Decline Of Honey Bees Research Articles

Interactive effects of chlorothalonil and Varroa destructor on Apis mellifera during adult stage

The interaction between environmental factors affecting honey bees is of growing concern due to their potential synergistic effects on bee health. Our study investigated the interactive impact of Varroa destructor and chlorothalonil on workers' survival, fat body morphology, and the expression of gene associated with detoxification, immunity, and nutrition metabolism during their adult stage. We found that both chlorothalonil and V. destructor significantly decreased workers' survival rates, with a synergistic effect observed when bees were exposed to both stressors simultaneously. Morphological analysis of fat body revealed significant alterations in trophocytes, particularly a reduction in vacuoles and granules after Day 12, coinciding with the transition of the bees from nursing to other in-hive work tasks. Gene expression analysis showed significant changes in detoxification, immunity, and nutrition metabolism over time. Detoxification genes, such as CYP9Q2, CYP9Q3, and GST-D1, were downregulated in response to stressor exposure, indicating a potential impairment in detoxification processes. Immune-related genes, including defensin-1, Dorsal-1, and Kayak, exhibited an initially upregulation followed by varied expression patterns, suggesting a complex immune response to stressors. Nutrition metabolism genes, such as hex 70a, AmIlp2, VGMC, AmFABP, and AmPTL, displayed dynamic expression changes, reflecting alterations in nutrient utilization and energy metabolism in response to stressors. Overall, these findings highlight the interactive and dynamic effects of environmental stressor on honey bees, providing insights into the mechanisms underlying honey bee decline. These results emphasize the need to consider the interactions between multiple stressors in honey bee research and to develop management strategies to mitigate their adverse effects on bee populations.

Decline in Honeybees and Its Consequences for Beekeepers and Crop Pollination in Western Nepal.

In understudied regions of the world, beekeeper records can provide valuable insights into changes in pollinator population trends. We conducted a questionnaire survey of 116 beekeepers in a mountainous area of Western Nepal, where the native honeybee Apis cerana cerana is kept as a managed bee. We complemented the survey with field data on insect-crop visitation, a household income survey, and an interview with a local lead beekeeper. In total, 76% of beekeepers reported declines in honeybees, while 86% and 78% reported declines in honey yield and number of beehives, respectively. Honey yield per hive fell by 50% between 2012 and 2022, whilst the number of occupied hives decreased by 44%. Beekeepers ranked climate change and declining flower abundance as the most important drivers of the decline. This raises concern for the future food and economic security of this region, where honey sales contribute to 16% of total household income, and where Apis cerana cerana plays a major role in crop pollination, contributing more than 50% of all flower visits to apple, cucumber, and pumpkin. To mitigate further declines, we promote native habitat and wildflower preservation, and using well-insulated log hives to buffer bees against the increasingly extreme temperature fluctuations.

Potential of Wormwood and Oak Bark-Based Supplement in Health Improvement of Nosema ceranae-Infected Honey Bees.

Nosema ceranae, a microsporidian parasite, as one of the stressors that contribute to honey bee decline, has a significant negative impact on the longevity, productivity, and reproductive capacity of honey bee colonies. There are several different strategies for Nosema infection control, including natural-based and antibiotic-based products. In this study, we tested wormwood and oak bark-based supplement "Medenko forte" on survival, Nosema infection, oxidative stress, and expression of immune-related genes in artificially N. ceranae-infected bees. The results revealed a positive influence on the survival of Nosema-infected bees, irrespectively of the moment of supplement application (day 1, day 3, or day 6 after bee emergence), as well as reduction of Nosema loads and, consequently, Nosema-induced oxidative stress. Supplementation had no negative effects on bee immunity, but better anti-Nosema than immune-stimulating effects were affirmed based on expression levels of abaecin, defensin, hymenoptaecin, apidaecin, and vitellogenin genes. In conclusion, the tested supplement "Medenko forte" has great potential in the health protection of Nosema-infected bees. However, further investigations need to be performed to elucidate its mechanisms of action.

VANISHING HONEY BEES: THE FULCRUM OF OUR ECOSYSTEM

Despite the presence of large numbers of pollinators in flowering plants, honey bee plays the important role in pollination of different crops. Many social insects, including honey bee declining in abundance in diversity. Pollutants such as heavy metals, pesticides and air born fine particulate matters from agricultural and industrial sources are responsible for this major threat. Therefore, we provide an overview of bee’s conservation in order to reduce the decline of honey bees.

Different effects of pesticides on transcripts of the endocrine regulation and energy metabolism in honeybee foragers from different colonies

Honeybees are important pollinators of many crops and contribute to biological biodiversity. For years, a decline in bee populations has been observed in certain areas. This decline in honeybees is accompanied by a decrease in pollinator services. One factor contributing to the decline of bee colonies is the exposure to pesticides. Pesticide exposure of bees, among other effects, can negatively affect orientation, memory, immune system function and gene expression. Among the altered expressed genes are transcripts of endocrine regulation and oxidative phosphorylation. Endocrine regulation plays an important role in the development of nurse bees into foragers and oxidative phosphorylation is involved in energy metabolism. Most of these transcriptional changes were investigated using mixed aged honeybees derived from the same colony. Experiments using nurse bees or foragers of the same age but from different colonies are rare. In the present study, effects of the two pesticides chlorpyrifos and pyraclostrobin on the expression of transcripts linked to endocrine regulation and oxidative phosphorylation in foragers of the same age from three different colonies are investigated to fill this gap. These two pesticides were selected because negative effects at sublethal concentrations on bees are known and because they are found in pollen and nectar of crops and wild plants. For this purpose, 20–22 days old foragers of three different colonies were exposed to different sublethal concentrations of the selected fungicides for 24 h, followed by analysis of the expression of buffy, vitellogenin, hbg-3, ilp-1, mrjp1, 2 and 3, cox5a, cox5b and cox17. Some significant changes in gene expression of both endocrine regulation transcripts and oxidative phosphorylation were shown. Furthermore, it became clear that forager bees from different colonies react differently. This is especially important in relation to the risk analysis of pesticides. In addition, it could be shown that the expression of hbg-3 in the brain of bees is a robust marker to distinguish nurse bees from foragers at the molecular biological level. In summary, this study clearly shows that pesticides, which are often detected in pollen and nectar, display negative effects at sublethal concentrations on bees and that it is important to use bees from different colonies for risk assessment of pesticides.

Long-term spatiotemporal patterns in the number of colonies and honey production in Mexico

Honey bee decline is currently one of the world's most serious environmental issues, and scientists, governments, and producers have generated interest in understanding its causes and consequences in honey production and food supply. Mexico is one of the world’s top honey producers, however, the honey bee population's status has not been documented to date. Based on 32 years of data from beekeeping, we make a country-level assessment of honey bee colony trends in Mexico. We use generalized additive mixed models to measure the associations between the percent change in honey bee hives and the percent change in honey yield per hive in relation to land-use, climate, and socioeconomic conditions. Despite the fact that the average annual yield per hive increased from 1980 to 2012, we detected a significant decline in the percent change in the number of honey bee hives across the time period studied. We also found a relationship between climatic conditions and agricultural land use, with agriculture increases and high temperatures producing a decrease in the percent change in honey yield. We found a relationship between a reduction in the temperature range (the difference between maximum and minimum temperatures) and a decrease in the percent change in the number of hives, while socioeconomic factors related to poverty levels have an impact on the number of hives and honey yields. Although long-term declines in hive numbers are not correlated with poverty levels, socioeconomic factors in states with high and medium poverty levels limit the increase in honey yield per hive. These results provide evidence that land-use changes, unfavorable climatic conditions, political, and socioeconomic factors are partially responsible for the reductions in the percent change in honey bee hives in Mexico.

The Common Law of Landscape Hostility in the Lives and Deaths of Honeybees

This article offers a legal explanation for the decline of honeybees. While most investigations into bee populations and bee survival rates have been scientific, this article provides an additional set of causes, showing how our legal definitions of property and standards of negligence contribute to a landscape hostile to the lives of bees. Examining recent litigation in the United States and Canada, it shows how legal concepts of property impact the lives of bees, especially in cases of pesticide overspray near property boundaries, and in the forms of knowledge and ignorance in play in contesting duties of care in negligence cases. By expanding our understanding of the causes of bee death, this article points toward additional ways in which the stressors that bees face might be reduced.

Dietary Supplement of Grape Wastes Enhances Honeybee Immune System and Reduces Deformed Wing Virus (DWV) Load.

Ingredients rich in phenolic compounds and antioxidants of winemaking wastes, which play an important role in the prevention of various diseases and the control of viruses, are being explored. Currently, there is a concern about honeybee population loss, with deformed wing virus (DWV) being the most common virus infecting apiaries and one of the main causes of honeybee decline. Hence, the effect of grape pomace powder (GPP) as a dietary supplement to enhance the immune system of honeybees affected by DWV was evaluated. The characteristics of the ingredient GPP, obtained by spray-drying, revealed a high anthocyanin content (1102.45 mg 100 g-1), and it was applied at doses of 0.5, 1, 2.5 and 5% as a dietary supplement for bees infected by DWV. The results showed that the GPP treatments strengthened the immune response of honeybees against DWV. Moreover, the expression of the Relish gene was significantly higher in bees fed with GPP compared to the infected control. This study, which is framed in the search of food waste valorization for environmental sustainability, proves the feasibility of using grape wastes as dietary supplements for pollinators, and provides knowledge of the influence of polyphenols on the expression profiles of immune-related genes in honeybees.

Risk assessment of honey bee stressors based on in silico analysis of molecular interactions.

A global decline of the honey bee Apis mellifera has been observed in the last decades. This pollinator plays a fundamental role in food production and the economy in Europe. The decline of honey bee colonies is linked to several stressors, including pesticides. The current pesticide risk assessment of honey bees in Europe focuses on lethal effects and lacks reflection on sublethal effects. A better understanding of the consequences that exposure to these chemicals has on honey bees is still needed. In this context, the aim of this European Food Risk Assessment Fellowship Programme fellowship project has been to use in silico methodologies, such as virtual screening, as a first step to identify possible interactions at the molecular level between A. mellifera proteins and pesticide ligands. For this purpose, a docking study of the proteins from A. mellifera and pesticide ligands extracted from online databases has been performed by using the software Autodock Vina. The results obtained were a ranking based on the predicted affinity of the pesticides for specific and non-specific binding sites on bee macromolecules. These results were compared with data obtained from the literature and linked to potential sublethal effects. Finally, a risk assessment analysis of the identified molecular stressors of honey bees was performed. The results of this study are considered a starting point to identify new sources of possible stress for honey bees and thereby contribute to the overall understanding of the honey bee decline.

Novel Pollination Drone for Agricultural Assistance

Abstract: One of the major issues concerning current agricultural productionis crop pollination. Approximately $74 billion per year worth of crops in rely on pollination by various pollinators. However, the recent decline ofhoney bees (i.e. colony collapse disorder) has greatly threatened productivity. Declines of other native pollinators, such as different insecttypes and animals, have also been reported. Such shortages of pollinatorshave significantly increased the cost of farmers and renting them for pollination services. To overcome this problem, this project presents an automated drone for pollination which uses deeplearning and machine learning algorithms to estimate the flower position, size, orientation, andphysical condition to guide the drone to capture and interact with flowersfor pollination. In this concept we use drone and artificial intelligence method to carry pre collected pollen and to inject them in flowers for pollination to increase productivity. Drone pollination bypasses many current issues with natural pollinators inagriculture, such as honeybee colony collapse disorder, pollinator parasites and diseases, predators, pesticide spray, adverse weather, and the availability of pollinators in a timely manner. Second, robotic pollinators will improve fruit quality andproduction. With the decreasing number of bees, artificial pollination is more in trend. If we take the example of China, 100% plants are pollinated artificially. So, we can see that artificial pollination is beneficial and can increase plant productivity. The successful completionof this project will significantly impact the field of artificial pollination inagriculture.

Specific Strains of Honeybee Gut Lactobacillus Stimulate Host Immune System to Protect against Pathogenic Hafnia alvei.

ABSTRACTHoneybee gut microbiota plays an important role in host physiology and metabolism. Recent studies have shown that the influence of the resident microorganisms in the regulation of honeybee immune system is profound, which protects against the pathogen Serratia marcescens. However, only few of the core gut members in the regulation of immune functions have been studied. Here, we explored how different bee gut bacterial species aided in the clearance of the pathogenic Hafnia alvei, which causes bee septicemia with a high mortality rate. We found that both Gilliamella apicola W8136 and Lactobacillus apis W8172 protect honeybees from the opportunistic pathogen, while two other strains from Gilliamella and Lactobacillus did not affect the invasion of H. alvei. Transcriptomic analysis revealed that gut species induced different expression profiles in the gut. Specifically, two regulator genes from the Toll pathway, PGRP-S3 recognizing Gram-positive and Spätzle that bind to the Toll protein for the downstream signal transduction, were elevated by L. apis. Correspondingly, multiple genes encoding antibacterial proteins were also stimulated by L. apis. Interestingly, we found an increased expression of apidaecin, which also exhibited a high in vitro inhibitory effect on H. alvei. To elucidate the difference of strains in the host’s immune regulation, comparative genomic analyses indicate that the S-layer proteins unique to L. apis are potentially involved in honeybee Toll signaling and the activation of antibacterial protein production.IMPORTANCE Honeybees are essential pollinators supporting global agricultural economies and food supplies. Recent honeybee decline has been linked to several factors, while pathogen infection is considered one of the most significant contributing factors. Although a limited number of bacterial pathogens have been identified, Hafnia alvei is one of the pathogens causing septicemia in adult bees. In this study, we showed that two bee gut members, Gilliamella and Lactobacillus, can clear H. alvei from invasion. Mono-colonization of specific strains can stimulate the host Toll signaling pathway and the downstream expression of AMPs. Specifically, apidaecin upregulated by the gut symbionts is more effective against the pathogen. Moreover, our genomic analysis suggests that the surface-layer proteins specific to Lactobacillus strains are an important driver of Toll signaling, highlighting the variation of bee gut strains in regulating the host immune system.

African endemic stingless bees as an efficient alternative pollinator to honey bees in greenhouse cucumber (Cucumis sativus L)

The current honey bee decline necessitates the use of alternative native pollinators to ensure global food security. Here, we compared the pollination behaviour and efficiency of the African honey bee (Apis mellifera) and six African endemic Meliponini (Meliponula bocandei, Dactylurina schmidti, Meliponula lendliana, Hypotrigona gribodoi, Meliponula ferruginea and Meliponula togoensis) in a greenhouse with the non-parthenocarpic cucumber variety Super Marketer. Honey bees and D. schmidti started foraging on introduction in the greenhouse, while M. lendliana and M. togoensis showed the longest delay. In most species, foragers collected nectar and pollen, excepting M. bocandei that specialized in nectar collection, and H. gribodoi and M. togoensis, specialized in pollen collection. African honey bees visited flowers the shortest, while H. gribodoi and D. schmidti had a 2-fold probing time, on average. Most stingless bees species had a lower hive activity with fewer foragers encountered per hour than for honey bees, except D. schmidti. M. bocandei, M. ferruginea, A. mellifera scutellata and H. gribodoi, yielded a seed germination percentage of around 90%. M. lendliana, M. togoensis and D. schmidti yielded a much lower seed germination percentage around 30%, which indicates that the quality of pollination was remarkably lower by using these three species. The highest sugar content was recorded in fruits from flowers pollinated by M. bocandei, African honey bees, D. schimdti or M. togoensis with the same solid content as the gold standard method, i.e., hand cross-pollination. We found that M. bocandei was the most efficient cucumber pollinator of all species tested: because pollination by this species yielded the largest and heaviest fruits and the highest seed numbers.

Natural extracts as potential control agents for Nosema ceranae infection in honeybees, Apis mellifera

Nosema disease is one factor that can cause colony decline in honeybees (Apis mellifera L.) worldwide. Nosema ceranae has outcompeted Nosema apis in the Western honeybee (A. mellifera) which is its original host. Fumagilin is an effective antibiotic treatment to control Nosema infection but currently it is forbidden in many countries. In this study, 12 plant extracts were evaluated for their toxicity to adult bees and antimicrosporidian activity under laboratory and field conditions. N. ceranae-infected adult bees were fed ad libitum with 50% sucrose solution containing 1% and 5% (w/v) of each plant extract. Bee mortality in N. ceranae-infected groups fed with plant extracts was higher than that in the control group treated with fumagilin. The results demonstrated that 9 of 12 extracts had high antimicrosporidian activity against N. ceranae and their efficacies were comparable to fumagilin. Spore reduction in infected bees was 4–6 fold less after extract treatment. Following laboratory screening, Annona squamosa, Ocimum basilicum, Psidium guajava and Syzygium jambos were tested in honeybee colonies. Plant extracts of 2% concentration (w/v) inhibited the development of Nosema spores after 30 days of treatment. At the end of experiment (90 days), spores in the plant extract treated groups were lower than in group treated with fumagilin but there was no significant difference. Although, extracts tested in this study showed high toxicity to bee in laboratory cages, they did not show negative affects on bees under whole colony conditions. Therefore, the effectiveness of plant extracts tested in this study was notable and warrants further study as potential Nosema control agents in honey bees. Plant extracts would offer a non-antibiotic alternative for Nosema control and help reduce the overuse of antibiotics in livestock.

Varroa mite and deformed wing virus infestations interactively make honey bees (Apis mellifera) more susceptible to insecticides

Varroa mite is one of the major adverse factors causing honey bee population decline. In this study, Varroa destructor-infested and uninfested honey bee colonies were established by selective applying miticide (Apivar® amitraz). Mite population was monitored monthly (April–October 2016), and deformed wing virus (DWV) loading was detected seasonally (April, July, and October). Four immunity- and two physiology-related gene expressions, natural mortality, and susceptibility to five insecticides were comparatively and seasonally examined in field-collected honey bee workers. Results showed that Apivar-treated bee colonies had minor or undetectable mite and DWV (using RT-qPCR) infestations in whole bee season, while untreated colonies had substantially higher mite and DWV infestations. In untreated colonies, Varroa mite population irregularly fluctuated over the bee season with higher mite counts in Jun (318 ± 89 mites dropped in 48 h) or August (302) than that (25 ± 4 or 34) in October, and mite population density was not dynamically or closely correlated with the seasonal shift of honey bee natural mortality (regression slope = −0.5212). Unlike mite, DWV titer in untreated colonies progressively increased over the bee season, and it was highly correlated (R2 = 1) with the seasonal increase of honey bee natural mortality. Significantly lower gene expressions of dor, PPO, mfe, potentially PPOa and eat as well, in untreated colonies also indicated an association of increased DWV infestation with decreased physiological and immunity-related functions in late-season honey bees. Furthermore, bees with lower mite/DWV infestations exhibited generally consistently lower susceptibilities (contact and oral toxicities) to five representative insecticides than the bees without Apivar treatment. All of these data from this study consistently indicated an interaction of Varroa/viral infestations with insecticide susceptibilities in honey bees, potentially through impairing bee's physiology and immunity, emphasizing the importance of mite control in order to minimize honey bee decline.

Combined Effects of Pesticides and Electromagnetic-Fields on Honeybees: Multi-Stress Exposure.

Simple SummaryMulti-stress conditions are considered the most putative cause of honeybee decline. The ongoing reduction of domestic and natural pollinators is considered a very severe signal of the current loss of biodiversity, and it requires a broad research effort to clarify the causes. In this research, the combined effects of two possible stress sources for bees, pesticides and electromagnetic fields (multi-stress conditions) were analyzed by a field trial. After one year of monitoring, a complex picture of several induced effects was present, especially in the multi-stress site, such as disease appearance (American foulbrood), higher mortality in the underbaskets (common to pesticide-stress site), behavioral alterations (queen changes, excess of both drone-brood deposition and honey storage) and biochemical anomalies (higher ALP activity at the end of the season). The multi-stress site showed the worst health condition of the bee colonies, with only one alive at the end of the experimentation out of the four ones present at the beginning.Honeybee and general pollinator decline is extensively reported in many countries, adding new concern to the general biodiversity loss. Many studies were addressed to assess the causes of pollinator decline, concluding that in most cases multi-stress effects were the most probable ones. In this research, the combined effects of two possible stress sources for bees, pesticides and electromagnetic fields (multi-stress conditions), were analyzed in the field. Three experimental sites were chosen: a control one far from direct anthropogenic stress sources, a pesticide-stress site and multi-stress one, adding to the same exposure to pesticides the presence of an electromagnetic field, coming from a high-voltage electric line. Experimental apiaries were monitored weekly for one year (from April 2017 to April 2018) by means of colony survival, queen activity, storage and brood amount, parasites and pathogens, and several biomarkers in young workers and pupae. Both exposure and effect biomarkers were analysed: among the first, acetylcholinesterase (AChE), catalase (CAT), glutathione S-transferase (GST) and alkaline phosphatase (ALP) and Reactive Oxygen Species (ROS); and among the last, DNA fragmentation (DNAFRAGM) and lipid peroxidation (LPO). Results showed that bee health conditions were the worst in the multi-stress site with only one colony alive out of the four ones present at the beginning. In this site, a complex picture of adverse effects was observed, such as disease appearance (American foulbrood), higher mortality in the underbaskets (common to pesticide-stress site), behavioral alterations (queen changes, excess of honey storage) and biochemical anomalies (higher ALP activity at the end of the season). The overall results clearly indicate that the multi-stress conditions were able to induce biochemical, physiological and behavioral alterations which severely threatened bee colony survival.

Co-occurrence of Lotmaria passim and Nosema ceranae in honey bees (Apis mellifera L.) from six states in the United States

Honey bee populations in the United States have been under stress for the past decade. Although no one cause has been able to explain this, recent studies have shown that multiple interactions among microorganisms may be behind honey bee decline. Several internal parasites may contribute to this, including the trypanosome Lotmaria passim and the microsporidian, Nosema ceranae. This study combined novel data with data from several previous molecular diagnostic surveys for L. passim and N. ceranae to determine co-infection rates of these honey bee parasites. A total of 782 honey bee samples from Arkansas, Oklahoma, Texas, Utah, Mississippi, and Hawaii were analyzed for co-occurrence of N. ceranae and L. passim. Of the 782 samples, 37 (4.7%) were co-infected with both N. ceranae and L. passim, while 110 (14.1%) were infected with N. ceranae alone, and 51 (6.5%) with L. passim alone. Co-infections occurred most frequently in honey bees from Hawaii (11.8%), followed by Utah (2.4%) and Arkansas (1.2%), and no co-infections were observed in samples from Mississippi, Oklahoma, or Texas. Statistical analysis revealed that N. ceranae and L. passim co-occur more frequently than expected in samples from Hawaii and Utah. Infection rates for N. ceranae, L. passim, and co-infections were similar between managed (n = 393) and swarms (n = 73) but were both greater than feral (n = 316) honey bee colonies.

Deformed wing virus variant shift from 2010 to 2016 in managed and feral UK honey bee colonies

Deformed wing virus (DWV) has been linked to the global decline of honey bees. DWV exists as three master variants (DWV-A, DWV-B, and DWV-C), each with differing outcomes for the honey bee host. Research in the USA showed a shift from DWV-A to DWV-B between 2010 to 2016 in honey bee colonies. Likewise, in the UK, a small study in 2007 found only DWV-A, whereas in 2016, DWV-B was the most prevalent variant. This suggests a shift from DWV-A to DWV-B might have occurred in the UK between 2007 and 2016. To investigate this further, data from samples collected in 2009/10 (n = 46) were compared to existing data from 2016 (n = 42). These samples also allowed a comparison of DWV variants between Varroa-untreated (feral) and Varroa-treated (managed) colonies. The results revealed that, in the UK, DWV-A was far more prevalent in 2009/10 (87%) than in 2016 (43%). In contrast, DWV-B was less prevalent in 2009/10 (76%) than in 2016 (93%). Regardless if colonies had been treated for Varroa (managed) or not (feral), the same trend from DWV-A to DWV-B occurred. Overall, the results reveal a decrease in DWV-A and an increase in DWV-B in UK colonies.

Chitosan-based gel application on model bees (Apis mellifera L.) for healing bite wounds caused by Varroa destructor

Chitin is basically responsible for protecting the body of honey bees against external attacks due to its hard cellulose structure. The chitin-structured body of honey bees is destroyed by Varroa destructor, the world’s most devastating pest of Western honey bees; causes honey bee decline. Varroa harms honey bees not only by feeding but also by the wounds it inflicts. Varroa bites cause a hole in the centre of the wound, which is a source of bacterial infection. In this study, the aim was to investigate the potential application of a chitosan-based gel to recover the chitin layer. The experiment was set up in eight cages. Varroa bites were artificially created on experimental bees called as model honey bees in cages. Different solutions of a chitosan-based gel at different doses were applied to the cages. Results revealed that Varroa bite wounds do not heal until day 9 in control cages. Healing of wounds by chitosan-based gel application on 1–3 and 3–6 days showed dose dependence. In addition, the gel prevented hair loss in honey bees, which was observed as a side effect of Varroa infestation. In addition, chitosan dissolved in organic acids is a key advantage for the treatment of V. destructor in parallel with wound healing.

In silico prediction of chemical acute contact toxicity on honey bees via machine learning methods

In recent years, the decline of honey bees and the collapse of bee colonies have caught the attention of ecologists, and the use of pesticides is one of the main reasons for the decline. Therefore, ecological risk assessment of pesticides is essential and necessary. In silico tools, such as QSAR models can play an important role in predicting physicochemical and biological properties of chemicals. In this study, a total of 54 classification models were developed by combination of 6 machine learning methods along with 9 kinds of molecular fingerprints based on the experimental honey bees acute contact toxicity data (LD50) of 676 structurally diverse pesticides. The best model proposed was SVM algorithm combined with CDK extended fingerprint. The analysis of the applicability domain of the model successfully excluded some extreme molecules. Additionally, 9 structural alerts about honey bees acute contact toxicity were identified by information gain and substructure frequency analysis.

Risk Assessment of Pesticidal Toxicity and Threats on Pollinators: A Review on Honey Bee

Pollinators play vital roles to the environment, biodiversity conservation, food security and several dimensions of global sustainable development. Honey bee is an important pollinator globally but has been exposed to increasing threats from diseases, pesticides and biotic stresses. This review paper highlights the role of honey bees as pollinators, addresses threats which influence decline of honey bees and assess pesticidal risk toxicity on non-target organisms. Decline of honey bee population is caused by several factors including habitat fragmentation, pesticidal toxicity, colony collapse disorder and climate change. Pesticidal residue and toxicity has an adverse effect which results in honey bee population decline, disturb foraging and contamination of bee products. Residues of agricultural pesticides like pyrethroid and neonicotinoid pose a serious threat on honey bee health further reducing agricultural production and diversity. Pesticidal risk assessments are carried out to study effects of pesticides on pollinators with an aim to provide measures to safeguard their abundance, diversity and health. Sustainable agriculture, effective policy and proper management can decrease pollinators' risk by helping to diversify the agriculture for pollen and nectars with reduced usage of pesticides and proper management.