Ski with a scientist?

Yes! That’s what occurred when community ecologist (and veteran skier) Rachel Vannette, professor and vice chair of the UC Davis Department of Entomology and Nematology, led a program on “Bees in Winter Survival Mode” in a Ski with a Scientist scientific event hosted by the UC Davis Tahoe Environmental Research Center (TERC).

The attendees–all on skis or snowboards–learned “where bees go in the winter” and “how they survive” during the 90-minute afternoon program, held recently at the Palisades Alpine Meadows,  located at Alpine Meadows, Calif., on the north shore of Lake Tahoe.

The event, with limited enrollment and a waiting list, drew the maximum 15 attendees, plus several TERC educators and mountain hosts from Palisades Tahoe Alpine Ski Resort.

“I talked about the different strategies that bees use to survive the winter, contrasting honey bees, bumble bees and solitary bees,” said Vannette, a TERC research affiliate. She discussed how young digger bees (genus  Anthophora), which overwinter in brood cells in underground burrows or tree holes, are susceptible to mold and fungi. “Fungal pathogens are a main source of mortality for many bee species,” Vannette told the attendees. “In some populations, that’s responsible for over 70 percent of young bee deaths.”

TERC educators also shared information on the geology of the region, reforestation in the Tahoe basin following fire, and how the snowpack season is changing.

The attendees, all in ski attire, including googles, maintained their balance with ski poles planted firmly in the snow, as they gathered around the professor to learn about bumble bees (genus Bombus) and digger bees. They skiied or snowboarded with the professor to multiple locations.

It was Vannette’s first Ski with a Scientist event, which is patterned after “Ski with a Ranger,” a free conservation program hosted by the Heavenly Mountain Resort and the USDA Forest Service.

Skiing was no challenge for the UC Davis professor. “My parents put me on skis before I turned 2.”

Ski with a Scientist takes place every Friday at 1 p.m. through March 28 at the Palisades Tahoe Alpine Ski Resort.   Like Ski with a Ranger, it is free and family friendly.

Vannette, an international leader in microbial ecology, studies interactions between plants, insects and microbes, focusing her research on the chemical and microbial ecology of plant-pollinator interactions and how microbes influence plant defense and resistance against insect pests. A member of the UC Davis Entomology and Nematology Department  since 2015, she  was named a five-year Chancellor’s Fellow in 2023 and a Hellman Fellow in 2018. She holds a doctorate in ecology and evolutionary biology (2011) from the University of Michigan.

The Vannette lab is a team of entomologists, microbiologists, chemical ecologists, and community ecologists trying to understand how microbial communities affect plants and insects.

“Much of the work in my lab focuses on how microorganisms affect plant defense against herbivores and plant attraction to pollinators,” Vannette related. “For example, we are interested in understanding the microbial drivers of soil health, which can influence plant attractiveness to herbivores and the plant’s ability to tolerate or defend against damage by herbivores. In addition, we are working to examine how microorganisms modify flower attractiveness to pollinators. This may have relevance in agricultural systems to improve plant and pollinator health.”

TERC, dedicated to interdisciplinary research and education, seeks to “advance the knowledge of aquatic and terrestrial ecosystems and their interactions within natural and developed Earth systems, and to communicate science-informed solutions worldwide,” according to its website.

Its vision is three-fold:

1. To achieve healthy aquatic and terrestrial ecosystems through scientific understanding and education for the benefit of communities locally and globally.
2. To guide the preservation of a resilient and sustainable ecosystem at Lake Tahoe for generations to come.
3. To provide objective scientific knowledge to the public, school children, private industry, government agencies, and elected officials.

Reporter Eli Ramos of the Tahoe Daily Tribune covered Vannette’s talk on bees and published the piece, titled “Tahoe’s Bees May Use Fermentation and Bacteria to Survive the Winter,” in the March 4th issue.

Community ecologist Rachel Vannette, professor and vice chair, UC Davis Department of Entomology and Nematology, talks bees and skis.

UC Davis distinguished professor Walter Soares Leal soared from a self-described “rough childhood” in his native Brazil to become an internationally recognized scientist celebrated for his research on chemical communication and olfaction in insects.

But in his early childhood, he disliked insects, especially the cockroaches that crawled into his mouth while he was sleeping, and mosquitoes that bit him when he was and wasn’t.

So related Marlin Rice when he chronicled the life of “living legend” Walter Leal in the winter issue of American Entomologist, published by the Entomological Society of America (ESA). Rice, an ESA past president who writes the interview-style Legends column, earlier spotlighted UC Davis entomologists Bruce Hammock, Frank Zalom and Robert E. Page Jr.

The Leal piece, titled “Walter Soares Leal: For the Love of Teaching,” zeroes in on his career accomplishments in Brazil, Japan and the United States, all of which led to his election to the prestigious National Academy of Sciences (NAS) in April of 2024.

Rice interviewed Leal last August in Kyoto at the International Congress of Entomology (ICE 2024), where Leal was chairing the International Congresses of Entomology Council and serving as a volunteer “citizen of the world” ambassador. Leal speaks Portuguese, Japanese and English.

Leal, who joined the UC Davis entomology faculty in 2000, advancing to professor and chair of the department, has served as professor of biochemistry with the Department      of Molecular and Cellular Biology, College of Biological Sciences, since 2013.

Highly honored by his peers, Leal is the only UC Davis faculty member to receive all three of the Academic Senate’s major honors: the 2020 Distinguished Teaching Award for Undergraduate Teaching, the 2022 Distinguished Scholarly Public Service Award, and the 2024 Faculty Distinguished Research Award. His teaching honors also include the 2020 Award for Excellence in Teaching from the Pacific Branch of ESA.

“Walter is the elevator bunny on high, a full-time teacher, a full-time scientist, and he is engaged in multiple projects that make the university community a better place, all at the same time,” commented UC Davis distinguished professor and longtime NAS member Bruce Hammock, in a 2024 UC Davis news story announcing Leal’s election to NAS.

Leal holds a bachelor’s degree in chemical engineering from the Federal University of Pernambuco, Brazil; a master’s degree in agricultural chemistry from Mie University, Japan; and a doctorate in applied biochemistry from the University of Tsukuba, Japan. He completed a postdoctoral fellowship in entomology and chemical ecology at the National Institute of Sericultural and Entomological Science, Japan.

Walter, the youngest of five siblings, related that his father was a baker and pastor, and his mother, a seamstress. “My dad passed when I was twelve,” Leal said. “It was a hard      time in my life. He got sick when I was six and could not do too much…Basically, my mother ran the whole family without any income. But it’s part of my life.”

Neither parent received a high school education, but it was his widowed mother who encouraged him to attend college. “She knew that technical school was not for me…She never went to high school, but she had a vision. Some people have little education, but that doesn’t mean they have no vision.”

In high school, Walter began earning money–and prestige–as a radio-broadcast journalist, covering soccer and other sports. He went on to cover the USA Open Cup in the          United States.

Rice began his Legends piece with: “When Walter Leal was offered a scholarship to leave his native Brazil and begin graduate education in Japan, he was required to become proficient in both Japanese and English–two languages he had never spoken–within six months. He accomplished this challenge, eventually earning both his master’s and Ph.D. degrees. He was then offered a research scientist position with the National Institute of Sericultural and Entomological Science in Tsukuba, Japan, eventually becoming head of the Laboratory of Chemical Prospecting for six years. Leal was the first foreigner to be granted tenure at that institution.”

Leal’s research accomplishments, Rice wrote, include “the identification of the first receptor in mosquitoes for the insect repellent DEET; the first isolation, cloning, and expression of pheromone-degrading enzymes in moths; and the identification and synthesis of complex pheromones from many insect species, including scarab beetles, true bugs, longhorned beetles, citrus leaf miner, navel orangeworm, citrus fruit borer, and many others. Synthetic sex pheromones for some of these pests are now being deployed via mating disruption in projects that have saved producers in Brazil and California hundreds of millions of dollars.”

Among Leal’s scores of accomplishments: he co-chaired the 2016 International Congress of Entomology in Orlando, Fla., a conference that drew 6,682 registrants from 102        countries. He is a Fellow of ESA (2009), Fellow of the American Association for the Advancement of Science (2005), Fellow of the National Academy of Inventors (2019),        and a trustee of the Royal Entomological Society (2024).

As a teacher, Leal seeks to inspire his students. “There was a particular student that came to me at the end of the course, and he says, ‘I was always not motivated in college, but when I saw you so inspired, then I catch up, and I study so hard now.’ That is why I say teaching is the big payoff, better than the paycheck, you know? That you motivate people.”

The Legends’ article includes an image of Leal sharing a laugh with noted chemical ecologist Murray Blum (1929-2015) of the University of Georgia, recipient of an ESA outstanding award in 1978, and the International Society of Chemical Ecology (ISCE) medal in 1989. Blum’s daughter, Deborah Blum, is a Pulitzer-Prize winning journalist (formerly with the Sacramento Bee ), an author, and the director of the Knight Science Journalism Program at the Massachusetts Institute of Technology.

“The image is from the ISCE meeting in Prague,” Leal recalled. “Murray said that he wished to speak as fast as I do, but he had to pronounce all the words, including verbs and prepositions, so he couldn’t. I rebutted that I don’t speak ‘fast.’ He heard that as ‘slowly.’ We all had a good laugh. Murray always had praise for my work and encouraging words when I was at the beginning of my research career.”

And about his dislike of insects in his early childhood? “I didn’t like insects—the cockroaches and mosquitoes,” Leal told Rice. “Once, a cockroach walked on my lips when I was sleeping. What’s with that? A kid who wakes up in the middle of the night with a cockroach in his mouth? Anyway, this was a bad entomology interaction in the beginning.”

That “bad entomology interaction” is now a distant memory.

The UC Davis Entomology Graduate Student Association (EGSA) is gearing up for the holiday season with items to “bug” you.

EGSA members design and sell insect- and arachnid-themed T-shirts and hoodies, as well as stickers. They can be ordered online at https://mkt.com/UCDavisEntGrad/.

Doctoral candidate Lexie Martin of the lab of community ecologist Rachel Vannette, associate professor and vice chair of the UC Davis Department of Entomology and Nematology, serves as EGSA president.

Treasurer Iris Quayle of the arachnology lab of Professor Jason Bond coordinates the EGSA store.

Popular T-shirts include “The Beetles” (featuring four beetles mimicking The Beatles walking across Abbey Road) and “Bugbie” (a take-off of the Barbie movie craze but spotlighting a pink insect, a rosy maple moth,  Dryocampa rubicunda.)

Among the many EGSA t-shirts:

• “Here for a Good Time, Not a Long Time” (female praying mantis eating the head of a suitor)
• “Would You Love Me If I Was a Worm?”
• “Hang in There: (a pseudoscorpion hanging onto a fly leg)
• “Bee Haw” (honey bee as a cowboy)
• “They See Me Rollin'”: (dung beetle)
• “Cicada Amp”
• “Whip Scorpion”

“We now have hoodies in the Bee-Haw, Whip Scorpion, and Worm designs and tank tops in the Cicada Amp and Dung Beetle designs,” Quayle says.

This is one of the T-shirts designed and offered by the UC Davis Graduate Student Association.

Effects Last Months, Reducing Nut Crop Yields

By Amy Quinton | October 2, 2023

Long-term smoke exposure from massive wildfires lowers the energy reserves of orchard trees and can cut their nut production by half, researchers at the University of California, Davis, found. The smoke can affect trees for months after a megafire, depressing their bloom and the next season’s harvest. This finding reveals a new danger from wildfires that could affect plant health in both agricultural and natural environments.

Nature Plants published the study today (Oct. 2).

“A lot of research focuses on the impact of smoke on humans but there is less study on the effects of smoke on plant health,” said lead author Jessica Orozco, a postdoctoral researcher with the UC Davis Department of Plant Sciences. “Our study suggests that trees are just as vulnerable as humans.”

Wildfire smoke blocks sunlight

Scientists studied almond, pistachio and walnut trees at 467 orchard sites in California’s Central Valley from 2018 to 2022. In 2020, megafires scorched more than 4.2 million acres in California, filling the skies with smoke and ash. At the time, researchers were studying how trees store energy, in the form of carbohydrates, to cope with heat and drought. But Orozco said the team saw an opportunity to study how smoke affects carbohydrate levels.

“Photosynthesis produces carbohydrates, which are critical elements for tree survival,” said Orozco. “Trees need carbohydrates not just to grow but to store energy for when they’re under stress or when photosynthesis isn’t happening.”

Photosynthesis changes under smoke-filled skies. Smoke particles block some sunlight but also reflect light, creating more diffused light. The diffused light can help trees make more carbohydrates. However, Orozco said the study found that while diffused light increased, the smoke was so thick that it likely didn’t compensate for the loss of direct light.

Megafires have lingering effects on tree health

The team found that megafire smoke not only reduced the amount of carbohydrates in trees but also caused losses that continued even after the fires were out. This led to nut yield decreases of 15% to as much as 50% in some orchards. The most active time for wildfires also coincides with the time trees start storing carbohydrates to sustain them through winter dormancy and spring growth.

“We were expecting to see some impact especially in the months when the smoke was really dense, but we weren’t expecting the smoke to have such a lingering effect and result in a significant drop in yield,” Orozco said.

Orozco said researchers still don’t know what components in megafire smoke caused the decrease in tree carbohydrates. During the 2020 megafires, the smoke reduced light and increased both ozone and particulate matter levels, all of which affect photosynthesis. One or a combination of these factors could have led to the drop in tree carbohydrates.

Additional authors on the study are Professor Maciej A. Zwieniecki and postdoctoral researcher Paula Guzmán-Delgado of the UC Davis Department of Plant Sciences.

The Almond Board of California, the California Pistachio Research Board, the California Walnut Board and the California Department of Food and Agriculture supported the research.