WORTHINGTON — In 2018, researchers with the University of Minnesota Bee Laboratory seeded a native bee mix of pollinators on an 11-acre area of David and Sally Anne Benson’s quarter-section farm in rural Bigelow. The plot joined 115 acres the Bensons previously restored to tallgrass prairie through continual re-enrollments in the Conservation Reserve Program and a permanent easement in Reinvest In Minnesota.
“I saw a notice through the University of Minnesota, and I’ve been interested in the bee issue,” said David Benson, adding that he and Sally Ann, along with their daughter and daughter-in-law took a course in bees led by Marla Spivak, a U of M professor of entomology and instructor in beekeeping.
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The bee lab was looking for southwest Minnesota landowners willing to rent a small amount of acres for bee research. The Bensons signed on, and have watched their pollinator mix — about 40 different forbs (flowers) and half a dozen grass species — flourish on their farm in the years since.
“Ours is a fairly large tract, but it’s adjacent to almost 80 acres of our farm that is in tall grass prairie … and adjacent to 30 acres of cropland,” Benson said.
Bee lab researchers visited their farm four to five times a year since 2018 to conduct research.
The results of their combined research on southwest Minnesota plots was presented Thursday, during a presentation in Worthington that continued with a visit to the Benson farm.
Dan Cariveau, head of the native bee lab at the University of Minnesota, said his Minnesota for Agriculture Pollinators Program involved a controlled experiment looking at what — and how much — pollinator seed goes into the ground.
“We wanted to measure lots of different things,” he said, noting their consideration for plot size, seed mix, where the planting was done on the landscape and economics.
Some plots had a honey bee mix of nine flower varieties, others a native bee mix of 40 forbs, and all were located in southwest Minnesota because Cariveau said he wanted his project to focus on just one area of the state.
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The plots were seeded in 2018, with data collected from 2019 through 2022. The research included documentation of what flowers were blooming when, and what flowers the bees were visiting.
“Not all flowers are created equal in the mind of the bee,” Cariveau said.
The research also included catching bees — 10,000 each in 2019 and 2021, and 6,000 in 2022.
“We had technicians and undergrads put pins through each and label where it was captured and when. Each bee was then identified by a taxonomist.
“There are 508 species of bees in the state that we’ve documented,” Cariveau said. “And now, 509 — a new species was found in the MAPP data.”
Just 150 bee species were collected from the MAPP sites in southwest Minnesota, but of those, four species were new state records, and eight species “most of which are really rare” of bumblebees were also captured, Cariveau said.
While Cariveau’s research project isn’t completely finished, he said the most common flowers visited by bees — according to the data collected — were Maximilian’s sunflower, golden Alexander, stiff goldenrod and Alsike clover.
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Other findings of the pollinator project include:
- Only 20% of bumblebees are social; most are solitary. Bumblebees hibernate underground, start a new nest in the spring, experience colony growth during the summer and the males come out to mate with the new queens in the autumn, then the entire colony dies.
- Clover mixes had higher levels of both predators (anything that’s an herbivore) and pests.
- 0% of flowerheads tested showed the presence of neonicotinoids, while 50% of soil samples had the chemical present. The samples were tested at the U.S. Department of Agriculture Pesticide Lab.
- Clover is really good for some bee species, particularly bumblebees.
- Diversity of seed mix will result in a greater diversity of bee species. “There’s a lot of rare and declining bee species in the state, and I think those will most benefit from more diverse plots,” Cariveau shared.
Cariveau’s MAPP research, including land rentals, seed mixes and researchers, was funded by the National Institute of Food and Agriculture and Minnesota’s Environmental and Natural Resources Trust Fund. The research project ended in 2022 and will not be continued due to the cost of land rent.
Meanwhile, Benson said the plot on his property has resulted in seeing a “tremendous amount of birds and bees,” including bumblebees, and some that are no larger than a pinhead.
“It’s amazing to see the diversity,” he said. “We’ll keep it in native prairie and hope that, maybe if they would like to without any reimbursement, they would study more.
“It’s just been such a wonderful time to be with excited young people that are eager to learn,” he added.
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