NDSU researchers study how to help bees survive winter conditions

Native and human-managed bees are essential pollinators for various crops in North Dakota. A significant question for researchers is to learn how these bees can best survive the harsh winter months to emerge and reproduce successfully each spring.

Researchers at North Dakota State University have been studying this topic for years. Still, recently they learned that scientists in other states and agencies were also examining this issue but with different methods. This was a perfect opportunity for collaboration.

To support this work, the researchers pursued and received a National Science Foundation (NSF) Track-2 Award. The Insect Cryobiology and Ecophysiology Network was created, with the goal of furthering the understanding of how bees overcome brutal winters to reappear each spring to thrive and reproduce. The ICE Network was to learn how bees overcome difficult winter conditions to emerge and reproduce successfully in the spring, and the research has had an impact.

“So often, we write the story of a project securing funding. Here we are hearing, so many years later, about just some of what the impacts are of a multi-state, federally funded collaboration like this, from students trained to publications to real-world impact on issues important to North Dakota’s economic prosperity, like pollinators,” said NDSU vice president for research and creative activity Colleen Fitzgerald.

NSF Track-2 funding builds collaborative teams of EPSCoR (Established Program to Stimulate Competitive Research) researchers in Science, Technology, Engineering and Mathematics, whose work is consistent with the NSF Strategic Plan.

“Track-2 awards are about building collaborations and research capacity,” said Julia Bowsher, principal investigator on the project and NDSU chair of biological sciences. “Kendra Greenlee and I had been working on how bees cope with winter cold for many years. We realized that researchers in other states were interested in the same problems and were using different approaches, so we thought we could move the field forward by bringing all the researchers together.”

Led by NDSU, the ICE Network consists of researchers from the United States Department of Agriculture – Agricultural Research Service in North Dakota, the University of Wyoming, and New Mexico State University. The project funding expanded research infrastructure, including building insect rearing facilities in NDSU’s Stevens Hall and other lab renovations for the project. It also built further infrastructure and collaboration between the four institutions. The grant has produced 68 peer-reviewed publications.

Bee research focuses at crucial pollinators

The bees used in the study – the blue orchard bee and alfalfa leafcutting bee -- are crucial pollinators of agricultural, rangeland and wild plants across North Dakota. Their survival is critical to pollinating crops and plants in the state of North Dakota.

One of the bees studied, the blue orchard bee, is native to North America, specifically pollinates tree crops, and is known for its cross-pollination abilities. The research produced the fist-ever genome sequence for this species, which is a significant research result.

“The blue orchard bee is an important pollinator of crops like apples,” Bowsher said. “This genome will be an important resource for scientists trying to improve management and agricultural use of this pollinator species.”

The alfalfa leaf-cutting bee also serves a critical role for North Dakota farmers because alfalfa is a primary food source for cattle in the state.

“We had bees nesting in alfalfa fields near campus so we set up nesting boxes nearby and would visit them daily to observe behavior and collect nests,” Bowsher said. “Back in the lab, we would X-ray the nests to see monitor how the bees were developing. At the same time, we also did sequenced the genomes and RNA and analyzed the proteins we found.”

Another research question the team wanted to answer was how mother leaf-cutter bees influence whether their offspring will overwinter. In mid-summer, when days are long, the leaf-cutter mother bee detects the extended daylight and lays eggs that develop into adult bees that do not overwinter. But as day length shortens and fall approaches, she begins to produce offspring with the ability to overwinter before reaching adulthood. The research team is still studying how the mother bee communicates this seasonal signal to her eggs.

“One long-term goal of our research is to improve management of alfalfa leaf cutting bees in the United States, which would help seed producers,” Bowsher said.

Students key contributors of research

The research was a great learning opportunity for NDSU students. “My involvement in the Insect Cryobiology and Ecophysiology (ICE) Network was transformative, not only for my research but also for my professional growth and outreach as a scientist,” said Gagandeep Brar, Ph.D., who worked on the project while pursuing his doctorate in entomology. “Through this collaborative platform, I explored critical aspects of insect cold physiology and nutrition, focusing on agriculturally important pollinators like the alfalfa leafcutter bee and overwintering honey bees.”

“This study was important as its findings could be used to promote many management goals, ranging from increasing alfalfa bee efficiency and yield to promoting conservation efforts in other solitary cavity nesting bee species,” said Joshua Rinehart, a Ph.D. candidate at NDSU who was part of the research group. “This study currently stands as one of the most intensive studies on this particular topic to date. I truly believe that the grant has allowed for great scientific advancement in our field, and that everyone in our society can benefit from our work.”

“Working as an undergraduate on the ICE Network grant showed me how diverse research can be, often encompassing a large network of people and expertise,” said student Madison Floden. “Applying the things I learned in my classes directly into my work enhanced my understanding and retention of the material. Presenting my work at local poster sessions aided my ability to communicate science effectively to peers and mentors.”

“By examining the physiological stressors that influence bee health and reproduction, our work provides valuable insights that can inform farmers, bee producers, and land managers, ultimately supporting pollinator sustainability and helping to ensure strong yields for agricultural producers,” student Jacob Pithan said.

The award supported two NDSU faculty members: NDSU assistant professors of biological sciences Giancarlo Lopez-Martinez, Ph.D., who studies stress tolerance in insects, and Sarah Signor, Ph.D. who is interested in how maternal signals are transmitted to offspring. Both teach undergraduate courses and mentor undergraduates in their research.

The partnerships built as part of the NSF Track-2 award continue and grow into other projects. NDSU researchers are working with University of Wyoming colleagues on a new NSF grant to determine how bees resist cellular aging. The USDA-ARS researchers are collaborating with New Mexico State on saving an endangered butterfly.

“Both projects grew out of the Track-2 collaboration and would not be possible without it,” Bowsher said.

Bowsher’s research is funded by NSF Award Track 2 Award #1826834.