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Bumblebees are members of one of six bee families that represent 276 bee species identified in Maine. Bumblebees are cavity-nesters, according to Jennifer Lund, state apiarist. They are one of the earliest bee species to emerge in the spring.

DOVER-FOXCROFT, Maine — Maine is known for its forests.

Forests, however, do not provide prime habitat for the majority of the 267 bee species found in the state, said Jennifer Lund, the Maine state apriarist, at a mid-August pollinators event, held at the Law Farm. Owned by the Piscataquis County Soil and Water Conservation District, the 115-acre farm, founded in 1945, was deeded to the conservation district in 2009, by Stephen and Elaine Law.

“Some pollinator populations are increasing or remaining stable while others are declining,” Lund said. “The rusty patched bumblebee is one that used to be found in the state of Maine, but now is thought to have been extirpated. Its populations have been declining across its range, and as a result, it became the first federally listed (endangered) bumblebee species.”

More than 90% of Maine is forested. Forests “are really wonderful for carbon sinking” and provide excellent habitats for a diversity of birds, animals and insects; “but it’s a terrible habitat for bees. Bees like open areas, pastures — they like wildflowers and trees that offer pollen and nectar,” Lund said.

There are six families of bees common in Maine, and members of each family display different foraging, nesting and social behaviors. For farmers, those behavioral differences are significant in relation to what is being grown on the farm.

When it comes to plants, there is not a one-size-fits-all bee species, Lund explained. As a rule of thumb, bees are attracted to “flowers that have bi-lateral symmetry. They also like flowers that are blue, purple, yellow and white — they don’t like red. They like flowers that have (ultraviolet) markers.”

Bees see colors based on ultraviolet light, blue and green, which means that they are unable to see the color red, but can see yellow and orange, which is part of the reddish wavelengths, Lund said. Human sight is based on a combination red, green and blue.

“So even the boring flowers, the ones that we don’t like to look at, the bees really love,” Lund said. “To a bee, a dandelion is white on the outside and bright red in the center. That red is where the nectar is — it’s like a neon sign. That red will shrink over time as the bees suck the nectar from it.”

Maine produces 10% of wild and cultivated blueberries in North America, according to the Maine Cooperative Extension. Wild, low-bush blueberries are gown on about 44,000 acres. High-bush blueberries are not part of the commercial blueberry industry in Maine and are grown in small plantings on various farms in the state.

“Bees like complex flowers that require some sort of effort to get the nectar or pollen resources,” Lund said. “Blueberry flowers are a perfect example. Blueberry flowers face down and have this little, tiny opening. Honey bees, even though they are the state insect, they are not native and did not co-evolve with blueberries, bumblebees did.”

When honey bees enter a blueberry flower, they struggle to get to the source of the pollen, and sometimes they eat a hole in the side of the flower, Lund said. As a result, honey bees “are not very efficient pollinators of blueberries.”

“It takes four to 16 to 20 visits by a honey bee to pollinate a blueberry flower,” Lund said. “Bumblebees — it only takes two to five visits to pollinate a blueberry flower. And, they have a technique called sonic action or buzz pollination, where they will hang upside down and then they will vibrate at a certain frequency and the pollen and nectar just runs out on their bellies and they collect it. You can actually get a tuning fork with the same frequency and hit the flower and the pollen and nectar will come out.”

Bees and other insect pollinators are not necessary for all plants and vegetables. Potatoes represent the largest crop produced in Maine. Potatoes are self-pollinators and do not require insects. Potatoes produce both male and female flowers on the same plant, and pollination can occur from wind and insects, but, potatoes do not require any pollination for underground tubers to form.

Bees, however, are a keystone organism and are essential to fruit, vegetable and flower growers, Lund said. “Not all bee populations in the world are dying off, but we do have several populations that are struggling. A 2013 bee study looked at several different groups of bees, and whether they have been increasing historically over the last 140 years, or decreasing. It’s a kind of mixed bag — some are doing well, some are not; and there’s a variety of reasons why that’s happening.”

In Maine, bee populations are impacted by climate change, habitat loss, pests and diseases, Lund said. A report on climate change, which came out the day before the event, documented that Maine has experienced a 2 degree F temperature rise since researchers in New England first began recording temperatures in the 1895.

“Climate change impacts bees in a couple of different ways,” Lund said. “What’s happened over this time period is that our bees are emerging at different times than the plants they forage. So there’s no food for them.”

Climate change has increased the number of drastic storms, which results in 4-5 inches of rain in a short period of time.

“Some of our bees are ground-nesters, and if it floods, it floods those bees out and they’re not going to survive,” Lund said. “There’s also been some research recently about increased (carbon dioxide) levels in the atmosphere that show that protein content in pollen is a third less in golden rod than it has been historically, so the bees have to forage that much more for the same amount of protein.”