What’s Happening to Honey Bees?
There’s a harmonious relationship between fruit and nut crops and honey bees. The fruit and nut industry depends on these pollinators. Honey bees are responsible for pollinating about $15 billion of crops each year. And, while there are alternative pollinators, no bee can do it as well as Apis mellifera. Especially in almonds, where alternative pollinator activity in early March is almost nonexistent.
“Honey bees cross-pollinate flowers very efficiently because of their ability to transfer pollen in the hive among nestmates,” says Dr. Gloria DeGrandi-Hoffman, Research Leader and Center Director for the USDA-ARS Carl Hayden Bee Research Center in Tucson, AZ. “They don’t have to move from tree to tree. Bees can come out of their hives with compatible pollen on their bodies as long as there’s bloom overlap between compatible cultivars.”
But this relationship isn’t without its ups and downs. Beekeepers generally expect up to 35% annual bee losses from numerous factors. And as researchers and beekeepers start to take a closer look, the more they learn how this decline is the product of interrelated factors.
“The science emerging says it’s a synergistic effect of all these different stressors, whether it be Varroa mites, pesticides, poor nutrition, diseases within the colony, and then just the stressors of the migratory circuit itself,” says Clint Otto, a United States Geological Survey (USGS) Research Ecologist at Northern Prairie Wildlife Research Center in Jamestown, ND.
Bee declines have been mislabeled as colony collapse disorder (CCD) by many outside of the bee industry. However, researchers are quick to point out that CCD has its own specific characteristics. Quite simply, the bees just don’t return to the hives.
“Old bees disappear. They go away and don’t come back,” Dave Hackenberg, a commercial beekeeper in Lewisburg, PA, says. Hackenberg was one of the first beekeepers to discover CCD.
He explains that each bee within a healthy hive has specific duties. Most worker bees live about 36 to 42 days, and generations overlap. Early in a bee’s life stage, the workers bees work in the hive and take care of the young bees. As the bees age, their roles expand to foraging. However, as older bees either die or don’t return, younger bees are forced to pick up the slack.
“The populations dwindle, and you start losing the older bees. All of a sudden, you have young bees trying to go to field to bring back food because something caused everything to go haywire,” he says. “Eventually you’ve got an empty hive or a beehive that still has a queen and a handful of bees, maybe three or four sheets a brood and there’s nobody to take care of them because they’re all gone.”
Little Pest, Major Cause
When you ask Hackenberg about mites in hives, he’ll quickly tell you that Varroa mites and tracheal mites were easy to deal with when they first came on the scene.
“All of a sudden, mites wouldn’t respond to chemical treatments, and we started to see mites build up a lot faster,” he says.
Varroa mites, aptly named Varroa destructor, have been identified as both a source of disease and viruses, and stress and strain on the bees they attach themselves to.
“That parasitic mite causes more colony losses than any other factor because it transmits viruses,” DeGrandi-Hoffman says. “A virus that comes up consistently in colonies that are lost over the winter is deformed wing virus (DWV), transmitted by Varroa .”
Within the last 10 years, Varroa populations in managed apiaries have increased at rapid rates. Diligent beekeepers clean hives of mites in the spring only to see those populations blow up by fall.
“We’ve found that these mites move among colonies on foragers,” says DeGrandi-Hoffman. “The mites attach to foragers, and the foragers drift into other colonies and increase the mite populations to levels you can’t explain with reproduction alone.”
What compounds this issue is that mites are moving among colonies when bees are flying, and warmer temperatures in the fall extend the period when bees are flying and mites are moving into colonies.
“Colonies that are treated in September or October are continually re-infected with Varroa if there’s still flight weather because of warmer temperatures which we know happens frequently these days,” DeGrandi-Hoffman says.
With these higher fall temperatures, DeGrandi-Hoffman says the nutritional intake of honey bee colonies are changing. Pollen at specific times of the season has a specific nutritional function for the hive.
“Someone who has kept bees for 20 or 30 years can see that fall forage plants — such as goldenrod — that used to bloom in the beginning of September now bloom in the middle of August. Instead of the bees collecting pollen and nectar from fall flowers and packing it away for the winter, they’re using it to fuel flight in the fall.”
A colony that should shut down in October may not shut down until November, and by that point the colony may have consumed much of its winter stores.
Summer is a time of respite for honey bee populations in the U.S. In fact, thousands upon thousands of colonies spend their summers in the Northern Great Plains to recharge and recuperate. Beekeepers look for a field with flowers away from agricultural areas. This land is typically grassland, either as idle prairie, rangeland, or cropland enrolled in the Conservation Reserve Program (CRP). Beekeepers often secure land access with a handshake and a promise of honey later on.
What makes the Northern Great Plains so ideal is the climate and weather are conducive to flowers and honey production. In fact, USDA data suggests the number of honey bee hives coming to the Northern Great Plains continues to increase. Meanwhile, a study conducted by the USGS tracks the change in land cover within the Northern Great Plains.
“One published study says over the course of a 10-year period, 2006 to present, we found that there was about a 3 million acre increase in the amount of corn and soybean around honey bee colonies,” Otto says. “More and more beekeepers are coming to the Northern Great Plains, but, during that time commodity prices have increased, and many farmers have opted to take their land out of CRP and put it into corn or soybean production.”
Nearly 402,782 acres have been converted from CRP to row crops between 2006 and 2012, which is about a 53% loss of conservation grassland around commercial apiaries in the Dakotas. Otto say this grassland is what many beekeepers call the “last frontier of the commercial beeping industry.”
“The Northern Great Plains are a part of the country that we believe is critically important for the commercial beekeeping industry, not only to make honey but also to provide a respite for the bees to recuperate from the stressors of being trucked across the country to pollinate a bunch of different ag crops.”
Otto conducted a study with Dr. Matthew Smart, a wildlife biologist with USGS Northern Prairie Wildlife Research, that followed beehives from their summer respite in North Dakota to overwintering in Idaho or Utah, or farther west to California to pollinate the almond crop the following February.
“We found a direct linkage between the habitat where the bees spent the summer, the quality of the habitat, and the size of the population in the almond orchard,” Otto says.
Work Together to Keep Bees Safe
Honey bees, beekeepers, and growers are all a vital part of fruit and nut production in this country. As such, it’s critical that all stakeholders work together.
“It’s important that growers and beekeepers talk about crop protection while the bees are in the orchard,” says DeGrandi-Hoffman.
Hackenberg says that while crop protection products are an obvious necessity for the tree fruit and nut industries, “Everybody needs to be responsible.”
DeGrandi-Hoffman says something as simple as applying products such as fungicides when bees aren’t foraging is a vital step.
“Not applying fungicides at times when bees can collect them in nectar and pollen and bring them back to hive can go a long way to maintaining colony health,” she says.
DeGrandi-Hoffman says growers are very attuned to the important role honey bees play in crop production. Beekeepers understand how important their bees are for income and for agriculture.
“They really need each other,” she says. “The closer relationship they can have with each other, the more successful both groups are going to be.”
Growers Have A Vested Interest
With a new Farm Bill being decided, it’s important to understand how allocations for the Conservation Reserve Program (CRP) are being established, as land-use decisions are often made based on CRP incentives and allocations.
“Habitat here in the Northern Great Plains matters for an almond grower. It matters for a farmer who owns an orchard in the Pacific Northwest,” Clint Otto, a United States Geological Survey Research Ecologist at Northern Prairie Wildlife Research Center in Jamestown, ND, says.
Otto says representatives from the Almond Board of California have visited the Northern Great Plains lately to see how these changes are affecting the honey bee populations. Commodity groups can help use their collective voice and presence with representatives to lobby for the renewed interest in the grasslands that provide honey bees their summer respite.
“It’s important for entities outside the Northern Great Plains, including farmers and producers that require bee pollination services, to take a hard look at what’s going on here and recognize the role of the habitat and the forage quality have on their own livelihood and the ability of those bees to pollinate crops,” he says.
Alternative forage also can be something to consider planting, too. In early spring there aren’t many food sources for the bees within the orchards, and alternative pollen sources are beneficial for pollinators.
“If there’s alternative forage before trees come into bloom, somewhere within a mile radius of the colony, the bees will find it,” says Gloria DeGrandi-Hoffman, Research Leader and Center Director for the USDA-ARS Carl Hayden Bee Research Center in Tucson, AZ. It could help the bees get by that period where there would be a dearth of pollens. Every little bit helps if some forage is available before the fruit or almond trees bloom.”