Farmers in Maine are expected to spend as much as $10 million renting honeybee hives this season to pollinate blueberry fields.

The state expects that 75,000 to 80,000 hives – as many as 4.8 billion bees – will be brought in from across the country to pollinate the fields and boost harvests, said Anthony Jadczak, Maine’s apiarist and bee inspector.

The number of beehives being brought into the state has increased as farmers have tried to increase their fruit yield per acre, Jadczak said.

“Each year we import more. The more bees, the better the blueberry yield. The bees are really good and healthy this year,” he said. “Bees have been rolling into Maine for more than three weeks. The bloom has been starting in areas like Gray and Dresden. The final loads will be coming in this weekend. They’ll stay for three weeks to a month.”

The cost to rent a hive for three to four weeks ranges from about $85 to $120, depending on the grade and quality of the bees, Jadczak said. The rental price has gone up about $5 per hive each year in recent years because of the cost of maintaining healthy hives and replacing dead or weak bees each year, beekeepers said.

“It’s an investment, but having one hive per acre can increase yield by 1,000 pounds,” said Phil Gaven, master beekeeper with The Honey Exchange in Portland.

Commercial farmers generally use at least three hives, and sometimes as many as 10, per acre of blueberries. Maine has about 60,000 acres of commercial blueberry barrens, but only half are in use each year because of the two-year cycle of the plant’s yield.

Beehives are moved into a blueberry field when the plants’ first flowers have emerged to ensure that the bees go for the easiest source of food, rather than foraging farther for other flowers. Although bees can fly several miles, they usually stay within 300 feet of their hive.

Blueberries, like most fruits and vegetables, must be pollinated. That process involves moving tiny pollen cells from one part of a plant to another part, so that the plant can produce seeds. Honeybees, which have hairy bodies that trap pollen and carry it between flowers, are rewarded with the nectar and pollen from the plants. Honeybees need a lot of food to rear their young, so they visit flowers many times.

A hive, or colony, generally has as many as 60,000 worker bees, several hundred drones and one queen. The queen reproduces and generates pheromones that help give each colony its unique identity. The main function of drones is to fertilize the queen, while the workers do all the labor of keeping the hive going, such as cleaning, feeding the brood, caring for the queen, handling incoming nectar, building beeswax combs and aerating and cooling the hive.

Maine farmers rent hives because keeping enough bees in the state year round would be difficult. There isn’t enough food to keep them hearty in the off-season, said Gaven, the master beekeeper.

“In the blueberry barrens, there’s nothing for bees to eat when (the plants) are not in bloom,” Gaven said.

Rented bees can start the year pollinating almond trees in California, then move on to apples, cherries and blueberries in other states in the spring, then go to the Midwest to pollinate clover and alfalfa, beekeepers said.

“The pollination companies are the cowboys and the bees are the cattle. They just herd them around the country,” said Jadczak, Maine’s apiarist.

Commercial hives are usually moved at night, when temperatures are cooler and bees are less active.

Lincoln Sennett, who owns Swan’s Honey in Albion, said large blueberry harvesters in Maine often rent extra hives in case there’s a rainy season.

“If you have great weather, you don’t need as many hives. But you never know whether it’s going to rain every day, and you need a lot of hives for those few sunny days. Basically, they’re willing to spend more as an insurance policy for pollination,” Sennett said.

Sennett rents more than 2,000 hives to small blueberry farms throughout Maine. On smaller farms, the bees forage beyond the fields and get a more mixed diet. In the large, commercial blueberry barrens, the diet is more uniform and more stressful for the bees, Sennett said.

Unlike beekeepers who ship their bees across the country chasing various crops, Sennett keeps his hives local so he can make honey when the blueberry pollination season is over.

“For most commercial beekeepers, honey is more of a byproduct. They rely on pollination to earn a living,” Sennett said. “What we find is that by doing fewer pollinations, we have less dead colonies at the end of the season. Pollination is nutritionally stressful for the bees.”

Gaven agrees. “The commonly accepted belief is that moving is stressful on the bees,” he said. “They only get to eat one thing for a month and then they move and eat just one other thing for the whole month. Their diet is difficult. Plus, the travel and shipping is stressful for them.”

Over the past decade, beekeepers have struggled with colony collapse disorder, which experts describe as a combination of problems rather than one specific disease or blight. Some beekeepers point to a mite or parasite, while others blame chemicals.

When bees pollinate one crop, they may be exposed to certain fungicides. Then they move on to another crop and potentially get exposed to other pesticides or herbicides. The chemicals can interact and harm the health of the bees, beekeepers said.

Jessica Hall can be contacted at 791-6316 or at:

jhall@pressherald.com

Twitter: @JessicaHallPPH