Part 2
https://doi.org/10.55406/ABRC.5.26.1
This is the second part of the ABRC proceedings. Part 1, was published in the previous issue of Bee Culture (Edward Hsieh and Walsh, 2026).
The editors of the 2026 ABRC Proceedings:
Edward Hsieh1,2 and Elizabeth M. Walsh1
1USDA-ARS, Honey Bee Breeding, Genetics, and Physiology Research, Baton Rouge, LA, USA
2ORISE-ORAU, US DOE, ARS Research Participation Program, Oak Ridge, TN, USA
Topic: Physiology
Impact of exposing bees to antibiotic residues in pollen
Poster presentation
Bhimavarapu K, Santana-Pereira ALR, Standley JM, Williams GR, Huber L
Our study aims to infer the effect of directly exposing bees to tetracycline concentrations reported in pollen in nature. In this controlled cage experiment, honey bees were fed pollen containing a low dose (11 ppb) and a high dose (280 ppb) of tetracycline previously reported in pollen collected from nature. For comparison, a control group was included in which pollen without antibiotics was offered to the bees. Mortality rates were recorded for all groups. Gut samples from both live and dead bees from all-time points were processed, and metagenomic sequencing was performed to compare the microbiome and resistome of bees in the 3 different treatment groups. The analysis revealed that bees exposed to antibiotics in pollen under controlled conditions have a significantly lower survival rate, change in microbiome composition and higher Shannon diversity compared with the bees in the control group. Moreover, bees exposed to the highest dose (280 ppb) of antibiotics had a higher relative quantification of antimicrobial resistance genes (ARGs) than bees exposed to the lowest dose (11 ppb) over time. This result demonstrates that even low, environmentally realistic doses of antimicrobials present in pollen are sufficient to impact bee health.
Examining the impacts of heat stress on honey bee physiology
Oral presentation
Chakrabarti P, Baugus L
Rapidly shifting climatic variable can impose stress on pollinators in several ways. Heat stress is one such factor which has been shown to affect plants and pollinators. This presentation will delve into the impacts of heat stress on honey bee survival, physiology and gut microbiome.
Assessing adult honey bee weight during a 10-day adult chronic laboratory bioassay
Oral presentation
De Souza DA, Zuber J, Olmstead A, Feken M, Singh R, St Clair A, Schmehl D
Adult honey bee toxicity data are required by global regulatory authorities to evaluate lethal and sublethal effects resulting from chronic exposed to a given pesticide. Regulatory authorities rely upon lethal and sublethal measurements to assess whether a pesticide may adversely impact pollinator health. Daily food consumption is measured to determine the dose of the pesticide ingested by the bees, yet food consumption measurements may also be considered by regulatory authorities as a surrogate for individual growth. The aim of our study was to investigate whether food consumption measurements can serve as a surrogate for individual growth. Young adult worker bees were provided with varying volumes of 50% (w/v) sucrose solution over a 10-day study duration and were repeated across three laboratories. Results from the ad libitum feeding group showed no significant weight changes over the 10-day exposure. Notably, body weights in control groups varied across replicates and throughout the test duration, and reduced food intake was linked to weight loss and/or higher mortality only under strict food limitations. Ongoing analyses aim to further elucidate the interplay between food consumption, body weight, and survival, thereby informing how adult consumption measurements in laboratory bioassays can be applied to a pesticide risk assessment.
The Effects of Heat Exposure on Drone (Apis mellifera) Competence
Oral presentation
Jendresky S, Fisher II A
Ongoing and expected global temperature increases threaten many organisms including pollinators critically important for human food production. The honey bee (Apis mellifera) exhibits numerous negative outcomes of temperature-related stress. Drones undergo key physiological processes during development, heat stress at this time has been shown to affect reproductive competence, body mass, and survivorship. Drone brood may be particularly vulnerable since they require a narrow range of rearing temperatures for optimal development and are exposed to greater fluctuations in temperature. To assess the consequences of heat stress on drone performance, Drones were maintained at supra-optimal temperatures during adulthood. Cognition, flight performance, and navigation were evaluated between different rearing temperatures. Heat exposure is expected to reduce learning and memory capabilities, maximal flight performance, and impair navigational capacities. These outcomes will elucidate sub-lethal effects resulting from climatic warming on honey bee drones.
Developing a novel immunohistochemistry system to study Deformed Wing Virus
Oral presentation
Santos RI, de Souza D, Tarpy DR
In our studies, white-eyed honeybee pupae were removed from combs using ethanol-cleaned forceps and placed in 24-well plates for rearing at 35°C and 70% relative humidity. Sixteen pink-eyed pupae per dose group were inoculated with 10 μL of DWV-A or DWV-B, using doses from 0.01 vp/μL to 10,000 vp/μL. Development of deformed wings, discoloration, shortened abdomens, or death at any dose was recorded. A biphasic mortality curve was observed for both DWV-A and DWV-B, with approximately 50% mortality at 0.1 vp/μL (low dose) and a second peak of ~30% mortality at 10,000 vp/μL (high dose). Histopathological analysis of low- and high-dose groups showed DWV mainly in the midgut, in oenocytes in the fat body, and in neuronal tissues such as the brain and nervous ganglia. High-dose infections increased viral spread to the brain, where DWV was detected before 2 dpi. In our persistently infected controls, the virus was consistently detected in the head, in cells that resemble trophocytes. These results show a dose-dependent pattern of DWV tissue tropism and provide a methodological framework for expanding infectivity and pathogenesis studies in honey bee pupae.
Honey bee hemocyte biology: Defining microRNA profiles in immune cell populations
Oral presentation
Tasnia N, Oeth M, Kumar D, Karim S
Small non-coding RNAs regulate gene expression in insects, including honey bees (Apis mellifera). In arthropods, miRNA-mediated regulation shapes development, immunity, and pathogen resistance. We conducted a consecutive 25-day study to define miRNA profiles of bees maintained under hive and cage conditions. Hemolymph was sampled daily from day 1 to 25 to compare hemocyte populations and cellular characteristics. In parallel, 18 small RNA libraries from Day 1, 10, and 20 hemolymph samples were sequenced to characterize the small RNA landscape in both environments. Hive-maintained bees consistently showed stronger cellular immunity, with significantly elevated granulocytes, plasmatocytes, prohemocytes, and oenocytoids, along with more organized cytoskeletal structure and higher lysosomal activity. In contrast, cage-maintained bees exhibited reduced survival, higher hemolymph volume, and accelerated declines in total and differentiated hemocytes. Sequencing yielded over 600 million reads and identified 175 miRNAs (170 known, 5 novel). Differential expression analysis revealed significant age and environment-dependent miRNA regulation. Immune-associated miRNAs including miR-34, miR-277, miR-279, miR-315, and miR-6001 showed strong differential expression and are predicted to interact with IMD, JAK/STAT, and Wnt signaling pathways. These findings indicate dynamic miRNA involvement in honey bee immune development and provide a foundation for future functional assays to define miRNA roles in innate immunity.
Topic: Varroa
Evaluation of delivery methods for the entomopathogenic fungus Beauveria bassiana in honey bee colonies for the control of Varroa destructor
Oral presentation
Ahn D, Arends J, Hack R, Johnson RM
Varroa destructor is a major driver of global honey bee declines, and resistance to synthetic acaricides has reduced the effectiveness of conventional control methods. Other chemical agents also pose risks to bee health and often show temperature-dependent limitations. As a biological alternative, entomopathogenic fungi have recently gained attention. In our preliminary cage study, we assessed the performance of Beauveria bassiana strain HF23 against Varroa mites and its safety to honey bees. Treatment with B. bassiana spores achieved an average mite-control efficacy of 94%, which was 57% higher than the untreated control (p < 0.005). Bee mortality did not differ between treated and control groups, demonstrating that the formulation was safe for bees. Building on these results, we investigated how spores spread and persisted within colonies by using fluorescein-stained spores, because B. bassiana infects arthropod hosts by attaching to the cuticle, germinating, and penetrating the integument to cause death. Among application strategies, applying spores to the top of the hive produced the most uniform distribution across bees, while entrance-based bottom application yielded poorer coverage. However, spore persistence declined rapidly within 24 hours for all methods, likely due to bees’ intensive grooming behavior, highlighting the need for improved delivery approaches.
How queen genetics emerges as the dominant determinant of Varroa dynamics within apiaries.
Oral presentation
Bartlett LJ, Binnie B
Herein I’ll present two quite different and separate studies which converged on the topic of queen genetics as it pertains to Varroa control: one beekeeper-led case of participatory science looking at queen bee breed and method of oxalic acid application for Varroa control across >800 colonies; and one purely theoretical modelling exercise using a newly-derived, coupled honey bee population x Varroa population growth model which explicitly accounts for movement of Varroa via drift and robbing. In the first empirical instance, we will see how the explanatory power of queen genetics rivals or even outweighs the effect size of ‘treatment’ on determining end-of-Summer Varroa counts in colonies. In the second theoretical instance, we show how queen genetics as it relates to permissiveness of Varroa replication can either shield or doom whole apiaries even with mixed-breed beekeeping. We’ll discuss the unanticipated consilience between the two.
Addressing the challenge of amitraz resistance: Varroa treatment recommendations for commercial beekeepers
Poster presentation
Cauvel J, Lee K, Rinkevich F, Milbrath MO
The parasitic mite Varroa destructor (varroa) is one of the primary causes of honey bee colony loss. Most commercial beekeepers have used the miticide amitraz to combat varroa infestations, but in recent years varroa mites have developed resistance. The objective of this work is to evaluate multiple varroa control strategies in a commercial beekeeping operation to develop guidelines for beekeepers, reducing the reliance on amitraz-based products. The 240 honey colonies from one commercial beekeeper were evaluated at four timepoints of the 2025 season. At each timepoint hive health metrics were taken including cluster size, queen status, mites levels, and nosema. Colonies received three treatments during the season: in May, colonies received either amitraz or formic acid; in June colonies received Formic pro, VarroxSan, Formic pro + VarroxSan, Towel Oxalic Acid, or no treatment (N=24 each group). In August (post-harvest), colonies received amitraz, VarroxSan, Formic pro, or Apiguard. Hives treated with Amitraz at timepoint 1 and 2, had significantly higher mite loads when compared with hives that received formic pro at timepoint 1 and 2. However, percentage growth of the colony between timepoints did not differ between treatment groups. These findings confer with previous studies that indicated a resistance to amitraz. This study suggests that relying on amitraz alone is an insufficient miticide strategy.
Mighty resistance: An exploration of the prevalence and mechanisms of amitraz resistance in Varroa destructor sampled from across the nation with an emphasis on Florida apiaries
Poster presentation
Epperson KJ, Jack C, Fulton JC
Amitraz has been beneficial in combating the ectoparasitic mite of honey bees, Varroa destructor. The acaracide targets the octopamine receptors of the mite; as an analog to adrenaline, it dictates responses for motor function, stress response, and sensory pathways. Resistance to amitraz has continued to build over the past few decades, with the possible cause being attributed to single nucleotide polymorphisms (SNPs), or a single nucleotide genetic change. Various SNPs have been reported in Asia, Europe, and North America. The presence of these SNPs in the United States has not been extensively studied, nor has the effect of these resistant mites on honey bee colonies. This study aims to investigate these gaps in two components. First, a survey of Varroa destructor populations from Florida apiaries and from the National Honey Bee Survey will be tested and analyzed for these SNPs. Second, colony strength parameters such as brood area and productivity, and pathogen screenings will be monitored throughout four complete brood cycles. Both components would determine the extent of resistance prevalence and taxation on colonies.
Characterization of immune cells in the hemolymph of Varroa destructor.
Poster presentation
Gonzalez FN, Oeth M, Kumar D, Amiri E, Goblirsch M, Karim S
Varroa destructor is an ectoparasite of the western honey bee Apis mellifera. It feeds on the body fluids of bees and transmits a wide range of viruses. Few studies have focused on reliable methods for extracting hemolymph from Varroa mites in order to analyze and identify their immune cells. In this study, we characterized Varroa immune cells using a combination of morphological and cellular approaches. Hemolymph was collected by dissecting the idiosoma of adult female Varroa mites, and the immune cell types (hemocytes) were identified based on their morphological characteristics. Hemocyte staining was performed with phalloidin, Lysotracker, and DAPI. Four hemocyte populations were identified using confocal microscopy: granulocytes, spherulocytes, prohemocytes, and plasmatocytes. Granulocytes were the most abundant, followed by spherulocytes and prohemocytes. These cell types showed typical morphological and cellular characteristics without notable variations. The identified plasmatocytes exhibited high morphological variability. These results provide a simple method for isolating Varroa hemocytes for further gene expression studies, which will help us better understand the mechanisms of their immune responses and uncover vulnerabilities that could contribute to improving control strategies against Varroa destructor.
Mitey Metabolism: Investigating Metabolic Mechanisms of Amitraz Resistance in Varroa destructor
Oral presentation
Keenan E, Harris J, Krishnan N, Ahn SJ
Since its host migration to the Western honey bee, the Varroa mite (Varroa destructor, Anderson and Trueman) has become one of the greatest threats to apiculture worldwide. Mite control is now a near-ubiquitous aspect of beekeeping and commercial pollination, with synthetic miticides typically considered the easiest and most cost-effective option. Overuse of these formulations has selected for mites resistant to the formerly popular tau-fluvalinate and coumaphos, driving many beekeepers to rely on the formamidine amitraz. Unfortunately, amitraz resistance was first confirmed in the United States in 2020 and has rapidly spread, with resistant mites potentially contributing to the abnormally high colony losses of the past year (>60%). Our project aims to address amitraz resistance by investigating the underlying metabolic resistance mechanisms. Dose-response assays will be used to characterize resistance phenotypes of mite populations, and discriminatory assays will be used to obtain susceptible and resistant mites for differential gene expression analysis. Combining dose-response assays with transcriptomic data should reveal both the prevalence and potential metabolic drivers of amitraz resistance in Mississippi mite populations. These insights could inform the development of improved amitraz formulations and alternative miticides, thus supporting sustainable Varroa management and safeguarding honey bee health.
Varroa destructor parasitizes virgin queens of Apis mellifera shortly after emergence from their pupal cell
Oral presentation
Lamas ZS, Fife A, Boncristiani D, Chen Y, Evans JD
As the sole reproductive member capable of laying fertile eggs, the queen, has an outweighed impact on the life trajectory of a populous honey bee colony. While viral infections have been shown to impact queen health, and are negatively associated with egg laying, there is scant information regarding Varroa destructor’s direct impact on queen health. We carried out a series of experiments to study if Varroa parasitize unmated (virgin) queens prior to their mating. By using fluorescent microscopy we determined bee material mites ingest while feeding on virgin queens. Next, we screened mating nucleus colonies, observing a significant difference in survivorship between parasitized and non-parasitized queens. Parasitized queens had significantly higher levels of DWV-B, but no significant difference in queen body weight or ovary size. Finally, through a carefully control lab-field trial, we infected virgin queens and then introduced them to mating colonies. Parasitized queens survived at significantly lower rates than non-parasitized queens. DWV-B abundance was significantly higher in queen tissue, and egg progeny in parasitized queens which successfully mated compared to non-parasitized counterparts. Cryptic queen events were observed over two months as colony members persistently attempted to replace queens who were parasitized through the production of supersedure cells.
Improving IPM control of Varroa destructor through miticide resistance monitoring and evaluation of mite-resistant colonies
Oral presentation
Simone-Finstrom M, Rinkevich F, Walsh EM, Ricigliano V, Cook S, Fine J, DeGrandi-Hoffman G, Carroll M, Saelao P, Castillo P, McCarthy J
Multiple IPM strategies are necessary to successfully reduce the impact of the parasitic mite Varroa destructor on honey bee colonies. As part of the USDA-ARS Areawide Pest Management program, miticide use was evaluated in commercial beekeeping operations around the country to determine the persistence of amitraz resistance and efficacy of other available products. Health metrics were compared between colonies treated with Apiguard (thymol), VarroxSan (oxalic acid), a combination of Apiguard and VarroxSan, and a control group treated with the standard miticides used by the beekeepers. To develop additional tools against Varroa, Pol-Line colonies, selected based on Suppressed Mite Reproduction (SMR) phenotyping to identify Varroa Sensitive Hygienic (VSH) behavior, were compared to non-VSH Italian colonies to measure differences in mite and virus loads, population size, and honey production. Stock comparisons took place at USDA locations in Baton Rouge, LA, Davis, CA, Tucson, AZ, and Beltsville, MD. Preliminary results from the first year of these trials will be used to shape the future of these projects and inform best management practices for Varroa control in the future.
Evaluation of the efficacy of promising compounds for the control of Varroa destructor and their toxicity to honey bees (Apis mellifera)
Oral presentation
Petit L, Jack C
To control Varroa destructor, beekeepers currently rely on synthetic acaricides, natural acaricides, and management practices. In the United States, only three modes of action are available among synthetic chemicals, and resistance has been detected for all of them, underscoring the continual need to develop new acaricides that are both effective and safe for colonies. In this study, we evaluated four promising compounds (pyridaben, fenpyroximate, fenazaquin, and carbamate 421) for their laboratory efficacy against mites and their safety for honey bees. Toxicity tests for honey bees included topical toxicity on adult bees, acute oral toxicity on larvae, chronic oral toxicity on adults, and potential synergism/antagonism effect with amitraz. All compounds were less toxic to mites than amitraz. Only carbamate 421 showed lower topical toxicity to adult bees than amitraz, making it the most selective compound. It also demonstrated low oral toxicity for both larvae and adults. Fenazaquin was significantly more toxic to larvae than amitraz, which is concerning given its low selectivity compared to amitraz. Oral toxicity to adults showed no major differences between amitraz, fenazaquin, and fenpyroximate. Finally, fenazaquin and fenpyroximate did not show strong synergistic or antagonistic interactions with amitraz.
A laboratory amitraz resistance assay for Varroa destructor may not be a reliable predictor of field-level amitraz efficacy
Oral presentation
Rawn D, Epperson K, Fulton J, Jack C
Amitraz is used by beekeepers to control Varroa destructor infestations within their colonies worldwide. Evidence for resistant mites continues to be reported and could be a major factor in widespread colony losses. Over two years, we investigated a diagnostic bioassay that tested our mites for susceptibility to amitraz. After diagnosing mites with the bioassay, we genotyped the mites searching for the Y215H mutation of the Octß2 receptor. We found that the diagnostic bioassay accurately predicted the resistant genotype 94.6% of the time, and it accurately predicted the susceptible genotype in 66.8% of mites. Additionally, we performed a standard treatment with the product Apivar®, on the source colonies of these mites. Colonies receiving the Apivar® treatment were categorized by the expected efficacy of amitraz on their mites and a group of colonies was designated as untreated controls. Both high and low expected efficacy groups significantly reduced mite infestations by the end of the treatment period (p=0.0012, p<0.0001 for high, low respectively) compared to control colonies which did not change in mites over the same period (p=0.9757). The diagnostic bioassay was a strong predictor of the genotype of V. destructor, but it was not an accurate predictor of field-level amitraz efficacy.
Evaluation of a new oxalic acid dribble formulation (Api-Bioxal RTU Beehive Solution) for the control of Varroa destructor
Oral presentation
Yanchak MT, Ellis JD, Jack CJ
As beekeepers continue to report elevated colony losses linked to Varroa destructor, the need for effective and efficient treatment methods is ever-growing. We sought to address the need for such treatments by investigating the miticidal effects of a new pre-formulated oxalic acid (OA) solution (Api-Bioxal RTU Beehive Solution; OA RTU). We implemented a field trial exposing Varroa-infested colonies during the Summer 2024 field season to OA RTU, and its performance was evaluated against those of OA vapor, OA/sugar syrup dribble, the industry standard dose of amitraz (Apivar), and an untreated control. Varroa infestation levels were measured using alcohol washes, brood infestation assessments, and sticky board traps. We assessed colony strength parameters before and after treatment administration to observe any potential effects of treatments on colony health. We found that the OA RTU solution significantly reduced Varroa infestation in honey bee brood, and that the OA RTU solution and Apivar led to significantly higher mite fall than those of all other groups. We found no impacts to colony health across all treatment groups. The successful registration of this product would provide beekeepers with a pre-formulated, shelf-stable OA dribble as another tool in the integrated Varroa management toolkit.
Topic: Extension
Citizen Scientists – key participants in Master Beekeeper Programs
Oral presentation; Keynote
Caron DM
Citizen Scientists are key to decentralized Master Beekeeper Programs and for bee research across the continent. As examples I cite the expansion of the winter brood study of Auburn University to include beekeeper participation and initiation of efforts in North Carolina and Kentucky to monitor for hornet hawking in apiaries as a means of tracking and potentially reducing the impact of the yellow legged hornet. Several in attendance provided additional examples of citizen science projects. In the Oregan Master Beekeeper program, a cooperative effort of Oregon beekeepers and Oregon State Extension, Citizen scientists serve as mentors in the Apprentice level. New beekeepers meet with a mentor in their or the mentors apiary four times a year to do a seasonal checklist. Mentors are recruited among individuals in the Journey and Master levels of the program and from bee clubs throughout the state and offered training within the program. At the Journey level, citizen scientists gather Journey students for “kitchen table” discussions to satisfy the requirements of 12 Guided Studies requirement. Master students may elect a local project and many involve other recruits to help with data collection or to assist in their meeting their two additional proficiencies, one of which is honey bee diseases and pest proficiency. The program relies on citizen beekeepers or others to advance students through the program levels.
Insights from PAm-Funded Projects on Colony Losses, Varroa Management, and Emerging Threats.
Oral presentation
Guarna MM
In response to unusually high colony losses reported by US beekeepers in early 2025, particularly among commercial operators preparing for almond pollination, Project Apis m (PAm) launched a national survey to document colony loss data and associated management practices. This presentation will share the analysis of the survey dataset, including colony losses across different beekeeper operation sizes and regions, associations with management practices, and the level of beekeepers’ financial concerns. The presentation will also highlight projects aimed at understanding colony losses, comparing diverse Varroa treatments, and advancing alternative management strategies, such as the selection or introduction of Varroa-resistant lines in beekeeping operations. Additional PAm-funded projects and resources will be presented, with emphasis on evolving and emerging threats such as Tropilaelaps mites and the yellow-legged hornet.
Managed Pollinator Protection Working Group
Oral presentation
Heck A
Michigan State University Extension coordinates the Managed Pollinator Protection Working Group, which includes university and government professionals from over 20 U.S. states and Canadian provinces. The working group meets monthly to receive professional development, collaborate, and share resources on reducing risks of pesticides to honey bees in agricultural settings and other topics related to managed pollinator health. The working group developed a presentation, online course, and other educational materials for pesticide applicators on how protect bees from pesticides. Members also received training on crisis communication in agriculture, tropilealaps mite biology and identification, and preparedness and response plans for tropilealaps mites. The North Central IPM Center has supported the Managed Pollinator Protection Working Group since 2020.
Topic: Management & Breeding
Improving honey bee health through breeding and integrated pest management of Varroa mites
Oral presentation
Castillo P, Simone-Finstrom M, Avalos A, Rinkevich F, Walsh EM
The mite Varroa destructor is an ectoparasite which is the most important biological threat to honey bee health today, because is the primary driver of elevated colony losses worldwide. Suppressed Mite Reproduction (SMR) is a set of strategies developed naturally by the honey bees to decrease Varroa reproduction rates in the hive. This includes the Varroa Sensitive Hygiene (VSH) behavior, where adult worker bees detect and remove mite-infested pupae from brood cells. This behavior is a heritable trait, and selection towards it has proven to be successful and sustainable in time to reduce the negative impact of Varroa in the hives. In our multi-disciplinary project, we aim to build a breeding program in collaboration with commercial beekeepers to select mite-resistant bees, to further establish their use nationwide. Thus, we propose utilizing our established VSH honey bee line (Pol-Line) as initial genetic material for the breeding program. Additionally, we will create workshops to train beekeepers and queen producers in methods of breeding and assessment of Varroa levels in the colonies. Our outcomes will be disseminated through meetings, best management practice guides, and industry publications to inform data-driven management decisions that enhance colony survival while reducing operational costs for commercial beekeeping operations.
Enhancing reproductive safety testing for honey bee drones
Oral presentation
Bezerra da Silva MC, Jose MS, Obshta O, Edirithilake TLK, Prieto EET, Camilli C, Neto BEL, Tregobov J, MerklR, Enadeghe R, De la Mora Pena A, Kondratiuk S, Wickramasinghe Y, Janser M, Katrii V, Simko E, Wood S
Honey bee drones play an essential role in the fertilization of the queen. Pesticide exposure has been linked to reduced drone sperm quality, which can impair colony reproductive success. Honey bee drones are not currently included in ecotoxicological risk assessments, highlighting a critical gap that indicates the need for enhanced approaches and methodologies. We aim to improve reproductive safety testing for honey bee drones by (1) developing a protocol to rear drones in vitro from larvae to adulthood, and (2) assessing amitraz-induced testis disruption using histopathology and in situ hybridization chain reaction (HCR) to evaluate germline and somatic cells distribution. We hypothesize that in vitro chronic amitraz exposure causes dose-responsive testicular changes detectable by histopathology and HCR. We successfully established an in vitro rearing protocol for honey bee drones with 74% ± 3.5% (SEM) survival to adulthood. Germline cells were significantly reduced in the high amitraz dose compared to the solvent control (Z = 3.5;P = 0.0015). In contrast, somatic cells did not differ between the solvent control and treatment groups. Reproductive safety testing for drones is increasingly important as agriculture intensifies. We developed an effective in vitro rearing protocol and tools to detect microscopic testicular changes linked to gonadotoxicity.
Honey bee colony losses: Causes and consequences
Oral presentation; Keynote
Evans JD
Honey bees, Apis mellifera, are vital for world economies and food security. With complex societies, they show a range of defenses against biological threats, yet remain an appealing and vulnerable target for organisms ranging from viruses to vertebrates. Coupled with climate, chemical, and nutritional stress, these threats limit colony growth and lead to losses at the colony and population levels. Managed colonies fail at high rates, impacting beekeepers and the industry. This talk will explore the science behind colony losses, the key roles played by mites and viruses, and worldwide efforts to breed and manage resilient honey bee colonies.
Enhancing Detection and Identification of Regulatory Species Through the
Application of Novel eDNA and eRNA Technologies
Poster presentation
Fulton JC, Epperson KJ, Marcelino J, Forsyth B, Ellis J
The primary purpose of this project is to enhance current diagnostic capabilities for invasive pests and pathogens of regulatory significance by validating an emerging sampling and sequencing technology, evaluating its application as a routine component of standard diagnostics procedures, and employing the methodology to identify traces of microbes and other biota associated with swarm bait traps located at high-risk maritime ports. The potential impacts of introduced exotic pests and pathogens such as Vespa velutina, Tropilaelaps spp., Apis cerana, Apis mellfiera subsp. capensis, and Iflavirus apistardum (slow bee paralysis virus) on the United States apiary industry include direct predation, enhanced disease transmission, and the possibility of destabilizing genetic admixture leading to reduced colony viability and outright losses. The presence of any of these species could result in trade restrictions, competition with native bees and other pollinators, and ecosystem perturbation. The risk of introduction can be mediated by active surveillance if followed by rapid and targeted eradication efforts. The approach investigated during this project should outperform conventional methodologies and allow us to update our view on the current community of pests and diseases actively circulating in Florida.
A Closer Look at Winter Brood Breaks Across the United States
Poster presentation
Tsuruda J, Amiri E, Breece C, Bruckner S, Caranton O, Chakrabarti Basu P, Cook S, Elliott B, Garrison J, Guillemette K, Johnson R, Johnson J, Kroh D, Lau P, Li-Byarlay H, McArt S, McBride H, McCalman P, Meikle W, O’Neil E, Oster C, Parton C, Rangel J, Sagili R, Shabel A, Sheridan A, Slater G, Smith K, Snellgrove A, Sweatman M, Tarpy DR, Topitzhofer E, Underwood R, Weiss M, Wilson J, Woodham R, Bartlett L, Goblirsch M, Jack C, Rinkevich F, Rogers S, Tokach R, Williams G
Winter management of honey bee colonies is often overlooked, but winter monitoring can improve understanding of the biology and needs of honey bees. For example, brood breaks/production are often assumed but the timing and interval are not validated. This information is vital for effective winter Varroa mite treatment (if/when there are periods of low/no capped brood during which treatment would be most effective), supplemental feeding, and predicting regions of susceptibility to the establishment of Tropilaelaps mites. This project was initiated in 2022 to monitor capped brood from mid-October to mid-February from colonies managed by a collective of collaborators across the U.S. Here, we present graphs of preliminary brood production data over time from key locations, allowing scientists and beekeepers to take a closer look at whether there have been brood breaks in their area, how long breaks have lasted, and whether the breaks were consistent (and therefore predictable). Since there is year-to-year variation in areas, we also encourage beekeepers to follow the current year’s bi-weekly map reports to treat colonies for Varroa based on the timing of winter brood. We also ask for feedback to help measure impacts related to the adoption of IPM practices in the beekeeping community.
Causes and implications of variability in pest and disease resistant bee breeding assays
Oral presentation
Wagoner K
The health of the honey bee (Apis mellifera) is declining, and sustainable solutions are needed to address one of their primary threats, the parasitic mite Varroa destructor (Varroa) and the diseases that it vectors. To be sustainable, solutions to the problem of Varroa must meet the needs of both bees and beekeepers, meaning that they must be long-term, affordable, and capable of generating healthy and productive honey bee colonies. The selective breeding of pest- and disease-resistant honey bee stock is a promising long-term, low-cost, and effective solution to the current honey bee health crisis. Numerous breeding programs have successfully produced Varroa-resistant stock using freeze-killed brood (FKB), Harbo (SMR), and UBeeO assays. Though useful, results of these assays can be highly variable in the same colony over time, complicating selection decisions and slowing progress of breeding initiatives. Here we will discuss temporal and environmental causes of assay score variability. We will also discuss implications of assay variability for pest and disease resistance selection programs, and propose strategies for improving assay reliability.
BeeSMART: Bee Sustainability Monitoring and Automated Response Technology
Poster presentation
Aiden Z
This project develops BeeSMART: Bee Sustainability Monitoring and Automated Response Technology, an AI- and IoT-based system for real-time honeybee colony health management and Varroa mite control. The system integrates solar-powered sensors, cameras, and an embedded computer to continuously monitor hive temperature, humidity, weight, and pressure. Using high-resolution imagery, a lightweight convolutional neural network (CNN) model—based on architectures such as YOLOv8 and EfficientDet—detects and counts Varroa mites on sticky boards in real time. Processed data are transmitted to a cloud-based dashboard for visualization, trend analysis, and alert generation. When mite populations exceed a threshold, the system automatically triggers a mechanical shaker that applies powdered sugar, a natural and chemical-free treatment that encourages bees to groom and remove mites. This closed-loop system combines automated monitoring, data-driven decision-making, and sustainable pest management to reduce colony losses and promote healthier hives. Designed for scalability and low cost, BeeSMART supports beekeepers, researchers, and educators by advancing practical applications of AI, IoT, and renewable energy in agriculture. Through continuous monitoring and automatic response, the project demonstrates how intelligent systems can improve pollinator health and contribute to global food security.
References
Edward Hsieh & Walsh E M. 2026. ABRC 2026 Proceedings: Part 2. Bee Culture May 2026, Volume 154, Issue 5, pp. 38-45. https://doi.org/10.55406/ABRC.6.25.2