Insect pollinators provide essential pollination services to growers of U.S. fruits, vegetables, nuts and seeds. Honey bees are the premier managed pollinators of most crops, accounting for $11.7 billion of the $15 billion of agricultural output attributable to insect-mediated pollination (Calderone, 2012). To satisfy the demand for pollination, about 2 million of the 2.6 million managed honey bee colonies in the U.S. are rented and placed in nearly 100 different crops each year.

Efficient delivery of managed pollination services is threatened by the poor state of U.S. honey bees. Since the mid-2000s beekeepers have consistently experienced annual colony losses of 31-46% (vanEngelsdorp et al., 2007-2012; Spleen et al., 2013; Steinhauer et al., 2014; Lee et al., 2015; Seitz et al., 2016; Kulhanek et al., 2017). While beekeepers can often make up for these losses through intensive management of surviving colonies, current management tools are costly and may not be sufficient to indefinitely sustain the honey bee colony numbers  or colony strength needed for pollination. Other managed pollinators such as the alfalfa leafcutting bees and unmanaged wild pollinators also contribute substantially to agricultural pollination in many crops (Garibaldi et al., 2013). Unfortunately, the long-term health and abundance wild pollinators is also under threat.

The causes of honey bee and pollinator declines in the U.S. are varied, complex, and defy a simplistic explanation, as multiple stressors are almost certainly involved. Significant progress in identifying contributing factors to bee declines has been made by many current members of the NC1173 multi-state project through collaborative programs. Previous collaborations include a $4.1M, 4-year USDA CAP project to study the causes of Colony Collapse Disorder (CCD) and other factors affecting bee populations; and a $5M CAP project through the USDA Global Food Security program to establish the Bee Informed Partnership, an extension-only effort to collect and disseminate information about the health of the managed honey bee population.

Many of the findings from these large collaborative and multistate projects were presented and synthesized at the Stakeholders Conference on Honey Bee Health convened by the USDA and the U.S. Environmental Protection Agency in October 2012. The summary of this conference provided a roadmap for future research and priority areas listed below continue to be relevant and are being addressed by members of the NC1173 multi-state project. 

Biotic Factors

Parasites, Pests and Pathogens. The parasitic mite, Varroa destructor, and the viruses it helps to transmit, remain a top concern for beekeepers. The gut microsporidian pathogen Nosema spp. has been implicated in honey bee colony losses and in managed and wild bumble bees. A range of other bacteria, fungi, and pests negatively affect bee health, particularly when colonies are at a weakened or immunosuppressed state. Improved understanding of the interaction between bees and their parasites, pests, and pathogens will yield better management and control strategies.

Breeding and genetic diversity. Breeding resistance to parasites and pathogens in bees is a long-term sustainable approach to mitigate colony losses, and stock improvement is an ongoing effort supported by industry, USDA and University programs.  Recent inclusion of the honey bee in the USDA National Animal Germplasm Program has resulted in cryogenic conservation of honey bee germplasm from original source populations in the Old World and commercial strains within the US.   Additionally, research on and applied efforts to maintain the genetic diversity of honey bee populations and improve mating success of queen honey bees under commercial production play important roles in pollination security.

Abiotic Factors

Forage availability and nutritional stress. The nutritional requirements of honey bees and other pollinators are not met by the floral landscape in some parts of the U.S. Research is needed to examine land- and farm-management practices associated with high levels of colony and pollinator success.

Pesticides and environmental contaminants. Insecticides designed to kill insects may also harm pollinating insects. Other pesticides and environmental contaminants also have the potential to adversely affect individual bees and colony development. Additionally, drugs used to control pathogens may have unintended side effects. Therefore, more work is needed to determine the effects of pesticide exposure on colony health, honey production and delivery of pollination services. Development and delivery of beekeeper practice recommendations that incorporate integrated pest management principles may reduce unintended side-effects and further stress on colonies. 

The consensus is that these multiple biotic and abiotic stressors, working in concert, are responsible for the honey bee and pollinator health issues currently manifested in the U.S. While advances are being made in all these key research areas, a real solution to honey bee and pollinator health will come through a combined broad approach, a task that is too big and complex to be managed by individual researchers.  As such, the collaborative work fostered by the NC1173 multi-state research project is critical to building a holistic understanding of honey bee and pollinator health. There is a clear need defined by stakeholders to mitigate the continued decline of honey bees and other insect pollinators. The consequences of inaction are a further destabilized food-production system, decreased yields and quality of fruits and vegetables, and potentially higher produce prices. The technical feasibility of the proposed working group is greatly facilitated by the existing practice of adjoining the American Bee Research Conference (ABRC), the annual professional meeting of the American Association of Professional Apiculturists (AAPA), with one of the three national apiculture associations in the U.S. in alternating years: the American Beekeeping Federation (ABF), the American Honey Producers of America (AHPA), and the Apiary Inspectors of America (AIA). This tradition of interfacing with clientele and other professional groups involved in beekeeping is ideally suited to collaboration, interaction, and discussion of current and emerging issues regarding honey bee health. Thus, there is a clear advantage of fostering this multi-state effort, because there is great similarity in the threats to American beekeeping across all regions. The impacts from these ongoing interactions have been significant (see above), and therefore, a continuation of the NC1173 working group will advance these successes going forward. We should note that a CRIS search was conducted for the expiring NC1173 project, so there is no overlap with any ongoing projects.