Honey Bee Health Improvement Project


The mysterious disappearance of bees, called Colony Collapse Disorder (CCD), is a growing threat to Honey Bees, the mainstay of pollination services in agriculture. The North American Pollinator Protection Campaign (NAPPC), a tri-national coalition dedicated to promoting the health of all pollinators, partners with different organizations to perform research for improving the health of honey bees and reversing the threats they face. The Honey Bee Health Improvement Project focuses on ways to help Honey Bees and beekeepers. In the absence of Colony Collapse Disorder, this task force will seek out and secure funding for innovative and important work to understand and promote genetic stock improvements, understand and promote best management practices for commercial beekeeping, and promote forage opportunities for colonies on public and private land.


Priority Areas

The Honey Bee Health Task Force has identified seven priority areas for funding, though other areas will be considered as well.

  1. Effects of pathogens and pests on honey bee behavior, physiology and/or colony health; including the development of novel methods to mitigate these effects.
  2. Effects of nutrition on pest, pathogen, and disease incidence.
  3. Effects of pesticides on pest, pathogen, and disease incidence.
  4. Effects of parasite and pathogen shared between bee species.
  5. Development of approaches for genetic stock improvement of honey bee populations to enhance resistance to pathogens and parasites.
  6. Effects of climate or environmental variables on honey bee pests, pathogens, and disease incidence.
  7. The development of diagnostics or indicators for the presence of pests, pathogens and diseases that affect honey bee health.

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Previous grantees are listed below by priority area.

Effects of Pathogens and Pests on Honey Bees

2020 – The Understudied Honey Bee: Exploring the Role of Feral Honey Bees in Pathogen Dynamics in Pollinator Communities of Southern California – James Nieh, UC San Diego, jnieh@ucsd.edu

We will explore pathogen dynamics in southern California pollinator communities. We will 1) characterize HBAV loads in feral and managed honey bees in southern California across time and 2) describe the directionality of pathogen transmission in this bee community. We hypothesize that feral honey bees play a key role in pathogen transmission dynamics.

2020 – Smart Tracking: How varroa impact the social cohesion and longevity of a colony – Kirsten Traynor, Arizona State University, ktraynor@asu.edu

Though we know varroa reduce honey bee lifespan in infected colonies, we don’t know how individually parasitized bees differ from healthy bees in colony contributions to nursing, foraging and their individual productivity during their lifespan. A small reduction to individual productiveness (i.e. 2 days shorter nursing duration/15% reduction in pollen carrying capacity/1.5 days shorter lifespan) can compound into large colony level effects when amplified over the season and throughout the superorganism. If we quantified the changes in the behavior of individually parasitized individuals, we could estimate the sublethal economic impact on colony productivity. We propose to investigate how varroa parasitization during pupal development has sub-lethal impacts on colony health, influencing the rate of maturation, the age of first foraging, and the social dynamics in a colony.

2019 – Varroa behavior: Invasion of brood cells and consequences of co-infested cells – Zachary Lamas, University of Maryland, zlamas@umd.edu

Our study takes a two-pronged approach to understand the dynamics of Varroa parasitism and nutritional stressors on honey bees. The first approach looks at the rate of varroa invasion on worker brood cells that were or were not stressed during early development. Transmission potentials of multiple varroa invading a single brood cell will be examined. The second approach investigates Varroa parasitism, nutritional deprivation, or a combination of the two stressors during brood development on adult bee behavior and physiology. Rates of Varroa parasitism are then revisited on the adult bees from all treatment groups.

2019 – Elucidating the role of crop flowers as reservoirs of pathogens and the influence of the pollinator community on pathogen transmission to honey bees – Ana Montero-Castaño, University of Guelph, ana.montero.castano@gmail.com

The general objective of this proposal is to understand the role of crop flowers as reservoirs of viable pathogens to honey bees and the most probable direction of transmission considering the influence of the entire pollinator community. Specifically, I want to address the following questions:

1. Are pathogens found on crop flowers?

2. Is the richness and prevalence of pathogens on flowers related to the richness and prevalence of pathogens in honey bees or other wild bee species, and to the rate at which they visit the crop? And according to that, which is the most probable direction of transmission?

3. Do the natural habitat cover and the density of honey bee hives in the surrounding landscape influence the risk that crop flowers pose to honey- and wild bees? Is there an optimum of both factors that minimizes the risk?

2019 – Assessing synthetic amorphous silica (SAS) for the management of small hive beetle (Aethina tumida) – Jacob Wenger, University of California State - Fresno, e.jawenger@mail.fresnostate.edu

We propose a simple but important investigation into the use of synthetic amorphous silica (SAS) coupled with Davren technology as a management strategy for A. tumida. Specifically, we are targeting management of adult and larval beetles in the hive, as well as pupae in the soil. These approaches would be most likely to target the beetle while leaving honey bees untouched.


1. Evaluate the efficacy of SAS for control of adult and larval A. tumida with screen traps.

2. Evaluate the use of SAS as a soil amendment against pupating A. tumida.

2018 – Ecology of shared honey bee and bumble bee pathogens: Floral transmission routes, pathogen interactions, and effects on host health – Alexander Burnham, University of Vermont, pburnham@uvm.edu

With this work, we aim to bridge disease ecology and conservation biology to ask how these multi-host pathogens are transmitted, how multiple pathogens interact, and how those interactions affect host health. This work will add to the growing body of peer-reviewed literature on both native bee conservation and the basic science of disease ecology. Building heavily on our previous work, this proposed project will address the following objectives: 1) We will experimentally test transmission of viruses between bee species through shared flowers, 2) Through field surveys, examine seasonal phenology and patterns of coinfection of four pathogens in two bumble bee species, and 3) Using laboratory experiments, examine interactions and effects of multiple pathogens on bumble bee health.

2018 – Development of an RNAi-based strategy for small hive beetle control – Marcé Lorenzen, North Carolina State University, marce_lorenzen@ncsu.edu

Since traditional pesticide-based small hive beetle control measures have a negative impact on bee health, we propose to develop and test a species-specific control method, one expected to have no negative impact on honey bees. RNA interference (RNAi) is a promising alternative to pesticides. It is a sequence-specific gene-silencing mechanism that is initiated by the introduction of double-stranded RNA (dsRNA) into a cell. The RNAi pathway is conserved in insects and has the potential to be used as an insect control technology. We propose developing an RNAi-based control strategy to address the needs of apiculturist globally. Our research plan is an interdisciplinary approach that will integrate transcriptomics, functional genomics, applied entomology and agricultural extension. Moreover, this research serves as proof-of-principal for use of RNAi in the control of honey bee pests. If successful, this approach could be extended to mites, and other more difficult to manipulate arthropods.

2018 – Natural products to control American Foulbrood in honey bees – Rod Merrill, University of Guelph, rmerrill@uoguelph.ca

The long-term goal is to characterize the extracts of essential oils to develop inhibitors (anti-virulence compounds) against key bacterial toxins produced by P. larvae for the prevention and treatment of AFB. This will be manifested in the development of a formulation consisting of inhibitory compounds extracted and purified from essential oils. The specific aims (short-term objectives) are: Aim#1: characterize natural products as effective compounds against P. larvae toxins; Aim#2: testing the best optimized compounds against AFB-infected honeybee larvae; Aim#3: testing of compounds in AFB-infected hives.

2017 – Phytochemicals as varroadices: The development of propolis-based miticides – William Collins, Fort Lewis College, collins_w@fortlewis.edu

The first objective of this study is the preparation of varroacides 1-5. Our research group has already developed an efficient, preliminary route to this class of molecules starting from inexpensive, commercially available reagents. The second objective will be to evaluate the effects of compounds 1-5 on varroa mites. Our research apiary will be fitted with drone brood frames in early spring 2017 that will be harvested throughout the spring/summer/fall to obtain varroa for testing. Solutions of compounds 1-5 at varying concentrations will be evaluated, and both toxicity and repellency toward varroa will be monitored. The goal of this part of the study will be to identify one or more molecules that possess exceptional miticidal efficacy when compared to thymol (positive control). Ultimately, the long-term objective of this project will be to not only identify novel, botanically derived molecules that possess exceptional miticidal efficacy but also to field-test them in colonies.

2017 – Viral transmission in bee communities: role of alternative hosts and environmental conditions – Briana Ezray, Penn State University, bde125@psu.edu

We seek to better understand the transmission of bee viruses within their communities by examining whether these viruses can be transmitted to honey bees via alternative hosts species and by determining the role of environmental exposure in the survival of these viruses on flowers, where inter and intraspecies/colony transmission is most likely to occur. We will focus the study on the persistence and transmission of the two most prevalent honey bee viruses, Deformed Wing Virus (DWV) and Black Queen Cell Virus (BQCV), both of which have been demonstrated to have substantial impacts with identifiable symptoms on bees. These viral transmission patterns will provide a baseline for understanding the transmission of other bee viruses. Specifically, we will address the following:

1) Can other organisms that live in and around honey bee hives or share floral resources with honey bees such as the German cockroach Blattella germanica, the small hive beetle Aethina tumida, and the orchard bee Osmia lignaria, transmit infective DWV and BQCV to honey bees?

2) What is the time course from ingestion to transmission of the virus in honey bees and alternative hosts?

3) How long after deposition on flowers or other spaces can pathogens survive to be transmitted and what role do environmental conditions play in this?

2017 – Phage binding to Paenibacillus larvae spores, Sandra Hope, Brigham Young University, sandrahope2016@gmail.com

We hypothesize that some bacteriophages can bind to bacterial spores of Paenibacillus larvae. To test this hypothesis, we divide the work into three primary tasks: 1) prepare P. larvae spores for testing, 2) test phage binding capabilities on spores, 3) test the phages that bind for the ability to kill the bacterium upon activation of the spore.

2017 – The predatory mite Stratiolaelaps scimitus as a biological control agent against Varroa destructor – Sabrina Rondeau, Universidad Laval, sabrina.rondeau.1@ulaval.ca

The main objective of our study is to evaluate the potential of Stratiolaelaps scimitus as a biological control agent against Varroa destructor. Specific objectives are: 1) to assess the risk of predation of honey bee eggs and brood by S. scimitus under both laboratory conditions and within the colony, 2) to study the behavior and movements of S. scimitus within a bee colony and 3) to evaluate the effectiveness of the predator in controlling Varroa densities during an autumn treatment. Our research hypotheses are that: 1) S. scimitus does not pose predation risk for honey bee eggs and brood within the colony, 2) the predator will remain in the hive after his introduction and will attack varroa mites for feeding, and 3) when introduced in the late fall, S. scimitus will effectively control varroa mite populations in the colonies before winter.

2016 – Changing perspectives: How pollinator community context influences honey bee virus prevalence – Michelle Fearon, University of Michigan, mlfearon@umich.edu

Although it has been widely documented that other bee species share the same pathogens with honey bees, the impact of pollinator community context on honey bee health has not been tested. The objectives of this proposal are to provide the first analysis of how honeybee pathogen prevalence changes with pollinator community context in an agricultural environment, and evaluate how pollinator species richness and overall abundance impact honey bee health. These results will set the stage for future experimental research investigating species specific contributions to increased viral prevalence in honey bees and the movement of viruses in pollinator communities.

Hypothesis 1: Honeybees will have decreased pathogen prevalence at sites with greater pollinator species richness.

Hypothesis 2: Honeybees will have increased pathogen prevalence at sites with greater overall pollinator abundance.

2016 – Testing the effects of nicotine, a natural plant metabolite found in nectar, on honey bee nosemosis – James Nieh, UC San Diego, jnieh@ucsd.edu

The honey bee gut parasite Nosema cerana weakens colonies and thereby contributes to poor colony health. Recent studies raise the interesting possibility that naturally occurring secondary plant metabolites such as caffeine or nicotine can alter pollinator behavior. Could these compounds also fight disease? We will test the hypothesis that plant defensive compounds in nectar, specifically nicotine, reduce Nosema infection. We will also test if infected bees prefer to forage at artificial nectar containing naturally relevant concentrations of nicotine. If so, this suggest the intriguing possibility of self-medication by bees.

2016 – Focused virological analysis of the Arnot Forest survivor bee population for evidence of protective Deformed Wing Virus genotypes – David Peck, Cornell University, dtp36@cornell.edu

Recent research on the genetic structure of a population of untreated Varroa-survivor bees living in the Arnot Forest in New York has demonstrated that these bees experienced dramatic genomic change during the recent invasion of the Varroa destructor mite. (Mikheyev et al. 2015) To our knowledge, this is the only known population of untreated, Varroa-survivor European honey bee in the US (though there are likely others). We propose to combine these two lines of research with help from the NAPPC, to find a sustainable, long-term solution to the Varroa-DWV crisis.

Objectives: To characterize the DWV strains present in the Arnot Forest Varroa survivor population, and to test the hypothesis that these bees harbor protective DWV strains that provide long-term protection to the bees, even after exposure to more virulent viral strains and despite high mite loads.

2016 – Investigating a new way to combat viruses with RNA-targeting biotechnology in Apis mellifera – David Tarpy, North Carolina State University, drtarpy@ncsu.edu

This project is to develop an innovative approach using CRISPR/Cas9 system to target highly conserved regions of the honey bee, Apis mellifera (L.) infecting dicistroviruses Israeli Acute Paralysis Virus (IAPV), Acute Bee Paralysis Virus (ABPV in vitro and in vivo. This project can serve as a model system for additional protection against other RNA viruses such as Deformed Wing Virus (DWV).

2015 – Do viruses manipulate honey bee behavior in ways that increase their transmission? – Adam Dolezal, Iowa State University, adolezal@iastate.edu

Despite the increasing interest in the effects of honey bee viruses, the behavioral repercussions of virus infection are not well-understood. What evidence does exist mostly focuses on the more observable pathogenic effects of viruses, e.g., paralysis (Chen 2011). Therefore, we seek to understand how viral infection affects the social behavior of honey bees, and to determine whether virus-induced changes in behavior act to increase virus transmission between individuals and hives.

2013 – Activating honey bee immunity against Nosema disease: a pilot experiment – James Nieh, UC San Diego, jnieh@ucsd.edu

The goal of our study is to determine if honey bee defenses to Nosema ceranae (Microsporidia) infection can be activated when larvae are fed probiotics or a dose of inactivated N. ceranae spores. In addition, we recently conducted experiments that suggest larval exposure to Nosema

can activate a beneficial immune response. Larvae can be infected, but larvae fed a higher Nosema dose were less infected as adults compared to larvae given a lower dose (Eiri et al., 2012, Fig. 1). Thus, a sufficiently high dose of spores may activate a larval immune response, which moderates adult infection. These results are based upon live spores, which may impair adult longevity. We will also test if larval exposure to dead spores provides protection, as it does in other animals where vaccination with inactivated microsporidian spores reduces subsequent infection (Speare et al., 2007).

2013 – Identification of IAPV Targets in Honey Bee (Apis mellifera) – Olav Rueppell, UNC Greensboro, o_ruppel@uncg.edu

Honey bee virology is a relatively new scientific field and many essential tools for the scientific investigation of the viruses are lacking. Most importantly for the direct study of honey bee viruses is the ability to localize the viruses in the honey bee body. The localization of the virus to find out precisely how it enters the bees and where it replicates is fundamental to the understanding of the viral pathogenesis and to the development of effective protective treatments.

Here, we propose to identify the target organs of an important honey bee virus (Israeli Acute Paralysis Virus: IAPV). With an already developed, specific antibody we will determine the location of IAPV in bees during various stages of infection by in-situ immuno-histochemical staining. The identification of virus entry and replication sites will be informative for antiviral treatment and drug development.

2012 – Stimulating propolis collection to benefit honey bee health and immunity – Renata Borba, University of Minnesota, rsborba@umn.edu

The goals of this research are to explore ways for beekeepers to encourage honey bee colonies to deposit a propolis envelope within standard beekeeping equipment, and to quantify the benefit of this natural propolis envelope to colony health and immune system functioning, particularly in early spring in northern climates. If a heavy propolis envelope is a vital component to a healthy bee colony, we can modify the equipment currently used for beekeepers and beekeeping practices nationwide. Such modifications will encourage the bees' natural construction of a necessary antimicrobial protective envelope in the nest cavity. A long-term outcome of this research is to promote honey bee health, which will directly support local, regional and national beekeepers by having stronger colonies to produce more honey.

2012 – Comparative analysis of honey bee survival and immune response to co-infections of IAPV and N. ceranae using quantitative mass spectrometry based proteomics – Leonard Foster, University of British Columbia

Using proteomic tools, our research was aimed at understanding honey bee immune responses to both fungal and viral pathogens in an effort to develop novel integrated pest management based tools including RNAi based gene silencing treatment systems as an alternative to antibiotics for the control of honey bee pathogens. Specifically, we aimed to evaluate survival and host immune response in honey bees infected with Israeli Acute Paralysis Virus (IAPV) and Nosema ceranae, both singly and in combination. Our overall goals of the project are to:

Test the effect of Israeli acute paralysis virus and Nosema ceranae infections both singly and in combination on larval, pupal, and adult honey bee (Apis mellifera L.) survival using adult cage and in vitro larval rearing assays.

Compare changes in host immune responses using mass spectromety based quantitative proteomics in larval, pupal and adult honey bees artificially innoculated with IAPV and N. ceranae, both singly and in combination.

2012 – Symbiont mediated pathogen protection – Lana Vojvodic, University of Arizona, vojvodic.sv@gmail.com

This project has three ongoing components that are focused on the bacterial gut symbionts (probiotics) interaction with their honey bee host and the fungal pathogens that are known to cause chalkbrood and stonebrood disease. We test for the:

Survival of larvae infected with different combination of brood fungal pathogens and beneficial bacteria;

Difference in the expression of six immune genes after the fungal and probiotic exposure;

Investigating overall host gene expression by using the next generation sequencing (RNAseq) of the whole larval genome post exposed to the probiotics and aseptic larvae.

2010 – Development of novel Varroa mite control methods from attractant and arrestants isolated from brood host volatiles – Mark Carroll, USDA-ARS Carl Hayden Bee Research Center, Mark.Carroll@ars.usda.gov

One approach for the control of Varroa mite is the identification of semiochemicals (signaling chemicals) that the mite uses to find its hosts. During cell invasion, a female mite detects and moves into the cell of an older bee larva just before capping. Two volatiles named CA and CB characterized from older capping larvae were previously shown to act as excitants and arrestants to female mites in bioassays. We have begun to investigate other brood volatiles to determine if these chemicals affect mite behavior, either individually or as synergists with CA and CB, using an EthoVision behavioral analysis system to analyze mite bioassay responses. One volatile specifically associated with non-host larvae, termed CC, acts as a repellent to mites at high concentrations. The limited responsiveness of mites to these volatiles at lower concentrations suggests that these three compounds could affect mite behavior at contact or near-contact distances. We will continue our efforts to develop CA and other signaling chemicals as flooding agents (to disrupt mite chemical communication) or as trap lures to control mites in the hive environment.

2009 – Health Effects of Israeli Acute Paralysis Virus (IAPV) on native pollinators – Edwin Rajotte, Penn State University, uvu@psu.edu

We found that IAPV can be transmitted from honey bees to bumble bees and that the colony survival was shortened as compared to uninfected, control colonies. The symptoms of the infection in the bumble bees differed as compared to honey bees and needs to be more fully defined. We plan to expand these preliminary trials into a full-fledged, well-replicated experiment to conclusively study the health impact of IAPV on bumble bees.

2008 – Effects of miticide and Fumagilin-B on honey bee survivorship and immune responses – Catherine Little, Acadia University, 076444l@acadiau.ca

Western honey bees (Apis mellifera) are exposed to a number of parasites. Varroa destructor, Nosema apis, and N. ceranae have particularly detrimental effects on colony productivity and survival. We will measure honey bee immune responses to infection by each of these three species of parasites and the effects of co-infection. We will then compare the results of infection with the effects of miticide and Fumagilin-B® use on honey bee physiology. Quantification of immune trade-offs which occur during infection by multiple parasites and the effects of standard chemical treatments may enable us to determine infection threshold levels for effective use of chemical treatments, thereby reducing the risk of chemical resistance developing in either Varroa or Nosema. We will also determine if immune protein concentrations resulting from parasitic infection are predictive of honey bee survival, potentially leading to a means of assessing mortality risk during preparations for over-wintering honey bee colonies.

Effects of Nutrition of Pest, Pathogen, and Disease Incidence

2020 – Using nutrition to combat the biggest threat to honey bee survival, Varroa destructor Meghan Bennett, USDA-ARS Carl Hayden Bee Research Center, meghbennett@gmail.com

New strategies for controlling Varroa are sorely needed because despite a myriad of strategies for controlling Varroa, colony losses remain high worldwide. If dietary essential fatty acids (EFAs) increase olfactory learning and enable nurse bees to better detect Varroa, we might be able to use diet as another weapon in our anti-Varroa arsenal. Thus, we aim to investigate the role of EFAs on cognition and hygienic behavior, at the individual and colony level. We will test this idea using individual cognitive tests and in-hive behavioral tests. We hope that the results stemming from these studies will lead to improved honey bee dietary recommendations and non-chemical options for enhanced mite control.

2020 – Can we alter the macronutrient rations within artificial diets to bolster honey bee pathogen defense? – Juliana Rangel, Texas A&M University, jrangel@tamu.edu

Our intention is to take an integrative approach by using a nutritional framework to find practical solutions that will help beekeepers manage pathogen levels within their colonies. To do this, we are using the Geometric Framework (GF), which can graphically represent an insect’s nutritional needs in a nutrient space defined by its food components, particularly the amounts of proteins, carbohydrates, and/or lipids that are present within a diet7. However, macronutrient ratios determined from the GF are not static and instead are dependent on the immediate physiological state of an organism. Therefore, when an organism is experiencing stress or is parasitized, the ratio of nutrients needed may differ from the ratios they would obtain in their natural, healthy state.

Objective 1: To determine the optimal P:L intake target of honey bees infected with either N. ceranae or DWV using a novel, artificial diet.

Objectives 2 & 3: To determine what macronutrient ratio(s) in honey bee diets can positively affect the survivorship, physiology, and expression of genes important for growth, development, and immunity in bees infected with either Nosema ceranae (Obj. 2), or DWV (Obj. 3).

2019 – Manipulating pollen macronutrient ratios to improve honey bee resilience to pesticide stress – Christina Grozinger, Penn State University, cmg25@psu.edu

We will further explore the role of dietary lipids in improving the resilience of bees to pesticides in the following Objectives: (1) Confirm that pollen-derived lipids contribute to resilience when honey bees are exposed to the pesticide chlorpyrifos. (2) Determine if dietary lipids broadly improve resilience of bees exposed to different pesticide classes. These will include chlorpyrifos (organophosphate), imidacloprid (neonicotinoid), cyfluthrin (pyrethroid), and propiconazole with acetamiprid (neonicotinoid with a DMI fungicide to demonstrate synergism). (3) Examine which detoxification genes respond to dietary lipids using quantitative PCR.

2017 – The effects of periodic confinement of water stress on colony health and worker behavior – Hailey Scofield, Cornell University, hns36@cornell.edu

Water stress and colony dehydration induced by transportation may lead to disruption of critical colony functions. Despite long held concern by beekeepers about the effect of water deprivation during transport no work has yet addressed how water stress affects brood production in honey bee colonies. We seek to address this critical gap in understanding by investigating how acute water stress impacts honey bee brood development, individual worker performance, and colony growth.

2016 – Effects of phytochemicals on longevity and pathogen resistance in honey bees – Louis Bjostad, Colorado State University, louis.bjostad@colostate.edu

Drawing strength from our preliminary results, here we propose to test additional compounds that are likely to play an important role in improving longevity, and also in pathogen tolerance. We will focus on specific phytochemical compounds from classes that have been reported in nectar and pollen, specifically phenolic acids (eg. p-coumaric acid), abscisic acids and flavonols.

Objective: (i) To conduct a structure-function study by testing compounds from different chemical classes similar in structure to p-coumaric acid, that occur in nectar and pollen and (ii) to test the effect of p-coumaric acid on pathogen-infested bees.

2014 – The effect of nutritional stress on the foraging and recruitment activity of honey bee workers – Heather Mattila, Wellesley College, hmattila@wellesley.edu

Despite the economic importance of honey bees and persistent suspicions that poor nutrition may play a role in declining pollinator health, no study has examined the effects of nutritional stress on the foraging performance of honey bees, which is at the heart of their efficacy as pollinators. This oversight is especially surprising given that colonies routinely experience food stress as part of their annual cycle and because of taxing management practices associated with commercial pollination. If nutritional stress occurs early in development and affects the ability of workers to perform critical tasks later in life, then it could have serious implications for colony function, worker health, and pollinator success. We seek to address this knowledge gap by assessing the foraging performance of adult workers who experience nutritional stress during larval development.

2014 – The effects of pollen diversity on bumble bee health in an agricultural environment – Anthony Vaudo, Penn State University, adb124@psu.edu

Herbivorous insects can actively assess nutritional value and choose host-plants to balance nutritional intake to optimize development11; whether this model applies to bees remains largely unexplored. Because bees collect large amounts of carbohydrates from flower nectar, carbohydrates are likely not limiting nutrients in bees’ diets. I hypothesize that 1) bees can assess pollen nutrition and balance their collections from different plant species to achieve an optimal nutritional ratio for their larvae, 2) bees forage on pollen sources to achieve a specific protein:lipid ratio to complement their carbohydrate intake, 3) monoculture pollen sources likely do not provide bees with their specific nutritional needs, and therefore diverse host-plant pollen sources are necessary for bee health.

2013 – Impacts of nectar compounds on honey bee gut microbes and disease – Jay Evans, University of Maryland, jay.evans@ars.usda.gov

The goal of our research is to assess how secondary compounds naturally found in nectar and pollen affect honey bees via changes in the gut microbiota. We will address this goal using experimental manipulations of secondary compounds and parasites combined with meta-genomic screens. Extending the well-known role of secondary compounds in plant-herbivore-natural enemy interactions to plant-pollinator-parasite interactions will open up new nutritional mechanisms to manage honey bee disease through the use of natural plant products.

2013 – Crop pollinator divsersity and abundance in relation to floral resources and forest cover in the landscape – Martha Lopezaraiza Mikel, Universidad Nacional Autónoma de México, mlopezaraiza@oikos.unam.mx

In a previous study funded by NAPPC we assessed the availability of floral resources for honey bees and native pollinators along the year in a tropical dry forest in the Pacific coast of Mexico, and identified the main floral resources for the species in the wet and dry seasons. We also documented the flower visitors of crop species grown in the region, and quantified the proportion of Apis mellifera vs. native pollinators at the crops. Native pollinator abundance was variable, and Apis mellifera always accounted for more than half of the visits. In this study, we propose to extend this work and a) study the factors that are affecting pollinator abundance in crop species of this region; in particular, nesting resources, floral resources and foraging distances of pollinators are predicted to determine the relative abundance of pollinators at crop species (Lonsdorf et al. 2009) and our previous work in the forest provides information to test this predictions; b) study the extent of pollinator dependence of the varieties of the studied crops in the area, and the efficiency of the main pollinator species; c) expand the survey of flower visitors of crop species to several locations along the Mexican Pacific Coast and inland towards higher altitudes where pollinator communities are expected to differ.

2011 – Assessing floral resource availability in the tropical dry forest and agricultural sites of the Pacific Coast of Jalisco, Mexico to promote honey bee colony maintenance and health - Martha Lopezaraiza Mikel, Universidad Nacional Autónoma de México, mlopezaraiza@oikos.unam.mx

In this study we propose to 1) identify and quantify the main floral resources used by honey bees along the year in secondary and old growth tropical dry forest, and agricultural sites in the Pacific Coast of Jalisco, Mexico; 2) identify the native bee species that pollinate crops in the area; and 3) register phenological patterns of the plant species that compose these resources. We aim to start a project on floral resource use by bees in this ecosystem, and the effects of climate on flowering phenology of these plant species. We will be able to relate phenology data with environmental data and determine if proximate factors such as environmental variables trigger phenological events of the different plant species. This will be helpful to assess the possible effects of climate change on plant phenology, and thus on resource availability to bees. We will generate useful information for honey bee keepers that will aid in taking decisions of when and where during the year hives should be placed, to maximize honey productivity, crop pollination and colony maintenance.

2010 – Evaluating effects of pollen quality on honey bee physiology, colony growth and behavior – Ramesh Sagili, Oregon State University, sagilir@hort.oregonstate.edu

In the wake of deteriorating honey bee health, bee nutrition has attained greater importance than ever. Loss of habitat and large monocultures have restricted the diet of honey bee. Specific objectives of this proposal were 1) to evaluate and compare the effects of single source pollen consumption versus mixed source pollen consumption on hypopharyngeal gland protein content, bee mass, lipid content, colony growth, immunocompetence and learning behavior in the honey bee and 2) to design a field test to assess the nutritional status of honey bee colonies in the field. Nurse bee hypopharyngeal gland protein content and colony growth in single-source pollen treatments were significantly low compared to multi-source pollen treatments (P < 0.01 and P < 0.05 respectively). Single-source pollen (SSP) treatments had significantly lower phenoloxidase and prophenoloxidase activity when compared to multiple-source pollen (MSP) treatments (P <0.001). BSA visual standard for the four treatments (no protein, 10% protein, 20% protein and 40% protein) was developed. We plan to compare the protein contents of field samples to this established standard.

2009 – Designing a field test to estimate the nutritional status of honey bee colonies in the field and evaluating effects of pollen quality on honey bee physiology and behavior – Ramesh Sagili, Oregon State University, sagilir@hort.oregonstate.edu

Pollen is the sole source of protein for honey bees and is vital for their development and survival (Schmidt and Buchmann 1992). Large monoculture and specialized greenhouse farming systems result in restricted choice of pollen diet in honey bees (Schmidt et al. 1995). Every year large numbers of colonies from all around the country are shipped to California for almond pollination, where the bees predominantly rely on almond pollen to fulfill their protein requirement. Almond pollen might be toxic to honey bees if consumed for an extended period of time (Kevan and Ebert 2005). Very little is known about effects of single source pollen consumption such as almond for extended periods on honey bees. Here we also propose to investigate and compare the effects of single source pollen consumption versus mixed (multi) source pollen on honey bee colonies.

The specific objectives of this proposal are 1) to design a field test to assess the nutritional status of honey bee colonies in the field and 2) to evaluate and compare the effects of single source pollen (almond) consumption versus mixed source pollen consumption on hypopharyngeal gland protein content, bee mass, lipid content, colony growth and learning behavior in the honey bee.

2009 – The Benefits of Propolis to the Immune System of Honey Bees: Do Bees Self-Medicate? – Marla Spivak, University of Minnesota, spiva001@umn.edu

In our previous work we asked if propolis, a complex plant resin with diverse antimicrobial properties, assists in the immune defense of bees against pathogens and the parasitic mite, Varroa destructor. A progress report of our previous work is attached. Now I am requesting funds to further explore an observation we made during the course of our experiments in 2008. We challenged propolis-rich and propolis-poor colonies with chalkbrood (a fungal disease of bee brood) to measure the relative effects of the propolis treatment and disease challenge on the immune system of bees. We noticed that the number of resin foragers in colonies challenged with chalkbrood increased after the challenge, while the number of resin foragers in unchallenged colonies remained constant during the same time course. If these results are repeatable, it would indicate that resin collection may be an inducible response; the bees may be self-medicating.

2009 – Food and fungi: The combined effects of food supplementation and Varroa mite control on honey bee health – Laura Burkle, Washington University in St. Louis, burkle@wustl.edu

We will manipulate food availability and a fungus (Beauveria bassiana) pathogenic to Varroa mites in a factorial design at the colony level in up to 100 colonies. Pesticides in honey bees will be also measured at our different sites, providing additional understanding of the relative importance of pesticides, and their interactions with food availability and Varroa mites, to honey bee health. Existing honey bee colonies established by Missouri honey beekeepers will be used in this experiment, encouraging partnerships and information exchange between academic researchers at Washington University in St. Louis and local apiculturists.

2008 – Nutritional Effects on Intestinal Health and Longevity of Honeybee Workers – Olav Rueppell, UNC Greensboro, olav_rueppell@uncg.edu

This research project seeks to identify the effects of diet quality and malnutrition on the health of the honey bee worker intestine, as assessed by the activity of their intestinal stem cells. The intestinal epithelium is crucial to organismal health and it is one of the most exposed tissues in the animal body. Its cells are continuously replaced in a wide variety of organisms (Finch and Kirkwood 2000).

Although early reports on proliferative cells in the intestine of insects exist (Snodgrass 1956), these cells have only recently been characterized as bona-fide stem cells in adults through molecular analyses in Drosophila (Micchelli and Perrimon 2006; Ohlstein and Spradling 2006). A certain level of cell proliferation is necessary to maintain a functional intestine, even in the adult insect. Thus, the activity of these cells has been linked to insect growth (Hakim et al. 2007) and they are responsive to toxin exposure (Loeb et al. 2001; Gregorc et al. 2004). Furthermore, their rate of cell proliferation is positively correlated with food quality (Zudaire et al. 2004). Thus, the proliferative activity of intestinal stem cells may be an indicator of malnutrition with direct relevance to bee health.

2008 – The benefits of propolis to the immune system of honey bees – Marla Spivak, University of Minnesota, spiva001@umn.edu

We have initiated a comprehensive line of research in my lab on the benefits of propolis collection to the immune system of honey bees. Propolis is a resin secreted by some plants that honey bees collect and deposit in the nest. Propolis has important antimicrobial value to humans, but its value to the bees is not known. Here I am requesting funds to test if colonies selectively bred for high- and low-propolis collection differ in immune-related gene transcript levels. The applied goals of this research are to promote the natural immune defenses of honey bees and to promote the human use of propolis as an antimicrobial value-added product from the beehive.

Effects of Pesticides on Pest, Pathogen, and Disease Incidence

2019 – Quantifying the impact of pesticide contamination in the wax rearing environment on developing honey bee queens – Juliana Rangel, Texas A&M University, jrangel@tamu.edu

In the experiments we are hereby proposing, we would like to 1) quantify the feeding rates and care that nurses provide to queen larvae reared in pesticide-laden vs. pesticide free wax, by calculating the nurses’ feeding and cell visitation rates toward larval queens. We would also like to 2) collect pooled samples of queen larvae at each of the five larval instars (or stages) and compare the chemical composition of larval pheromones when reared in pesticide-laden vs. pesticide-free wax. Finally, we would like to 3) measure and compare the morphological characteristics of virgin queens reared in pesticide-laden and pesticide-free after they transition from larvae to pupae to discover if queens reared in wax contaminated with pesticides are treated differently by nurse workers because the nurses detect subtle differences in the type and/or concentration of the chemical compounds present in the larval queen pheromones, thus impacting queen development due to differential visitation and/or feeding rates by the nurses. Our research will help us better understand why queens that are exposed to pesticides during development grow up to exhibit sub-optimal reproductive quality.

2018 – Sublethal effects of tank-mix pesticides in combination with honey phytochemicals on queen cell nursing behavior and queen quality – May Berenbaum, University of Illinois at Urbana-Champaign, maybe@illinois.edu

We are proposing a follow-up study that may lead to changes in beekeeping practices that can improve the success of queen-rearing. Specifically, we would like to test whether the application of fungicides and tank-mixed insecticides will cause sublethal effects on the nursing behavior of workers. Johnson and Percel (2013) demonstrated that the common orchard insecticide diflubenzuron was likely responsible for problems in queen-rearing operations. So, we will include diflubenzuron as a positive control in this experiment. We also want to test whether dietary phytochemicals may “rescue” queen-rearing behavior impaired by pesticide ingestion, much as it can “rescue” bees from longevity-reducing effects of ingesting pesticides (Liao et al. 2017). Finally, as there is a relationship between quality of queen and performance in mating flight, we will evaluate, by using a flight treadmill, we propose to measure the flight performance of queens reared by nurses consuming different pollen diets.

2015 – Do bees self-medicate? An examination of the impacts of xenobiotics on anti-viral defenses in honey bees – Diana Cox-Foster, Penn State University, dxc@psu.edu

We propose to assess whether immune-challenged honey bees would actively seek p-coumaric acid, nicotine or caffeine, with choice experiments using sucrose solutions containing different concentrations of p-coumaric acid, nicotine, or caffeine, versus sucrose alone. We also propose to address the effect of chronic exposure of Imidacloprid and phenolic nectar on the viral pathogens and immunity related genes in honey bees. Given that transmission of viruses between species is through a fecal/oral route, we will determine if phenolic nectar exposure affects the titers of virus found in fecal materials; alteration of the rate or likelihood of viral transmission would impact pollinator health. Potentially, the inclusion of such phenolics in sugar/corn syrup feedings might help to protect honey bee colonies from the interactions of pesticides and diseases in the colony.

2015 – Investigating the effects of fumagillin and other common in-hive xenobiotics on immune function in honey bees – Rodney Richardson, The Ohio State University, richardson.827@osu.edu

Here, we propose to investigate three xenobiotics -- fumagillin, clothianidin, and amitraz -- to assess their capacity to disrupt normal immune function in bees. We will investigate immune effects at two levels of biological organization, in extracted hemocytes and live adult bees. Following xenobiotic exposure in honey bee hemocytes, we will measure rates of reactive oxygen species production and phagocytosis, two important components of insect immunity (Lavine and Strand, 2002). Following xenobiotic exposure in nurse bees, we will assess the viral load of deformed wing virus, quantifying the severity of covert infections. Knowledge gained from our experiments will be informative in the following ways: 1) whether direct effects on hemocytes are generalizable to effects on adult nurse bees, 2) whether sub-lethel exposures to these agents are potentially consequential to honey bee colonies under pathogenic stress, and 3) whether functional screening of hemocytes may be a useful methodology for application to risk assessment.

2015 – Sublethal effects of neonicotinoids (imidacloprid) on embryogenesis, hygienic behavior and grooming of worker honey bees – Elemir Simko, University of Saskatchewan, elemir.simko@usask.ca

The general opinion on the impact of neonicotinoid (neonic) insecticides on honey bee health is extremely polarized and controversial. Scientific studies are often contradictory. Policy makers and regulatory agencies among various countries have taken different and sometimes completely opposite positions. It is obvious that one decade of intense research in this area has not been sufficient for evidence-based decisions and polices. Our hypothesis and proposed histopathological evaluation of impacts of neonics on the embryogenesis of honey bees brings a novel investigative approach in an attempt to resolve these important issues. While application of histopathology is an indispensable tool for the diagnosis of developmental defects and disease in vertebrate species, it has yet to be rigorously applied to the study of honey bee embryogenesis and disease. Furthermore, our research will investigate concurrently the impact of neonics on hygienic behavior and varroa grooming of worker bees and the resultant levels of colony infestation. We hypothesize that sublethal negative effects of low doses of neonics on the embryogenesis and on hygienic and grooming behavior of honey bees contribute to an ultimate decline in the overall strength and viability of the entire overwintering colony resulting in increased winter losses.

2015 – Elucidating the effects of real world pesticide load and diet variety on honey bee health – Dennis VanEngelsdorp, University of Maryland, dennis.vanengelsdorp@gmail.com

There is a general consensus that the three main factors contributing to colony losses are nutrition, pesticides, and pathogens. Here I propose to examine possible interactions between these three factors. I will do this by feeding newly emerged bees diets of single source or multiple source pollen collected from colonies being used to pollinate various crops. We will infect these bees with Nosema ceranae spores and measure their susceptibility to infection. Further, our analysis of pesticide levels in these diets will help us elucidate the role that real world pesticide contaminations of pollen has on bee susceptibility to N. ceranae. Importantly, we will be able to look at the role (if any) a varied diet has on mediating the negative effects of pesticide exposure.

2015 – Assessing the impact of pesticides on honey bee health using a network of controlled, experimental hives – Scott Mcart, Cornell University, shm33@cornell.edu

Studies that fall in between observational and manipulative can provide the necessary bridge to understanding how pesticide stress that bees are experiencing in the real world is (or is not) related to reductions in colony performance and health. Surprisingly, such a study is absent from the literature to date. To fill this gap, we are proposing to conduct a highly controlled field experiment using a network of experimental hives. Each hive will be delivered to beekeeper locations throughout the state, along with one of 120 nucleus colonies (4 colonies per beekeeper, 30 beekeepers total). By supplying each beekeeper with identical pesticide-free experimental hives and bees from the same genetic source, maximum control will be achieved for subsequent measurements of colony performance among beekeepers and sites.

2014 – Exposure of honey bees to neonicotinoids in corn guttation fluid – Jonathan Lundgren, South Dakota State University, jgl.entomology@gmail.com

Corn guttation fluid may pose a potentially high toxicological risk to honey bees if neonicotinoids are present (ICPBR 2011, European Commission 2013). Recently Greenpeace released a report on the risks of neonicotinoids in corn guttation fluid, finding lethal concentrations of the neonicotinoids clothianidin and thiamethoxam in some samples (Greenpeace 2013). Based on these results and other studies finding high levels of neonicotinoids in the guttation fluid of corn (Girolami et al. 2009) and other crops such as melon (Hoffmann and Castle 2012), the report urged further study on the levels of neonicotinoids in crops under a variety of growing conditions and research on the extent to which honey bees use guttation fluid in cropfields as a source of water.

Because all of the corn guttation fluid studies were conducted in Europe (Girolami et al. 2009, Pistorius et al. 2011, Greenpeace 2013) and soil and climatic conditions can affect the distribution of neonicotinoids (Pistorius et al. 2011), research is needed evaluating levels of neonicotinoids in North American corn guttation fluid. In addition, to our knowledge no field studies have observed honey bee use of corn guttation fluid, although one field study observed honey bee use of oilseed rape guttation fluid (Joachimsmeier et al. 2011b). This information is critical to determining the extent to which honey bees may be exposed to corn guttation fluid in the field.


1) We will measure levels of clothianidin in corn guttation fluid to determine the level of toxicity present in cornfields adjacent to honey bee hives in eastern South Dakota.

2) We will record the extent to which honey bees are exposed to clothianidin in guttation water in cornfields.

2013 – Behavioral responses of honey bees, Apis mellifera, to neonicotinoid insecticides – Catherine Dana, University of Illinois at Urbana-Champaign, cdana2@illinois.edu

While many recent studies have addressed the sublethal effects of pesticides in honey bees, there have been very few that examine how and when honey bees come into contact with pesticides in their environment. Although honey bees possess few gustatory receptors, they have been shown to detect some toxins that might be present in nectar sources (Wright et al. 2010). A recent study showed that neonicotinoids can have impacts on foraging behavior, by turning bees into potentially “picky eaters” (Eiri and Nieh 2010).

Hypothesis: Honey bees can behaviorally avoid exposure to neonicotinoid pesticides and their metabolites that they encounter in agricultural nectar and pollen sources.

2011 – Honeybees and field crops: What fills the risk cup for honeybees foraging in areas of corn and soybean production? – Christian Krupke, Purdue University, ckrupke@purdue.edu

We plan to continue and expand our 2010 studies with some key alterations: we will plant fields of treated and untreated corn during the standard April/May period. This past season, after we were first alerted to the problem in late April, we were unable to begin our experiments until June/July. This results in different foraging opportunities for bees than the late spring planting that dominates the Midwest. To investigate whether talc exhausted from planters may be contaminating both nearby flowers/pollen and the bees themselves, we will plant cornfields surrounded with hives with both treated and untreated corn. These fields will be located a minimum of 1 km apart and each seed type will be planted both with and without an exhaust filter (i.e. 4 combinations). Using the techniques described above, we will sample the bees themselves and pollen collected from pollen traps both before and after planting.

Our preliminary data suggest that talc exhausted from corn planters presents a potential route for large volumes of pesticide abraded from treated seed to enter the environment where honeybee foragers may contact it. We expect this study to help quantify this risk further and ultimately lead to planting modification recommendations for growers that will help safeguard pollinators and other non-target insects near production fields.

2010 – A survey to determine imidacloprid contamination in water sources used by honeybees – Josephine Johnson, USDA-ARS Bee Research Laboratory, jdjohnson@epi.umaryland.edu

Imidacloprid (IMI), a neonicotinoid pesticide, is water soluble and has had sub-lethal effects on honey bees. The intent in this study was to determine the presence of IMI in water sources frequented by honey bees across the state of Maryland. Rural, suburban, and urban sites were chosen for sampling and IMI was found in 9 samples at a range of 7 -131 ppb in a total of 108 samples. Thirteen other samples gave results at the threshold of detection (0.2-.3ppb). Positive samples accounted for 19 % of all samples. Water sampling occurred on Jun 1-2, 2010 and ELISA results were available in Sept 2010 .The decision was made to resample positive samples on Oct 15-18, 2010 and to assay them by GC/MS as a comparison of methodology and time lapse in IMI concentrations. The results of the October samples (analysis completed on Nov 20, 2010) generally showed smaller concentrations, perhaps due to degradation of IMI in the environment or a cleansing by environmental circumstance (rain, snow). Notably, some samples that had shown no detection in June showed positive detection of IMI in October suggesting that concentrations of IMI in water sources may shift as water shifts or as weather, the environment, or human interactions change circumstances. In conclusion, this study showed that imidacloprid is present in 19% of water sources frequented by honey bees and the levels of imidacloprid shift with time presumably due to changes from weather, environment, degradation, and human interaction.

2010 – CCD and the empty-colony syndrome: effect of the pesticide imidacloprid on honey bee distance estimation – James Nieh, UC San Diego, jnieh@ucsd.edu

Much attention on honey bee declines has focused on the sublethal effects the pesticide, imidaclorpid, has on honey bee behavior. How it affects individual foragers and their ability to navigate to communicated food sources or their preferences for nectar is unknown. Using tunnels to provide optic flow, preliminary data suggest that bees treated with sublethal doses of imidacloprid travel shorter distances than control bees to a trained location. We also use the proboscis extension reflex (PER) assay to test an individual’s response threshold. Bees treated with the pesticide have higher response thresholds and respond less often to high concentrations of sucrose than control bees. The navigational inefficiency and increased preference for sweeter sucrose concentrations may contribute to a colony’s decline.

2009 – The effects of pesticides on immature honey bee (Apis mellifera) development – James Ellis, University of Florida, jdellis@ufl.edu

The overall objective of this research project is to determine the effects of pesticides on immature honey bees. More specifically, a UF post doc will determine the LD50 values of 5 insecticides (chlorpyrifos, imidacloprid, amitraz, fluvalinate, coumaphos), 2 fungicides (mycobutanil, chlorothalonil), and 2 herbicides (glyphosate, simazine) on developing bee larvae and pupae. Based on earlier data collected by my lab, I hypothesize that exposure to these pesticides while feeding will significantly reduce the probability that larvae will survive to adulthood. This effort is consistent with the North American Pollination Protection Campaign’s priority research areas, specifically area 2 as outlined in the call for proposals. Furthermore, the pesticidal effects I propose to investigate—those on immature bees rather than on adult ones— are novel, often being overlooked in general toxicological studies targeting honey bees.

2009 – Sublethal effects of pesticide combinations on honey bee (Apis mellifera L.) larval development and adult associative learning – James Frazier, Penn State University, jff2@psu.edu

There have been numerous studies done on acute and sublethal effects of single pesticides on adult honey bees, however few studies have examined the effects of pesticides on larval honey bee development and how this exposure may translate into a decreased fitness once reaching adulthood. Our recent work shows that bees are readily exposed to numerous pesticides in their pollen food as larvae and this may cause both neural and hormonal changes that may alter development (Mullin et al. 2009). The proposed research will examine how individual and combinations of commonly encountered pesticides affect larval development, survival, and adult learning capabilities. This research will further our understanding of the roles of combinations of pesticides within the hive and how they influence honeybee learning capability necessary for successful foraging and numerous communication tasks.

2008 – Assessment of Sublethal Effects of Imidacloprid on Honey Bee and Colony Health – Galen Dively, University of Maryland

While the extent and causes of CCD are unknown, many believe that honey bees have reached a tipping point wherein the colony can no longer protect itself from a barrage of problems. The CCD Working Group developed an action plan of research that addresses four categories of factors that impact bee and colony health: 1) new or re-emerging pathogens; 2) bee pests; 3) environmental and nutritional stresses; and 4) pesticides. This project will address the latter category and examine the sublethal effects of pesticides, which is one of the priority areas identified by the HBHI Task Force for funding.

Genetic Stock Improvement of Honey Bee Populations

2019 – Breeding tolerance to DWC in honey bees – Margarita Lópex-Uribe, Penn State University, mml64@psu.edu

The associations between Varroa mites, DWV and other viruses have been directly linked to the high proportion of colony losses that beekeepers are experiencing in the United States (US). Our recent studies of feral honey bees—surviving colonies that live in wild conditions without beekeeper management for at least one winter—have elucidated striking differences on disease dynamics between feral and managed colonies. Specifically, we have found higher pathogen pressures in feral compared to managed colonies but similar overwintering losses between the two groups. These results suggest that feral honey bees may be more tolerant of DWV (a virus transmitted mostly by varroa mites) than managed colonies and creates a unique opportunity for the identification of biomarkers that can be used for breeding disease tolerant honey bees in the US. The goal of this project is to use genomic assisted approaches to (1) identify the genetic basis of traits for viral tolerance, and (2) run a pilot study to quantify and identify genetic differentiation across the genomes of feral populations. Funds for this project to pinpointing biomarkers of tolerance to DWV tolerance in feral honey bee colonies will facilitate the development of a methodology that can be implemented in North America to create effective regional honey bee breeding programs.

2018 – Identifying key loci for honey bee stock improvement using genomic signatures of selection in Africanized bees – Erin Calfee, UC Davis, ecalfee@ucdavis.edu

This study uses the Africanized honey bee invasion to characterize the genetic basis of honey bee fitness in the context of current ecological and environmental stressors such as Varroa mites and other pests and pathogens. Novel statistical methods will be applied to identify signatures of natural selection in bees sampled across two African-to-European ancestry transition (hybrid) zones, in California and Argentina. The primary result of this research will be a prioritized list of high-fitness Africanized loci that will be published as an open-access community resource to inform marker-assisted breeding of genetically more robust bees. Africanized bees are a rich genetic resource because African ancestry (A) has 2-3 times more genetic diversity (π) than European ancestry and is associated with high fitness. In fact, the higher fitness of Africanized honey bees has allowed them to outcompete European bees across much of the Americas in less than 50 years. Specific genetic advantages of Africanized bees include resistance to Varroa mites, the number one reported cause of colony loss, and twice the tolerance of European bees to three classes of widely used insecticides.

Major Aim of the Project: Identify high-fitness resilience alleles using genomic signatures of selection in Africanized honey bees.

2014 – Honey bee hemocyte profiles associated with winter hardiness – James Burritt, University of Wisconsin-Stout, burrittj@uwstout.edu

Several independent lines of evidence indicate honey bee pathogens are an important contributing factor of winterkill in hives. For instance, stress on bees caused by Varroa destructor mites and viral diseases they transmit amplify problems in overwintered colonies. In response to this problem, strategies are needed to develop new strains of bees with better resistance to bee pathogens, resulting in improved winter hardiness. However, few parameters are currently available that can be directly measured to help monitor disease resistance in bees. Our proposal describes a novel method to “fingerprint” the cellular immune profiles of honey bees, thereby providing a new way to characterize their defense capacities. Some of these immune functions are likely to be crucial in mitigating the effect of Varroa mites and associated viral infections. If these immune factors can be identified and selected in bee rearing programs, winter survival of bees will improve.

2013 – Sustainable approaches to improving honey bee disease: a pilot experiment – Maryann Frazier, Penn State University, mfrazier@psu.edu

Several groups of northern beekeepers across the US (including in Pennsylvania) are attempting to develop commercially viable local queen-rearing businesses, under the hypothesis that locally reared stock will perform better. Indeed, previous local breeding efforts for parasite resistance have been successful, since there is considerable genetic variation in honey bee populations in terms of pathogen and parasite resistance (Spivak and Gilliam, 1998; Harbo and Harris 1999; Spivak and Reuter 2001; Ibrahim and Spivak, 2006). However most northern breeding operations are relatively small, with limited numbers of colonies to select from, and there are no standardized protocols available for assessing stocks.

In this proposal, our objectives are to: (1) Determine if, in northern climates, northern-reared stock is indeed superior to southern-reared stock. (2) To assist northern beekeepers in developing high-quality and reliable sources of local queens and bees.

2011 – Genetic evaluation of a surivior stock in the northeastern United States: the honey bees of Arnot Forest – Thomas Seeley, Cornell University, tds5@cornell.edu

Our proposed investigation will include two parallel avenues of study. In the first, we will see if the feral bees living in the Arnot Forest are genetically distinct from the closest managed bees living outside the Arnot Forest. In the second, we will see if the intracolonial genetic diversity is higher for the feral bees living in the Arnot Forest than for the managed bees living nearby. The first line of study will address the possibility that the honey bee colonies in the Arnot Forest are not a self-sustaining population of healthy colonies, but are instead a “death row group” that persists only through input of swarms from managed colonies outside the forest (i.e.,“escaped swarms”). The second line of study will test the hypothesis that the honey bee colonies in the Arnot Forest are able to persist without human assistance at least in part because they have an exceptionally high level of intracolonial genetic diversity. We will compare the colonies in the Arnot Forest to the closest managed colonies outside the forest in terms of intracolonial genetic diversity to see if higher genetic diversity could be contributing to the survival of the Arnot Forest bees without mite-control treatments or other forms of assistance from beekeepers.

2010 – Selection of honey bees for resistance to Nosema ceranae – Jose Villa, USDA-ARS Honey Bee Breeding Laboratory, jose.villa@ars.usda.gov

N. ceranae is a widespread fungal parasite in beekeeping operations throughout North America. We surveyed the possibility of genetic resistance in ten commercial sources from a wide array of geographic and genetic origins. Queens from the ten sources were introduced into colonies kept in an infected apiary that received no treatment. Surviving colonies with original queens were sampled monthly from May 2010 to April 2011. Overall average infections through samplings for one year were moderately high (about 1 million N. ceranae per bee) but did not differ between sources. Infections in colonies from the same source varied greatly at each sampling time. Also, infection in most colonies fluctuated widely through time. A small proportion of the surviving colonies have been identified as having relatively low or high infections. Their workers will be tested in standardized, laboratory cage tests for responses when fed spores of N. ceranae. This research is part of a larger project at our laboratory using different approaches to find genetic resistance to this parasite.

2009 – Genes over expressed in Varroa resistant honey bee strains: a novel tool to identify and select enhanced Varroa resistant honey bees – Spencer Johnston, Texas A&M University, spencerj@tamu.edu

We propose to use the best-studied Varrao resistance lines and employ a Roche-Nimblegen tiling array to identify all genes that are differentially upregulated in Varroa resistance. The proposed method is a breakthrough – a sophisticated, novel molecular analyses of resistance that could not be conducted except for information contained in the completed honey bee genome. All too little is known about the mechanisms of resistance and even less is known about the differences and similarities among Varroa resistant and Varroa sensitive strains. This research will identify existing strains that harbor hidden genetic resistance variation. Without appropriate identification tools, undetected sources of resistance will likely be lost in the intense selection effort needed to produce a fully resistant honeybee.

2008 – Diagnostic gene panel for honey bee breeding and disease management – Jay Evans, USDA-ARS Bee Research Laboratory, jay.evans@ars.usda.gov

Honey bees face numerous challenges, from nutritional stress to dedicated parasites and pathogens. A long-term goal of bee research is to develop and maintain honey bee lines that are resistant to disease, and that thrive with a minimum of chemical treatment of disease agents. New molecular-genetic tools can aid research on breedable traits, and, ultimately, these tools could be used directly by commercial bee breeders or others in the private sector. Beekeepers also rely on disease indicators and established thresholds while making management decisions. Such decisions could also be helped by genetic indicators for pests and for bee health.

This gene panel would differ from previous entries into disease forensics (e.g., Evans, 2006) by including only the most informative markers, alongside reportable diseases found in bee colonies. In so doing, the panel can be cheaply applied to bee problems, and can also be ‘exported’ to future technologies for bee diagnostics and genetic research.

2008 – Enabling genetic selection for resistance to viral pathogens: Developing a rapid and inexpensive cytometric method for screening honey bees for viral resistance – Spencer Johnston, Texas A&M University, spencerj@tamu.edu

Preliminary evidence suggests that honey bee strains are more resistant to IAPV than honey bee lines from other sources. We propose to use quantitative PCR, flow cytometry and direct monitoring of colony health to rapidly compare changes in blood cells number, pathogen titre and colony level response. We hypothesize that it will be possible to use flow cytometry to distinguish resistant bees from susceptible bees and evaluate the efficacy or extent of immune response to viral infection. If we are correct, then the results of the flow cytometry experiments could be used (in the place of more time consuming and expensive field trials) to quickly assess the presence or absence of viral resistance in aid of breeding programs to develop or propagate virus resistant honey bees. Perhaps more importantly, flow cytometry should reveal whether differential immune responses correlate with virus resistant phenotypes, offering clues to some mechanisms of viral resistance.

Effects of Climate or Environmental Variables on Honey Bee Pests, Pathogens, and Disease Incidence

2020 Effects of landscape and floral resources on population density, honey composition, nutritional stress and prevalence of parasites and pathogens in Apis mellifera in Mexico – Mauricio Quesada, Universidad Nacional Autónoma de México, mquesada@cieco.unam.mx

The overall objective of this proposal is to determine the effect of the combined factors of landscape composition and the spatio-temporal dynamics of floral resources on the status of population density, nutritional stress and prevalence of parasites and pathogens in colonies of honey bees. In this study, we will to: 1) Perform metagenomic characterization of honey across five beekeeping regions of Mexico, 2) Determine the nutritional quality of honey through the content of protein, fatty acids and carbohydrates, 3) Determine the effect of landscape composition on colonies health (measured as worker density and protein content in worker honey bees), and 4) Evaluate the effects of diversity of floral resources, genetic ancestry, and incidence of parasites and pathogens on hives nutritional status.

2017 – Location, Location, Location: Developing tools for selection and management of landscapes to promote healthy bee populations – Tyler Jones, Penn State University, toj2@psu.edu

We have recently developed a generalized index of “Forage Resource Quality” in the landscape and we are currently developing an index of agricultural pesticide use. We will use these indices to map the forage quality and pesticide us in Pennsylvania. We have also developed a network of citizen-scientist beekeepers around Pennsylvania (31 beekeepers representing 33 locations), who are providing monthly reports of their colony health metrics, survival, and management practices. Here, we propose to (1) increase our citizen scientist network, and (2) evaluate and improve the predictive power of our current models of forage quality and pesticide exposure risk using data collected from participating beekeepers.

2014 – Assessing the role of environmental conditions on efficacy rates of entomopathogenic nematodes for controlling small hive beetles in honey bee hives - a citizen science approach – Elizabeth Hill, Center for Urban Bee Research, izzy@urbanbeeresearch.org

Certain species of entomopathogenic nematodes (EPNs) have the potential to be effective controls for small hive beetles (Aethina tumida) in honey bee (Apis mellifera) hives—even more so than standard cultural and mechanical controls (Ellis et al., 2010; Schäfer et al., 2010). However, these nematodes are often incorrectly assumed to be ineffective as they are frequently applied in unsuitable environmental conditions by beekeepers who are untrained in application methods. In order for EPNs to be a useful Integrated Pest Management (IPM) tool, they must be applied correctly and be an economically feasible treatment for beekeepers. This proposal addresses these issues by training beekeepers on how they themselves can create ideal environmental conditions for nematodes and rear an especially efficacious species of EPN—Heterorhabditis indica—using materials that can be found around their own homes. These beekeepers will then be invited to participate in a small hive beetle research program during the 2014 season. They will have access to an online database where they can enter information about environmental conditions, treatment results, and overwintering survivorship of control versus treatment hives. Data collected through this online database will then be analyzed through regression analyses to better understand (1) what factors drive efficacy rates when applying nematodes for A. tumida control and (2) overwintering impacts from EPN applications.

2014 – How do drought stress related alterations to floral traits and reward profiles in canola influence honey bee foraging and colony health? – Arathi Seshadri, Colorado State University, arathi@colostate.edu

Although, the majority of our food crops are wind pollinated, with increasing need for alternate energy sources, insect pollinated oilseed crops of the Brassicaceae family, including canola, mustard, camelina etc., are expanding in acreage as biofuel crops. In this project, we aim to study the floral reward profile in canola, a cross-pollinated, edible oil and biofuel crop, grown under drought stress in Colorado. A comparison of the reproductive investment (flower number, size and reward profile) between two treatments – rain fed (drought stress) and irrigated, will provide information on the reward quantity and quality, available to pollinators foraging on plants growing under stress. By determining bee colony performance when placed in canola fields in the above two treatments, we aim to explain how stressful growing conditions for plants can affect pollinator health via the quality of forage obtained.

2013 – Plant-pollinator interactions across a disturbance gradient – Karlie Carman, University of Central Florida, karlielino3@knights.ucf.edu

This study will investigate how increased levels of disturbance of natural scrub habitat impacts flower visitation by bees and whether the level of disturbance in a system can predict a change in honey bee flower visitation. This study will provide data that applies not only to those natural systems with the threat of alteration, but also agricultural systems which heavily rely on honey bee pollination services.

The focus of this study is to determine network structure of plant-bee interactions, how interactions change across a disturbance gradient, and how habitat alteration impacts individual players in a network. This will be accomplished by gathering bee-flower visitation data on all flowering plants in a system across a disturbance gradient.

Development of Diagnostics or Indicators for the Presence of Stressors that Affect Honey Bee Health

2016 – Development of novel Nosema infection assays for diagnostics – Jonathan Snow, Barnard College, Columbia University, jsnow@barnard.edu

In non-model organisms such as Nosema ceranae, tools for immunofluorescence are limited, so we hypothesized that dyes used to identify specific cellular structures in live cells might allow for recognition of non-spore stages of the parasite. In fact, we have found that Lysotracker dyes, which specifically mark acidic vacuoles, allowed visualization of non-spore stages of Nosema in lysates from infected midguts and stained vacuole-like structures in these cells. As honey bee cells are lysed by this treatment, background staining of these structures from honey bee cells is minimal. Thus, we hypothesize that alternate cellular dyes might also provide potential tools for quantification of Nosema infection in the lab and in the field.


1) To develop the method using chitin-binding dyes for diagnosis of Nosema infection in the field by beekeepers.

2) To develop the use of alternate cellular dyes as a tool for quantification of Nosema infection.

2012 – Honey Hydrogen Peroxide: Diet Effects and Use as a Colony Stress Indicator – Berry Brosi, Emory University

It has been known for a half---century that honey bees add hydrogen peroxide (H202) to honey and that H202 has a strong antibacterial effect arising from the oxygen free radicals that it produces. While this mechanism in its role as a preservative food stores is well understood, it is also known that all organisms are to some degree susceptible to oxygen free radical damage. In this project we built from previously collected pilot data to explore the potential that honey H202 production may comprise a generalized colony defense mechanism, beyond its role as a honey preservative. Our project had two specific aims: 1) Investigate the effects of supplemental sugar feeding on honey H202, with a particular emphasis on supporting H202 production 2) Investigate the potential for using honey H202 as an early---warning indicator of colony stress.

2011 – Forager Energetic Stress as a Casual Mechanism for the Depopulation of Honeybee Colonies – Christopher Mayack, Colorado State University, chris85@rams.colostate.edu

The project proposed aims to 1) investigate if energetic stress can uncouple the energetic state of the individual from that of its colony and 2) determine if hemolymph trehalose levels can act as a modulator of individual foraging regulation independent of colony social cues such as colony demand of nectar. The experimental treatment will mimic the pathophysiological effect of a disease such as Nosemosis caused by N. ceranae in which the additional energetic demand from the pathogen can possibly dissociate the colony and individual energetic states (Mayack and Naug 2010).

2008 – Changes in hormonal and protein levels in honey bees that are experiencing migratory transportation – Zachary Huang, Michigan State University, jeff.pettis@ars.usda.gov

Aside from pesticides, perhaps the strongest stress honey bees experience comes from long distance transportation, commonly used for pollination purposes. For example, bees can transported from Maine to California, across four different time zones. No studies have ever been conducted to determine the physiological or behavioral changes induced by such stress. In this study, I propose to piggyback with Dr. Jeff Pettis’s group to obtain data on physiological changes in honey bees that are experiencing migratory transportation. The objectives of this study is to 1) measure changes in juvenile hormones in bees that are being transported from Florida to California, and 2) determine the protein nutrition of the same bees. Proper control will be obtained from bees which are staying in Florida.


This program is supported by USDA APHIS who works to protect honey bees, managed bumble bees and other managed pollinators, and native pollinators, by conducting research, surveys of pathogens and diseases, and regulatory oversight of pollinator imports and interregional movements. APHIS is a multi-faceted agency with a broad mission area that includes protecting and promoting U.S. agricultural health, regulating genetically engineered organisms, administering the Animal Welfare Act and carrying out wildlife damage management activities.