Bee Colony Health Research Articles

Longitudinal survey reveals delayed effects of low gene expression on stingless bee colony health

Bee populations are declining globally due to different environmental stressors, such as pathogens, malnutrition, and agrochemicals. Brazil is the home of hundreds of stingless bee species, some of them now considered endangered, though very little is known about the impact of disease on native bees. In Southern Brazil the endangered stingless bee Melipona quadrifasciata is affected by an annual syndrome that causes sudden death of workers, eventually leading colonies to collapse. Although novel viruses were found in foragers from diseased colonies, none has been consistently implicated in the outbreak. Here we conducted an integrative longitudinal survey on M. quadrifasciata managed colonies, measuring individual- and colony-level traits, to identify the causes behind the syndrome. We found that key genes related to xenobiotic metabolization, nutrition and immune responses are downregulated in foragers from colonies that became diseased two months later. The period that preceded the outbreak was also marked by pronounced forager weight loss as well as behavioural changes. Our findings reveal the syndrome may result from the stingless bee failure to respond to sublethal stressors and disruption of colony dynamics. These results support the proposition that worldwide bee mortality is influenced by a combination of diverse sublethal factors, and increase awareness of the long-term effects of genetic diversity erosion in stingless bee species, which can be enhancing their vulnerability to environmental stressors.

Detection Bioactive Metabolites of Fructobacillus fructosus Strain HI-1 Isolated from Honey Bee's Digestive Tract Against Paenibacillus larvae.

American foulbrood is a devastating disease of honey bee, causing economic loss in the beekeeping industry. The disease mainly causes reduction in honeybee populations which negatively affect the honey bee's major role as natural pollinators of significant crops and wildflowers. Thus, it is crucial to develop safe efficient strategies to control the disease and to improve bee colony health. Using lactic acid bacteria (LAB) as an alternative to chemical treatments is a promising novel technique for tackling honeybee diseases and improving their immunity. The endogenous LAB isolates were recovered from honeybee gut samples collected from different apiaries in two Egyptian governorates and screened for antagonistic activities against Paenibacillus larvae (pathogen of AFB disease). The results showed that 53.3% of tested LAB isolates (n = 120) exhibited antagonistic activities against P. larvae. The minimum inhibitory concentration and minimum bactericidal concentration of the most potent LAB isolate (with an inhibition zone of 44 mm) were 100 and 125 µL/mL, respectively. 16S rRNA sequencing identified the most potent isolate as Fructobacillus fructosus HI-1. The bioactive metabolites of F. fructosus were extracted with ethyl acetate and fractionated on thin-layer chromatography (TLC); also, bioactive fractions were detected. Heptyl 2-methylbutyrate, di-isobutyl phthalate, D-turanose, heptakis (trimethylsilyl), di-isooctyl phthalate, and hyodeoxycholic acid compounds were identified in the bioactive fractions. The result explores the promising administration of probiotic metabolites to control honeybee AFB disease, as a natural tool to substitute antibiotics and chemicals in disease-controlling strategies.

Research project on field data collection for honey bee colony model evaluation

As part of the MUST-B project, a research project on field data collection for honey bee colony model evaluation was carried out in 2018-2020. In a preparatory phase (2018), methods for monitoring of honey bee colonies were tested, field operators trained, and experimental colonies established. The main field experiment was conducted in 2019-2020, during which bee colonies in six experimental apiaries were closely monitored in both Denmark and Portugal. An experimental spraying (spraying of Pirimor G in 6 ha of flowering oilseed rape) was carried out at one of the sites in Denmark in 2019. During the two-year experiment, climate variables were recorded continuously, and availability of floral resources was mapped regularly in the landscapes surrounding each apiary (within an area of 1.5 km radius). Adult bee population, brood and provision were assessed approximately every three weeks in experimental colonies. Furthermore, the weight of colonies was logged continuously during the field seasons by automatic hive scales. At four sites, foraging activity was monitored continuously in 1-2 colonies in 2019 and 2020. Spatial foraging was decoded from honey bee waggle dances observed once per month in four apiaries, at the same time as floral mapping. Finally, samples for analysis of diseases (varroa, Nosema and viruses), pesticide residues and botanical composition of pollen were collected. All data were organized in a relational database. Whereas previous studies have monitored similar aspects of honey bee colony development and health, the current dataset is unique in encompassing a large number of variables measured simultaneously. In particular, the current study emphasized a detailed data collection on population dynamics and development for the testing and calibration of the ApisRAM model developed in the MUST-B project. Methods used encompassed manual and automatic monitoring. Recommendations for future data collection include an assessment of variables currently collected with confidence and variables in need of further development.

The costs and benefits of sunflower pollen diet on bumble bee colony disease and health

AbstractPathogen transmission between domesticated and wild host species has important implications for community ecology, agriculture, and wildlife conservation. Bumble bees provide valuable pollination services that are vital for both wildflowers and agricultural production. Intense concerns about pathogen spillover from commercial bumble bees to wild bee populations, and the potential harmful effects of pathogen spillback to commercial bees, has stimulated a need for practical strategies that effectively manage bumble bee infectious diseases. Here, we assessed the costs and benefits of a medicinal sunflower pollen diet (Helianthusannuus) on whole‐colony bumble bee disease and performance using commercial colonies of the common eastern bumble bee,Bombus impatiens, and its protozoan pathogen,Crithidia bombi(Trypanosomatida). We first found that a 1:1 mixture of sunflower combined with wildflower pollen reducedC. bombiinfection prevalence and intensity within individualB. impatiensworkers by nearly 4‐fold and 12‐fold, respectively, relative to wildflower pollen. At the colony level, a 1:1 mixture of sunflower and wildflower pollen reducedC. bombiinfection prevalence by 11% averaged over a 10‐week period and infection intensity by 30% relative to wildflower pollen. Colony performance was similar between pollen diets and infection treatments, including the number of workers and immatures produced, and size and weight of workers, drones, and queens. Infection significantly reduced the probability of queen production in colonies fed a pure wildflower pollen diet, but not colonies fed a mixed sunflower pollen diet, suggesting that the medicinal benefits of a mixed sunflower pollen diet can reverse the negative effects of infection on reproductive success. This study provides evidence that sunflower pollen as part of a mixed pollen diet can reduce infection in individual bees and whole colonies with no significant nutritional trade‐offs for colony worker production and most aspects of colony reproduction. A supplemental mixed sunflower pollen diet may provide a simple and effective solution to reduce disease and improve the health of economically and ecologically important pollinators.

Tracing the Fate of Pollen Substitute Patties in Western Honey Bee (Hymenoptera: Apidae) Colonies.

Commercial beekeepers need healthy, productive honey bee (Apis mellifera L.) colonies, even when the landscape lacks adequate pollen forage to sustain the colonies. As a result, many commercial beekeepers spend significant money and labor on the use of pollen substitutes in their colonies. However, there is little consensus in the literature about the benefits and drawbacks of pollen substitute use on honey bee colony health. In order to understand this critically, it is important to know first how honey bees distribute pollen substitute patties throughout their colonies. We traced the fate of three commercially available pollen substitute patties (MegaBee, UltraBee, AP23) dyed with a nontoxic food coloring (Brilliant Blue FCF) and undyed as negative controls, a dyed positive control (fondant), and a dyed consumption control (Crayola Model Magic Clay) in 44 honey bee colonies. Using spectrophotometry and visual inspection, we analyzed adult bee guts, larval guts, bee bread stores and colony debris underneath the hive for presence of the dye. Our data suggest that (1) a proportion of adult bees ingest the patty, (2) adult bees likely do not feed patty directly to larvae, (3) adult bees do not store patty like bee bread, and (4) only a very small proportion of patty is lost as debris. Collectively our data suggest that honey bee colonies use pollen substitute patties. However, patties likely do not replace the function of natural pollen entirely in terms of larval provisioning and long-term storage as bee bread.

Potential of Fumagillin and Agaricus blazei Mushroom Extract to Reduce Nosema ceranae in Honey Bees.

Simple SummaryNosemosis is a disease in bees that causes severe problems for their vitality, reproduction and productivity. Traditionally, the treatment involves the application of fumagillin, an antibiotic with proven effect. Recently, fumagillin production and registration has faced problems worldwide, leading to the absence of adequate treatment. Motivated by the reported health issues and the occurrence of residues after fumagillin application, scientists around the world have sought a medication or a supplement that could help beekeepers to control Nosema. Current trends include the search for alternative non-antibiotic treatments. In a laboratory (cage) experiment, we studied the effect of fumagillin and natural extract of mushroom Agaricus blazei on the survival of Nosema infected bees, Nosema spore loads and levels of immune-related gene expression and oxidative stress markers. The results undoubtedly confirmed the anti-Nosema effect of fumagillin, as seen in better bee survival and monitored parameters; its application without Nosema infection (preventive) caused disturbance in some of the parameters. The application of A. blazei extract, however, showed positive effects in both preventive and curative applications. These beneficial properties of A. blazei extract indicate a potential that needs to be further investigated.Depending on the infection level and colony strength, Nosema ceranae, a microsporidian endoparasite of the honey bee may have significant consequences on the health, reproduction and productivity of bee colonies. Despite exerting some side effects, fumagillin is most often used for Nosema control. In this study, in a cage experiment, N. ceranae infected bees were treated with fumagillin or the extract of Agaricus blazei mushroom, a possible alternative for Nosema control. Bee survival, Nosema spore loads, the expression levels of immune-related genes and parameters of oxidative stress were observed. Fumagillin treatment showed a negative effect on monitored parameters when applied preventively to non-infected bees, while a noticeable anti-Nosema effect and protection from Nosema-induced immunosuppression and oxidative stress were proven in Nosema-infected bees. However, a protective effect of the natural A. blazei extract was detected, without any side effects but with immunostimulatory activity in the preventive application. The results of this research suggest the potential of A. blazei extract for Nosema control, which needs to be further investigated.

Effects of sugar feeding supplemented with three plant extracts on some parameters of honey bee colonies.

Sugar feeding is crucial to bee colonies during periods without natural nectar resources. The health and the development of bee colonies are affected by the sugar feeding type. Also, some materials can be added to the sugar feeding to boost the ability of bee colonies to withstand parasites. Three materials (mint, cinnamon, and chamomile) are used commonly to control bee parasites (e.g. Varroa mites). In the present study, the effects of these materials on the development and health of bee colonies were assessed. Sugar candy supplemented with these materials plus sugar candy only as a control group were tested. Bee colonies were fed with these feeding types weekly. Then, some parameters were evaluated. The results showed the suitability of the tested feeding types to bee colonies. Building of wax foundations was accelerated in cinnamon group. This group had also the lowest infestation rates with Varroa mites, suggesting a specific role of cinnamon in Varroa control. The colony development was significantly better in chamomile group than the other groups. Mint group showed no variations than the control group in most parameters. All feeding types showed safety to bees based on morphological characteristics and bee survival results. Practically, cinnamon is advised when building of wax combs is required while chamomile is recommended when increasing strength of colonies is needed. The role of cinnamon in controlling Varroa is recommended for further investigations.

Can pollen supplementation mitigate the impact of nutritional stress on honey bee colonies?

One of the main driving forces of the Apis mellifera colony losses reported worldwide is the nutritional stress associated with monoculture areas. We previously demonstrated under field conditions that nutritional stress that occurred during the fall impacts honey bee colony strength and health in the short and long-term. Pollen supplementation to colonies during a nutritionally stressful period increased adult and brood populations and decreased the infection level of Nosema ceranae. When brood production continues in the winter season, pollen supplementation during this period could be another strategy to help colonies recover from the negative impact of the nutritional stress that occurred in the fall. Thus, in this study, we analyzed if supplementing colonies with polyfloral pollen in winter could be a useful strategy to mitigate fall nutritional stress. Firstly, colonies were exposed to a natural nutritional stress scenario. Secondly, they were relocated and divided into two experimental groups: one group was supplemented with polyfloral pollen, while the other remained as a control. The strength and health of the colonies were analyzed. Pollen supplementation increased adults and brood populations in the coldest months and it did not affect the infection level of Nosema spp. or RNA viruses. These results suggest that the negative impact of nutritional stress during the fall is difficult to mitigate during the winter.

The neonicotinoid imidacloprid alone alters the cognitive behavior in Apis mellifera L. and the combined exposure of imidacloprid and Varroa destructor mites synergistically contributes to trial attrition

Honey bee (Apis mellifera L.) populations have undergone a dramatic decline as an outcome of an increasing incidence of colony collapse disorder (CCD). The honey bee is a unique keystone species because its pollination activities are not only necessary for the viability of many flowering plant species in the wild, but are also necessary for many human agricultural practices. The increasing prevalence of CCD is a threat to the economic and nutritional security of all societies that rely on efficient pollination for large monoculture crops. Although there is ample evidence that Varroa mites, pesticides, disease, and climate change contribute to CCD, only a few studies have investigated the contribution of synergism across multiple factors to the development of CCD and CCD-like symptoms. However, there is increasing acknowledgement in the scientific community that synergism across different factors affects honey bee colony health and behavior. Here, we provide evidence that sub-lethal levels of imidacloprid neonicotinoid pesticide reduce learning and memory capabilities. Synergistic effects become apparent when Varroa mites together with imidacloprid exposure to individual bees more than doubled average mortality and attrition per trial.

Comparative transcriptomics indicates endogenous differences in detoxification capacity after formic acid treatment between honey bees and varroa mites

Formic acid (FA) has been used for decades to control Varroa destructor, one of the most important parasites of the western honey bee, Apis mellifera. The rather unselective molecular mode of action of FA and its possible effects on honeybees have long been a concern of beekeepers, as it has undesirable side effects that affect the health of bee colonies. This study focuses on short-term transcriptomic changes as analysed by RNAseq in both larval and adult honey bees and in mites after FA treatment under applied conditions. Our study aims to identify those genes in honey bees and varroa mites differentially expressed upon a typical FA hive exposure scenario. Five detoxification-related genes were identified with significantly enhanced and one gene with significantly decreased expression under FA exposure. Regulated genes in our test setting included members of various cytochrome P450 subfamilies, a flavin-dependent monooxygenase and a cytosolic 10-formyltetrahydrofolate dehydrogenase (FDH), known to be involved in formate metabolism in mammals. We were able to detect differences in the regulation of detoxification-associated genes between mites and honey bees as well as between the two different developmental stages of the honey bee. Additionally, we detected repressed regulation of Varroa genes involved in cellular respiration, suggesting mitochondrial dysfunction and supporting the current view on the mode of action of FA—inhibition of oxidative phosphorylation. This study shows distinct cellular effects induced by FA on the global transcriptome of both host and parasite in comparison. Our expression data might help to identify possible differences in the affected metabolic pathways and thus make a first contribution to elucidate the mode of detoxification of FA.

Development of Imaging-Based Honeybee Traffic Measurement System and Its Application to Crop Pollination

Bee traffic can be used as an indicator of the health of bee colonies, age, production of honeybee products, and crop pollination. To study bee pollination processes, we developed an algorithm that can automatically measure bee traffic through an image processing system. The match rate between the bee traffic observed through the system and the traffic that was visually observed was 93.6%. However, the higher the bee traffic, the lower the match rate. We applied the system in a strawberry cultivation greenhouse containing two colonies (one with 12500 bees and one with 10000 bees), and there was a significant difference in bee traffic between the two colonies. In addition, bee traffic depends on the climatic conditions inside the greenhouse (air temperature, relative humidity, illumination, and UV radiation), and there was a significant correlation between these indicators and the level of bee traffic observed. There was also a strong correlation (R>0.8) between bee traffic and foraging activity (which is correlated with pollination), and the foraging activity could be estimated with a high probability (R²=0.74). Therefore, the bee traffic measurement system developed in this study can be used to study the effect of pollination on crops, and is expected to be applied as a major model for producing high-quality agricultural products in smart beekeeping and crop smart farms.

Colony field test reveals dramatically higher toxicity of a widely-used mito-toxic fungicide on honey bees (Apis mellifera).

Honey bees (Apis mellifera) and other pollinator populations are declining worldwide, and the reasons remain controversial. Based on laboratory testing, fungicides have traditionally been considered bee-safe. However, there have been no experimental tests of the effects of fungicides on colony health under field conditions, and limited correlational data suggests there may be negative impacts on bees at levels experienced in the field. We tested the effects of one of the most commonly used fungicides on colony health by feeding honey bee colonies pollen containing Pristine® (active ingredients: 25.2% boscalid, 12.8% pyraclostrobin) at four levels that bracketed concentrations we measured for pollen collected by bees in almond orchards. We also developed a method for calculating per-bee and per-larva dose. Pristine® consumption significantly and dose-dependently reduced worker lifespan and colony population size, with negative health effects observed even at the lowest doses. The lowest concentration we tested caused a 15% reduction in the worker population at an estimated dosage that was three orders of magnitude below the estimated LD15 values for previous acute laboratory studies. The enhanced toxicity under field conditions is at least partially due to activation of colonial nutritional responses missed by lab tests. Pristine® causes colonies to respond to perceived protein malnutrition by increasing colony pollen collection. Additionally, Pristine induces much earlier transitioning to foraging in individual workers, which could be the cause of shortened lifespans. These findings demonstrate that Pristine® can negatively impact honey bee individual and colony health at concentrations relevant to what they experience from pollination behavior under current agricultural conditions.

BIRDS AND HONEY BEES: A BRIEF OVERVIEW ON THIS ANTAGONISTIC RELATIONSHIP AND ITS POTENTIAL IMPACT ON BEEKEEPING

The human-wildlife conflict between beekeeping and wild birds is complicated, and further detailed studies are needed for a deeper understanding of the role and possible impact of predation by wild birds on honey production and bee colony health. Another potentially negative effect of birds on bees could be the dissemination of pathogens, such as Nosema ceranae. However, other important aspects of the complex relationship between bees and wild birds should be considered. First, honey bees have developed behavioural defences against the pressure of native predatory birds. Second, the ethology of some of these predators is fascinating like the interesting mutualistic relationship established between the so-called honeyguides and beekeepers. Finally, predatory birds could be important in the biocontrol of other bee enemies such as the invasive Asian hornet. Taking these additional aspects into consideration would provide a better insight into the conflict between wild animal conservation and human activity.

Toward Audio Beehive Monitoring Based on IoT-AI techniques: A Survey and Perspective

In beekeeping, monitoring beehives plays an important role to make sure the health of bee colonies and to reduce negative effects that could happen for the colonies. A large number of studies have been carried out to improve the performance of monitoring beehives from the traditional manual methods. Especially, the application of Artificial Intelligence (AI) technologies in recent time has led to significant effects in the monitoring process. These new methods, however, have not yet been interested and applied in Vietnam. To understand the use of the AI-based technologies in automatic monitoring beehives, this paper provides a survey on the beehive monitoring system based on audio data and AI techniques. Opportunities and perspectives for the applications of these techniques in audio-based monitoring beehive in Vietnam are also discussed.

Longitudinal monitoring of honey bee colonies reveals dynamic nature of virus abundance and indicates a negative impact of Lake Sinai virus 2 on colony health.

Honey bees (Apis mellifera) are important pollinators of plants, including those that produce nut, fruit, and vegetable crops. Therefore, high annual losses of managed honey bee colonies in the United States and many other countries threaten global agriculture. Honey bee colony deaths have been associated with multiple abiotic and biotic factors, including pathogens, but the impact of virus infections on honey bee colony population size and survival are not well understood. To further investigate seasonal patterns of pathogen presence and abundance and the impact of viruses on honey bee colony health, commercially managed colonies involved in the 2016 California almond pollination event were monitored for one year. At each sample date, colony health and pathogen burden were assessed. Data from this 50-colony cohort study illustrate the dynamic nature of honey bee colony health and the temporal patterns of virus infection. Black queen cell virus, deformed wing virus, sacbrood virus, and the Lake Sinai viruses were the most readily detected viruses in honey bee samples obtained throughout the year. Analyses of virus prevalence and abundance revealed pathogen-specific trends including the overall increase in deformed wing virus abundance from summer to fall, while the levels of Lake Sinai virus 2 (LSV2) decreased over the same time period. Though virus prevalence and abundance varied in individual colonies, analyses of the overall trends reveal correlation with sample date. Total virus abundance increased from November 2015 (post-honey harvest) to the end of the almond pollination event in March 2016, which coincides with spring increase in colony population size. Peak total virus abundance occurred in late fall (August and October 2016), which correlated with the time period when the majority of colonies died. Honey bee colonies with larger populations harbored less LSV2 than weaker colonies with smaller populations, suggesting an inverse relationship between colony health and LSV2 abundance. Together, data from this and other longitudinal studies at the colony level are forming a better understanding of the impact of viruses on honey bee colony losses.

Diagnosis of varroosis taking into account modern requirements

Pollination is an indispensable service for the ecosystem in which bees are distributed, therefore the health of bee colonies is one of the most important conditions, primarily for plant biodiversity, and is extremely important for sustainable and cost-effective agricultural production. Honey bees are susceptible to various diseases. Currently, the invasion caused by the tick Varroa destructor covers every apiary, taking the scale of panzootia. The fight against tick invasion is carried out, achieving only temporary success. Varroa destructor, parasitizing on a bee, opens the gates of a viral infection into its body, which significantly aggravates the situation and leads to the phenomenon of “Colony collapse disorder (CCD)”, reducing the number of families. Ordinary beekeepers and scientific researchers apply various methods of diagnosing invasion. Most of these methods have a significant error - from 2 to 12%, which, in some cases, exceeds the safe threshold for varroa tick content in the bee family. Therefore, science must develop new, humane and accurate methods for determining the degree of affection of the bee family with the varroa tick. Currently, work is underway at the Federal State Budget Institution «Federal Scientific Centre VIEV» (FSC VIEV) on accurate methods for the intravital diagnosis of varrozis.

Screening and Validation of Reference Genes for RT-qPCR Under Different Honey Bee Viral Infections and dsRNA Treatment.

Honey bee viruses are one of the most important pathogens that have contributed to the decrease in honey bee colony health. To analyze the infection dynamics of honey bee viruses, quantification of viral gene expression by RT-qPCR is necessary. However, suitable reference genes have not been reported from viral and RNAi studies of honey bee. Here, we evaluated the expression of 11 common reference genes (ache2, rps18, β-actin, tbp, tif, rpl32, gadph, ubc, α-tubulin, rpl14, and rpsa) from Apis mellifera (Am) and Apis cerana (Ac) under Israeli acute paralysis virus (IAPV), chronic bee paralysis virus (CBPV), and Chinese sacbrood virus (CSBV) infection as well as dsRNA-PGRP-SA treatment, and we confirmed their validation by evaluating the levels of the defensin 1 and prophenoloxidase (ppo) genes during viral infection. Our results showed that the expression of selected genes varied under different viral infections. ache2, rps18, β-actin, tbp, and tif can be used to normalize expression levels in Apis mellifera under IAPV infection, while the combination of actin and tif is suitable for CBPV-infected experiments. The combination of rpl14, tif, rpsa, ubc, and ache2 as well as more reference genes is suitable for CSBV treatment in Apis cerana. Rpl14, tif, rps18, ubc, and α-tubulin were the most stable reference genes under dsRNA treatment in Apis mellifera. Furthermore, the geNorm and NormFinder algorithms showed that tif was the best suitable reference gene for these four treatments. This study screened and validated suitable reference genes for the quantification of viral levels in honey bee, as well as for RNAi experiments.

Effects of the Neonicotinoid Imidacloprid on the Feeding Behavior of Melipona quadrifasciata anthidioides Lep.

Even though meliponines are among the greatest pollinating agents in Neotropical ecosystems, the populations of these bees are in decline due to anthropic actions, such as the indiscriminate use of pesticides. Neonicotinoids, such as Imidacloprid, are used in many crops and have been shown to be one of the pesticides groups with the most damaging effects on the health of bee colonies. The goals of this work were (1) to evaluate the ability of Melipona quadrifasciata, a native Brazilian stingless bee species, to detect the presence of Imidacloprid in artificial diets, and (2) to evaluate how this insecticide may affect their behavior. For this purpose, behavioral experiments were carried out in observation arenas where artificial flowers containing different concentrations of Imidacloprid (0%, 1%, 5%, 10%, and 20%) were made available to forager bees and their choice and behavior were registered. Our results showed that bee choices were not affected by the different concentrations of Imidacloprid, even at extremely high doses in the flowers (20%). It was also found that the presence of this insecticide interfered with the communication between individuals as a result of reduced antennation events. Both findings, the apparent inability of bees to detect the presence of the insecticide and the change in behavior caused by the exposition to the volatilized product, may rapidly lead to colony losses in nature.

Honey Bee Queen Production: Canadian Costing Case Study and Profitability Analysis.

The decline in managed honey bee (Hymenoptera: Apidae) colony health worldwide has had a significant impact on the beekeeping industry. To mitigate colony losses, beekeepers in Canada and around the world introduce queens into replacement colonies; however, Canada’s short queen rearing season has historically limited the production of early season queens. As a result, Canadian beekeepers rely on the importation of foreign bees, particularly queens from warmer climates. Importing a large proportion of (often mal-adapted) queens each year creates a dependency on foreign bee sources, putting beekeeping, and pollination sectors at risk in the event of border closures, transportation issues, and other restrictions as is currently happening due to the 2020 Covid-19 pandemic. Although traditional Canadian queen production is unable to fully meet early season demand, increasing domestic queen production to meet mid- and later season demand would reduce Canada’s dependency. As well, on-going studies exploring the potential for overwintering queens in Canada may offer a strategy to have early season domestic queens available. Increasing the local supply of queens could provide Canadian beekeepers, farmers, and consumers with a greater level of agricultural stability and food security. Our study is the first rigorous analysis of the economic feasibility of queen production. We present the costs of queen production for three Canadian operations over two years. Our results show that it can be profitable for a beekeeping operation in Canada to produce queen cells and mated queens and could be one viable strategy to increase the sustainability of the beekeeping industry.

Cuticular pheromones stimulate hygienic behavior in the honey bee (Apis mellifera)

The health of western honey bee (Apis mellifera) colonies is challenged by the parasitic mite Varroa destructor and the numerous harmful pathogens it vectors. Selective breeding for the naturally occurring social immune trait “hygienic behavior” has emerged as one sustainable approach to reducing the mites’ impact on honey bees. To expand our understanding of hygienic triggers and improve hygienic selection tools, we tested the hypothesis that the cuticular compounds (Z)-10-tritriacontene and (Z)-6-pentadecene, previously associated with unhealthy honey bee brood and/or brood targeted for hygiene, are triggers of honey bee hygienic behavior independent of brood health. In support of our hypothesis, application of synthetic (Z)-10-tritriacontene and (Z)-6-pentadecene onto brood and brood cell caps significantly increased hygienic behavior compared to application of similarly structured hydrocarbon controls (Z)-16-dotriacontene and (Z)-7-pentadecene. Furthermore, we demonstrate a significant positive correlation between colony-level hygienic responses to (Z)-10-tritriacontene and the traditional freeze-killed brood assay for selection of hygienic honey bee stocks. These results confirm biological activity of (Z)-6-pentadecene and reveal (Z)-10-tritriacontene as a novel hygiene trigger. They also support development of improved tools for honey bee colony monitoring and hygienic selection, and thus may accelerate development of honey bee stocks with greater resistance to Varroa and associated pathogens.