It Takes a Colony

Surveys of U.S. beekeepers have documented a 28 percent decline (on average) in honey bee colonies each winter during the last ten years, and a 28-45 percent decline (on average) during the full year. In Pennsylvania, beekeepers reported a loss of 52 percent of their colonies over the last winter (2016-2017).

This decrease in honey bee colonies threatens our economy and food security. These insects, along with other pollinators, pollinate three-quarters of the world's major food crops, including the fruits, vegetables, and nuts that are the major sources of critical vitamins, minerals, and micronutrients in our diets. In Pennsylvania alone, pollinated crops contribute $260 million per year to our economy.

However, recent postings on several websites and on social media claim that populations of bees are increasing. These articles question the need for continued concern about pollinator health. What is the reason for this disconnect between the opinions presented in these articles and the data generated by beekeepers and scientists? Do we still need to support efforts to improve pollinator health?

The USDA National Agricultural Statistics Service (NASS) tracks the numbers of honey bee colonies each year. In previous years, colonies would be censused only during the summer months. From 2006 to 2014, these surveys showed an increase of 1.13 percent in the number of colonies (2.4 to 2.7 million colonies), leading to articles stating that bee populations are healthy and expanding. How can beekeepers report tremendous annual losses while the overall honey bee population seems to be stable or even growing?

To address these questions, in recent years the USDA NASS has conducted its surveys on a quarterly basis, instead of just during the summer months. These data show that although the number of colonies rises from January to December each year as beekeepers nurture and split their colonies during the growing season, beekeepers regularly lose large percentages of their colonies during the winter months. Thus, while there may a small increase (1.13 percent over nine years) in the total number of U.S. colonies present each summer, honey bees--and their beekeepers--are clearly struggling.

Moreover, declines have been documented in half of the studied U.S. bumble bee species, and monarch butterfly populations show declines of nearly 80 percent. In Pennsylvania, 51 species of butterflies, 111 species of moths, and three species of bumble bees are considered to be threatened.

Scientists around the world are studying the reasons for these declines. Study after study reports strong negative effects of parasites, diseases, pesticides, poor nutrition (due to loss of flowering plants), and poor nesting conditions (due to habitat loss and degradation) on pollinator populations. However, understanding exactly how these factors interact to impact pollinator populations is complex and requires detailed understanding of local pollinator populations and the conditions they experience.

Similarly, there is no "one-size-fits-all" approach for improving pollinator health. Slowing or reversing pollinator declines requires science-based, location-specific, practical recommendations, developed in close collaboration between researchers, stakeholders, and policymakers. An outstanding example of this is the Pennsylvania Pollinator Protection Plan, which contains information, recommendations, and best practices--all based on scientific information--that can help us better preserve and protect pollinators and their important pollination services in our state.

Successfully protecting our pollinators depends on our ability to conduct rigorous, comprehensive research that is supported by and meets the needs of the public; to effectively communicate this information to the stakeholders that need it most; and to train the next generation of beekeepers, farmers, gardeners, urban planners, policymakers, and scientists to understand and tackle these issues. To do all of this, it is vital that we support the efforts of researchers and educators at public, land-grant institutions to continue this critical work.

-- Christina Grozinger, director of the Center for Pollinator Research at Penn State