refrigerator to firm up for a few minutes. You want it cool, but malleable. Dip cookie stamp in flour, and press down on the ball of dough until it is about 1/4-inch thick. Remove stamp. (If dough sticks to stamp, carefully peel it off. Don't worry about excess flour as you will brush it off after chilling.) Trim the edges using a 2-inch cookie cutter, and transfer dough rounds to 2 parchment- or silicone mat-lined baking sheets, arranging them about 1 1/2 inches apart. Repeat with remaining dough.
5. Once you have stamped out all the cookies, knead together the scraps to make a few more. Chill in the freezer until very firm, about 10 minutes. When cold, brush off any excess flour with a dry pastry brush.
6. Bake until cookies just start to turn golden underneath, 12 to 14 minutes, switching the baking sheets from front to back and top to bottom halfway through baking time.
7. Make the glaze while the cookies bake: Zest the remaining skin from the reserved lemon and orange into a small bowl. Add the confectioners' sugar, butter and orange juice and whisk until smooth. If glaze is too thick, add more orange juice. If it is too thin, add more confectioners' sugar. It should be the consistency of thin custard.
8. Let the cookies cool for a few minutes on the baking sheets, and transfer to a wire rack set over a parchment- or wax paper-lined baking sheet. Pick up a cookie, and using the back of a small spoon, spread a generous teaspoon of glaze on a cookie, letting any excess drip onto the next cookie. Repeat until all the cookies are glazed. Cool completely. Cookies will keep in an airtight container at room temperature for up to 1 week.

Community ecologist Rachel Vannette. (Photo by Kathy Keatley Garvey)

Vannette, an assistant professor, seeks to unlock the mysteries of flower microbes: how do plants protect against them, and can bees benefit from them?

“I am interested in understanding and predicting how microbial communities influence interactions between plants and insects,” she says. Her lab uses "tools and concepts from microbial ecology, chemical ecology, and community ecology to better understand the ecology and evolution of interactions among plants, microbes and insects."

Vannette recently received a five-year Faculty Early Career Development (CAREER) Program award, titled “Nectar Chemistry and Ecological and Evolutionary Tradeoffs in Plant Adaptation to Microbes and Pollinators. NSF grants CAREER awards to early career faculty “who have the potential to serve as academic role models in research and education and to lead advances in the mission of their department or organization,” a NSF spokesman said.

The other grant is a three-year grant, “The Brood Cell Microbiome of Solitary Bees: Origin, Diversity, Function, and Vulnerability.” Vannette serves as a co-principal investigator with professor Bryan Danforth, Cornell University; research entomologist Shawn Steffan of the USDA's Agricultural and Research Service, University of Wisconsin; and assistant professor Quinn McFrederick, UC Riverside.

Of the CAREER grant, Vannette explained in her abstract:
“Plants interact with a variety of organisms. The flowers and the nectar plants produce are adapted to attract beneficial organisms like bees or hummingbirds. However, microbes like bacteria and fungi also inhabit flowers and can reduce plant reproduction. Plant traits can reduce microbial growth in nectar, but this may also reduce pollinator visitation. This project will investigate if plants that are pollinated by different organisms (e.g. birds vs bees vs flies) differ in their ability to reduce microbial growth and if nectar chemistry is associated with microbial growth. This project will examine if nectar traits can be used to breed plants to be more resistant to harmful microbes without reducing attraction to pollinators. Resistance to microbes is beneficial in agricultural contexts where floral pathogens can limit food production but crops still rely on pollination. 

“This research will link variation in plant phenotype to microbial abundance and species composition, and microbial effects on plant-animal interactions,” she noted. “This project will use a tractable system: the microorganisms growing in floral nectar, which can influence floral visitors and plant reproduction. The underlying hypothesis tested is that plant traits can facilitate or reduce microbial growth, and the community context (e.g., presence of pollinators) influence ecological and evolutionary outcomes.”

Vannette will perform the research activities using 1) a community of co-flowering plant species and 2) genotypes within California fuchsia (Epilobium canum). “Experiments will characterize variation in microbial growth, nectar chemistry, and microbial effects on plant reproduction and floral visitor behavior and the interactions of these factors,” she related in her abstract. “ Experiments and analysis will reveal how variation in nectar chemistry is associated with microbial growth and species composition in nectar, and subsequent effects on plant-pollinator interactions including plant reproduction. Experiments across Epilobium genotypes will elucidate how microbes affect microevolution of floral traits in a community context.”

The project “will engage students from a large undergraduate class to participate in practitioner-motivated research projects,” she wrote. “Students from the Animal Biology major, including in the class ABI 50A will participate in outreach on pollinator-friendly plantings for horticultural and landscaping. The project will support students recruited from diverse and underrepresented backgrounds to participate in independent projects related to project objectives, including hosting students through the Evolution and Ecology Graduate Admissions Pathway (EEGAP), a UC-HCBU program." The program connects faculty and undergraduate scholars at both UC (University of California) and HBCU (Historically Black Colleges and Universities) campuses

Collaborative Grant
The collaborative grant will enable the researchers to do cutting-edge research as they investigate the diverse community of bacteria and yeasts in the pollen and nectar diet of bees.

“Bees are the single most important pollinators of flowering plants worldwide,” the co-investigators wrote in their abstract. “Over 85% of the 325,000 flowering plant species on earth depend on animals for pollination, and the vast majority of pollination is carried out by bees. Annually, bees are estimated to contribute $15 billion to US crop production and $170 billion to global crop production. High-value bee-pollinated crops include apple and other early spring tree fruits, strawberries, blueberries, cherries, cranberries, squash and pumpkins, tomatoes, almonds, and many others. The economic viability of US agricultural production is dependent on stable and healthy wild and domesticated bee populations.”

“However, bee populations are threatened by a variety of factors, including habitat loss, pathogen spillover, invasive plants and animals, and pesticide use, which can disrupt the normal microbial symbionts essential for bee larval development (the ‘brood cell' microbiome),” they pointed out in their abstract. “This research project focuses on understanding what role microbes play in the larval nutrition in a wide variety of bee species. Previous research has documented a diverse community of bacteria and yeasts in the pollen and nectar diet of bees. As larvae consume these pollen/nectar provisions they are ingesting microbes, and our preliminary results indicate that these microbes form an essential component of the larval diet. This project has the potential to significantly modify how we view the 120 million-year-old partnership between bees and flowering plants, and will provide essential information for developing long-term bee conservation efforts. Project outreach efforts include educational activities on solitary bees for K-12 students and interactive demonstrations of bee-microbe-flower interactions for broad audiences.

The co-principal investigators said that the project will use cutting-edge methods to (1) document the microbial diversity in flowers and pollen provisions, (2) determine the nutritional role of microbes in larval development and health, and (3) understand how alterations in microbial community impact larval development.

To document microbial diversity in both host-plant flowers and pollen provisions, the research team will use amplicon sequencing and microbial metagenomics. These methods will document the microbial species present in pollen provisions as well as the metabolic activities these microbes perform during pollen maturation. Screening the pollen and nectar of host-plant species will provide key insights into the source of the brood cell microbiome. To determine the nutritional role of the microbial community the research team will use two methods from trophic ecology: compound specific isotope analysis and neutral lipid fatty acid analysis. These analyses will permit the research team to track the origin (floral or microbial) of amino acids and fatty acids in the larval diet of 15 focal bee species.

Finally, through manipulative laboratory experiments, the research team will determine how modifications of the microbial communities impact larval development. They hope by combining the results of these studies, the researchers will provide a comprehensive understanding of how bees and flowering plants interact via their shared microbial partners. 

The collaborative project is funded jointly by the Systematics and Biodiversity Sciences Cluster (Division of Environmental Biology) and the Symbiosis, Defense and Self-recognition Program (Division of Integrative Organismal Systems).

Vannette, a Hellman Fellow, joined the UC Davis Department of Entomology and Nematology in 2015 after serving as a postdoctoral fellow at Stanford University's biology department. As a Gordon and Betty Moore Foundation Postdoctoral Fellow from 2011 to 2015, she examined the role of nectar chemistry in community assembly of yeasts and plant-pollinator interactions.

A native of Hudsonville, Mich., Vannette received 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.”