MACHIAS, Maine — Beekeepers across Maine are scrambling this summer to rebuild their hive populations after most experienced a weather-related 40 percent loss of bees last fall.

Livermore beekeeper Charlie Merrill said last year’s long, hot summer resulted in bees remaining active longer than usual and beyond when plants were still producing nectar and pollen for them to feed on.

“Everything was dried up,” Merrill said. “They ate all they had stored and then they starved.”

Standish beekeeper Larry Peiffer, vice president of the Maine State Beekeepers Association, said, “It was the worst fall we have ever had.”

This spring and summer, though, the weather has been perfect for raising bees. And as Peiffer, Merrill and Maine’s other 1,000 beekeepers work to rebuild their stock, researcher Frank Drummond of the University of Maine is capturing and testing bumblebees in an effort to rebuild bee supplies nationwide.

Bumblebees are used for the research because they are so large and hairy that they collect far more pollen than their relatives, the honeybees.

The importance of bees to mankind cannot be underestimated, scientists say. Honeybees help pollinate about one-third of all foods, including fruits and vegetables.

Scientists like Drummond are spending time in fields and inside laboratories in an effort to discover how pesticides, weather and even cellphone signals are affecting bees.

Caramel-colored tents dot the blueberry fields at Blueberry Hill, the University of Maine Agriculture Experiment Station in Jonesboro, providing controlled environments for Drummond to conduct his experiments. This summer he is attempting to determine what quantities of pesticides are absorbed by bumblebees, in both their bodies and the pollen they collect.

When blueberry bushes were in bloom, Drummond sprayed a controlled area inside the tents with a pesticide being developed by Bayer AG, the global corporation best known for making aspirin. Bayer is trying to create a pesticide that will not harm the bees and Drummond is working with the U.S. Environmental Protection Agency to develop protocols for pesticide registration.

“We are trying to develop a method that people can use all over the U.S.,” he said.

Drummond captures the bumblebees, quick-freezes them and then carefully vacuums all the pollen from their bodies. The bees are then opened and the honey removed from their honey stomachs. The pollen and honey are then sent out for testing.

The research results should be complete by December, but Drummond said he has already found 44 different pesticides in the bees.

“This suggests that native bees are dealing with the same thing,” he said. Of most concern is that the impact of “this chemical soup” is unknown. Drummond said no one knows how all these chemicals — even though found in low, acceptable levels individually — affect people, water and bees when combined.

“Can the same chemicals make it into the honey? Can a blueberry raker in the fields be susceptible? Can the local water supply become impacted? We don’t know the answer to these questions,” Drummond said.

As unnerving as it might sound, Drummond said, Maine, particularly Down East, is still far ahead of many other farming states in reducing pesticide use, particularly on blueberry bushes.

“The pesticides found on a given field of low-bush blueberries is really low compared to other crops,” he said. He said high-bush blueberries in Michigan and New Jersey have eight to ten times the amount of pesticides used on them.

“Even though Maine’s levels are low, the goal is to get lower. But at the same time, we realize that farmers must manage pests. It’s a tightrope,” Drummond said. “Over the last ten years, Maine’s food producers have become aware that bees are their bread and butter.”

He said pesticide attitudes by large producers have changed rapidly over the last five years. Blueberry growers and processors such as Wyman’s of Maine and Cherryfield Foods are investing hundreds of thousands of dollars into research. Drummond said international markets are also motivating some of that change because other countries often have far lower tolerance levels for pesticides than the U.S.

Drummond said pesticides are just one nemesis to healthy bees. Researchers across the country are trying to determine the cause or causes of colony collapse disorder. Since 2006, seemingly healthy bees have abandoned their hives and never returned. Researchers estimate nearly one-third of all honeybee colonies in the U.S. have disappeared, Drummond said.

Poor nutrition, pesticides, pathogens and even cellphone signals have been blamed, but the true cause remains a mystery. The loss of so many bees has pushed hive rental costs up 35 percent. Blueberry producers in Washington County were paying up to $160 per hive this year. More than 52,000 hives a year are imported to Maine for use in pollinating blueberries and apples.

“Our native bee population is extremely healthy compared to the rest of New England,” Drummond said. “In fact, in Maine, we discovered two species of bumblebees that people had thought were extinct in New England.”

By summer’s end, Drummond will have dissected and sampled more than 600 bees. “This is important. All life is held up by the bee,” he said.