Honeybee Biology Research Articles

HONEY BEE BIOLOGY by B.R. Johnson

HONEY BEE BIOLOGY by B.R. Johnson

Mechanisms of Pathogen and Pesticide Resistance in Honey Bees.

Bees are the most important insect pollinators of the crops humans grow, and Apis mellifera, the Western honey bee, is the most commonly managed species for this purpose. In addition to providing agricultural services, the complex biology of honey bees has been the subject of scientific study since the 18th century, and the intricate behaviors of honey bees and ants, fellow hymenopterans, inspired much sociobiological inquest. Unfortunately, honey bees are constantly exposed to parasites, pathogens, and xenobiotics, all of which pose threats to their health. Despite our curiosity about and dependence on honey bees, defining the molecular mechanisms underlying their interactions with biotic and abiotic stressors has been challenging. The very aspects of their physiology and behavior that make them so important to agriculture also make them challenging to study, relative to canonical model organisms. However, because we rely on A. mellifera so much for pollination, we must continue our efforts to understand what ails them. Here, we review major advancements in our knowledge of honey bee physiology, focusing on immunity and detoxification, and highlight some challenges that remain.

Apis mellifera Mitochondrial DNA (mtDNA), A Rewiew Paper

This review paper presents a comprehensive analysis of the mitochondrial DNA (mtDNA) of Apis mellifera, commonly referred to as the Western honey bee. The present study aims to examine the genetic diversity, population structure, and evolutionary history of a species of insect that holds economic significance. This study elucidates the genetic determinants that impact the adaptive capacity, behavioral patterns, and overall well-being of honey bees through the examination of mitochondrial DNA (mtDNA) sequences derived from diverse honey bee populations across the globe. Furthermore, this study examines the potential implications of mitochondrial DNA (mtDNA) research on various aspects of beekeeping practices, conservation initiatives, and the comprehension of honey bee biology. This paper serves as a significant asset for researchers, beekeepers, and conservationists with a keen interest in exploring the genetic characteristics of Apis mellifera

The Potential of Complementary Sex-Determiner Gene Allelic Diversity for Studying the Number of Patrilines within Honeybee Colonies

Polyandry, a fundamental aspect of honeybee biology, influences genetic diversity within bee colonies. The Csd gene, responsible for sex determination, exhibits a high intraspecific polymorphism, making it a promising candidate for studying patrilines. This study investigates the potential of the complementary sex-determiner gene (Csd) as a marker for genetic studies of honeybee colonies, comparing its efficacy with standard microsatellite markers. A worker bee brood from five colonies was genotyped using both Csd and microsatellite markers. The results showed that Csd alleles offer higher variability than microsatellite markers, providing a superior resolution in genotyping. The number of distinct Csd alleles in each colony surpassed microsatellite markers, demonstrating the potential of Csd for detailed genetic analyses. Despite challenges in Csd amplification efficiency, a two-step nested PCR protocol proved effective. Interestingly, Csd genotyping alone identified more patrilines than the set of five microsatellite markers, emphasizing its efficacy. Combining Csd and microsatellite genotyping enhances the resolution of genetic studies in honeybee colonies, offering valuable insights into genetic diversity, reproductive success, and social dynamics. The Csd gene emerges as a promising tool for advancing genetic studies in honeybee populations.

Varroa destructor and its impacts on honey bee biology

Varroa destructor is considered one of the greatest threats to the health of the honey bee, A. mellifera. In recent years, there has been a considerable increase in the number of studies on the mite and its interaction with the bee at a cellular and molecular level. However, these studies have also revealed just how complex the interaction is. A significant factor in the virulence of V. destructor is the proteins secreted in its saliva, but only a fraction of these have yet been examined. These proteins can negatively affect the bee’s immune system and promote viruses associated with mite parasitism. Initially, studies on parasitized bees concentrated on immune-related genes, but as more genes of the bees have been examined, it is clear that many other aspects of the bee are affected, such as metabolism and neural functioning. Some of those could be responsible for the detrimental changes in certain behaviors of parasitized bees, which compromises the health of the entire colony. Several viruses are associated with V. destructor parasitism, but it remains difficult to distinguish the effects of the viruses from those of the mite. Reduced immunity in parasitized bees also opens the possibility of secondary microbial infections, adding complexity to the mite-bee interaction. Further complicating studies is the impact of other factors, like agrochemicals, which can alter how V. destructor parasitism affects bee immunity, metabolism, and neural functioning. In addition, differences due to age and sex of the bee being parasitized is a factor that needs to be considered in all studies. While much has been learned in recent years about this complex interaction, the number of unanswered questions only increases.

Cellular heterogeneity of the developing worker honey bee (Apis mellifera) pupa: a single cell transcriptomics analysis.

It is estimated that animals pollinate 87.5% of flowering plants worldwide and that managed honey bees (Apis mellifera) account for 30-50% of this ecosystem service to agriculture. In addition to their important role as pollinators, honey bees are well-established insect models for studying learning and memory, behavior, caste differentiation, epigenetic mechanisms, olfactory biology, sex determination, and eusociality. Despite their importance to agriculture, knowledge of honey bee biology lags behind many other livestock species. In this study, we have used scRNA-Seq to map cell types to different developmental stages of the worker honey bee (prepupa at day 11 and pupa at day 15) and sought to determine their gene expression signatures. To identify cell-type populations, we examined the cell-to-cell network based on the similarity of the single-cells transcriptomic profiles. Grouping similar cells together we identified 63 different cell clusters of which 17 clusters were identifiable at both stages. To determine genes associated with specific cell populations or with a particular biological process involved in honey bee development, we used gene coexpression analysis. We combined this analysis with literature mining, the honey bee protein atlas, and gene ontology analysis to determine cell cluster identity. Of the cell clusters identified, 17 were related to the nervous system and sensory organs, 7 to the fat body, 19 to the cuticle, 5 to muscle, 4 to compound eye, 2 to midgut, 2 to hemocytes, and 1 to malpighian tubule/pericardial nephrocyte. To our knowledge, this is the first whole single-cell atlas of honey bees at any stage of development and demonstrates the potential for further work to investigate their biology at the cellular level.

An interdisciplinary course on evolution and sustainability increases acceptance of evolutionary theory and increases understanding of interdisciplinary application of evolutionary theory

BackgroundAlthough evolutionary theory is foundational and integrative in modern biology, there remains widespread lack of acceptance among U.S. residents. An interdisciplinary approach to teaching evolutionary theory at the undergraduate level has many advantages, such as giving students a context for learning about evolution and application of evolutionary theory to other academic disciplines and everyday life. While there are foundational examples of interdisciplinary approaches to teaching evolutionary theory, there are few examples of courses with application of evolutionary theory to issues of sustainability, such as conservation or global climate change. We build on the practical and theoretical work of others to create an interdisciplinary course on evolutionary theory for non-science majors, with ties to sustainability. Our course is taught in three modules, with extensive readings and hands-on lab activities. The first module is focused on honey bee biology, with hands-on beekeeping experiences; the second module on native plants and community education on sustainability; and the third module on the evolution of the subjective human experience of free will.ResultsWe found that students in our course experienced an increased acceptance of evolutionary theory. We found that students also met the course leaning objectives, of basic knowledge of evolutionary theory and application of evolutionary theory to other disciplines, assessed through group and individual major assignments. We also found that students had an expanded perspective on interdisciplinary application of evolutionary theory, assessed through closed-ended survey questions and analysis of open-ended writing.ConclusionsStudents in our course experienced an increase of acceptance of evolutionary theory and an expanded perspective on interdisciplinary application of evolutionary theory, despite the fact that many students were not science majors.

Using the Honey Bee (Apis mellifera L.) Cell Line AmE-711 to Evaluate Insecticide Toxicity.

One of the main contributors to poor productivity and elevated mortality of honey bee colonies globally is insecticide exposure. Whole-organism and colony-level studies have demonstrated the effects of insecticides on many aspects of honey bee biology and have also shown their interactions with pathogens. However, there is a need for in vitro studies using cell lines to provide greater illumination of the effects of insecticides on honey bee cellular and molecular processes. We used a continuous cell line established from honey bee embryonic tissues (AmE-711) in assays that enabled assessment of cell viability in response to insecticide exposure. We exposed AmE-711 cells to four formulations, each containing a different insecticide. Treatment of cells with the insecticides resulted in a concentration-dependent reduction in viability after a 24-h exposure, whereas long-term exposure (120 h) to sublethal concentrations had limited effects on viability. The 24-h exposure data allowed us to predict the half-maximal lethal concentration (LC50) for each insecticide using a four-parameter logistical model. We then exposed cells for 12 h to the predicted LC50 and observed changes in morphology that would indicate stress and death. Reverse transcription-quantitative polymerase chain reaction analysis corroborated changes in morphology: expression of a cellular stress response gene, 410087a, increased after an 18-h exposure to the predicted LC50. Demonstration of the effects of insecticides through use of AmE-711 provides a foundation for additional research addressing issues specific to honey bee toxicology and complements whole-organism and colony-level approaches. Moreover, advances in the use of AmE-711 in high-throughput screening and in-depth analysis of cell regulatory networks will promote the discovery of novel control agents with decreased negative impacts on honey bees. Environ Toxicol Chem 2023;42:88-99. Published 2022. This article is a U.S. Government work and is in the public domain in the USA. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Honey bee functional genomics using symbiont-mediated RNAi.

Honey bees are indispensable pollinators and model organisms for studying social behavior, development and cognition. However, their eusociality makes it difficult to use standard forward genetic approaches to study gene function. Most functional genomics studies in bees currently utilize double-stranded RNA (dsRNA) injection or feeding to induce RNAi-mediated knockdown of a gene of interest. However, dsRNA injection is laborious and harmful, and dsRNA feeding is difficult to scale cheaply. Further, both methods require repeated dsRNA administration to ensure a continued RNAi response. To fill this gap, we engineered the bee gut bacterium Snodgrassella alvi to induce a sustained host RNA interference response that reduces expression of a targeted gene. To employ this functional genomics using engineered symbionts (FUGUES) procedure, a dsRNA expression plasmid is cloned in Escherichia coli using Golden Gate assembly and then transferred to S. alvi. Adult worker bees are then colonized with engineered S. alvi. Finally, gene knockdown is verified through qRT-PCR, and bee phenotypes of interest can be further assessed. Expression of targeted genes is reduced by as much as 50-75% throughout the entire bee body by 5 d after colonization. This protocol can be accomplished in 4 weeks by bee researchers with microbiology and molecular cloning skills. FUGUES currently offers a streamlined and scalable approach for studying the biology of honey bees. Engineering other microbial symbionts to influence their hosts in ways that are similar to those described in this protocol may prove useful for studying additional insect and animal species in the future.

New insight into phosphoproteome research improves the in-depth understanding of honey bee biology

Protein phosphorylation is essential in a variety of biological activities. Notably, phosphoproteomics has opened new possibilities for honey bee biological study at the molecular and biochemical levels, considering the advancements in LC-MS/MS apparatus and computational analysis. This review extensively evaluated recent advances in honey bee biology utilizing phosphoproteomics methodologies in terms of progressive physiology, age polytheism, and biological changes in some organs, tissues, and cells. Furthermore, a comprehensive phosphoproteomic is necessary for new insight into honey bee biology, a better understanding of the research subject, and determining prospective future research areas.

Distinct gut microbiota profiles of Asian honey bee (Apis cerana) foragers.

Bee gut microbial communities have been studied extensively and linked to honey bee biology in terms of stages of bee development and behavior. Associations of bee gut microbiota in health and disease have also been explored. A large number of studies have centered on the gut microbiome of Apis mellifera, with similar investigations lagging far behind in Asian honey bee foragers. In this study, we characterized and compared the gut bacterial profiles of foragers and nurse bees of A. cerana and A. mellifera. Analysis of 16S rRNA partial gene sequences revealed significant differences in gut bacterial communities between the two honey bee species. Despite sharing dominant taxa, Bacteroides was more abundant in A. cerana, while Proteobacteria was higher in A. mellifera. Specific gut members are distinctly associated with hosts performing different tasks (i.e. nurse bees versus foragers). An exclusive abundance of Apibacter detected in Asian honey bee seemed to be a microbial signature of A. cerana foragers. Overall, our study highlights that variations in gut microbiota could be linked to task-specific (nurse bees and foragers) bacterial species associated with honey bees. Future investigations on the symbiotic relationship between host and the resident microbiota would be beneficial for improving honey bee health.

РАЗВИТИЕ ПЛЕМЕННОГО ДЕЛА В ПЧЕЛОВОДСТВЕ

The theoretical basis of breeding is the biology of honey bees and, first of all, genetics. Scientists of the Moscow State University have made a great contribution to the study of the honey bee. Under the leadership of Professor of Moscow State University G. A. Kozhevnikov, F. A. Tyunin took place, who in 1919 created the Tula Experimental Beekeeping Station, and on its basis in 1930 the Scientific Research Institute of Beekeeping was organized. P. M. Komarov enriched science with his research on the physiology of honey bees, breeding and reproduction of queen bees. V. V. Alpatov's research intraspecific variability of bees served as the basis for the development of a classical methodology for biometric assessment of the exterior features of bees of various breeds. At the Tula experimental beekeeping station, A. S. Mikhailov was the first in Russia to manufacture equipment for instrumental insemination of queen bees and revealed the nature of inheritance of a number of traits in bees. In the 50s, an employee of the Research Institute of Beekeeping V. V. Shakes discovered the phenomenon of polyandry, improved the design of the apparatus for instrumental insemination of queen bees and revealed patterns of inheritance of exterior and interior features in bees. The work planned and carried out during 1964-1975 on the comparative study of the main bee breeds in specific beekeeping zones of the country under the leadership of the Research Institute of Beekeeping was completed by the preparation of the first plan for the breed zoning of bees in 1979 in 1992. according to the results of the approbation, the order of the Ministry of Agriculture of Russia approved the breeding achievement of the breed type "Prioksky", bred by the staff of the Research Institute of Beekeeping on the basis of crossing the gray mountain Caucasian and Central Russian breeds. The work on the breeding and testing of bees was carried out, as a result of which the Bashkir (2006), Far Eastern (2016), breed types Orlovsky (2008), Tatar (2010), Burzyanskaya Bortevaya (2011) of the Central Russian breed were approved and entered into the register of breeding achievements, "Krasnopolyansky (2008) gray mountain Caucasian, "Maykop" (2006), "Moscow" (2017) Carpathian breeds. Improved technologies of reproduction of high-quality queens with the use of modern inventory and equipment are proposed, the use of which allows to increase the productivity of bee colonies by 10-15%, and the yield of royal jelly by two times. In the 90s, according to the results of research by the staff of the Research Institute of Beekeeping and the Institute of General Genetics, the technology of deep freezing of drone sperm in liquid nitrogen at t-196 0C was patented. According to the results of selection and breeding work, the leading farms in Russia are recognized: for the gray mountain Caucasian breed - Krasnopolyanskaya experimental station of beekeeping, and for the Carpathian - "Maikopskoye", which are currently branches of the Federal State Budgetary Institution "FNC of Beekeeping". The Oryol Experimental Beekeeping Station was specialized in breeding Central Russian bees. Along with classical methods, the Research Institute of Beekeeping, in cooperation with the Institute of General Genetics and the Research Institute of Animal Husbandry, has begun work on the use of molecular genetic methods for identifying breeds of bees in Russia. The accumulated knowledge and experience in genetics, breeding and reproduction of bees is summarized in a number of publications and is widely covered in periodicals. The Research Institute of Beekeeping is approved by the breeding and information center for bee breeds and performs scientific and methodological guidance, as well as coordination of breeding work in the country. To this end, the necessary regulatory documents have been developed and a number of methodological recommendations have been issued for conducting breeding work in beekeeping.

Warmer winters are associated with lower levels of the cryoprotectant glycerol, a slower decrease in vitellogenin expression and reduced virus infections in winter honeybees

Within the context of climate change, winter temperatures at high latitudes are predicted to rise faster than summer temperatures. This phenomenon is expected to negatively affect the diapause performance and survival of insects, since they largely rely on low temperatures to lower their metabolism and preserve energy. However, some insects like honeybees, remain relatively active during the winter and elevate their metabolic rate to produce endothermic heat when temperatures drop. Warming winters are thus expected to improve overwintering performance of honeybees. In order to verify this hypothesis, for two consecutive years, we exposed honeybee colonies to either a mild or cold winter. We then monitored the influence of wintering conditions on several parameters of honeybee overwintering physiology, such as levels of the cryoprotectant glycerol, expression levels of immune and antioxidant genes, and genes encoding multifunctional proteins, including vitellogenin, which promotes bee longevity. Winter conditions had no effect on the expression of antioxidant genes, and genes related to immunity were not consistently affected. However, mild winters were consistently associated with a lower investment in glycerol synthesis and a higher expression of fat body genes, especially apidaecin and vitellogenin. Finally, while we found that viral loads generally decreased through the winter, this trend was more pronounced under mild winter conditions. In conclusion, and without considering how warming temperatures might affect other aspects of honeybee biology before overwintering, our data suggest that warming temperatures will likely benefit honeybee vitality by notably reducing their viral loads over the winter.

Honeybee intestines retain low yeast titers, but no bacterial mutualists, at emergence.

Honeybee symbionts, predominantly bacteria, play important roles in honeybee health, nutrition, and pathogen protection, thereby supporting colony health. On the other hand, fungi are often considered indicators of poor bee health, and honeybee microbiome studies generally exclude fungi and yeasts. We hypothesized that yeasts may be an important aspect of early honeybee biology, and if yeasts provide a mutual benefit to their hosts, then honeybees could provide a refuge during metamorphosis to ensure the presence of yeasts at emergence. We surveyed for yeast and fungi during pupal development and metamorphosis in worker bees using fungal-specific quantitative polymerase chain reaction (qPCR), next-generation sequencing, and standard microbiological culturing. On the basis of yeast presence in three distinct apiaries and multiple developmental stages, we conclude that yeasts can survive through metamorphosis and in naïve worker bees, albeit at relatively low levels. In comparison, known bacterial mutualists, like Gilliamella and Snodgrassella, were generally not found in pre-eclosed adult bees. Whether yeasts are actively retained as an important part of the bee microbiota or are passively propagating in the colony remains unknown. Our demonstration of the constancy of yeasts throughout development provides a framework to further understand the honeybee microbiota.

Overwintering Honey Bee Colonies: Effect of Worker Age and Climate on the Hindgut Microbiota.

Simple SummaryThe honey bee is managed worldwide for use in pollinating crops and producing honey. Healthy overwintered colonies are paramount to meeting spring agricultural pollination demands, but beekeepers typically report high rates of winter colony loss. Although many factors affect winter survival, the gut microbiome, demonstrated to facilitate healthy metabolism and physiology, is understudied in this context. Here, we investigate how overwintering climate (warm versus cold) alters the honey bee gut microbiome. In both climates, the gut bacteria were generally stable during overwinter. However, microbiota changes in the warm climate suggest compromised host physiology. The abundance of fungus increased two-fold in the warm climate and was strongly associated with potentially harmful bacteria. The life expectancy of worker bees in warm climates was low compared to that known for cold climates. Our results indicate that colony loss in warm climates is associated with shortened life expectancy of overwintering workers, and alterations in the gut microbiome. We suggest that overwintering in warm climates can worsen preexisting conditions of disease, parasites, and poor nutrition, increasing winter colony loss. Ultimately, our results provide new insights into overwintering honey bee management strategies.Honey bee overwintering health is essential to meet the demands of spring pollination. Managed honey bee colonies are overwintered in a variety of climates, and increasing rates of winter colony loss have prompted investigations into overwintering management, including indoor climate controlled overwintering. Central to colony health, the worker hindgut gut microbiota has been largely ignored in this context. We sequenced the hindgut microbiota of overwintering workers from both a warm southern climate and controlled indoor cold climate. Congruently, we sampled a cohort of known chronological age to estimate worker longevity in southern climates, and assess age-associated changes in the core hindgut microbiota. We found that worker longevity over winter in southern climates was much lower than that recorded for northern climates. Workers showed decreased bacterial and fungal load with age, but the relative structure of the core hindgut microbiome remained stable. Compared to cold indoor wintering, collective microbiota changes in the southern outdoor climate suggest compromised host physiology. Fungal abundance increased by two orders of magnitude in southern climate hindguts and was positively correlated with non-core, likely opportunistic bacteria. Our results contribute to understanding overwintering honey bee biology and microbial ecology and provide insight into overwintering strategies.

The honey bee genome-- what has it been good for?

In 2006, the full complement of DNA sequence information (or ‘genome’) of the Western honey bee, Apis mellifera, was published. This important resource was one of the most important advances in the history of honey bee research, with seemingly limitless applications to unlocking the secrets of honey bee biology and social life and for improving health, breeding and management. Honey bee genomics has seen immense growth in the past one and a half decades. In this article, we reflect on what the genome has added to our understanding of fundamental aspects of honey bee biology, including evolutionary origins, behaviour and health/disease. We conclude that while the genome has fuelled growth in many areas of honey bee research, it is only one part of an emerging systems-based, multi-omics approach. Moving forward, we posit that honey bee research will benefit most from an even fuller integration of genomics with classical approaches in evolution, ethology, physiology and microbiology.

Introduction of Varroa destructor has not altered honey bee queen mating success in the Hawaiian archipelago

Beekeepers struggle to minimize the mortality of their colonies as a consequence of the parasitic mite Varroa destructor in order to maintain a sustainable managed pollinator population. However, little is known about how varroa mites might diminish local populations of honey bee males (drones) that might affect the mating success of queens. As one of the world’s last localities invaded by varroa mites, the Hawaiian Islands offer a unique opportunity to examine this question by comparing queens mated on mite-infested and mite-free islands. We raised queen bees on four Hawaiian Islands (Kaua‘i, O‘ahu, Maui, and Hawai‘i) and subsequently collected their offspring to determine queen mating frequency and insemination success. No significant difference for mating success was found between the islands with and without varroa mites, and relatively high levels of polyandry was detected overall. We also found a significant association between the number of sperm stored in the queens’ spermathecae and the number of managed colonies within the localities of the queens mated. Our findings suggest that varroa mites, as they currently occur in Hawai‘i, may not significantly reduce mating success of honey bee queens, which provides insight for both the reproductive biology of honey bees as well as the apiculture industry in Hawai‘i.

Two routes of transmission for Nosema infections in a honeybee population model with polyethism and time-periodic parameters can lead to drastically different qualitative model behavior

Nosema ceranae is a widespread microsporidian parasite of the Western honeybee (Apis mellifera). We extend a previous mathematical model of the disease by including mass action infection as a second route of transmission. The underlying honeybee population model accounts for polyethism by considering hive and forager bees separately. It accounts for seasonal variations in honeybee biology by considering model parameters as time-periodic functions. The resulting model is too complex for an insightful rigorous analysis, wherefore we study it primarily with numerical techniques. Our results suggest that direct transmission alone can lead to chaotic behavior in the underlying model, but that this behavior is dampened or suppressed when both transmission routes are considered simultaneously.

The Emerging Proteomic Research Facilitates in-Depth Understanding of the Biology of Honeybees.

Advances in instrumentation and computational analysis in proteomics have opened new doors for honeybee biological research at the molecular and biochemical levels. Proteomics has greatly expanded the understanding of honeybee biology since its introduction in 2005, through which key signaling pathways and proteins that drive honeybee development and behavioral physiology have been identified. This is critical for downstream mechanistic investigation by knocking a gene down/out or overexpressing it and being able to attribute a specific phenotype/biochemical change to that gene. Here, we review how emerging proteome research has contributed to the new understanding of honeybee biology. A systematic and comprehensive analysis of global scientific progress in honeybee proteome research is essential for a better understanding of research topics and trends, and is potentially useful for future research directions.

The Role of Whole-Genome Studies in the Investigation of Honey Bee Biology

Given is an overview of original publications devoted to the investigation of the honey bee genome. The history of honey bee genome studies and its characteristics are described. The results of genetic studies of honey bees using genome-wide data are presented. A special focus is put on the search for alleles associated with economically valuable, adaptive, and other important honey bee traits.