Host-microbiome metabolism of a plant toxin in bees

Origin and function of beneficial bacterial symbioses in insects

Beneficial bacterial symbionts are widespread in insects and affect the fitness of their hosts by contributing to nutrition, digestion, detoxification, communication or protection from abiotic stressors or natural enemies. Decades of research have formed our understanding of the identity, localization and functional benefits of insect symbionts, and the increasing availability of genome sequences spanning a diversity of pathogens and beneficial bacteria now enables comparative approaches of their metabolic features and their phylogenetic affiliations, shedding new light on the origin and function of beneficial symbioses in insects. In this Review, we explore the symbionts' metabolic traits that can provide benefits to insect hosts and discuss the evolutionary paths to the formation of host-beneficial symbiotic associations. Phylogenetic analyses and molecular studies reveal that extracellular symbioses colonizing cuticular organs or the digestive tract evolved from a broad diversity of bacterial partners, whereas intracellular beneficial symbionts appear to be restricted to a limited number of lineages within the Gram-negative bacteria and probably originated from parasitic ancestors. To unravel the general principles underlying host-symbiont interactions and recapitulate the early evolutionary steps leading towards beneficial symbioses, future efforts should aim to establish more symbiotic systems that are amenable to genetic manipulation and experimental evolution.

Lactic Acid Bacteria: A Probiotic to Mitigate Pesticide Stress in Honey Bee

Using probiotics, especially those containing lactic acid bacteria (LAB), to support honey bee health and alleviate the negative effects of pesticides represents a promising approach for sustainable beekeeping. Probiotics have shown their ability to boost honey bee immune systems, counteract pesticide impacts, and lower disease rates. Bacteria like Lactobacillus and Bifidobacterium have demonstrated their ability to degrade organophosphorus pesticides using phosphatase enzymes. Additionally, these bacteria are resistant to the harmful effects of pesticides and aid in detoxification. Furthermore, supplementing with LAB positively affects colony growth, resulting in increased honey production, improved pollen storage, and higher brood counts. Various methods of delivering probiotics, such as powdered supplements, sucrose syrup, and pollen patties, have been explored, each with its own set of challenges and considerations. Despite making significant progress, further study is still required to fully comprehend the precise interactions between probiotics and the physiology of honey bees, to improve delivery strategies, and to evaluate the wider ecological effects on hive microbiomes. By implementing probiotic strategies in beekeeping practices, we can create stronger and more resilient honey bee colonies that can thrive amidst environmental challenges, thus promoting the sustainability of pollination services.

The role of microbiomes in shaping insecticide resistance: current insights and emerging paradigms

Insecticide resistance is a global challenge in agriculture and public health, with the microbiome increasingly recognized as a key contributor. This review synthesizes current research on the microbiome's roles in insecticide resistance, emphasizing mechanisms like microbe-mediated insecticide detoxification, bioactivation, and modulation of host gene expression and physiology. We also explore how different environmental factors impact microbe-host interactions and the roles of epigenetics and post-transcriptional regulation in linking microbial effects to resistance. Integrating evidence from various insect species, this review also proposes strategies for resistance management, including genetically engineered microbes to detoxify insecticides and microbial diagnostic tools for monitoring resistance markers.

Glyphosate and spinetoram alter viral communities with different effects on antibiotic resistance genes in the bumblebee gut

Limited research investigating the impact of pesticides on antibiotic resistance genes (ARGs) and viral community in the gut of wild animals. In this study, we employed metagenomic to investigate the effects of glyphosate and spinetoram on the gut viral communities, ARGs, and their interactions in a key wild pollinator, bumblebees. The results showed that both 2.5 mg/L glyphosate and 2.5 mg/L spinetoram did not significantly alter the α-diversity of the ARGs (p > 0.05). However, spinetoram significantly enriched core ARG subtypes, such as Bado_rpoB_RIF, Bbif_ileS_MUP, and CRP, and total abundance of ARGs (p < 0.05). In contrast, glyphosate had no significant impact on ARG subtypes or total abundance (p > 0.05). The mantel test (R = 0.455, p = 0.020) and Procrustes analysis (M2 = 0.095, p = 0.069) revealed a significant correlation between the bacterial community and ARGs. Although glyphosate and spinetoram had no significant effect on the relative abundance of mobile ARGs (p > 0.05), both significantly altered the alpha diversity (p < 0.05) and compositional structure (one-way PERMANOVA, p = 0.003) of the gut viral communities, with glyphosate increasing the abundance of lytic phages (p < 0.05). Notably, a phage and host relationship network constructed revealed no evidence of phage-mediated ARGs transduction, but five associations between lytic phages and antibiotic-resistant bacteria (ARB) were identified. Furthermore, glyphosate and spinetoram exposure significantly reduced the total relative abundance of these five lytic phages in the viral community (p < 0.001), indicating that phages primarily function in lysing ARBs. These findings suggest that glyphosate may inhibit the enrichment of ARGs by increasing the abundance of lytic phages, while spinetoram may promote the enrichment of total ARGs by affecting the bacterial community.

Microbial bases of herbivory in beetles

The ecological radiation of herbivorous beetles is among the most successful in the animal kingdom. It coincided with the rise and diversification of flowering plants, requiring beetles to adapt to a nutritionally imbalanced diet enriched in complex polysaccharides and toxic secondary metabolites. In this review, we explore how beetles overcame these challenges by coopting microbial genes, enzymes, and metabolites, through both horizontal gene transfer (HGT) and symbiosis. Recent efforts revealed the functional convergence governing both processes and the unique ways in which microbes continue to shape beetle digestion, development, and defense. The development of genetic and experimental tools across a diverse set of study systems has provided valuable mechanistic insights into how microbes spurred metabolic innovation and facilitated an herbivorous transition in beetles.

Life history strategies complement niche partitioning to support the coexistence of closely related Gilliamella species in the bee gut

The maintenance of bacterial diversity at both species and strain levels is crucial for the sustainability of honey bee gut microbiota and host health. Periodic or random fluctuation in diet typically alters the metabolic niches available to gut microbes, thereby continuously reshaping bacterial diversity and interspecific interactions. It remains unclear how closely related bacteria adapt to these fluctuations and maintain coexistence within the bee gut. Here, we demonstrate that the five predominant Gilliamella species associated with Apis cerana, a widely distributed Asiatic honey bee, have diverged in carbohydrate metabolism to adapt to distinct nutrient niches driven by dietary fluctuation. Specifically, the glycan-specialists gain improved growth on a pollen-rich diet, but are overall inferior in competition to non-glycan-specialist on either a simple sugar or sugar-pollen diet, when co-inoculated in the bee host and transmitted across generations. Strikingly, despite of their disadvantage in a high-sugar condition, the glycan-specialists are found prevalent in natural A. cerana guts. We further reveal that these bacteria have adopted a life history strategy characterized by high biomass yield on a low-concentration sugar diet, allowing them to thrive under poor nutritional conditions, such as when the bee hosts undergo periodical starvation. Transcriptome analyses indicate that the divergence in life history strategies is attributed to gene expression programming rather than genetic variation. This study highlights the importance of integrative metabolic strategies in carbohydrate utilization, which facilitate the coexistence of closely related Gilliamella species in a changing bee gut environment.

Dietary Quercetin Regulates Gut Microbiome Diversity and Abundance in Apis cerana (Hymenoptera Apidae)

Honeybee gut microbiota plays a crucial role in maintaining their health and digestive function. Studies have confirmed that quercetin improves honeybee health by enhancing their pesticide tolerance and survival rates. This study aimed to examine the effects of quercetin on the bee gut microbiome by absolute quantification sequencing. We included 1800 bees from the experimental apiary and exposed them to 151.2, 75.6, and 37.8 mg/L of quercetin. Gut samples were collected on the 5th and 9th days, subjected to a polymerase chain reaction and 16S rRNA sequencing, and analyzed. After 5 days of quercetin treatment, the diversity of the honeybee gut microbiota was altered, and total bacterial copies and Lactobacillus abundance significantly decreased at high quercetin concentrations (151.2 and 75.6 mg/L). On day 9, the gut microbial community had recovered from the adverse effects, and Gilliamella abundance increased in response to 37.8 mg/L quercetin treatment. However, quercetin had no noticeable effects on survival rate, food consumption, and gut structure. Our study confirmed the effect of short-term quercetin intake on the gut microbiota of A. cerana, providing valuable insights into how phytochemicals alter the bee gut microbiome, and their repercussions on host physiology.

Colony performance of three native bumblebee species from South China and association with their gut microbiome

Bumblebees play an important ecological economic role as pollinators in nature and agriculture. For reasons of biosecurity, many countries promote the cultivation of native bumblebee species for crop pollination instead of importing "alien" species. In South China, a few bumblebee species are considered useful in this way, particularly, Bombus atripes, Bombus bicoloratus and Bombus breviceps. However, whether they are suitable for artificial rearing and forming healthy colonies for pollination, remains unknown. In this project, queens from the 3 native species of Guizhou Province were collected and colonies were started under standardized conditions. The colonies were scored based on 19 parameters, including the stage of colony development, number and weight of offspring, and diet consumed. The data revealed that B. breviceps had the best performance, produced more workers and consumed the smallest diet. Next, we performed 16S rDNA sequencing of the bacterial communities found in the guts of offspring workers, and then a correlation analysis between colony performance and gut bacteria was conducted. Here, B. breviceps showed the highest diversity in gut bacterial composition, dominated by the bacteria Gilliamella, Snodgrassella, Enterobacter, and Lactobacillus Firm5. The higher the abundance of Snodgrassella, the better the performance of the colony in the foundation stage, and later Lactobacillus Firm5, Apibacter and Bifidobacterium were beneficial during the stages of rapid growth and colony decline. Although we do not understand all of the interactions yet, these correlations explain why B. breviceps demonstrated better colony performance. Our data provide valuable information for breeding local Bombus species and will contribute to developing strong colonies for crop pollination.

Type VI secretion systems promote intraspecific competition and host interactions in a bee gut symbiont

The Type VI Secretion System (T6SS) is a sophisticated mechanism utilized by gram-negative bacteria to deliver toxic effector proteins into target cells, influencing microbial community dynamics and host interactions. In this study, we investigated the role of T6SSs in Snodgrassella alvi wkB2, a core bacterial symbiont of the honey bee gut microbiota. We generated single- and double-knockout mutants targeting essential genes (tssD and tssE) in both T6SS-1 and T6SS-2 and assessed their colonization and competition capabilities in vivo. Our results indicate that T6SSs are nonessential for colonization of the bee gut, although T6SS-2 mutant strains exhibited significantly lower colonization levels compared to the wild-type (WT) strain. Further, a defined community experiment showed that S. alvi wkB2 T6SSs do not significantly impact interspecific competition among core gut bacteria. However, cocolonization experiments with closely related S. alvi strains demonstrated that T6SS-1 plays a role in mediating intraspecific competition. Transcriptomic analysis of bee guts monocolonized by WT or T6SS mutants revealed differential expression of host immunity-related genes relative to microbiota-deprived bees, such as upregulation of the antimicrobial peptide apidaecin in the presence of WT S. alvi and the antimicrobial peptide defensin in the presence of T6SS-2 mutant S. alvi, suggesting that T6SSs contribute to shaping host immune responses. These findings provide insight into the ecological roles of T6SSs in the honey bee gut microbiota, emphasizing their importance in maintaining competitive dynamics and influencing host-bacterial interactions.

Disarming the defenses: Insect detoxification of plant defense-related specialized metabolites

The ability of certain insects to feed on plants containing toxic specialized metabolites may be attributed to detoxification enzymes. Representatives of a few large families of detoxification enzymes are widespread in insect herbivores acting to functionalize toxins and conjugate them with polar substituents to decrease toxicity, increase water solubility and enhance excretion. Insects have also developed specific enzymes for coping with toxins that are activated upon plant damage. Another source of detoxification potential in insects lies in their microbiomes, which are being increasingly recognized for their role in processing plant toxins. The evolution of insect detoxification systems to resist toxic specialized metabolites in plants may in turn have selected for the great diversity of such metabolites found in nature.

Phytochemical profiles of honey bees (Apis mellifera) and their larvae differ from the composition of their pollen diet

Pollen and nectar consumed by honey bees contain plant secondary metabolites (PSMs) with vital roles in plant-insect interactions. While PSMs can be toxic to bees, they can also be health-promoting, e.g. by improving pesticide and pathogen tolerances. As xenobiotics, PSMs undergo post-ingestion chemical modifications that can affect their bioactivity and transmission to the brood. Despite the importance of understanding honey bee PSM metabolism and distribution for elucidating bioactivity mechanisms, these aspects remain largely unexplored. In this study, we used HPLC-MS/MS to profile 47 pollen PSMs in honey bees and larvae. Both adult bees and larvae had distinct PSM profiles that differed from their diet. This is likely due to post-ingestion metabolism and compound-dependent variations in PSM transmission to the brood via nurse bee jelly. Phenolic acids and flavonoid aglycones were most abundant in bees and larvae, whereas alkaloids, cyanogenic glycosides and diterpenoids had the lowest abundance despite being consumed in higher concentrations. This study documents larval exposure to a variety of PSMs for the first time, with concentrations increasing from early to late larval instars. Our findings provide novel insights into the post-ingestion fate of PSMs in honey bees, providing a foundation for further exploration of biotransformation pathways and PSM effects on honey bee health.

Glyphosate effects on growth and biofilm formation in bee gut symbionts and diverse associated bacteria

Biofilm formation is a common adaptation enabling bacteria to thrive in various environments and withstand external pressures. In the context of host-microbe interactions, biofilms play vital roles in establishing microbiomes associated with animals and plants and are used by opportunistic microbes to facilitate survival within hosts. Investigating biofilm dynamics, composition, and responses to environmental stressors is crucial for understanding microbial community assembly and biofilm regulation in health and disease. In this study, we explore in vivo colonization and in vitro biofilm formation abilities of core members of the honey bee (Apis mellifera) gut microbiota. Additionally, we assess the impact of glyphosate, a widely used herbicide with antimicrobial properties, and a glyphosate-based herbicide formulation on growth and biofilm formation in bee gut symbionts as well as in other biofilm-forming bacteria associated with diverse animals and plants. Our results demonstrate that several strains of core bee gut bacterial species can colonize the bee gut, which probably depends on their ability to form biofilms. Furthermore, glyphosate exposure elicits variable effects on bacterial growth and biofilm formation. In some instances, the effects correlate with the bacteria's ability to encode a susceptible or tolerant version of the enzyme inhibited by glyphosate in the shikimate pathway. However, in other instances, no such correlation is observed. Testing the herbicide formulation further complicates comparisons, as results often diverge from glyphosate exposure alone, suggesting that co-formulants influence bacterial growth and biofilm formation. These findings highlight the nuanced impacts of environmental stressors on microbial biofilms, with both ecological and host health-related implications.

IMPORTANCE

Biofilms are essential for microbial communities to establish and thrive in diverse environments. In the honey bee gut, the core microbiota member Snodgrassella alvi forms biofilms, potentially aiding the establishment of other members and promoting interactions with the host. In this study, we show that specific strains of other core members, including Bifidobacterium, Bombilactobacillus, Gilliamella, and Lactobacillus, also form biofilms in vitro. We then examine the impact of glyphosate, a widely used herbicide that can disrupt the bee microbiota, on bacterial growth and biofilm formation. Our findings demonstrate the diverse effects of glyphosate on biofilm formation, ranging from inhibition to enhancement, reflecting observations in other beneficial or pathogenic bacteria associated with animals and plants. Thus, glyphosate exposure may influence bacterial growth and biofilm formation, potentially shaping microbial establishment on host surfaces and impacting health outcomes.

Temporospatial dynamics and host specificity of honeybee gut bacteria

Honeybees are important pollinators worldwide, with their gut microbiota playing a crucial role in maintaining their health. The gut bacteria of honeybees consist of primarily five core lineages that are spread through social interactions. Previous studies have provided a basic understanding of the composition and function of the honeybee gut microbiota, with recent advancements focusing on analyzing diversity at the strain level and changes in bacterial functional genes. Research on honeybee gut microbiota across different regions globally has provided insights into microbial ecology. Additionally, recent findings have shed light on the mechanisms of host specificity of honeybee gut bacteria. This review explores the temporospatial dynamics in honeybee gut microbiota, discussing the reasons and mechanisms behind these fluctuations. This synopsis provides insights into host-microbe interactions and is invaluable for honeybee health.

The Key Role of Amino Acids in Pollen Quality and Honey Bee Physiology-A Review

When studying honey bee nutrition, it is important to pay attention not only to the quantity but also to the quality of pollen for floral visitors. The recommended way to determine the value of pollen is to determine both the protein concentration and the amino acid composition in the insect's hemolymph. In addition, the composition of pollen also includes lipids, sterols and biogenic elements such as carbon, nitrogen, etc. Very high protein concentration is observed in aloe pollen, averaging 51%. Plants with a high protein content, at the level of 27% in Europe, are rapeseed and phacelia. In turn, a plant that is poor in protein (at the level of 11%) is buckwheat. The aforementioned plants are sown over very large areas. Vast acreages in Central and Eastern Europe are occupied by pollen- and nectar-providing invasive plants, such as goldenrod. Therefore, bees are forced to use one food source-a mono diet-which results in their malnutrition. In the absence of natural pollen, beekeepers use other foods for bees; including soy protein, powdered milk, egg yolks, fish meal, etc. However, the colony is the strongest when bees are fed with pollen, as opposed to artificial protein diets. More research is needed on the relationship between bee pollen composition and nutrition, as measured by protein concentration and amino acid composition in apian hemolymph, colony strength, honey yield and good overwintering.

Insects' essential role in understanding and broadening animal medication

Like humans, animals use plants and other materials as medication against parasites. Recent decades have shown that the study of insects can greatly advance our understanding of medication behaviors. The ease of rearing insects under laboratory conditions has enabled controlled experiments to test critical hypotheses, while their spectrum of reproductive strategies and living arrangements - ranging from solitary to eusocial communities - has revealed that medication behaviors can evolve to maximize inclusive fitness through both direct and indirect fitness benefits. Studying insects has also demonstrated in some cases that medication can act through modulation of the host's innate immune system and microbiome. We highlight outstanding questions, focusing on costs and benefits in the context of inclusive host fitness.

Bumble bee microbiota shows temporal succession and increase of lactic acid bacteria when exposed to outdoor environments

Question

The large earth bumble bee (Bombus terrestris) maintains a social core gut-microbiota, similar as known from the honey bee, which plays an important role for host health and resistance. Experiments under laboratory conditions with commercial hives are limited to vertically transmitted microbes and neglect influences of environmental factors or external acquisition of microbes. Various environmental and landscape-level factors may have an impact on the gut-microbiota of pollinating insects, with consequences for pollinator health and fitness in agroecosystems. Still, it is not fully clear whether access to different flower diversities will have a significant influence on the bumble bee microbiota. Here, we tested in a semi-field experiment if the bumble bee microbiota changes over time when exposed to different flower diversities within outdoor flight cages. We used commercial hives to distinguish between vertically and horizontally transmitted bacteria, respectively from the nest environment or the exposed outside environment.

Result

The sequential sampling of foraging workers over a period of 35 days indicated a temporal progression of the bumble bee microbiota when placed outside. The microbiota increased in diversity and changed in composition and variability over time. We observed a major increase in relative abundance of the families Lactobacillaceae, Bifidobacteriaceae and Weeksellaceae. In contrast, major core-taxa like Snodgrassella and Gilliamella declined in their relative abundance over time. The genus Lactobacillus showed a high diversity and strain specific turnover, so that only specific ASVs showed an increase over time, while others had a more erratic occurrence pattern. Exposure to different flower diversities had no significant influence on the progression of the bumble bee microbiota.

Conclusion

The bumble bee microbiota showed a dynamic temporal succession with distinct compositional changes and diversification over time when placed outdoor. The exposure of bumble bees to environmental conditions, or environmental microbes, increases dissimilarity and changes the gut-community composition. This shows the importance of environmental influences on the temporal dynamic and progression of the bumble bee microbiota.

The honeybee microbiota and its impact on health and disease

Honeybees (Apis mellifera) are key pollinators that support global agriculture and are long-established models for developmental and behavioural research. Recently, they have emerged as models for studying gut microbial communities. Earlier research established that hindguts of adult worker bees harbour a conserved set of host-restricted bacterial species, each showing extensive strain variation. These bacteria can be cultured axenically and introduced to gnotobiotic hosts, and some have basic genetic tools available. In this Review, we explore the most recent research showing how the microbiota establishes itself in the gut and impacts bee biology and health. Microbiota members occupy specific niches within the gut where they interact with each other and the host. They engage in cross-feeding and antagonistic interactions, which likely contribute to the stability of the community and prevent pathogen invasion. An intact gut microbiota provides protection against diverse pathogens and parasites and contributes to the processing of refractory components of the pollen coat and dietary toxins. Absence or disruption of the microbiota results in altered expression of genes that underlie immunity, metabolism, behaviour and development. In the field, such disruption by agrochemicals may negatively impact bees. These findings demonstrate a key developmental and protective role of the microbiota, with broad implications for bee health.

Phylogenomics of the Ecdysteroid Kinase-like (EcKL) Gene Family in Insects Highlights Roles in Both Steroid Hormone Metabolism and Detoxification

The evolutionary dynamics of large gene families can offer important insights into the functions of their individual members. While the ecdysteroid kinase-like (EcKL) gene family has previously been linked to the metabolism of both steroid molting hormones and xenobiotic toxins, the functions of nearly all EcKL genes are unknown, and there is little information on their evolution across all insects. Here, we perform comprehensive phylogenetic analyses on a manually annotated set of EcKL genes from 140 insect genomes, revealing the gene family is comprised of at least 13 subfamilies that differ in retention and stability. Our results show the only two genes known to encode ecdysteroid kinases belong to different subfamilies and therefore ecdysteroid metabolism functions must be spread throughout the EcKL family. We provide comparative phylogenomic evidence that EcKLs are involved in detoxification across insects, with positive associations between family size and dietary chemical complexity, and we also find similar evidence for the cytochrome P450 and glutathione S-transferase gene families. Unexpectedly, we find that the size of the clade containing a known ecdysteroid kinase is positively associated with host plant taxonomic diversity in Lepidoptera, possibly suggesting multiple functional shifts between hormone and xenobiotic metabolism. Our evolutionary analyses provide hypotheses of function and a robust framework for future experimental studies of the EcKL gene family. They also open promising new avenues for exploring the genomic basis of dietary adaptation in insects, including the classically studied coevolution of butterflies with their host plants.

Microbes, the 'silent third partners' of bee-angiosperm mutualisms

While bee-angiosperm mutualisms are widely recognized as foundational partnerships that have shaped the diversity and structure of terrestrial ecosystems, these ancient mutualisms have been underpinned by 'silent third partners': microbes. Here, we propose reframing the canonical bee-angiosperm partnership as a three-way mutualism between bees, microbes, and angiosperms. This new conceptualization casts microbes as active symbionts, processing and protecting pollen-nectar provisions, consolidating nutrients for bee larvae, enhancing floral attractancy, facilitating plant fertilization, and defending bees and plants from pathogens. In exchange, bees and angiosperms provide their microbial associates with food, shelter, and transportation. Such microbial communities represent co-equal partners in tripartite mutualisms with bees and angiosperms, facilitating one of the most important ecological partnerships on land.

Microbial degradation of plant toxins

Plants produce a variety of secondary metabolites in response to biotic and abiotic stresses. Although they have many functions, a subclass of toxic secondary metabolites mainly serve plants as deterring agents against herbivores, insects, or pathogens. Microorganisms present in divergent ecological niches, such as soil, water, or insect and rumen gut systems have been found capable of detoxifying these metabolites. As a result of detoxification, microbes gain growth nutrients and benefit their herbivory host via detoxifying symbiosis. Here, we review current knowledge on microbial degradation of toxic alkaloids, glucosinolates, terpenes, and polyphenols with an emphasis on the genes and enzymes involved in breakdown pathways. We highlight that the insect-associated microbes might find application in biotechnology and become targets for an alternative microbial pest control strategy.

The role of the veterinary diagnostic toxicologist in apiary health

Susceptibility of individuals and groups to toxicants depends on complex interactions involving the host, environment, and other exposures. Apiary diagnostic investigation and honey bee health are truly population medicine: the colony is the patient. Here we provide basic information on the application of toxicology to the testing of domestic honey bees, and, in light of recent research, expand on some of the challenges of interpreting analytical chemistry findings as they pertain to hive health. The hive is an efficiently organized system of wax cells used to store brood, honey, and bee bread, and is protected by the bee-procured antimicrobial compound propolis. Toxicants can affect individual workers outside or inside the hive, with disease processes that range from acute to chronic and subclinical to lethal. Toxicants can impact brood and contaminate honey, bee bread, and structural wax. We provide an overview of important natural and synthetic toxicants to which honey bees are exposed; behavioral, husbandry, and external environmental factors influencing exposure; short- and long-term impacts of toxicant exposure on individual bee and colony health; and the convergent impacts of stress, nutrition, infectious disease, and toxicant exposures on colony health. Current and potential future toxicology testing options are included. Common contaminants in apiary products consumed or used by humans (honey, wax, pollen), their sources, and the potential need for product testing are also noted.

Synergy in symbiosis

Honeybees rely on their microbial gut symbionts to overcome a potent toxin found in pollen and nectar.