Colony Collapse Disorder (CCD) and bee age impact honey bee pathophysiology

Buzzing with Intelligence: Current Issues in Apiculture and the Role of Artificial Intelligence (AI) to Tackle It

Honeybees (Apis mellifera L.) are important for agriculture and ecosystems; however, they are threatened by the changing climate. In order to adapt and respond to emerging difficulties, beekeepers require the ability to continuously monitor their beehives. To carry out this, the utilization of advanced machine learning techniques proves to be an exceptional tool. This review provides a comprehensive analysis of the available research on the different applications of artificial intelligence (AI) in beekeeping that are relevant to climate change. Presented studies have shown that AI can be used in various scientific aspects of beekeeping and can work with several data types (e.g., sound, sensor readings, images) to investigate, model, predict, and help make decisions in apiaries. Research articles related to various aspects of apiculture, e.g., managing hives, maintaining their health, detecting pests and diseases, and climate and habitat management, were analyzed. It was found that several environmental, behavioral, and physical attributes needed to be monitored in real-time to be able to understand and fully predict the state of the hives. Finally, it could be concluded that even if there is not yet a full-scale monitoring method for apiculture, the already available approaches (even with their identified shortcomings) can help maintain sustainability in the changing apiculture.

Computational Modeling Oriented Substructure Splicing Application in the Identification of Thiazolidine Derivatives as Potential Low Honeybee Toxic Neonicotinoids

With the aim of identifying novel neonicotinoid insecticides with low bee toxicity, a series of compounds bearing thiazolidine moiety, which has been shown to be low bee toxic, were rationally designed through substructure splicing strategy and evaluated insecticidal activities. The optimal compounds A24 and A29 exhibited LC50 values of 30.01 and 17.08 mg/L against Aphis craccivora, respectively. Electrophysiological studies performed on Xenopus oocytes indicated that compound A29 acted on insect nAChR, with EC50 value of 50.11 μM. Docking binding mode analysis demonstrated that A29 bound to Lymnaea stagnalis acetylcholine binding protein through H-bonds with the residues of D_Arg55, D_Leu102, and D_Val114. Quantum mechanics calculation showed that A29 had a higher highest occupied molecular orbit (HOMO) energy and lower vertical ionization potential (IP) value compared to the high bee toxic imidacloprid, showing potentially low bee toxicity. Bee toxicity predictive model also indicated that A29 was nontoxic to honeybees. Our present work identified an innovative insecticidal scaffold and might facilitate the further exploration of low bee toxic neonicotinoid insecticides.

A systemic study of cyenopyrafen in strawberry cultivation system: Efficacy, residue behavior, and impact on honeybees (Apis mellifera L.)

The pesticide application method is one of the important factors affecting its effectiveness and residues, and the risk of pesticides to non-target organisms. To elucidate the effect of application methods on the efficacy and residue of cyenopyrafen, and the toxic effects on pollinators honeybees in strawberry cultivation, the efficacy and residual behavior of cyenopyrafen were investigated using foliar spray and backward leaf spray in field trials. The results showed that the initial deposition of cyenopyrafen using backward leaf spray on target leaves reached 5.06-9.81 mg/kg at the dose of 67.5-101.25 g a.i./ha, which was higher than that using foliar spray (2.62-3.71 mg/kg). The half-lives of cyenopyrafen in leaves for foliar and backward leaf spray was 2.3-3.3 and 5.3-5.9 d, respectively. The residues (10 d) of cyenopyrafen in leaves after backward leaf spray was 1.41-3.02 mg/kg, which was higher than that after foliar spraying (0.25-0.37 mg/kg). It is the main reason for the better efficacy after backward leaf spray. However, the residues (10 d) in strawberry after backward leaf spray and foliar spray was 0.04-0.10 and < 0.01 mg/kg, which were well below the established maximum residue levels of cyenopyrafen in Japan and South Korea for food safety. To further investigate the effects of cyenopyrafen residues after backward leaf spray application on pollinator honeybees, sublethal effects of cyenopyrafen on honeybees were studied. The results indicated a significant inhibition in the detoxification metabolic enzymes of honeybees under continuous exposure of cyenopyrafen (0.54 and 5.4 mg/L) over 8 d. The cyenopyrafen exposure also alters the composition of honeybee gut microbiota, such as increasing the relative abundance of Rhizobiales and decreasing the relative abundance of Acetobacterales. The comprehensive data on cyenopyrafen provide basic theoretical for environmental and ecological risk assessment, while backward leaf spray proved to be effective and safe for strawberry cultivation.

Studies on the novel effects of electron beam treated pollen on colony reproductive output in commercially-reared bumblebees (Bombus terrestris) for mass pollination applications

Commercially-reared bumblebees provide an important pollinator service that helps support food production and security. The deployment of an appropriate non-thermal disinfection technology for the bulk treatment of pollen collected from honeybees for the feeding of commercial bumblebees is important in order to mitigate against complex diseases and unwanted pathogen spillover to native bees. High level disinfection of pollen was achieved using an electron (e)-beam dose of 100 kGy that corresponded to 78 % loss of cellular viability of bee pathogens before feeding to bumblebees as measured by the novel in vitro use of flow cytometry (FCM). Novel findings showed that e-beam treated-pollen that was fed to bumblebees produced fewer females, gynes and exhibited an absence of males when compared to control bumblebee colonies that were fed untreated commercial pollen. A similar trend emerged in bumblebee colony reproductive outputs when using membrane filtered washed pollen. Proteomic analysis of bumblebees from individual colonies fed with treated-pollen revealed a differential abundance of proteins associated with stress, immunity and metabolism when compared to the untreated pollen control group. Microbiome analysis of the bumblebee gut content revealed differences in microbiota between treated and untreated pollen in bumblebee colony studies. This novel study evaluated the impact of industrial e-beam treated-pollen on complex bee disease mitigation where physically treated-pollen fed to bumblebees was shown to substantially affect colony reproductive outputs.

Resilin Distribution and Abundance in Apis mellifera across Biological Age Classes and Castes

The presence of resilin, an elastomeric protein, in insect vein joints provides the flexible, passive deformations that are crucial to flapping flight. This study investigated the resilin gene expression and autofluorescence dynamics among Apis mellifera (honey bee) worker age classes and drone honey bees. Resilin gene expression was determined via ddPCR on whole honey bees and resilin autofluorescence was measured in the 1m-cu, 2m-cu, Cu-V, and Cu2-V joints on the forewing and the Cu-V joint of the hindwing. Resilin gene expression varied significantly with age, with resilin activity being highest in the pupae. Autofluorescence of the 1m-cu and the Cu-V joints on the ventral forewing and the Cu-V joint on the ventral hindwing varied significantly between age classes on the left and right sides of the wing, with the newly emerged honey bees having the highest level of resilin autofluorescence compared to all other groups. The results of this study suggest that resilin gene expression and deposition on the wing is age-dependent and may inform us more about the physiology of aging in honey bees.

Detrimental consequences of tebuconazole on redox homeostasis and fatty acid profile of honeybee brain

Excessive use of azole fungicides in agriculture poses a potential threat to honeybees and other pollinator insects; however, the detailed effects of these molecules remain largely unclear. Hence, in the present study it was aimed to investigate the acute sublethal effects of tebuconazole on the redox homeostasis and fatty acid composition in the brain of honeybees. Our findings demonstrate that tebuconazole decreased total antioxidant capacity, the ratio of reduced to oxidized glutathione and disturbed the function of key antioxidant defense enzymes along with the induction of lipid peroxidation indicated by increased malondialdehyde levels, while it also altered the fatty acid profile of the brain. The present study highlights the negative impact of tebuconazole on honeybees and contributes to the understanding of potential consequences related to azole exposure on pollinator insects' health, such as the occurrence of colony collapse disorder.

Honey bee larval culture in vitro: gut emptying determines the transition from larva to prepupa and recombinant AccApidaecin improves antibacterial activity

In vitro rearing of honey bee larvae is ideal for bioassay studies; no honey bee stable cell lines are available. Inconsistency of internal development staging of reared larvae and a susceptibility to contamination are common problems encountered. Standardized protocols on rearing larvae in vitro to make the larvae growth and development more similar to that of natural colonies are necessary to ensure the accuracy of experimental results and promote honey bee research as a model organism. Here, we concluded that when larval fasting weight was >160 mg, the time point of gut emptying can be defined as the critical point separating the larval and prepupal stages. In this way, we can conduct precise studies on the prepupal stage, such as organ remodeling during metamorphosis. Simultaneously, we further verified that recombinant AccApidaecin in genetic engineered bacteria added to the larval diet upregulated antibacterial peptide gene expression, and did not stimulate the stress response in larvae, nor did it affect the pupation rate or eclosion rate. This demonstrated that feeding recombinant AccApidaecin can enhance the individual antibacterial ability at the molecular level.

Isolation and characterization of Lactobacillus casei A14.2, a strain with immunomodulating activity on Apis mellifera

Considering the economic and environmental role played by bees and their present threats it is necessary to develop food supplements favoring their health. The aim of this work was to isolate and characterize an immunomodulating probiotic capable to improve the health of honeybee colonies. For this purpose, bacterial strains were isolated from Apis mellifera bees (N = 180) obtained at three apiaries. A total of 44 strains were isolated and 9 of them were identified as Lactobacillus having the capacity to grow under saccharose osmotic stress, at pH 4.0 and possessing a wide susceptibility to antibiotics. Results allowed to select two strains but finally only one of them, strain A14.2 showed a very significant immunomodulating activity. This strain increased the expression of mRNA codifying the antimicrobial peptides 24 h post-administration. We evaluated its growth kinetics under aerobic and microaerobic conditions and its survival in the presence of high concentrations of saccharose. Results demonstrated that Lactobacillus casei A14.2 strain was highly tolerant to oxygen and that it was able to adapt to saccharose enriched environments (50% and 100% w/v). Finally, L. casei A14.2 strain was administered monthly during summer and early fall to 4 honeybee colonies (2 controls and 2 treatments). The results showed a gradual sustained decrease of infestation (p < 0.05) by the pathogenic Nosema spp. but no reduction in the infestation by the mite Varroa destructor. These results suggest that the administration of this potential probiotic, may increase the resistance of honeybee colonies to infectious diseases caused by Nosema spp.

Developing Strategies to Help Bee Colony Resilience in Changing Environments

Climate change, loss of plant biodiversity, burdens caused by new pathogens, predators, and toxins due to human disturbance and activity are significant causes of the loss of bee colonies and wild bees. The aim of this review is to highlight some possible strategies that could help develop bee resilience in facing their changing environments. Scientists underline the importance of the links between nutrition, microbiota, and immune and neuroendocrine stress resistance of bees. Nutrition with special care for plant-derived molecules may play a major role in bee colony health. Studies have highlighted the importance of pollen, essential oils, plant resins, and leaves or fungi as sources of fundamental nutrients for the development and longevity of a honeybee colony. The microbiota is also considered as a key factor in bee physiology and a cornerstone between nutrition, metabolism, growth, health, and pathogen resistance. Another stressor is the varroa mite parasite. This parasite is a major concern for beekeepers and needs specific strategies to reduce its severe impact on honeybees. Here we discuss how helping bees to thrive, especially through changing environments, is of great concern for beekeepers and scientists.

First national survey of residues of active substances in honeybee apiaries across Spain between 2012 and 2016

This nationwide monitoring aimed to investigate the prevalence of residues of plant protection products (PPPs) and veterinary medicine products (VMPs) based on random selection of apiaries of Apis mellifera. For a three-year period (2012, 2013 and 2016), this study targeted 306 PPPs, VMPs and other active substances in 442 samples of bee bread honeycomb (BBHC) and 89 samples of honeybees collected from up to 177 apiaries. The results indicate that honeybees were most often exposed to residues of coumaphos, tau-fluvalinate, chlorfenvinphos, and acrinathrin, with a prevalence from a maximum of 98.8% to 49.4% in BBHC samples. Residues of coumaphos, tau-fluvalinate, amitraz (DMF + DMPF), carbendazim and orthophenylphenol were also frequently detected, from a maximum of 55.1% to 13.5% of the honeybee samples. Neonicotinoid residues, namely clothianidin and thiamethoxam, whose outdoor uses in crops are completely banned in EU, were not detected. Imidacloprid was found in 3.4% to 13.3% of samples during 2013 and 2016, respectively. Imidacloprid exceeded its acute toxicity (LD₅₀) value for honey bees in two samples of BBHC. Fipronil was detected in 0.5% of the samples during 2013. The diversity of active substances found (% of different residues analyzed) ranged from 33.9% to 37.2% in BBHC from 2012, 2013 to 2016, and was of 26.5% in honeybees in 2016. In at least 54% of the samples, the total residue load was in the range of 200 to 1500 μg·kg^-1. Up to 50% of BBHC samples were positive for one or two residues. No toxic residues for honeybees were detected in up to 88.8% of bee samples. This systematic surveillance of active substances assisted the evaluation of which target pesticides to look for and provided support to the competent authorities in the bee health decision-making.

Impact of demographic variability on the disease dynamics for honeybee model

For the last few years, annual honeybee colony losses have been center of key interest for many researchers throughout the world. The spread of the parasitic mite and its interaction with specific honeybee viruses carried by Varroa mites has been linked to the decline of honeybee colonies. In this investigation, we consider honeybee-virus and honeybee-infected mite-virus models. We perform sensitivity analysis locally and globally to see the effect of the parameters on the basic reproduction number for both models and to understand the disease dynamics in detail. We use the continuous-time Markov chain model to develop and analyze stochastic epidemic models corresponding to both deterministic models. By using the disease extinction process, we compare both deterministic and stochastic models. We have observed that the numerically approximated probability of disease extinction based on 30 000 sample paths agrees well with the calculated probability using multitype branching process approximation. In particular, it is observed that the disease extinction probability is higher when infected honeybees spread the disease instead of infected mites. We conduct a sensitivity analysis for the stochastic model also to examine how the system parameters affect the probability of disease extinction. We have also derived the equation for the expected time required to reach disease-free equilibrium for stochastic models. Finally, the effect of the parameters on the expected time is represented graphically.

Bee Stressors from an Immunological Perspective and Strategies to Improve Bee Health

Honeybees are the most prevalent insect pollinator species; they pollinate a wide range of crops. Colony collapse disorder (CCD), which is caused by a variety of biotic and abiotic factors, incurs high economic/ecological loss. Despite extensive research to identify and study the various ecological stressors such as microbial infections, exposure to pesticides, loss of habitat, and improper beekeeping practices that are claimed to cause these declines, the deep understanding of the observed losses of these important insects is still missing. Honeybees have an innate immune system, which includes physical barriers and cellular and humeral responses to defend against pathogens and parasites. Exposure to various stressors may affect this system and the health of individual bees and colonies. This review summarizes and discusses the composition of the honeybee immune system and the consequences of exposure to stressors, individually or in combinations, on honeybee immune competence. In addition, we discuss the relationship between bee nutrition and immunity. Nutrition and phytochemicals were highlighted as the factors with a high impact on honeybee immunity.

Supplemental Stingless Bee Pollination in Fennel (Foeniculum vulgare Mill.): An Assessment of Impacts on Native Pollinators and Crop Yield

The yield of many crops benefits from pollinating insects; thus, recently reported declines in pollinator abundance and diversity are concerning for global food production. The pollinator dependency and amount of yield enhancement may vary according to crop species and geographical location. Fennel (Foeniculum vulgare) is an important spice crop cultivated in Indian states. However, comprehensive knowledge about pollination demand and yield enhancement potential of managed bees is still unknown. Here, we conducted a replicated study in two successive years (2020 and 2021) in West Bengal by combining pollinator surveys, pollinator-exclusion experiments, and field manipulation on fennel, which quantifies the impacts of supplemental stingless bees (Tetragonula iridipennis) pollination on native pollinators and crop yield. The crop species attracted many insect species belonging to diverse groups. Among those, important native pollinators (based on “approximate pollination value”) were Apis cerana, Apis dorsata, Apis florea, and Oxybelus furculatus in open condition (i.e., without field manipulation and in the absence of managed bees). We derived the coefficient of pollination deficit (D) from the fruit set percentages in open and manual cross-pollination treatments. The obtained value (D = 0.18) implies that the crop species have pollen transfer limitations, resulting in retardation of crop yield. From field manipulation with managed stingless bee colonies, the abundance of visitors (especially stingless bee foragers) on fennel increased (without altering the foraging activity of other native pollinators), thereby fruit set and crop yield increased by about 14.89 and 19.31%, respectively. Native managed stingless bees had no negative impacts on other native unmanaged species and can be promoted as complementary and short-term means of boosting yields and improving agricultural sustainability.

Assessing Repeated Oxalic Acid Vaporization in Honey Bee (Hymenoptera: Apidae) Colonies for Control of the Ectoparasitic Mite Varroa destructor

The American beekeeping industry continually experiences colony mortality with annual losses as high as 43%. A leading cause of this is the exotic, ectoparasitic mite, Varroa destructor Anderson & Trueman (Mesostigmata: Varroidae). Integrated Pest Management (IPM) options are used to keep mite populations from reaching lethal levels, however, due to resistance and/or the lack of suitable treatment options, novel controls for reducing mites are warranted. Oxalic acid for controlling V. destructor has become a popular treatment regimen among commercial and backyard beekeepers. Applying vaporized oxalic acid inside a honey bee hive is a legal application method in the U.S., and results in the death of exposed mites. However, if mites are in the reproductive stage and therefore under the protective wax capping, oxalic acid is ineffective. One popular method of applying oxalic is vaporizing multiple times over several weeks to try and circumvent the problem of mites hiding in brood cells. By comparing against control colonies, we tested oxalic acid vaporization in colonies treated with seven applications separated by 5 d (35 d total). We tested in apiaries in Georgia and Alabama during 2019 and 2020, totaling 99 colonies. We found that adult honey bees Linnaeus (Hymenoptera: Apidae), and developing brood experienced no adverse impacts from the oxalic vaporization regime. However, we did not find evidence that frequent periodic application of oxalic during brood-rearing periods is capable of bringing V. destructor populations below treatment thresholds.

Environmental exposures associated with honey bee health

Bee health is declining on a global scale, yet the exact causes and their interactions responsible for the decline remain unknown. To more objectively study bee health, recently biomarkers have been proposed as an essential tool, because they can be rapidly quantified and standardized, serving as a comparable measure across bee species and varying environments. Here, we used a systems biology approach to draw associations between endogenous and exogenous chemical profiles, with pesticide exposure, or the abundance of the 21 most common honey bee diseases. From the analysis we identified chemical biomarkers for both pesticide exposure and bee diseases along with the mechanistic biological pathways that may influence disease onset and progression. We found a total of 2352 chemical features, from 30 different hives, sampled from seven different locations. Of these, a total of 1088 significant associations were found that could serve as chemical biomarker profiles for predicting both pesticide exposure and the presence of diseases in a bee colony. In almost all cases we found novel external environmental exposures within the top seven associations with bee diseases and pesticide exposures, with the majority having previously unknown connections to bee health. We highlight the exposure-outcome paradigm and its ability to identify previously uncategorized interactions from different environmental exposures associated with bee diseases, pesticides, mechanisms, and potential synergistic interactions of these that are responsible for honey bee health decline.

Deformed wing virus infection affects the neurological function of Apis mellifera by altering extracellular adenosine signaling

Deformed wing virus (DWV) infection is believed to be closely associated with colony losses of honeybee (Apis mellifera) due to reduced learning and memory of infected bees. The adenosine (Ado) pathway is important for maintaining immunity and memory function in animals, and it enhances antivirus responses by regulating carbohydrate metabolism in insects. Nevertheless, its effect on the memory of invertebrates is not yet clear. This study investigated how the Ado pathway regulates energy metabolism and memory in honeybees following DWV infection. Decreased Ado receptor (Ado-R) expression in the brain of infected bees resulted in a carbohydrate imbalance as well as impairments of glutamate-glutamine (Glu-Gln) cycle and long-term memory. Dietary supplementation with Ado not only increased the brain energy metabolism but also rescued long-term memory loss by upregulating the expression of memory-related genes. The present study demonstrated the regulation of the Ado pathway upon DWV infection and provides insights into the mechanisms underlying energy regulation and the neurological function of honeybees.

Resistance and Vulnerability of Honeybee (Apis mellifera) Gut Bacteria to Commonly Used Pesticides

Agricultural and apicultural practices expose honeybees to a range of pesticides that have the potential to negatively affect their physiology, neurobiology, and behavior. Accumulating evidence suggests that these effects extend to the honeybee gut microbiome, which serves important functions for honeybee health. Here we test the potential effects of the pesticides thiacloprid, acetamiprid, and oxalic acid on the gut microbiota of honeybees, first in direct in vitro inhibition assays and secondly in an in vivo caged bee experiment to test if exposure leads to gut microbiota community changes. We found that thiacloprid did not inhibit the honeybee core gut bacteria in vitro, nor did it affect overall community composition or richness in vivo. Acetamiprid did also not inhibit bacterial growth in vitro, but it did affect community structure within bees. The eight bacterial genera tested showed variable levels of susceptibility to oxalic acid in vitro. In vivo, treatment with this pesticide reduced amplicon sequence variant (ASV) richness and affected gut microbiome composition, with most marked impact on the common crop bacteria Lactobacillus kunkeei and the genus Bombella. We conducted network analyses which captured known associations between bacterial members and illustrated the sensitivity of the microbiome to environmental stressors. Our findings point to risks of honeybee exposure to oxalic acid, which has been deemed safe for use in treatment against Varroa mites in honeybee colonies, and we advocate for more extensive assessment of the long-term effects that it may have on honeybee health.

Effects of Insecticides and Microbiological Contaminants on Apis mellifera Health

Over the past two decades, there has been an alarming decline in the number of honey bee colonies. This phenomenon is called Colony Collapse Disorder (CCD). Bee products play a significant role in human life and have a huge impact on agriculture, therefore bees are an economically important species. Honey has found its healing application in various sectors of human life, as well as other bee products such as royal jelly, propolis, and bee pollen. There are many putative factors of CCD, such as air pollution, GMO, viruses, or predators (such as wasps and hornets). It is, however, believed that pesticides and microorganisms play a huge role in the mass extinction of bee colonies. Insecticides are chemicals that are dangerous to both humans and the environment. They can cause enormous damage to bees' nervous system and permanently weaken their immune system, making them vulnerable to other factors. Some of the insecticides that negatively affect bees are, for example, neonicotinoids, coumaphos, and chlorpyrifos. Microorganisms can cause various diseases in bees, weakening the health of the colony and often resulting in its extinction. Infection with microorganisms may result in the need to dispose of the entire hive to prevent the spread of pathogens to other hives. Many aspects of the impact of pesticides and microorganisms on bees are still unclear. The need to deepen knowledge in this matter is crucial, bearing in mind how important these animals are for human life.

Monitoring bee health in European agro-ecosystems using wing morphology and fat bodies

Current global change substantially threatens pollinators, which directly impacts the pollination services underpinning the stability, structure and functioning of ecosystems. Amongst these threats, many synergistic drivers, such as habitat destruction and fragmentation, increasing use of agrochemicals, decreasing resource diversity, as well as climate change, are known to affect wild and managed bees. Therefore, reliable indicators for pollinator sensitivity to such threats are needed. Biological traits, such as phenotype (e.g. shape, size and asymmetry) and storage reserves (e.g. fat body size), are important pollinator traits linked to reproductive success, immunity, resilience and foraging efficiency and, therefore, could serve as valuable markers of bee health and pollination service potential.

This data paper contains an extensive dataset of wing morphology and fat body content for the European honeybee (Apis mellifera) and the buff-tailed bumblebee (Bombus terrestris) sampled at 128 sites across eight European countries in landscape gradients dominated by two major bee-pollinated crops (apple and oilseed rape), before and after focal crop bloom and potential pesticide exposure. The dataset also includes environmental metrics of each sampling site, namely landscape structure and pesticide use. The data offer the opportunity to test whether variation in the phenotype and fat bodies of bees is structured by environmental factors and drivers of global change. Overall, the dataset provides valuable information to identify which environmental threats predominantly contribute to the modification of these traits.

Bees and pesticides: the research impact and scientometrics relations

Bees are fundamental insects in agroecosystems, mainly due to pollination. However, its decline has been observed in recent years, and the contamination by pesticides is suspected to be responsible. This relationship is the objective of our research, which is the first scientometric study on this subject. The data were obtained from the Web of Science database (1231) and were analyzed using Microsoft Office Excel and CiteSpace. The results point to a significant increase in pesticide and bee reseach in the last 15 years in the most influential scientific journals. The USA and France have the largest number of publications and a moderade relationship between this trait and GDP (gross domestic product) was observed (r = 0.80; r2 = 0.60). There is no correlation between the use of pesticides and studies of the effects on pollinators and the use of pesticides and the countries' GDP. In general, studies have shown the negative effects of the contamination by pesticides on bees; however, most publications are with bees of the Apis genus, and therefore it is necessary to explore the action of pesticides on bumble bees and wild bees, as well furthur as studies are needed regarding the sublethal effects of these products on bees as the number of molecules used in the management of agricultural crops is vast.

Characterization of Apis mellifera Gastrointestinal Microbiota and Lactic Acid Bacteria for Honeybee Protection-A Review

Numerous honeybee (Apis mellifera) products, such as honey, propolis, and bee venom, are used in traditional medicine to prevent illness and promote healing. Therefore, this insect has a huge impact on humans’ way of life and the environment. While the population of A. mellifera is large, there is concern that widespread commercialization of beekeeping, combined with environmental pollution and the action of bee pathogens, has caused significant problems for the health of honeybee populations. One of the strategies to preserve the welfare of honeybees is to better understand and protect their natural microbiota. This paper provides a unique overview of the latest research on the features and functioning of A. mellifera. Honeybee microbiome analysis focuses on both the function and numerous factors affecting it. In addition, we present the characteristics of lactic acid bacteria (LAB) as an important part of the gut community and their special beneficial activities for honeybee health. The idea of probiotics for honeybees as a promising tool to improve their health is widely discussed. Knowledge of the natural gut microbiota provides an opportunity to create a broad strategy for honeybee vitality, including the development of modern probiotic preparations to use instead of conventional antibiotics, environmentally friendly biocides, and biological control agents.

Set of stress biomarkers as a practical tool in the assessment of multistress effect using honeybees from urban and rural areas as a model organism: a pilot study

A decrease among honey bee populations (Apis mellifera) in the traditional apiaries has been observed in recent years. In light of this negative phenomenon, urban beekeeping seems to be an appropriate alternative solution for the bee population in reducing the toxic effects of a large number of pesticides that are commonly used in agricultural ecosystems. Despite the rapid development of urban beekeeping, there is little information regarding the different aspects of the defense effectiveness of bees from the urban and rural areas. The study was aimed to show whether honey bees from these two locations differ in the level of the valuable biomarkers of stress exposure helpful in establishing which bees, from urban or rural areas, are under greater environmental pressure. For this purpose, foragers from an urban rooftop apiary and a traditional rural apiary were collected. The chosen biomarkers were measured in various tissues of bees. The activity of glutathione S-transferase and acetylcholinesterase, the level of total antioxidant capacity, heat shock protein 70 (Hsp70), and defensin were selected for the analyses. In our opinion, the Hsp70 and defensin levels seemed to be important in the indication of urban multistress factors. The higher level of heat shock proteins and defensins in tissues/organs of bees from the urban apiary-in the gut (an increase, respectively, 92% and 7.3%) and fat body (an increase, respectively, 130% and 7.8%), known as targets of environmental toxins, pointed out the urban environment as highly stressful at both the individual and colony levels. In turn, high total antioxidant capacity was measured in the guts of honey bees from rural area (an increase 107%). Such a situation suggests a different mechanism of defense and specificity of rural and urban environmental stressors and also honey bees foraging activity.

Pollen analysis of honeys from Apis mellifera and Tetragonisca fiebrigi (Hymenoptera: Apidae) in the Upper Paraná Atlantic Forest, Argentina

Abstract Nectariferous and polliniferous resources are key to the survival of social bees, so identifying the origin sources allows the implementation of management actions aimed at a greater supply of nutrients for the colonies. Besides, defining the floral origin of honeys contributes to their characterization and commercialization. The objective of our work was to identify the plants that provide nectar to the bees Apis mellifera and Tetragonisca fiebrigi in northern Misiones, through palynological analysis of honey samples collected between 2006 and 2008. Both bees showed a polylectic foraging habit. Richness of pollen types per sample ranged between 10 and 34 (mean = 20.5 ± 7.7) for A. mellifera, and between 13 and 43 (mean = 24.8 ± 7.1) for T. fiebrigi. The 15 most abundant pollen types in the honeys of A. mellifera were, in decreasing order of importance, Euphorbiaceae, Euterpe edulis, Holocalyx balansae, Calyptranthes concinna-type, Actinostemon, Salix, Ruprechtia laxiflora, Myrcianthes pungens-type, Thinouia mucronata, Allophylus edulis, Ilex, Syagrus romanzoffiana, Gouania latifolia-type, Parapiptadenia rigida, and Baccharis-type, whereas in the honeys of T. fiebrigi the most important pollen types included S. romanzoffiana, Schinus weinmannifolius-type, Baccharis-type, H. balansae, E. edulis, Rhamnaceae, Citrus, Leonurus japonicus, G. latifolia-type, A. edulis, Gomphrena perennis-type, Pouteria gardneriana, P. rigida, Zanthoxylum, and Actinostemon.

Long-term effects of antibiotic treatments on honeybee colony fitness: A modelling approach

Gut microbiome disequilibrium is increasingly implicated in host fitness reductions, including for the economically important and disease-challenged western honey bee Apis mellifera. In laboratory experiments, the antibiotic tetracycline, which is used to prevent American Foulbrood Disease in countries including the US, elevates honey bee mortality by disturbing the microbiome. It is unclear, however, how elevated individual mortality affects colony-level fitness.We used an agent-based model (BEEHAVE) and empirical data to assess colony-level effects of antibiotic-induced worker bee mortality, by measuring colony size. We investigated the relationship between the duration that the antibiotic-induced mortality probability is imposed for and colony size.We found that when simulating antibiotic-induced mortality of worker bees from just 60 days per year, up to a permanent effect, the colony is reduced such that tetracycline treatment would not meet the European Food Safety Authority's (EFSA) honey bee protection goals. When antibiotic mortality was imposed for the hypothetical minimal exposure time, which assumes that antibiotics only impact the bee's fitness during the recommended treatment period of 15 days in both spring and autumn, the colony fitness reduction was only marginally under the EFSA's threshold. Synthesis and Applications. Modelling colony-level impacts of antibiotic treatment shows that individual honey bee worker mortality can lead to colony mortality. To assess the full impact, the persistence of antibiotic-induced mortality in honey bees must be determined experimentally, in vivo. We caution that as the domestication of new insect species increases, maintaining healthy gut microbiomes is of paramount importance to insect health and commercial productivity. The recommendation from this work is to limit prophylactic use of antibiotics and to not exceed recommended treatment strategies for domesticated insects. This is especially important for highly social insects as excess antibiotic use will likely decrease colony growth and an increase in colony mortality.

Identification of Immune Regulatory Genes in Apis mellifera through Caffeine Treatment

Plants and pollinators are mutually beneficial: plants provide nectar as a food source and in return their pollen is disseminated by pollinators such as honeybees. Some plants secrete chemicals to deter herbivores as a protective measure, among which is caffeine, a naturally occurring, bitter tasting, and pharmacologically active secondary compound. It can be found in low concentrations in the nectars of some plants and as such, when pollinators consume nectar, they also take in small amounts of caffeine. Whilst caffeine has been indicated as an antioxidant in both mammals and insects, the effect on insect immunity is unclear. In the present study, honeybees were treated with caffeine and the expression profiles of genes involved in immune responses were measured to evaluate the influence of caffeine on immunity. In addition, honeybees were infected with deformed wing virus (DWV) to study how caffeine affects their response against pathogens. Our results showed that caffeine can increase the expression of genes involved in immunity and reduce virus copy numbers, indicating that it has the potential to help honeybees fight against viral infection. The present study provides a valuable insight into the mechanism by which honeybees react to biotic stress and how caffeine can serve as a positive contributor, thus having a potential application in beekeeping.

Significance of Apoidea as Main Pollinators. Ecological and Economic Impact and Implications for Human Nutrition

Wild and managed bees provide pollination services to crops and wild plants, as well as a variety of other services beneficial to humans. Honey bees are the most economically valuable pollinator worldwide. It has been calculated that 9.5% of the total economic value of agricultural production comes from insect pollination, thus amounting to just under USD 200 billion globally. More than 100 important crops depend on pollination by honey bees. The latter pollinate not only a wide number of commercial crops but also many wild plants, some of which are threatened by extinction and constitute a valuable genetic resource. Moreover, as pollinators, honey bees play a significant role in every aspect of the ecosystem by facilitating the growth of trees, flowers, and other plants that serve as food and shelter for many large and small creatures. In this paper, we describe how the reduction in honey bee populations affects various economic sectors, as well as human health.

Sugar-Induced Obesity and Insulin Resistance Are Uncoupled from Shortened Survival in Drosophila

High-sugar diets cause thirst, obesity, and metabolic dysregulation, leading to diseases including type 2 diabetes and shortened lifespan. However, the impact of obesity and water imbalance on health and survival is complex and difficult to disentangle. Here, we show that high sugar induces dehydration in adult Drosophila, and water supplementation fully rescues their lifespan. Conversely, the metabolic defects are water-independent, showing uncoupling between sugar-induced obesity and insulin resistance with reduced survival in vivo. High-sugar diets promote accumulation of uric acid, an end-product of purine catabolism, and the formation of renal stones, a process aggravated by dehydration and physiological acidification. Importantly, regulating uric acid production impacts on lifespan in a water-dependent manner. Furthermore, metabolomics analysis in a human cohort reveals that dietary sugar intake strongly predicts circulating purine levels. Our model explains the pathophysiology of high-sugar diets independently of obesity and insulin resistance and highlights purine metabolism as a pro-longevity target.

Citizen science improves our understanding of the impact of soil management on wild pollinator abundance in agroecosystems

Native bees provide essential pollination services in both natural and managed ecosystems. However, declines in native bee species highlight the need for increased understanding of land management methods that can promote healthy, persistent populations and diverse communities. This can be challenging and costly using traditional scientific methods, but citizen science can overcome many limitations. In this study, we examined the distribution and abundance of an agriculturally important wild bee species, the squash bee (Eucera (Peponapis) pruinosa, Hymenoptera: Apidae). They are ground nesting, specialist bees that depend on cultivated varieties of Cucurbita (squash, pumpkins, gourds). The intimate relationship between squash bees and their host plants suggests that they are likely sensitive to farm management practices, particularly those that disturb the soil. In this study, citizen scientists across Michigan used a survey to submit field management and bee observation data. Survey results indicated that squash bees occupy a wide geographic range and are more abundant in farms with reduced soil disturbance. Citizen science provided an inexpensive and effective method for examining impacts of farm management practices on squash bees and could be a valuable tool for monitoring and conserving other native pollinators.

Age and Method of Inoculation Influence the Infection of Worker Honey Bees (Apis mellifera) by Nosema ceranae

The microsporidian parasite Nosema ceranae is a highly prevalent, global honey bee pathogen. Apis mellifera is considered to be a relatively recent host for this microsporidia, which raises questions as to how it affects its host's physiology, behavior and longevity, both at the individual and colony level. As such, honey bees were inoculated with fresh purified spores of this pathogen, both individually (Group A) or collectively (Group B) and they were studied from 0 to 15 days post-emergence (p.e.) to evaluate the effect of bee age and the method of inoculation at 7 days post-infection. The level of infection was analyzed individually by qPCR by measuring the relative amount of the N. ceranae polar tubule protein 3 (PTP3) gene. The results show that the bee's age and the method of infection directly influence parasite load, and thus, early disease development. Significant differences were found regarding bee age at the time of infection, whereby the youngest bees (new-born and 1 day p.e.) developed the highest parasite load, with this load decreasing dramatically in bees infected at 2 days p.e. before increasing again in bees infected at 3-4 days p.e. The parasite load in bees infected when older than 4 days p.e. diminished as they aged. When the age cohort data was pooled and grouped according to the method of infection, a significantly higher mean concentration and lower variation in N. ceranae infection was evident in Group A, indicating greater variation in experimental infection when spores were administered collectively to bees through their food. In summary, these data indicate that both biological and experimental factors should be taken into consideration when comparing data published in the literature.

Anthropocene Crisis: Climate Change, Pollinators, and Food Security

In this paper, we propose a new approach—understood as a whole-of-community approach—to address a dualistic and dysfunctional human/nature relationship. Of particular concern is the decline in health and numbers of the insects that pollinate an estimated 90 percent of the Earth’s flora and an estimated 35 percent of global crop volume. Specifically, bees provide the majority of biotic pollination and play a critical role in food crop pollination. Multiple factors are contributing to this growing problem including a changing climate. In 2016, the International Commission on Stratigraphy agreed that the concept of the Anthropocene—the human epoch—is of sufficient scale to be considered part of the geological time scale. This indicates that these crises are not random or passive—they are largely the direct result of human activities. Despite decades of awareness of these socio-ecological issues, they continue to worsen. In addition, the growing awareness of the critical role of pollinators is creating a new understanding of our interconnectedness with the “natural” world. We introduce the Bee City movement as a way to operationalize a whole-of-community approach. Individual action is critical, but addressing pollinator health in these forums legitimizes and provides an institutional space for otherwise fringe, or even marginalized, activities and more coherent spaces for habitat creation.

Ecotoxicological effects of the insecticide fipronil in Brazilian native stingless bees Melipona scutellaris (Apidae: Meliponini)

Melipona scutellaris Latreille, 1811 (Hymenoptera, Apidae) is a pollinator of various native and cultivated plants. Because of the expansion of agriculture and the need to ensure pest control, the use of insecticides such as fipronil (FP) has increased. This study aimed to evaluate the effects of sublethal doses of FP insecticide on M. scutellaris at different time intervals (6, 12, and 24 h) after exposure, via individually analyzed behavioral biomarkers (locomotor activity, behavioral change) as well as the effect of FP on different brain structures of bees (mushroom bodies, antennal cells, and optic cells), using sub-individual cell biomarkers (heterochromatin dispersion, total nuclear and heterochromatic volume). Forager bees were collected when they were returning to the nest and were exposed to three different concentrations of FP (0.40, 0.040, and 0.0040 ng a.i/bee) by topical application. The results revealed a reduction in the mean velocity, lethargy, motor difficulty, paralysis, and hyperexcitation in all groups of bees treated with FP. A modification of the heterochromatic dispersion pattern and changes in the total volume of the nucleus and heterochromatin were also observed in the mushroom bodies (6, 12, and 24 h of exposure) and antennal lobes (6 and 12 h) of bees exposed to 0.0040 ng a.i/bee (LD_50/100). FP is toxic to M. scutellaris and impairs the essential functions required for the foraging activity.

Omega-6:3 Ratio More Than Absolute Lipid Level in Diet Affects Associative Learning in Honey Bees

Floral pollen is a major source of honey bee nutrition that provides them with micro- and macro-nutrients, including proteins, fatty acids, vitamins, and minerals. Different pollens vary in composition, including in the essential fatty acids, alpha-linolenic acid (omega-3) and linoleic acid (omega-6). Monocultures, prevalent in modern agriculture, may expose honey bee colonies to unbalanced omega-6:3 diets. The importance of omega-3 in the diet for adequate learning and cognitive function, with a focus on suitable omega-6:3 ratio, is well documented in mammals. We have recently shown, for the first time in invertebrates, the importance of omega-3 in diets for associative learning ability in honey bees. In the current work, we examine the effect of the absolute amount of omega-3 in diet compared to the omega-6:3 ratio on honey bee associative learning. We fed newly emerged bees for 1 week on different artificial diets, which had lipid concentration of 1, 2, 4, or 8%, with omega-6:3 ratios of 0.3, 1, or 5, respectively. We then tested the bees in a proboscis-extension response olfactory conditioning assay. We found that both omega-6:3 ratio and total lipid concentration affected learning. The most detrimental diet for learning was that with a high omega-6:3 ratio of 5, regardless of the absolute amount of omega-3 in the diet. Bees fed an omega-6:3 ratio of 1, with 4% total lipid concentration achieved the best performance. Our results with honey bees are consistent with those found in mammals. Best cognitive performance is achieved by a diet that is sufficiently rich in essential fatty acids, but as long as the omega-6:3 ratio is not high.