July 7, 2016

Honey Bees: Are They in Decline?

Pollinators—birds, bats and insects that carry pollen from one plant to another—contribute substantially to the economy of the United States. Pollinators are essential for maintaining many types of ecosystems and play a key role in food security and the sustainability of our food supply. Honey bees, in particular, enable the production of at least 90 commercially-grown crops in North America.

Every year, thousands of commercial beekeepers transport hives of bees to pollinate almonds, blueberries, cranberries and other fruits and vegetables. They play a vital role in keeping fruits, nuts and vegetables in our diets. Honey bees’ colony numbers have changed over time. Some talk about long versus short term changes. What is really happening to honey bees?

Late in 2006, mortality rates higher than previously recorded on bee populations were reported and attributed to a phenomenon called Colony Collapse Disorder (CCD). When a bee hive has been impacted by CCD, adult bees disappear and there are no signs of dead bees. There has been speculation about its causes, and currently there is general agreement that a combination of several factors may have contributed to this situation.

According to a 2012 report authored by Randal R. Rucker and Walter N. Thurman, between 2007 and 2011, approximately 30 percent of U.S. bees alive each fall failed to survive to pollinate blossoms in the spring. Widespread die-offs due to disease have long been recorded, but CCD was worse than usual. The authors believe that political and socioeconomic factors have contributed to colony declines in Europe and the United States over the past half-century. Yet the overall global number of colonies has increased 45 percent since 1961. Beekeepers have reported high hive losses, but they typically rebuild their colonies, which explains why the colony numbers continue to increase.

Long-term and short-term statistics can be used out of context if background information is not provided. In a White House statement, it was reported that the number of managed honey bee colonies in the United States has declined steadily over the past 60 years, from six million colonies (beehives) in 1947 to four million in 1970, three million in 1990, and just 2.5 million in 2014. According to USDA statistics, the number of managed honey bee colonies in the United States has increased in the last 10 years—hitting a 20-year high of 2.7 million colonies in 2014.

While both statements highlight historical data, they can be confusing. The fact is that these declines in colony numbers did not begin to level off until the mid-1990s; colony numbers have slightly increased in the last 10 years, but are still lower than levels before 1990.

Beekeepers are currently dealing with more challenges than decades ago; scientists believe that bee losses may be caused by a combination of stressors including:

•    Parasites and diseases: Varroa destructor is the most destructive parasite beekeepers deal with. Introduced in 1987, these mites are becoming resistant to commercial miticides and cause massive annual losses of colonies in the United States.

•    Less genetic diversity: Commercial queen production in southern and western states has produced almost 900,000 queens from about 600 queen mothers. This has resulted in the best quality queen bees, but has also raised concerns about genetic bottlenecks impacting bee health.

•    Lack of forage diversity: Extensive areas of monocultures limit the sources of pollen for bees, which requires many beekeepers to provide less-than-optimal sugar water substitutes.

•    Poor bee nutrition: Bees need nutrients from diverse flora, and pollen from different plants to sustain their colony health.

•    Exposure to pesticides: Some pesticides can be toxic to bees and could reduce the number of flowering plants available to foraging bees.

•    Migratory stresses: Transporting bees can restrict bees diets and expose them to parasites and diseases, some studies report up to 10 percent losses after transportation takes place.

There are still some research gaps, which could bring opportunities to develop strategies that maintain healthy bee populations, increase their survival rate and reduce bee losses. The list above illustrates that several factors can contribute to poor bee health and bee losses. They must be completely understood and addressed to implement a holistic solution based on science and facts. Actions should not be based on emotions and special interests. While we are not in a bee crisis, we are facing a very challenging period. A comprehensive solution is needed to benefit bees, beekeepers, producers and consumers.

In June 2014, President Barack Obama issued a Presidential Memorandum aimed at creating a federal strategy to promote the health of honey bees and other pollinators in response to the challenges related to commercial bee-keeping. One of the major steps to tackle these challenges is the establishment of the Pollinator Health Task Force lead by the U.S. Department of Agriculture and U.S. Environmental Protection Agency. In May 2015, this Task Force released the following overarching goals: 1) restore honey bee colony health to sustainable levels by 2025; 2) increase Eastern monarch butterfly populations to 225 million butterflies by year 2020; and 3) restore or enhance seven million acres of land for pollinators over the next five years.

In addition, a Pollinator Research Action Plan was released and outlines needs and actions to understand pollinator losses and improve pollinator health; this plan made clear the importance of coordination existing federal research efforts and additional resources moving forward.

While producers have a limited role in filling these research gaps, there are a couple of things producers can certainly do to support bee health: 1) provide habitat and/or diverse forage for bees in particular when limited crops or only one crop is grown by a producer, for example extra planting in orchards can help; and 2) continue to follow pesticide label instructions to avoid any negative impacts on all pollinators.

This second point is particularly important considering there has already been an incident of pesticide misuse in an urban area that brought emotional issues into policy. This incident took place in Wilsonville, Oregon, in 2013. It caused the largest mass poisoning of bumble bees ever documented in that region. This happened as the result of applying an insecticide to flowering trees that attracted bees, which was against the instructions of that label and violated the law. Unfortunately, the conversation did not focus on this violation, on training or preventing incidents like this, but in restricting the use of this insecticide. While crop protection tools are needed, they must be used as directed by the label.

Pollinators play a key role in the production of most fruits and vegetables. What happens to honey bees is relevant to the produce sector, beekeepers, consumers and ultimately to our ecosystems.