NC1173: Sustainable Solutions to Problems Affecting Bee Health

(Multistate Research Project)

Status: Approved Pending Start Date

NC1173: Sustainable Solutions to Problems Affecting Bee Health

Duration: 10/01/2024 to 09/30/2029

Administrative Advisor(s):

NIFA Reps:

Non-Technical Summary

Pollinators play a critical role in the reproduction of plants within both natural and agricultural habitats; however, their numbers have been in decline over the past few decades leading to problems with pollination limitation and yield losses in crops. Consequently, research focused on understanding the causes of pollinator decline and developing strategies for mitigation is crucial for the sustainability of our agricultural systems and our national food security. This multi-state project aims to address four key objectives: (1) understand the underlying mechanisms of biotic (pest and pathogens) and abiotic (pesticides, nutrition, and climate change) stressors on wild and managed bee individual, colonies and populations, (2) integrate assessments of genetic diversity and breeding to enhance pollinator resilience to stressors, (3) develop monitoring programs of wild bee species and communities to detect changes over time, and (4) develop and recommend best management practices to promote wild and managed bee health. The stakeholder groups targeted by the objectives of this multi-state project are researchers from academic institutions and government agencies, beekeepers, growers, land managers, conservation agencies and non-profits, and the general public. The specific goals of this project will be achieved through coordinated multi-state efforts aimed at synthesizing information generated from studies conducted by various contributors involved in this project.


Statement of Issues and Justification

Bees provide essential pollination services to natural and agricultural areas in the United States (US) that have been valued at $50 billion per year (Bauer and Sue Wing 2016; Jordan et al. 2021). These pollination services are provided through complementarity between managed and wild bees that handle crop flowers in different ways to maximize pollination and yield (Isaacs et al. 2017; Garibaldi et al. 2013). As part of the pollination systems in the US, about 2 million managed honey bee colonies are rented and used for the pollination of over 100 fruit, vegetable, and fiber crops each year. Thus, both beekeepers and growers of pollination-dependent crops need science-based information that can support healthier managed and wild pollinators. 

Efficient delivery of managed pollination services is therefore critical for the sustainability of agricultural systems but is also threatened by the poor state of US honey bees and the decline in wild bee populations. Since the mid-2000s, beekeepers have consistently experienced annual colony losses of 31-46% (Vanengelsdorp et al. 2007; Lee et al. 2015; Bruckner et al. 2023; Steinhauer et al. 2014; vanEngelsdorp and Hayes 2011; Spleen et al. 2013). 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 needed for crop pollination (Aizen and Harder 2009; Aizen, Garibaldi, and Harder 2022). Other pollinators such as mason bees and unmanaged wild pollinators also contribute substantially to agricultural pollination in many crops (Garibaldi et al. 2013; Koh et al. 2018). Unfortunately, the long-term health and abundance of wild pollinators are also under threat (Koh et al. 2016; Turley et al. 2022) and there is an increasing need to monitor populations of wild pollinators to detect declines and develop management, conservation, and restoration action plans (Woodard, Federman, and James 2020).

The proposed objectives of this multi-state project align with the research priorities identified by the USDA—developed through a collective consensus of needs and priorities obtained from 15 federal agencies—that include the following five subject matter areas for research: (1) status and trends of pollinator populations; (2) forage, habitat, and nutrition; (3) environmental stressors, (4) pest and pathogens; and (5) genetics and breeding (USDA Annual Strategic Pollinator Priorities Report 2022). The role of scientists from Land-Grant universities and their extension system is critical in contributing to these research priorities for the development of science-based information that can directly inform the needs of stakeholders about pollinator abundance and diversity, their health status, and what practices can improve their health and pollination services.      

The causes of honey bee and wild pollinator declines in the US are varied, complex, and defy a simplistic explanation, as multiple stressors are almost certainly involved (LeBuhn and Vargas Luna 2021). Ongoing changes in the predictability of climate and increases in the frequency of extreme weather events are exacerbating several of these stressors (Harvey et al. 2023). Participants of this project include many of the leaders and pioneers of research in the field of pollinator health. Members of the NC1173 multi-state project have made significant progress in identifying a mechanistic understanding of how stressors impact bee health at the individual, colony, and population levels (López-Uribe, Ricigliano, and Simone-Finstrom 2020). While advances are being made in many key research areas related to pollinator health, a real solution to managed and wild pollinator health problems needs a combined broad approach that integrates diverse expertise and members from geographically widespread areas. As such, the collaborative work fostered by the NC1173 multi-state research project is critical to building a holistic understanding of the status and health problems of managed and wild pollinators. In our previous multi-state project, over 240 peer-reviewed papers were published (Table 1), and over 100+ extension publications and events were hosted. These research outputs have significantly advanced our understanding of the underlying stress responses of pollinators to environmental changes while contributing to science-based information needed for the implementation of mitigation approaches to these problems,

Many of the findings from these large collaborative and multistate projects have been presented and synthesized at national and international meetings including the American Bee Research Conference (ABRC), the Entomological Society of America (ESA), and the USDA/EPA State of the Science Conference. These research efforts and presentations at conferences have provided a roadmap for the research priority areas that are listed in the USDA Annual Strategic Pollinator Priorities Report. The newly proposed NC1173 multi-state project will continue to work on this critical research while expanding our scope to include climate change research and wild bee monitoring efforts.

There is a clear need defined by stakeholders to mitigate the continued honey bee losses and the decline of wild bees. The consequences of inaction will further destabilize the food-production system, decrease yields and quality of fruit and vegetable production, and potentially increase produce prices. The technical feasibility of the proposed working group is greatly facilitated by the participation of nationally renowned scientists in this project, as well as the existing practice of adjoining the American Bee Research Conference (ABRC) with the largest national apiculture associations in the US: the American Beekeeping Federation (ABF). These meetings are also attended by members of the two largest honey bee associations: the American Honey Producers of America (AHPA) and the Apiary Inspectors of America (AIA). The International Conference on Pollinator Biology, Health and Policy is also attended by several key stakeholder groups including the Xerces Society for Invertebrate Conservation, representatives from the pesticide industry, and the Food and Agriculture Organization (FAO). This tradition of interfacing with stakeholders and other professional groups involved in managed and wild bee management is ideally suited to collaboration, interaction, and discussion of current and emerging issues regarding pollinator health. Thus, there is a clear advantage of fostering this multi-state effort, because the threats to pollinator health are likely context-dependent, and solutions to these problems require geographically specific research and coordinated efforts to synthesize findings and develop action plans. The impacts from our ongoing interactions with stakeholders and research efforts have been significant (see above), and therefore, a continuation of the NC1173 working group will advance these successes going forward.


Related, Current and Previous Work

A total of 40 NC1173 participants, representing 23 Universities and Agricultural Experiment Stations across the country have used the NC1173 multi-state project to leverage over $40 million in grants from several agencies including USDA-NIFA, National Institutes of Health (NIH), National Science Foundation (NSF), Sustainable Agriculture Research and Education Program (SARE-Regional USDA programs), and other federal and state agencies, commodity groups, beekeeping organizations, and non-profit groups. During the last five-year project, this group contributed over 240 publications related to the three main objectives included in the proposal (Table 1). Currently, this is the only multi-state project directly addressing problems related to pollinator health.


Table 1. Summary of the publications contributed for each proposed objective by NC1173 members during the last five-year project. 







Obj 1a: Biotic (Pests & pathogens)






Obj 1b: Abiotic (Pesticides, nutrition, landscapes)






Obj 2: Genetics, Breeding, Diversity






Obj 3: Management






Other Publications













Below, we list some of the accomplishments and ongoing work from this group. A complete list of the publications generated during the past five years is included in the document “NC1173 attachment”. 

  • Development of new compounds against varroa mites and tests for toxicity to adult honey bees to identify new active ingredients for Varroa and small hive beetle control (Ellis and Jack, UF; Shepard, WSU; Johnson, OSU; Bartlett, UGA). Other developments include new assays investigating how behavioral responses linked to hygienic behavior may impact intra-colony virus transmission and Varroa control (Spivak, UM; Li-Byarlay Central State; and Rangel, TAMU).

  • Studies on the mating biology and chemical ecology of small hive beetles are under development with the goal of better understanding what is driving their spread and establishment in new areas (Williams, Auburn). Assays for new compounds for small hive beetle control (including acetamiprid and fipronil) are under development (Jack and Ellis, UF).

  • The antagonistic interactions between malnutrition and insecticides negatively impact traits linked to fitness and immunity traits such as sperm quality and hypopharyngeal gland activity (Williams, Auburn).

  • Studies demonstrating that larval nutritional stress in bees can have long-lasting effects on honey bee health including their ability to respond to viral infection as adults (Walton, Dolezal, and Toth, ISU). Studies looking at the influence of nutrition (specifically phytosterols, protein and lipid ratios) and their interactions with pathogenic infections (Sagili OSU; Rangel, TAMU; Grozinger, PSU).

  • Models based on national weather data demonstrated that weather instability and extreme weather events are key drivers of honey bee colony losses in the United States (Williams, Auburn; Grozinger, PSU; Rangel, TAMU). 

  • Pesticide residue analyses on pollen from agricultural and urban sites indicate that pesticide exposure is lower in urban than in agricultural areas (Ellis, UF; Huang, MSU; Rangel, TAMU).

  • Pesticide residue analysis from bee-collected pollen from colonies adjacent wildflower planting indicates a benefit of such clean forage resources for colony performance (Williams, UCDavis)

  • Identified harmful and improper pesticide disposal practices that negatively impact the environment and local wildlife, including pollinators, under a One Health framework. These data have resulted in state policy changes regarding the need to prevent pesticide pollution of neonicotinoid insecticides and fungicides in water, soil, air, and plants (Wu-Smart, UNL)

  • Toxicology effects of fungicides and adjuvants on bee health (Danforth, Cornell; Reed, OSU).

  • The efficacy of Oxytetracycline (OTC) for control of European Foulbrood (EFB) disease in honey bee colonies pollinating early-season specialty crops such as blueberries (Sagili, OSU).

  • Data directly linking virus levels in mites and bees supports evidence for the amplification of viruses using mites as vectors (Tarpy, NCSU). 

  • Empirical studies surveying bees have found support for the shared prevalence of several pathogens but no evidence of infections of honey bee pathogens in wild bees (Tarpy, NCSU; López-Uribe, PSU). 

  • Novel developments in the implementation of genomic selection into breeding decisions with international collaborations (Harpur, Purdue) 

  • Studies of genetic diversity of honey bees in the United States have provided new insights into baseline levels of genetic diversity and levels of Africanization of populations in northern states (Harpur, Purdue; López-Uribe, PSU).

  • Efforts to select stocks with high grooming and mite biting behavior from local feral colonies (Li-Byarlay CSU; Harpur, Purdue). 

  • Side-by-side comparisons of honey bee stock performance indicate that locally bred stocks outperform other stocks in northern states (Harpur, Purdue; López-Uribe, PSU).

  • Development of protocols and recommendations on how to integrate Varroa mite management using organic acids and cultural measures (López-Uribe, PSU; Williams, Auburn).

  • New results on the implementation of thyme oil and thymol for immune stimulation of honey bees in response to virus infections (Flenniken, MSU).

  • Successful implementation of the use of the rough surface texture and other management practices to natural colony defenses and homeostasis (Spivak, UMN).

  • Development and implementation of novel technologies for queen presence in honey bee colonies (via sound detections) (Huang, MSU).

  • Studies to determine whether particular tree species are associated with diverse and abundant pollinator communities, and/or whether particular tree and bee species are associated (Winfree, Rutgers).

  • Field data on native plant bee associations demonstrating the relative importance of different plant species for supporting bees and use of mixtures in habitat plantings (Williams, UC Davis)

  • Empirical data from pollination experiments of several crops across the United States indicate that there is pollinator limitation in about 25%-30% of crop fields (Winfree, Rutgers). 

  • Identification of critical periods of forage dearth in highly farmed landscapes (corn and soybean monocultures) which contribute to honey bee colony decline and loss, along with demonstrations that late summer/early fall native perennial vegetation can mitigate these losses (Toth and O’Neal, ISU, Dolezal, Univ. Illinois)

  • Developed a comprehensive network of educators and teaching apiaries (17 apiaries across 8 states) for beekeepers in the Midwest to promote experiential hands-on guidance, particularly as there is a distinct lack of inspection services, support, and expertise in the Great Plains region (Wu-Smart, UNL; O’Neal and Cass, ISU; Milbrath and Heck, MSU). 

  • NC1173 members have provided expertise for legislative efforts in many states (CA, VT, WA, OR, MN, NE, NJ, NY) that incorporate pollinator-friendly practices, habitat, and education training. These include several new bills that restrict pesticide use and reduce pesticide exposure risk as well as bills to develop and or implement statewide Managed Pollinator Protection Plans (MP3s).


  1. To evaluate the role, causative mechanisms, and interaction effects of biotic stressors (i.e., parasitic mites, pests, and pathogens) and abiotic stressors (i.e., climate change, exposure to pesticides, poor habitat, and nutrition, management practices) on the survival, health, and productivity of wild and managed pollinators.
  2. To facilitate the assessments of genetic diversity of wild bees, and the development of honey bee stock selection, maintenance, and production programs that incorporate traits conferring resistance to parasites and pathogens.
  3. To develop monitoring programs that assess bee species richness and abundance in agroecosystems, and how these metrics of bee communities are changing over time.
  4. To develop and recommend "best management practices" for beekeepers, growers, land managers, and homeowners to promote wild and managed bee health.


Objective 1. To evaluate the role, causative mechanisms, and interaction effects of biotic stressors (i.e., parasitic mites, pests, and pathogens) and abiotic stressors (i.e., climate change, exposure to pesticides, poor habitat, and nutrition, management practices) on the survival, health, and productivity of wild and managed pollinators. 

Rationale and significance:  The massive modification of landscapes at global scales has precipitated reductions in the abundance and quality of floral resources to bees. Low nutritional landscapes have made bees more susceptible to other biotic and abiotic stressors such as existing pest and disease complexes, agrochemicals, and climate change. Over the past five years, committee members have focused research efforts to better understand responses to these stressors on multiple levels of biological organization, from effects at the cellular, individual, colony, and population levels. A new direction for our group is to better understand how these biotic and abiotic factors are impacting bee health in concert with other stressors, particularly in the context of climate change. Efforts to address responses to these stressors will be a major emphasis of this new multi-state project.

Methods to assess biotic stressors: The main biotic stressors for managed and wild bees are different in nature, in part because of differences in the epidemiology of diseases in managed and natural conditions. Managed bees are often placed in higher densities compared to bees in wild settings, thus management often facilitates pathogen transmission and can amplify their replication. However, managed and wild bees regularly interact through shared floral resources that can facilitate the spread of pathogens through entire bee communities (Olgun et al. 2020; Figueroa et al. 2020). One important current gap in knowledge about pathogen stressors is a general lack of understanding of the specificity of pathogens to different bee hosts, and what the fitness consequences of these potential interactions are. For honey bees, Varroa destructor mites are one of the most detrimental pests because they suppress the immune response of parasitized worker bees and transmit a large number of virus complexes that greatly impact their survival (Posada-Florez et al. 2019; Chen et al. 2004). Many of these viruses have been detected in wild bees but the fitness consequences of these viruses in non-Apis bees are largely unknown. Similarly, several other honey bee pathogens (microsporidians, trypanosomes, neogregarines) have been detected in wild bees with little understanding of their fitness consequences and the context-dependency of these interactions (Jones et al. 2022; Cohen et al. 2021; Ivers et al. 2022). Members of this multi-state project plan to use multiple approaches combining laboratory and field bioassays to study these questions to allow for a more holistic understanding of the impacts of biotic stressors alone and in concert with other biotic and abiotic factors (O’Neal, Anderson, and Wu-Smart 2018). Below, we provide some examples describing the projects and methods that will be used to address this objective.

  • Surveys of viral, bacterial, and eukaryotic pathogens in managed and wild pollinators sharing floral resources. These surveys could use metagenomic approaches to capture the wide diversity of pathogens present in these pollinator communities, which can help overcome the honey bee bias for known pathogen screening and allow the identification of currently unknown biotic stressors among bees (e.g., Galbraith et al. 2018)
  • Studies assessing both the prevalence and intensity of bee pathogens in different bee species using quantitative PCR measures to not only report detections but quantify levels of infection (e.g., McNeil et al. 2020; Jones et al. 2021). These studies require the development of new species-specific pathogen primers and standardized quantitative methods that will facilitate the quantitative synthesis of the information generated.  
  • Cage and semi-field experiments to characterize the impact of pathogen infections on the health and survival of bees exposed to different pathogens. These experiments will be combined with experimental settings manipulating exposure to other stressors (e.g., pesticides, nutrition, temperature) to identify the conditions that make different bee pollinators more susceptible to these pathogenic infections (e.g., Figueroa et al. 2021). 

Methods to assess abiotic stressors (nutrition): Flowering plant species differ considerably in the nutritional content of their pollen (Chakrabarti et al. 2019), and this can have important ramifications for bee health (Lau et al. 2023; Vaudo et al. 2020). Nectar is also important for bee nutrition because, as the primary carbohydrate source for bees, sufficient quantities are essential for larval growth and meeting the energetic demands of bee activity (Brodschneider and Crailsheim 2010). The diversity and quality of floral resources at the landscape level may therefore have a significant impact on the nutrition of bees and may be a key determinant factor of the presence or absence of different bee species at local spatial scales. We will investigate the role of nutrition on individual and colony physiology, growth, immunocompetence, and detoxification capacity to develop recommendations for both bee and land managers about best practices to improve bee health. In parallel, we will work with citizen scientists, stakeholders, and collaborating researchers on developing publicly available databases with more information about the nutritional content of plants in different types of habitats (e.g., agricultural, urban, rural) across the United States. These public datasets can also be incorporated into spatially explicit models that support quantitative and qualitative assessments of habitat for different pollinators (e.g., Beescape: Prestby et al. 2023). Here we list some of the methods and projects that we will work on to address this objective.

  • Study how land use and the diversity of foraging resources affect the growth, development, and health (as per López-Uribe, Ricigliano, and Simone-Finstrom 2020) of bees by experimentally placing nests/colonies into landscapes that vary in floral resource quality and diversity, and subsequently measuring variables related to individual bee or overall nest/hive health (e.g., Milano et al. 2019). 
  • The nutritional quality of landscapes will be characterized through a combination of satellite imagery data, assessments of plant diversity and bloom quantity through ground truthing, and information on the nutritional value (protein, lipids, carbohydrates and other micronutrients) of plants through pollen collected in pollen traps and bee scopa (as per Vaudo et al 2020). The nutritional quality of nectar will also be assessed.
  • Foraging preferences of managed and wild pollinators will be inferred through the collection of observational data on the diversity of floral species that are preferred by different bee pollinator species and through the identification of pollen use by bees at the nest or colony (e.g., Rundlöf et al. 2022; Williams and Kremen 2007). This information can be validated through flight cage or flight tunnel experiments where pollinator species can choose to forage on different floral resources and information about their survival and other fitness traits is assessed.

Methods to assess abiotic stressors (pesticides):  Due to the pervasive nature of xenobiotics in human-dominated landscapes, bees are regularly exposed to an array of compounds during the course of their lifetimes (e.g., plant-derived toxins, metals, pollutants, pesticides, and spray adjuvants among others) (Johnson et al. 2010). In high concentrations, these xenobiotics have direct negative effects on bees, which can be either lethal or sublethal in nature (e.g., Wu-Smart and Spivak 2018, Rundlöf et al. 2022). Combinations of xenobiotics may increase bees' susceptibility to exposure to a particular pesticide, have unexpected synergistic interactions (Glavan and Božič 2013), and make them more susceptible to other stressors such as pathogens (Harwood and Dolezal 2020). Significant work is needed to determine field-relevant xenobiotic exposures that can be incorporated into an Integrated Pest and Pollinator Management framework (IPPM) that supports bee health and crop protection simultaneously (Biddinger and Rajotte 2015). Insights gained can be provided to beekeepers, growers, manufacturers, and regulators (EPA) to develop science-based recommendations for labels and applications that can help reduce xenobiotic exposure on bees while supporting productive agricultural systems. Some specific projects and methods implemented under this objective include:

  • Existing literature on surveys of apiaries in areas of intensive row-crop production (e.g., corn and soybean), and major fruit and vegetable pollinator-dependent crops (e.g., almonds, apples, blueberries, pumpkins) will be summarized to assess the risk posed to bees by pesticide applications in highly managed agroecosystems. Risks of pesticide exposure vary by crop and may differentially impact the health and survival of different pollinators. This information will inform the development of IPPM recommendations.  
  • Lethal and sublethal effects of exposure to “inert” ingredients included in spray adjuvants and pesticide formulations will continue to be investigated. Due to the multi-dimensionality of these interactions, this will be an ongoing project for this group. These studies will assess toxic and sublethal effects (e.g., interference with associative learning) on honey bees and wild bees of pesticide and inert combinations relative to formulation controls.
  • Differentiating individual and colony-level impacts of active ingredients alone or in combination for social and solitary bees will be determined in controlled and field experiments. Even though honey bees are used as surrogates to determine pesticide toxicity, susceptibility to xenobiotics varies widely across bee species (Sgolastra et al. 2019). Therefore, assessments of the toxicity of common pesticide compounds beyond honey bees are critical for the protection of pollinators in agricultural areas. Experimental methods described in (Phan et al. 2020) will be used for these experiments.


Objective 2. To facilitate the assessments of genetic diversity of wild bees, and the development of honey bee stock selection, maintenance, and production programs that incorporate traits conferring resistance to parasites and pathogens.

Rationale and significance:  The numerous stressors affecting bee populations in the US emphasize the necessity for a more comprehensive understanding of the genetic diversity within managed and wild bee species. Insufficient knowledge regarding the levels of genetic diversity and its distribution across space and time poses a challenge for developing effective conservation strategies and managing wild crop pollinators. In the case of honey bees, a critical aspect is characterizing the genetic diversity of the US population to enhance breeding and management efforts. The genetic diversity of the honey bee population in the US is the result of multiple importations of subspecies and queens, selective pressures from parasites and pathogens (especially parasitic mites), and commercial queen-production practices that have streamlined the breeding population by reducing the number of queen mothers. Currently, we lack an understanding of the genetic composition and differentiation of various honey bee populations in the US, as well as the genetic distinctions among commercially marketed lines and stocks. In response to these needs, an additional goal of this multi-state group is to measure the genetic diversity of key crop pollinators including both managed and wild species, and support the development of domestic stocks that are resistant to pests and pathogens.

Methods to assess genetic diversity: The growing availability of genomic resources has catalyzed recent efforts to characterize the levels and distribution of genetic diversity and what it means for the adaptability and management of bees. Ongoing efforts led by the Beenome project ( are generating high-quality chromosomal-level assemblies of over 100 bee species of agricultural importance in the US. As a result, methods to assess the genetic diversity of wild and managed bees will use a combination of genomic and transcriptomic approaches that can be assembled with well-annotated reference genomes. A project associated with the California Conservation Genomics Project ( is resequencing hundreds of genomes for six bumble species across California to understand patterns of genetic diversity. In parallel, there are ongoing efforts to develop pangenomes for honey bees through full genome resequencing, which incorporates information on the geographically variable diversity of honey bees. For breeding purposes, phenotype-genotype association studies of currently commercialized honey bee lines are necessary to continue with targeted breeding efforts. Specific projects and methods under this objective include:

  • Assessment of the genetic diversity and population structure of agriculturally important wild pollinators will combine high-quality reference genomes and population genome resequencing (as per Pope et al. 2023). These studies will identify the presence of cryptic diversity among wild bee pollinators. Information on genetic diversity will be reported with summary statistics such as expected heterozygosity and nucleotide diversity. Population structure will be investigated through clustering analyses, and F-statistics. Patterns of genetic isolation and inbreeding will be used to identify potentially threatened populations. More information on the genetic diversity of wild bees in the US is critical for the conservation of agricultural pollinators as well as their potential movement and management for crop pollination. 
  • Characterization of the ancestry of the US honey bee populations and their levels of African ancestry. These studies will require low-coverage sequencing of pooled samples from honey bee colonies from northern and southern populations of the US (as per Harpur et al. 2020). The genetic information will be combined with phenotype assays of defensiveness to assess correlations between the presence of African ancestry and defensive behavior in honey bee colonies.  
  • Preservation of favorable genetics and augmentation of diversity using imported honey bee semen through cryogenic storage and recovery of honey bee germplasm from imported material. The phenotypic evaluation of honey bee germplasm for evaluation and breeding purposes will also be possible through effective cryopreservation and importation of semen. 


Objective 3. To develop monitoring programs that assess bee species richness and abundance in agroecosystems, and how these metrics of bee communities are changing over time. 

Rationale and significance:  Significant declines in bee pollinators have been detected in several regions of the US (Aldercotte, Simpson, and Winfree 2022; Janousek et al. 2023). These declines are primarily attributed to stressors outlined in objective 1, yet the specific reasons for taxon- or region-specific declines remain largely unknown. The full extent of pollinator declines in the US is also largely unknown, and its documentation is often difficult due to the lack of baseline inventory and monitoring data of most bees. Bee declines have exacerbated an increase in public and scientific interest in the status and trends of wild bees in the US (Woodard et al 2020). Current efforts to track wild bee populations for conservation purposes and to ensure stable crop pollination services are largely driven by strategic collaborations between academic researchers, agricultural extension professionals, and the general public. To gain a comprehensive understanding of the trends and status of wild bee populations across the US, there is a pressing need for coordinated multi-state efforts. Members of the NC1173 project are committed to addressing this shared goal through the development of coordinated initiatives for wild bee monitoring at the state level.

Methods for bee monitoring: Methods implemented in ongoing projects include a wide range of approaches from photography-based community science approaches (that involve more people and cover more area) to collection-based methods (that provide more geographically restricted data with more accuracy in the identifications). Several states in this group have already initiated monitoring projects (e.g., Oregon, Pennsylvania, Minnesota), while others express keen interest in adopting these established methods to launch new programs in their respective regions.

  • Develop a repository of protocols and methods for standardized sampling of bees using active and passive methods (as per Woodard et al 2020). This collaborative, multi-state effort aims to streamline the implementation of monitoring methods across various states, fostering consistency and compatibility between datasets. The primary methods used by existing monitoring projects include a combination of time-standard netting events, pan traps, and blue vane traps regularly used (e.g., twice per month) throughout the year. All individual bees are processed, pinned, labeled, identified to species, and databased. All the information is deposited in public repositories. 
  • Facilitate the establishment of new monitoring projects in other NC1137 states through partnerships with states that have successfully established such programs. All the existing bee monitoring projects have strong partnerships with agricultural extension and leverage participatory science for data collection (e.g., Bumble Bee Atlas, Oregon Bee Project, PA Wild Bee Monitoring). 
  • Synthetic data is a crucial step for this objective as it involves synthesizing data from all participating states to create a comprehensive public repository. This compilation of datasets will enable (1) state and county inventories, (2) information about species distribution, and (3) detections of non-native species. Quantitative analyses of the data will facilitate the development of ecological studies that investigate broader patterns of bee population changes across different spatial and temporal scales.
  • Integration of monitoring-related data into state wildlife agency conservation plans. This effort will connect researchers with state representatives of wildlife agencies to ensure direct information transfer from monitoring activities about species status and trends.


Objective 4. To develop and recommend best management practices for beekeepers, growers, land managers, and homeowners to promote wild and managed bee health. 

Rationale and significance: Best management practices to support and promote wild and managed bee health encompass information developed to (1) manage landscapes to promote bees through augmentation of floral and nesting resources, and (2) manage pollinators following practices that support healthier bee populations that can perform better pollination services. There is growing information about plant lists to use for the creation of pollinator habitat, as well as several government-funded programs to incentivize pollinator habitat in agricultural areas. However, for these programs to work effectively, there is a need for geographic-specific information not only about the types of plans but also other recommendations related to weed control, and soil quality among others. Similarly, the growing enthusiasm from the general public to begin beekeeping has increased the number of honey bee colonies in the US but the lack of training and guidance for those who start beekeeping often leads to high colony losses. This fact is supported by the high average winter losses among small (“backyard”) beekeepers in the United States (Bruckner et al. 2023). The high losses among new beekeepers reflect a critical need for training new and experienced beekeepers alike. The growing research knowledge about the effects of landscape and nutrition on bee health (objective 1) needs to be adapted for practical use by many diverse audiences, from homeowners to conservation organizations to government agencies.

Methods for the development of best management practices: Members will continue to collect data on pollinator preferences in different landscapes, and how to incorporate pollinator habitat in agricultural areas and urban gardens. This information will be disseminated through training opportunities that advance knowledge on management skills, improve understanding of bee biology, ecosystem functions, and conservation practices to promote more pollinator-friendly landscapes, and provide tools that promote economic growth and professional development. Members also work with a wide range of land managers, including growers, city, and state government agencies, land trusts, and conservation groups,  to create and improve pollinator habitat in their own states through workshops, field days, and fact sheets. Members also actively work through extension apiculture on training new and established beekeepers on how to incorporate best management beekeeping practices to maintain healthy honey bee colonies with low pest and disease pressure and well-fed. Our annual conference is one of the platforms used by this multi-state group to communicate the results of this project to beekeepers and other stakeholder groups.

Measurement of Progress and Results


  • Novel data characterizing pathogens in wild and managed bees, their ability to use multiple hosts, and their fitness consequences.
  • Publish shared protocols for pathogen quantification in honey bees and wild bees to increase opportunities for meta-analyses of data collected across the United States.
  • Publish a pipeline for generating pesticide toxicity data at landscape scales across the United States.
  • Laboratory and field studies investigating the interactions between biotic and abiotic stressors in the context of extreme weather events.
  • Development of pollen lipids, proteins, phytosterols, and amino acids database that will be publicly available for researchers, policymakers, citizens, and stakeholders.
  • Joint review publication on the available honey bee stock in the United States and their phenotypic traits.
  • Centralized repository with documents about best management practices for honey bees and landscapes for pollinators including information for different regions across the United States.
  • Genomic data sets available in key open public repositories.
  • Continued annual delivery of research updates to beekeepers, land managers, and growers through extension meetings, published proceedings, and reports published in trade journals (e.g., American Bee Journal).

Outcomes or Projected Impacts

  • Creation of a website that can serve as a public repository for protocols, datasets, and articles published by the NC1173 multistate group. This information will benefit the scientific community and the development of projects based on participatory science.
  • Creation of a website that can serve as a public repository for protocols, datasets, and articles published by the NC1173 multistate group. This information will benefit the scientific community and the development of projects based on participatory science.
  • Guidelines for beekeepers to reduce harmful effects of Varroa mites and viruses including information about the resistance, tolerance, and susceptibility of different stocks commercialized in the US. This information will result in improved honey bee colony survival and profits for beekeepers.
  • Recommendations for plant species (e.g., seed mixes) that are nutritious to wild and managed bees, and that likely improve their health and survival.
  • Synthesis of the pesticide toxicity, routes of exposure, and recommendations for best application methods to reduce the exposure of pollinators.
  • Continued engagement with regulators and legislators at local, state, and federal levels that lead to new legislative policies promoting pollinator health.


(1):* Review and synthesis of protocols for pathogen detection and quantification in Apis and non-Apis bees (Obj. 1) * Creation of an NC1173 website that will serve as a public repository for protocols, datasets, papers, and extension materials. This website will host blogs that will digest the information from peer-reviewed publications to make it more accessible to stakeholder groups and the general public. When possible the content will be available in both English and Spanish. * Progress reports on all objectives due to be presented in ABRC talks and published in Proceedings

(2):* Joint review publication on the available honey bee stock in the United States and their phenotypic traits (Obj. 2) * Extension publications and talks disseminating information about the phenotypic differences of honey bee lines and stocks in the US. * Synthesis paper with the results of native bee monitoring studies and the methods used (Obj. 3). This publication will make all associated data publicly available. * Progress reports on all objectives due to be presented at the International Pollinator Conference

(3):* Synthesis of the pesticide toxicity, routes of exposure, and recommendations for best application methods to reduce the exposure of pollinators (Obj. 1) * Free online materials summarizing the pesticide toxicity information for bees, and recommended best practices to reduce exposure. Information will be hosted on several websites (including the NC 1173 page). * Progress reports on all objectives due to be presented in ABRC talks and published in Proceedings

(4):* Development of a pollen lipids, proteins, phytosterols, and amino acids database that will be publicly available for researchers, policymakers, citizens, and stakeholders (Obj. 1) * Progress reports on all objectives due to be presented in ABRC talks and published in Proceedings * Discuss renewal of multi-state project and plan for submission of renewal.

(5):* Publication of general recommendations for plant species (e.g., seed mixes) and their nutritional value to wild and managed bees (Obj. 1 and 4). * Extension talks and articles disseminating the pollinator plant preference data information. * Progress reports on all objectives due to be presented in ABRC talks and published in Proceedings * Prepare final report for expiring project.

Projected Participation

View Appendix E: Participation

Outreach Plan

The stakeholder groups targeted by this NC1173 multi-state project include (1) researchers from academic institutions and government agencies, (2) beekeepers, (3) growers, (4) land managers, (5) conservation agencies and non-profits, and (6) the general public. As such, the outreach plan for the outcomes of the proposed goals of this multi-state project includes a diversity of platforms. These include peer-reviewed publications, extension articles (e.g., facts sheets and booklets), workshops conducted both in-person and online, as well as general information sessions through talks and webinars. Moreover, certain initiatives within this proposal are designed to involve community participation, thereby enhancing engagement and outreach with the general public. The communication and outreach strategies will be facilitated through the extension systems of the land-grant universities where project participants are based. To ensure that the information developed through our coordinated research efforts reaches under-served communities, collaboration will be established with extension offices and the USDA Honey Bee and Pollinator Research Coordinator (Dr. Elizabeth Hill). For example, many of the factsheets and extension materials will be translated into Spanish to facilitate outreach to the LatinX community. Recognizing these needs to reach underrepresented and underserved communities, project participants who are situated in urban and rural areas and routinely interact with other underserved groups will develop educational materials tailored to address the specific needs of these communities.


The governance of this group consists of a chair and a chair-elect. The chair is responsible for planning and conducting the annual meeting and coordinating proposal writing. The timing and location for the annual meeting will be established the previous year and, will alternate with the annual meeting of the American Association of Professional Apiculturists (AAPA), and the Entomological Society of America or the International Pollinator Health. The scientific program and research discussion for the multi-state project will be a substantial component of the American Bee Research Conference (ABRC) organized by the AAPA or a specific symposium organized during the other meetings. Candidates for the chair position are nominated by the participants of the project and elected to a two-year term. It is customary for the chair-elect to serve as the secretary be responsible for meeting minutes and assist with annual reports. We will develop chairs for the subcommittees working on the different objectives to achieve the proposed goals following the established timeline. The chairs of each subcommittee will be actively involved in the accountability of each working group and the write-up of the annual report for each of the sections.

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