OLYMPIC VALLEY, Calif. – At the Tahoe Environmental Research Center’s (TERC) “Ski with a Scientist” event, Dr. Rachel Vannette spoke to the Tribune on her lab’s exciting research on how bees survive harsh winters, using preservation techniques that can resemble how humans ferment food.

Vannette is an associate professor and vice chair of the University of California, Davis’ entomology and nematology department. Her work primarily focuses on plant and insect interactions—more specifically, how microbes from those plants can impact pollinators like butterflies and bees. These insects are key to making native landscapes and cultivated crops thrive.

But when winter comes, how do bees survive? On the whole, insects can’t tolerate freezing weather, so adult bees have a variety of strategies to survive. Some bumblebees create hibernacula: refuges from cold temperatures, often in plant material like pine duff, that keep them just above lethal temperatures. Others drink up sugar alcohols before the season starts, which essentially act as antifreeze in their systems, keeping their body functioning.

However, some bees spend the winter as larvae, laid on top of food stores that they eat during the season, until they emerge as adults in spring. Here in the Tahoe area, chimney bees, leafcutter bees, and some bees in the genus Anthophora face the snow as newly hatched young.

These young are kept in brood cells, which are formed in small nooks and crannies: underground burrows or in holes in trees. At their size, mold and fungi can be a killer. “Fungal pathogens are a main source of mortality for bees. In some populations, that’s responsible for over 70% of young bee deaths,” said Vannette. It’s an image straight out of a horror movie: fungi feeds on the stores meant for bees, overtaking the tight space with spores.

To avoid this, bees have developed a strategy to preserve this food. One method is through fermentation. “It’s kind of like making kimchi or kombucha—they ferment their provision with the lactobacillus bacteria, which acidifies the food and makes it more stable,” said Vannette.

Lactobacillus can be found in fermented food like kimchi, sauerkraut, and yogurt, but bees are likely deriving it from the flowers that they consume. Vannette’s lab is currently researching what plants can create or host the bacteria.

Even more unusual is that some bees have created a new, unique strain of Streptomyces that acts as an antifungal for their brood cells. Streptomyces is the largest source of antibiotics that humans use—this new strain could help researchers develop new drugs and medication, especially as antibiotic resistance is on the rise. Now, Vannette’s lab is studying where the strain originated and how it was passed down.

“I’ve always been interested in the natural world and studying it, pursuing scientific knowledge. And this application to other fields, such as food preservation and medical use really excites me,” said Vannette. “By looking to the natural world, especially to insects that are so threatened by fungal pathogens, we can find new applications of chemistry and biology that can expand our understanding.”

This year, TERC’s Ski with a Scientist runs every Friday until March 28, starting at 1 p.m. at Palisades Tahoe Alpine Ski Resort. The tours are free, open to the public, and last for roughly two hours.

Eli Ramos is a reporter for Tahoe Daily Tribune. They are part of the 2024–26 cohort of California Local News Fellows through UC Berkeley.