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Heat waves are becoming increasingly common due to climate change, making it crucial to identify and understand the capacities for insect pollinators, such as honey bees, to avoid overheating. We examined the effects of hot, dry air temperatures on the physiological and behavioral mechanisms that honey bees use to fly when carrying nectar loads, to assess how foraging is limited by overheating or desiccation. We found that flight muscle temperatures increased linearly with load mass at air temperatures of 20 or 30 °C, but, remarkably, there was no change with increasing nectar loads at an air temperature of 40 °C. Flying, nectar-loaded bees were able to avoid overheating at 40 °C by reducing their flight metabolic rates and increasing evaporative cooling. At high body temperatures, bees apparently increase flight efficiency by lowering their wingbeat frequency and increasing stroke amplitude to compensate, reducing the need for evaporative cooling. However, even with reductions in metabolic heat production, desiccation likely limits foraging at temperatures well below bees critical thermal maxima in hot, dry conditions.

In this research, for the first time, 16 polycyclic aromatic hydrocarbons (PAHs) in 33 types of honey samples have been analyzed using an efficient, sensitive and rapid high-density solvent-microextraction (HDS-ME) technique coupled to gas chromatography-mass spectrometry (GC-MS). Important parameters in the extraction process were optimized using central composite design (CCD). Good linear relationships were chosen for 16 PAHs in the range of 1–200 ng g−1, with a correlation coefficient (R2) higher than 0.94. The limits of detection and limits of quantification were 0.3–0.8 ng g−1 and 0.9–2.4 ng g−1, respectively. The relative standard deviations for six similar analyses at the optimized point were less than 9%. The recoveries of the proposed method were obtained between 86% and 102%. High recovery, low consumption of the solvent, speed, ease of use and good elimination of matrix interference compared to other methods are the advantages of the proposed method. The performance of the present work was confirmed by the standard addition method and satisfactory results were obtained. The concentrations of PAHs in honey samples were found lower than 11 ng g−1. [ABSTRACT FROM AUTHOR]

In a year-long research study, we delved into the thermoregulation and performance of twenty-one honey bee colonies situated in three distinct landscape settings: 1- Urban, 2- Agricultural (AG), and 3- Non-agricultural (Non-AG) environments. All colonies, consistent in size, were equipped with sensors designed to record inner hive temperature and humidity. Additionally, colonies were placed on precision electronic scales for weight monitoring. Varroa mite infestations were documented at seven different time points throughout the experiment. Colonies were genetically analyzed for subspecies and haplotype identification using the in silico DraI mtDNA COI-COII test. Our results unveiled an overall significant (p < 0.001) weight gain (5.76 kg) in colonies located within the urban setting, in stark contrast to both AG and Non-AG locations. Notably, colonies situated in the natural refuge center (Non-AG) experienced a weight loss of −0.05 kg, signaling a lack of sustainable forage resources in such a setting. Similarly, the inner hive temperature was significantly (p < 0.001) higher in the urban area (33.65 °C) with a significantly lower relative humidity (61.2%) compared to both other locations. Among the locations, the temperature variable displayed the strongest significant correlation (p < 0.001) with a positive correlation coefficient (r = 0.95). Two distinct mtDNA haplotypes were identified: C1 and C2j, characterizing the ligustica and carnica maternal origin, respectively. These haplotypes consistently demonstrated significant differences in their thermoregulation and weight gain, irrespective of the landscape compositions. The C1 haplotype displayed significantly higher weight gain alongside lower inner hive temperature and humidity levels compared to the C2j haplotype. No differences in mite infestation were observed between the various locations or haplotypes. Our data underscores the substantial impact of landscape composition on honey bee performance. It also unveils significant variations in thermoregulation and adaptation between haplotypes, shedding light on the multifaceted relationship between environmental factors, genetics, and bee colony dynamics. [ABSTRACT FROM AUTHOR]

Exposure to pesticides may affect the survival and normal physiological functions of the honey bee (Apis mellifera L.). The fungicide propiconazole (PRO) and the biofungicide Trichoderma are widely used in agroecosystems, and their effects on the physiology of the honey bee have been largely neglected in risk assessment procedures. We investigated the mortality and variations in physiological biomarkers of honey bee larvae and newly emerged workers exposed to PRO and Trichoderma. Exceeding the field-recommended concentrations of Trichoderma decreased the survival of newly emerged bee workers significantly through oral exposure. PRO, however, showed no significant lethal effects. Contact or oral exposure to field-realistic concentrations of PRO and Trichoderma profoundly altered the activities of detoxification, antioxidative, and digestive enzymes along with energy reserve concentrations of honey bee larvae and adult workers. Integrated biological index (IBRv2) values suggested potential risks of PRO and Trichoderma to honey bees by impairing the physiological status of larvae and newly emerged workers. [ABSTRACT FROM AUTHOR]

Simple Summary: The utilisation of oxygen for cellular respiration and other metabolic pathways in aerobic organisms is inherently associated with the production of reactive oxygen species, a group of highly reactive and oxidising small molecules. Reactive oxygen species can cause oxidative modifications of biomolecules and cellular components, thus compromising their native structure and biological functions. The role of the antioxidant defence is to tightly control levels of reactive species by connecting diverse antioxidant small molecules and antioxidant enzymes. This review summarises the actual knowledge on the role of the crucial part of the antioxidant system in insects termed the thioredoxin system. It is composed of redox-active protein thioredoxin, which interacts with and reduces the oxidised forms of multiple proteins. It is assisted by the enzyme thioredoxin reductase, catalysing the reductive regeneration of thioredoxins. Recent advances have uncovered how the functions of the thioredoxin system extend beyond its primary function in controlling the cell redox state to diverse developmental processes and the regulation of stress and immune responses. Increased levels of reactive oxygen species (ROS) produced during aerobic metabolism in animals can negatively affect the intracellular redox status, cause oxidative stress and interfere with physiological processes in the cells. The antioxidant defence regulates ROS levels by interplaying diverse enzymes and non-enzymatic metabolites. The thioredoxin system, consisting of the enzyme thioredoxin reductase (TrxR), the redox-active protein thioredoxin (Trx) and NADPH, represent a crucial component of antioxidant defence. It is involved in the signalling and regulation of multiple developmental processes, such as cell proliferation or apoptotic death. Insects have evolved unique variations of TrxR, which resemble mammalian enzymes in overall structure and catalytic mechanisms, but the selenocysteine–cysteine pair in the active site is replaced by a cysteine–cysteine pair typical of bacteria. Moreover, the role of the thioredoxin system in insects is indispensable due to the absence of glutathione reductase, an essential enzyme of the glutathione system. However, the functions of the Trx system in insects are still poorly characterised. In the present review, we provide a critical overview of the current knowledge on the insect Trx system, focusing mainly on TrxR's role in the antioxidant and immune system of model insect species. [ABSTRACT FROM AUTHOR]

Commercially cultivated Prunus species are commonly grown in adjacent or mixed orchards and can be infected with unique or commonly shared viruses. Apple (Malus domestica), another member of the Rosacea and distantly related to Prunus, can share the same growing regions and common pathogens. Pollen can be a major route for virus transmission, and analysis of the pollen virome in tree fruit orchards can provide insights into these virus pathogen complexes from mixed production sites. Commercial honey bee (Apis mellifera) pollination is essential for improved fruit sets and yields in tree fruit production systems. To better understand the pollen-associated virome in tree fruits, metagenomics-based detection of plant viruses was employed on bee and pollen samples collected at four time points during the peak bloom period of apricot, cherry, peach, and apple trees at one orchard site. Twenty-one unique viruses were detected in samples collected during tree fruit blooms, including prune dwarf virus (PDV) and prunus necrotic ringspot virus (PNRSV) (Genus Ilarvirus, family Bromoviridae), Secoviridae family members tomato ringspot virus (genus Nepovirus), tobacco ringspot virus (genus Nepovirus), prunus virus F (genus Fabavirus), and Betaflexiviridae family member cherry virus A (CVA; genus Capillovirus). Viruses were also identified in composite leaf and flower samples to compare the pollen virome with the virome associated with vegetative tissues. At all four time points, a greater diversity of viruses was detected in the bee and pollen samples. Finally, the nucleotide sequence diversity of the coat protein regions of CVA, PDV, and PNRSV was profiled from this site, demonstrating a wide range of sequence diversity in pollen samples from this site. These results demonstrate the benefits of area-wide monitoring through bee pollination activities and provide new insights into the diversity of viruses in tree fruit pollination ecosystems. [ABSTRACT FROM AUTHOR]

Simple Summary: In agriculture, plant protection products are used to improve crop yields. They pose a threat to organisms that are not the target of their control. For this purpose, biopesticides have been used, which are supposed to show less toxicity to the environment and non-targeted organisms. On the other hand, natural pesticides can also show toxicity to insects. The honey bee is one of the insects that is still exposed to contact with residues of plant protection products, which poses a threat to this organism. Honey bees use pollen and nectar from flowers to produce food. Because they often forage on crops, they are at risk of being exposed to plant protection products (PPPs), both directly and in stored food. Due to the adverse effects of synthetic PPPs on pollinators, biopesticides may be a viable alternative. Common tansy extract is used as one of the natural substitutes for synthetic pesticides. In our study, the effect of fermented common tansy extract on aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), and gamma-glutamyl transpeptidase (GGTP) activity and the concentration of triglycerides (TGs), total protein (TP), total antioxidant status (TAS), and glucose in honey bee workers' hemolymph was assessed. These biochemical markers give valuable information about the immunity, detoxification, and nutrition of a bee's body. Caged bees were given tansy extract added at various concentrations in sugar syrup for 24 h. Then, they were provided with only sugar syrup. After 7 days of the experiment, hemolymph was collected and analyzed. We observed changes in the activity of AST, ALT, GGTP enzymes and TG, TP, and glucose levels, but not all changes were statistically significant. In terms of AST activity, statistically significant differences were found. All groups tested, including the negative control group, showed reduced enzyme activity values compared to the positive control group. In TG concentration, differences were observed between the groups receiving 2% extract and 1% ethanol. Glucose levels differed between the groups receiving 1% extract and 2% extract and between the positive control group and 1% extract. Bee body proper functioning is affected by changes in enzyme activity, especially those responsible for immunity and detoxification, such as AST, ALT, ALP, and GGTP. Despite the short time of bees' exposure to the agent, the results of study show visible effects. Our results provide a basis for further research on the impact of tansy extract on honey bees. [ABSTRACT FROM AUTHOR]

Honey bees, Apis mellifera , are important pollinators, and they face many natural and anthropogenic challenges that affect their ability to collect the resources needed to maintain the colony. Foragers can make use of a remarkable repertoire of communication behaviours that help colonies to exploit their environment successfully. Food source availability is a key factor for colony success and, therefore, survival and reproduction. Few studies have investigated how food stores impact forager communication strategies and bee physiology. We experimentally manipulated honey stores and (1) quantified the production and following of waggle dances, (2) quantified the expression of immune-related genes using qPCR and (3) analysed fatty acids from bee abdomens using GC-MS 6 days after the experimental manipulation. We found that the number of waggle dances increased by about 60% when honey bees were starved of honey. The number of followers per dance, however, decreased, which may be due to a switch to proactive, solitary foraging or to the occurrence of more waggle dances. Waggle dance duration, the number of waggle phase followers that were followed and foraging distances were not affected by the treatments. Bees in starved colonies showed a higher expression of the gene defensin 1 , which is an important predictor of overwinter survival, but there was no treatment effect on fatty acid content. Our results show that the amount of honey stored in hives affects communication behaviours and the investment in immunocompetence of bees, possibly to counter the negative health effects of nutritional stress. However, fat content does not seem to be affected in the time span of the study. • The amount of honey stored in hives affected dance communication in honey bees. • Dance frequency increased and followers per dance decreased in honey-depleted hives. • Bees in honey-depleted hives expressed the immunity gene Defensin 1 more. • Six days of honey depletion did not affect body fat content. [ABSTRACT FROM AUTHOR]

Honey bees play a pivotal role in shaping ecosystems and sustaining human health as both pollinators and producers of health‐promoting products. However, honey bee colony mortality is on the rise globally, driven by various factors, including parasites, pesticides, habitat loss, poor nutrition, and climate change. This has far‐reaching consequences for the environment, economy, and human welfare. While efforts to address these issues are underway, the current progress in electron paramagnetic resonance (EPR) instrumentation affords using the immense potential of this magnetic resonance technique to study small samples such as honey bees. This paper presents the pioneering 2D in vivo EPR imaging experiment on a honey bee, revealing the ongoing redox‐status of bees' intestines. This way, by monitoring the spatio‐temporal changes of the redox‐active spin‐probes' EPR signal, it is possible to gain access to valuable information on the course of ongoing bees' pathologies and the prospect of following‐up on the efficiency of applied therapies. Employing a selection of diverse spin‐probes could further reveal pH levels and oxygen concentrations in bee tissues, allowing a noninvasive assessment of bee physiology. This approach offers promising strategies for safeguarding pollinators and understanding their biology, fostering their well‐being and ecological harmony. Research Highlights: Honey bees face rising mortality from parasites, pesticides, and climate change. This paper introduces original use of in vivo electron paramagnetic resonance imaging (EPRI) method to explore redox processes in honey bee intestines, advancing our understanding of these vital insects' health. [ABSTRACT FROM AUTHOR]

BACKGROUND: The parasitic mite, Varroa destructor has posed a threat to the health and survival of European honey bees, Apis mellifera worldwide. There is a prevailing belief that small comb cells could provide a management tool against Varroa mites. However, the hypothesis that smaller cells can impede Varroa reproduction has not been fully tested. Here, we tested this hypothesis under laboratory conditions by using two distinct Varroa in vitro rearing systems: one involved gelatin capsules of different sizes, specifically size 00 (0.95 mL) versus size 1 (0.48 mL), and the second consisted of brood comb cells drawn on 3D printed foundations with varying cell sizes, ranging from 5.0 mm to 7.0 mm at 0.5 mm intervals. RESULTS: The results showed that mother mites in size 00 cells had significantly lower fecundity and fertility compared to those in size 1 cells. Interestingly, the reproductive suppression in larger cells could be reversed by adding an extra worker larva. Similarly, gonopore size of mother mites was smaller in size 00 cells, but restored with another host larva. Furthermore, both the fecundity and fertility of mother mites decreased linearly with the size of brood comb cells. CONCLUSIONS: Our results suggest that the reproduction of V. destructor is hindered by larger cells, possibly because larger brood cells disperse or weaken host volatile chemical cues that are crucial for Varroa reproduction. The insights derived from this study are expected to hold significant implications for the implementation of Varroa management programs. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Background: The evaluation of the impact of pesticides on non-target species, like bees, is a crucial factor in registration procedures. Therefore, standardized test procedures have been developed on OECD level assessing the effects of chemicals on honey bees or bumble bees. Unfortunately, these protocols cannot directly be adapted for testing products that contain microorganisms. Interest in the use of microorganisms has increased in recent years due to their specificity to target species while not harming non-target organisms. This study aimed to evaluate optimal conditions to assess the effects of microbial plant protection products on bee species according to currently available test protocols. Some of the most commonly used microorganisms for plant protection, Bacillus thuringiensis subspecies aizawai (B. t. a. ABTS 1857) and Beauveria bassiana (B. b. ATCC 74040) were tested on Apis mellifera, Bombus terrestris, and Osmia bicornis at different temperatures (18, 26, 33 °C) under laboratory conditions. Results: Exposure to the product containing B. t. a. ABTS 1857 resulted in higher mortality compared to B. b. ATCC 74040 in all tested bee species. A temperature-dependent effect towards higher mortality at higher temperatures of 26 °C or 33 °C was observed in O. bicornis exposed to both microorganisms. A. mellifera showed variable responses, but for B. terrestris there was mostly no effect of temperature when exposed to microorganisms in high concentrations. However, temperature affected longevity of bee species in the non-exposed control group. A. mellifera mortality increased with decreasing temperatures, while B. terrestris and O. bicornis mortality increased with increasing temperatures. A test duration of 15 or 20 days was found to be suitable for testing these microorganisms. Conclusion: In conclusion, 26 °C should be considered the worst-case scenario for testing B. bassiana on all tested bee species. For testing B. thuringiensis, a temperature of 33 °C is recommended for A. mellifera, whereas B. terrestris and O. bicornis should be tested at 26 °C. [ABSTRACT FROM AUTHOR]

Bees can be exposed to pesticides when visiting crops or plants in adjacent areas affected by spray drift. Among pesticide categories, fungicides tend to be considered relatively safe, though they also can negatively affect pollinators. Most evidence of damage by fungicides to bees comes from laboratory tests; there is little information concerning contamination levels in the field. We examined exposure of honey bees (Apis mellifera L.) (Hymenoptera: Apidae) and a common Brazilian native species of social stingless bees (Scaptotrigona postica Latreille; Hymenoptera: Apidae), which is about a third the size of a honey bee, to a commercial fungicide (Fox Xpro), with three active ingredients (trifloxystrobin, bixafen, and prothioconazole), applied to crops they often visit according to label directions. A spraying apparatus mounted on tracks in a laboratory spray room was used to simulate field conditions. Soybean and cotton plants grown in pots were transferred to the spray room when the plants were in flower. Anaesthetized bees were attached with insect pins at the top and middle of the plants, on leaves and flowers. The fungicide was applied using fine or coarse droplets. The amounts of the individual active ingredients absorbed by bees were then quantified. Concentrations of trifloxystrobin were highest in both honey bees and stingless bees, followed by bixafen, and then prothioconazole, which was detected in the bees at much lower levels. Overall, bees at the top of the plants and those sprayed with fine droplets absorbed more pesticide. As a function of body mass, the stingless bees were more heavily contaminated than the larger honey bees. Tests using spraying systems that simulate field conditions can better estimate the actual doses that contaminate bees to help determine the impact of fungicides and other pesticides applied to crops. [ABSTRACT FROM AUTHOR]

Most bee stings are not life-threatening. Bee venom often causes local, mild allergic reactions in people, but even a single bee sting may induce a fatal anaphylactic reaction. Usually, anaphylactic reaction is the cause of death, but, when a child suffers multiple stings (more than 30), direct toxicity of venom can also be fatal. A three-year-old male child was brought to the hospital with pain, swelling and redness at the sting sites. He had more than 35 stings at various sites over his face, on his tongue and over his body. He died 10 hours after the incidence of the honey bee stings and was maintaining oxygen saturation until the terminal stage of his life. At autopsy, the honey bee sting sites showed redness, swelling and a small effusion of blood surrounding the stinger tracks. On the tongue two stingers were found in situ. Facial puffiness and eyelid swelling, along with congested organs, were also found, but features suggestive of anaphylactic death like airway oedema, mucous plug or cyanosis were absent. Hospital treatment records show that blood pressure remained low with tachycardia despite treatment. Having regard for all the evidence it was concluded that death was due to multiple honey bee stings that caused direct venom toxicity. [ABSTRACT FROM AUTHOR]

The study of insect behavior, particularly that of honey bees, has a broad scope and significance. Tracking bee flying patterns grants much helpful information about bee behavior. However, tracking a small yet fast-moving object, such as a bee, is difficult. Hence, we present artificial intelligence, machine-learning-based bee recognition, and tracking systems to assist the researcher in studying the bee’s behavior. To develop a machine learning system, a labeled database is required for model training. To address this, we implemented an automated system for analyzing and labeling bee videos. This labeled database served as the foundation for two distinct bee-tracking solutions. The first solution (planar bee tracking system) tracked individual bees in closed mazes using a neural network. The second solution (spatial bee tracking system) utilized a neural network and a tracking algorithm to identify and track flying bees in open environments. Both systems tackle the challenge of tracking small-bodied creatures with rapid and diverse movement patterns. Although we applied these systems to entomological cognition research in this paper, their relevance extends to general insect research and developing tracking solutions for small organisms with swift movements. We present the complete architecture and detailed methodologies to facilitate the utilization of these models in future research endeavors. Our approach is a simple and inexpensive method that contributes to the growing number of image-analysis tools used for tracking animal movement, with future potential applications under less sterile field conditions. The tools presented in this paper could assist the study of movement ecology, specifically in insects, by providing accurate movement specifications. Following the movement of pollinators or natural enemies, for example, greatly contributes to the study of pollination or biological control, respectively, in natural and agro-ecosystems. [ABSTRACT FROM AUTHOR]

This study was conducted to investigate the effects of pantothenic acid (PA) on the lipid metabolism, and antioxidant function of Apis mellifera workers. The results showed that ether extract (EE) content of bees' body was significantly decreased when workers were supplemented with 147 mg/kg PA (P < 0.05). Further, supplemental PA reduced triglycerides (TG) and total cholesterol (TCHO) content in the hemolymph (P < 0.05), while 39.2 mg/kg PA supplementation improved hemolymph high-density lipoprotein cholesterol (HDL-c) concentration, while 261.6 mg/kg PA reduced low-density lipoprotein cholesterol (LDL-c) concentration (P < 0.05). C12:0, C14:1, and C18:0 content values were notably increased in PA-supplemented groups, while those of C14:0, C18:2n-6, C20:4n-6, polyunsaturated fatty acids (PUFA), and PUFA/saturated fatty acids were decreased (P < 0.05), while levels correlated with those of dietary PA. Malondialdehyde (MDA) content showed a downward trend in response to PA supplementation; however, total superoxide dismutase (T-SOD) was increased (P < 0.05). Furthermore, fatty acid synthase (FAS) mRNA levels were significantly downregulated in bees supplemented 9.8, 19.6, and 39.2 mg/kg (P < 0.05) and lipase activity significantly improved following supplementation with 39.2, 78.4, and 147 mg/kg PA (P < 0.05). Thus, dietary PA significantly influenced worker bee lipid metabolism, and improved antioxidant function. [ABSTRACT FROM AUTHOR]

The honey bee parasite, Varroa destructor, is susceptible to removal by dusting agents that physically interfere with its ability to cling to its phoretic hosts. Here we describe modifications to established powdered sugar dusting techniques that modestly increased mite separation from hosts and allowed for greater reductions in whole colony mite infestation rates. These modifications increased body-to-body contact through crowding and mechanical agitation to supplement dusting effects on mite removal. Adult workers were isolated in a screened sugar shake box outside the colony, dusted with powdered sugar, then carefully shaken and bounced in crowded piles for one minute to separate mites from their hosts. Whole colony powdered sugar shake treatments resulted on average in a 92% reduction in post-treatment mite infestation rates over three successive mite treatments. Our modifications provided effective mite control comparable to the miticide Apiguard (thymol) without discernable negative effects on colonies. Four months after treatment, powdered sugar shake treated colonies had relatively similar-sized adult worker and brood populations as Apiguard treated colonies and larger adult populations than controls. Colonies also maintained queens and reared relatively few queen cells across treatments. Further comparisons of method components revealed that mechanical agitation of crowded workers enhanced mite separation from hosts due to powdered sugar dusting. Mechanical agitation alone only modestly increased mite separation compared to controls; however, high levels of mite separation associated with sugar dusting increased with agitation. These modified methods provide a rapid if laborious technique for reducing mite populations without chemical residues from restricted miticides. [ABSTRACT FROM AUTHOR]

In 2017, the European Commission initiated the EurBeST study to explore the possibilities of using selective breeding of honey bees to increase Varroa resistance traits. One of the specific aims of the study was to assess the process of honey bee queen breeding through an economic analysis. The methodology for calculating the costs of queen production (queen rearing and mating), colony evaluation and expenses for estimating breeding values is based on the Cost of Production (CoP). Cost data were collected via tailor-made questionnaires and interviews performed in five European countries (France, Germany, Greece, Italy, and Poland). The sample population consisted of 20 queen producers and 20 performance testers who participated in the study. The results showed that the average costs for queen production amounted to 22.58 € per queen, ranging from 8.22 € in Poland to 37.30 € in France. The difference between the selling price and the production cost was on average 3.08 € per queen, ranging from 15.86 € in Germany to −12.30 € in France. On average, the colony evaluation costs were 193.40 € per colony. The average cost for breeding value estimation per queen was 8.09 €. Thus, the average total cost per selected queen was 224 €. The selective breeding of honey bees is an efficient way to increase productivity, reduce colony losses, improve bee health and enable profitable operations, but it is expensive, is usually promoted, practiced and implemented by scientists and researchers, and in most cases is financed by external sources. [ABSTRACT FROM AUTHOR]

Bees play an essential role in the sustainability of terrestrial and agricultural ecosystems as pollinators. However, external factors such as pesticides can negatively affect both bees and plants pollinated by bees, as well as human health. Therefore, less toxic or non-toxic plant protection products have become a popular research topic for a sustainable environment. The purpose of this study was to determine the effects of four different commercial products of diatomaceous earth (Bio, Demite, Detech, Detech WP) on workers of Apis mellifera and Bombus terrestris under controlled laboratory conditions. Each diatomaceous earth product was sprayed on the bees as dust particles for 15 seconds at Maximum Field Dose (10 g/m2). While the worker bees in positive control groups (control +) were exposed to flour, those in the negative control groups (control –) were not exposed to any treatment. The highest mortality rates for B. terrestris and A. mellifera were 22% in Detech WP and 16% in Demite, respectively. However, since mortality rates were under 25% for all the tested DE products, they were classified as harmless for both bee species. Additionally, the direct effect of diatomaceous earth products on honey bees and bumble bees was revealed for the first time in this study. [ABSTRACT FROM AUTHOR]

Brazil is the leading soybean producing country in the world, and soybean is the major crop of Brazilian agriculture, spread over 36 million hectares during the 2020/21 season, producing almost 125 million tons. The honey bee, Apis mellifera Linnaeus, 1758 (Hymenoptera: Apidae), and other bees are known as soybean flowers visitors, being potential pollinators of the crop, normally resulting in higher soybean yields. Over the last ten years, it has been observed an increasing interest of both beekeepers and soybean growers, to place honey bee colonies close to soybean fields, using the crop as a forage source. In the majority of the reports of soybeans growers, an increase of the soybean yield was observed when following this practice, while a small number claimed no yield modification. The purpose of the present work was to study the effect of visits of individuals of A. mellifera to soybean flowers and the consequent pollination on soybean productivity, when there is a constraint to the expression of the potential crop yield. The experiments were set up in Londrina, Brazil, during the 2016/17 and 2019/20 crop seasons, in areas with known sub superficial compaction layers, preventing soybean roots from deepening in the soil, therefore restricting the absorption of water and nutrients by the plants. Treatments consisted of 1) open plots, resembling a typical grower field with free access of bees; 2) a caged plot with an A. mellifera beehive inside, and 3) a caged plot with no bees or any other potential pollinating insect inside. Results indicated no yield differences due to the pollination of soybean flowers by the bees, compared to the treatment with the absence of bee visit. Among the yield components, only pods with 1 or 2 seeds were lower on caged plots with bees on the 1st experiment. No differences were detected for all others observed parameters on 1st and for all components on 2nd experiments. Observations of the honey bee behavior demonstrated that only 27.9% of the bee visits to soybean flowers resulted in nectar hoarding, with a time lapse of 4.52 seconds for a visit to a single flower. When a flower was only tested (72.1%), without nectar collection, the average time of a honey bee visit was 1.38 seconds. New studies should be performed to verify if other biotic or abiotic stresses that depress soybean yield also prevent the expression of the benefit of bees' pollination to soybean yield. [ABSTRACT FROM AUTHOR]

The ectoparasitic mite Varroa destructor has become a major worldwide pest of the honey bees (Apis mellifera L). Intensive use of chemical acaricides has led to the development of acaricide resistance in mites, thereby reducing the efficacy of acaricides and causing contamination of hive products. Thus, natural products such as essential oils can become an important alternative to synthetic chemicals in controlling Varroa mites. In this study, essential oil from Thymus schimperi grown in the Ethiopian highland was investigated for its chemical composition and toxicity against Varroa mites through complete exposure tests. Hydrodistillation of T. schimperi leaves yielded a pale yellow essential oil (0.8% v/w) with a strong and pleasant odor. Analyzed by GC-MS, 29 compounds, comprising 96.67% of the oil, were identified. Carvacrol (34.84%), thymol (23.03%), and p-cymene (14.20%) were found to be the main constituents. In the toxicity assay, T. schimperi essential oil showed high acaricidal activity against Varroa mites, with a 4 h-LC50 value of 109.16 µg/ml (5.46 mg oil/l air volume). Among the main constituents, thymol and carvacrol induced high toxicity to Varroa mites, with 4 h-LC50 values of 70.71 µg/ml (3.54 mg thymol/l air volume) and 106.10 µg/ml (5.31 mg carvacrol/l air volume), respectively. However, p-cymene was less effective in toxicity testing (4 h-LC50 > 5000 µg/ml). The results show for the first time that the essential oil of Thymus schimperi and its two main constituents, thymol and carvacrol, are highly acaricidal and can be used to control Varroa mite infestations. [ABSTRACT FROM AUTHOR]

BACKGROUND: The Varroa mite (Varroa destructor) is considered to be the greatest threat to apiculture worldwide. RNA interference (RNAi) using double‐stranded RNA (dsRNA) as a gene silencing mechanism has emerged as a next‐generation strategy for mite control. RESULTS: We explored the impact of a dsRNA biopesticide, named vadescana, designed to silence the calmodulin gene in Varroa, on mite fitness in mini‐hives housed in a laboratory. Two dosages were tested: 2 g/L dsRNA and 8 g/L dsRNA. Vadescana appeared to have no effect on mite survival, however, mite fertility was substantially reduced. The majority of foundress mites exposed to vadescana failed to produce any offspring. No dose‐dependent effect of vadescana was observed, as both the low and high doses inhibited mite reproduction equally well in the mini‐hives and neither dose impacted pupal survival of the honey bee. Approximately 95% of bee pupae were alive at uncapping across all treatment groups. CONCLUSION: These findings suggest that vadescana has significant potential as an effective alternative to conventional methods for Varroa control, with broader implications for the utilization of RNAi as a next‐generation tool in the management of pest species. © 2024 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Honey bees are commonly exposed to a broad spectrum of xenobiotics, including heavy metals. Heavy metal toxicity is of concern in the context of global pollinator declines, especially since honey bees seem to be particularly susceptible to xenobiotics in general. Here we summarize current knowledge on the interplay between cadmium, one of the most toxic and mobile elements in the environment, and honey bees, the primary managed pollinator species worldwide. Overall, cadmium pollution has been shown to be ubiquitous, affecting industrial, urban and rural areas alike. Uptake of this heavy metal by plants serves as the primary route of exposure for bees (through pollen and nectar). Reported cadmium toxicity consists of lethal and sublethal effects (reduced development and growth) in both adult and larval stages, as well as various molecular responses related to detoxification and cellular antioxidant defence systems. Other effects of cadmium in honey bees include the disruption of synaptic signalling, calcium metabolism and muscle function. [ABSTRACT FROM AUTHOR]

Understanding the diversity of nectar sources in urban honey samples is crucial for effectively managing honey bee (Apis cerana indica Fabricius, 1978.) colonies and promoting pollinator health. This study analysed honey samples from various urban locations in Bangalore to assess pollen diversity, foraging behaviour, and the significance of urban flora in supporting beekeeping practices. A total of 39 pollen types were identified, with 62.50% of samples being unifloral, predominantly from Eucalyptus sp., followed by Casuarina equisetifolia, Areca catechu, Citrus sp., Mallotus philippensis, Cocos nucifera, and Ocimum sp. Multifloral samples (37.50%) highlighted the diverse diet available to urban bees, promoting biodiversity within urban landscapes. Major plant families contributing to pollen content included Myrtaceae, Arecaceae and Fabaceae. Seasonal variation in pollen composition reflected shifts in dominant nectar sources, with the monsoon season characterized by Casuarina equisetifolia, Areca catechu, Citrus sp., Mallotus philippensis, and Cocos nucifera, while winter saw Eucalyptus sp. and Ocimum sp. as predominant sources, and summer featured Pongamia pinnata. Cluster analysis found high similarity in pollen composition in honey samples from Bagalur, Yelahanka and M S Palya but distinct pollen in GKVK, suggesting unique conditions and emphasizing the importance of considering spatial variations in beekeeping practices and conservation strategies. This research underscores the importance of floral diversity in sustaining urban bee populations and provides guidance for urban planning and policy decisions to promote pollinator health and urban sustainability. [ABSTRACT FROM AUTHOR]

Abstract Background Honey bees are the principal commercial pollinators. Along with other arthropods, they are increasingly under threat from anthropogenic factors such as the incursion of invasive honey bee subspecies, pathogens and parasites. Better tools are needed to identify bee subspecies. Genomic data for economic and ecologically important organisms is increasing, but in its basic form its practical application to address ecological problems is limited. Results We introduce HBeeID a means to identify honey bees. The tool utilizes a knowledge-based network and diagnostic SNPs identified by discriminant analysis of principle components and hierarchical agglomerative clustering. Tests of HBeeID showed that it identifies African, Americas-Africanized, Asian, and European honey bees with a high degree of certainty even when samples lack the full 272 SNPs of HBeeID. Its prediction capacity decreases with highly admixed samples. Conclusion HBeeID is a high-resolution genomic, SNP based tool, that can be used to identify honey bees and screen species that are invasive. Its flexible design allows for future improvements via sample data additions from other localities.

Abstract In Argentina, migratory activity in search of floral diversity has become a common approach to maximizing honey production. The Entre Ríos province possesses a floral diversity that allows beekeepers to perform migratory or stationary management. Beyond the impact caused by transhumance, migratory colonies in this province start and end the season in monoculture areas. To study the effect of these practices on viral infection, we assayed for the presence, abundance and genetic characterization of the Deformed Wing Virus (DWV) in honey bees from apiaries with both types of management. In migratory apiaries, DWV was detectable in 86.2% of the colonies at the beginning of the season (September 2018), and 66% at the end of the season (March 2019). On the other hand, DWV was detected in 44.11% and 53.12% of stationary samples, at the beginning and the end of the season, respectively. Sequence analysis from migratory and stationary colonies revealed that all samples belonged to DWV-A type. The highest viral loads were detected in migratory samples collected in September. Higher DWV presence and abundance were associated with migratory management and the sampling time. Based on our findings we propose that the benefit of migration to wild flowering areas can be dissipated when the bee colonies end the season with monoculture.

Abstract Climate change significantly affects the diversity, growth, and survival of indigenous plant species thereby influencing the nutrition, health and productivity of honey bees (Apis mellifera). Hypoestes forskaolii (Vahl) is one of the major honey bee plant species in Ethiopia’s Tigray region. It is rich in pollen and nectar that typically provides white honey, which fetches a premium price in both local and inter-national markets. Despite its socio-economic and apicultural significance, the distribution of H. forskaolii has been declining, raising concerns regarding its conservation efforts. However, there is limited knowledge on how environmental and climatic factors affect its current distribution and response to future climate change. The study investigates the current and projected (the 2030s, 2050s, 2070s, and 2090s) habitat distributions of H. forskaolii under three future climate change scenarios (ssp126, ssp245, and ssp585) using the Maximum Entropy Model (MaxEnt). The results show that land use (50.1%), agro-ecology (28%), precipitation during the Driest Quarter (11.2%) and soil texture (6.1%) predominantly influence the distribution of H. forskaolii, collectively explaining 95.4% of the model's predictive power. Habitats rich in evergreen trees and mosaic herbaceous with good vegetation cover are identified as the most suitable for H. forskaolii. The spatial distribution of H. forskaolii is concentrated in the highlands and mid-highlands of the eastern and southern parts of Tigray, characterized by a colder temperature. Across the three climate change scenarios, the size of suitable habitat for H. forskaolii is projected to decrease over the four time periods studied. Predictions under the ssp585 scenario reveal alarming results, indicating a substantial decrease in the suitable habitat for H. forskaolii from 4.26% in the 2030s to 19.09% in the 2090s. Therefore, given the challenges posed by climate change, research efforts should focus on identifying and evaluating new technologies that can help the H. forskaolii species in adapting and mitigating the effects of climate change.

Varroosis is a disease that can be observed in all life stages of honey bees and causes serious clinical findings in infested hives. This study aimed to investigate and compare the efficiency of thyme oil, Cinnamomum verum, Melaleuca viridiflora, Syzygium aromaticum essential oils, and amitraz against Varroosis in the field. After the essential oils were dissolved in glycerin, they were impregnated on strips and applied by placing them between frames. Amitraz was applied by fumigation. Positive and phoretic Varroa negative control groups were also included. Treatments were applied once a week for four weeks during the autumn season. The rates of acaricide efficacy and weekly mite count per bottom frame were determined for each of the treatments. According to the results, the highest effectiveness against Varroosis was detected in the amitraz treatment group at 81.3%. The C. verum treatment group had the highest efficacy of all the essential oil treatment groups at 73.5%. The efficacies in thyme oil, M. viridiflora, and S. aromaticum essential oils treatment groups were 71.9%, 71.3%, and 67.4%, respectively. According to the findings of the study, natural extracts can be used instead of chemical drugs in the fight against Varroosis. No toxicity or unnatural death was observed in honey bees throughout the study.

The three honey bee phenotypes - queens, workers, and drones differ in the size and shape of body parts. We used a large dataset to describe how the three phenotypes differed with regard to fore wings and applied the methodology of geometric morphometrics to measure the wings using the coordinates of nineteen landmarks. On average, queens had wings larger than workers, but the two castes had a broad overlap. Drones, on the other hand, had distinctly larger wings. Wing shape differed markedly among queens, workers and drones and can be used to reliably differentiate them from one other. Surprisingly, the fore wing shape of workers was more similar to that of drones than to that of queens. Small queens were not more similar to workers than large queens, and large workers were not more similar to queens than small workers. Because wing size, unlike body mass, does not change over the life of the queen, it can be used to evaluate the quality of a queen throughout its life and not only during a short period after emergence. We provide a large number of wing images of queens and drones, which can be used as a reference in future studies.

Abstract In honey bees, circulation of blood (hemolymph) is driven by the peristaltic contraction of the heart vessel located in the dorsal part of the abdomen. Chlorantraniliprole (CHL) is an insecticide of the anthranilic diamide class which main mode of action is to alter the function of intracellular Ca2+ release channels (known as RyRs, for ryanodine receptors). In the honey bee, it was recently found to be more toxic when applied on the dorsal part of the abdomen, suggesting a direct cardiotoxicity. In the present study, a short-term exposure of semi-isolated bee hearts to CHL (0.1–10 µM) induces alterations of cardiac contraction. These alterations range from a slow-down of systole and diastole kinetics, to bradycardia and cardiac arrest. The bees heart wall is made of a single layer of semi-circular cardiomyocytes arranged concentrically all along the long axis of tube lumen. Since the heart tube is suspended to the cuticle through long tubular muscles fibers (so-called alary muscle cells), the CHL effects in ex-vivo heart preparations could result from the modulation of RyRs present in these skeletal muscle fibers as well as cardiomyocytes RyRs themselves. In order to specifically assess effects of CHL on cardiomyocytes, for the first time, intact heart cells were enzymatically dissociated from bees. Exposure of cardiomyocytes to CHL induces an increase in cytoplasmic calcium, cell contraction at the highest concentrations and depletion of intracellular stores. Electrophysiological properties of isolated cardiomyocytes were described, with a focus on voltage-gated Ca2+ channels responsible for the cardiac action potentials depolarization phase. Two types of Ca2+ currents were measured under voltage-clamp. Exposure to CHL was accompanied by a decrease in voltage-activated Ca2+ currents densities. Altogether, these results show that chlorantraniliprole can cause cardiac defects in honey bees.

Background: Honey bees are the principal commercial pollinators. Along with other arthropods, they are increasingly under threat from anthropogenic factors such as the incursion of invasive honey bee subspecies, pathogens and parasites. Better tools are needed to identify bee subspecies. Genomic data for economic and ecologically important organisms is increasing, but in its basic form its practical application to address ecological problems is limited. Results: We introduce HBeeID a means to identify honey bees. The tool utilizes a knowledge-based network and diagnostic SNPs identified by discriminant analysis of principle components and hierarchical agglomerative clustering. Tests of HBeeID showed that it identifies African, Americas-Africanized, Asian, and European honey bees with a high degree of certainty even when samples lack the full 272 SNPs of HBeeID. Its prediction capacity decreases with highly admixed samples. Conclusion: HBeeID is a high-resolution genomic, SNP based tool, that can be used to identify honey bees and screen species that are invasive. Its flexible design allows for future improvements via sample data additions from other localities. [ABSTRACT FROM AUTHOR]

The brain of adult honeybee (Apis mellifera) workers is larger than that of queens, facilitating behavioural differentiation between the castes. This brain diphenism develops during the pharate‐adult stage and is driven by a caste‐specific gene expression cascade in response to unique hormonal milieus. Previous molecular screening identified minibrain (mnb; DYRK1A) as a potential regulator in this process. Here, we used RNAi approach to reduce mnb transcript levels and test its role on brain diphenism development in honeybees. White‐eyed unpigmented cuticle worker pupae were injected with dsRNA for mnb (Mnb‐i) or gfp, and their phenotypes were assessed two and 8 days later using classic histological and transcriptomic analyses. After 2 days of the injections, Mnb‐i bees showed 98% of downregulation of mnb transcripts. After 8 days, the brain of Mnb‐i bees showed reduction in total volume and in the volume of the mushroom bodies (MB), antennal, and optic lobes. Additionally, signs of apoptosis were observed in the Kenyon cells region of the MB, and the cohesion of the brain tissues was affected. Our transcriptomic analyses revealed that 226 genes were affected by the knockdown of mnb transcripts, most of which allowing axonal fasciculation. These results suggest the evolutionary conserved mnb gene has been co‐opted for promoting hormone‐mediated developmental brain morphological plasticity generating caste diphenism in honeybees. [ABSTRACT FROM AUTHOR]

Varroa destructor is a dangerous pest directly for beekeeping and indirectly for crops that require insect pollination. In recent years, the application of chemical pesticides has led to the occurrence of mite resistance and contamination of hive products. Plant extracts are considered as a suitable alternative to chemical acaricides for the Varroa mite control. Therefore, the present study aimed to investigate the acaricidal and insecticidal activity of extract of Prangos ferulacea plant against the Varroa mite and its host in the honey bee colonies in the climatic conditions of Kurdistan province from 2022 to 2024. The P. ferulacea plant was collected in June 2022 from different regions of Kurdistan province in the flowering stage, extracted and then its chemical compounds were identified using GC-MS. The present study was conducted in the form of a factorial experiment based on a completely random basic design with four treatments and seven replications. Before conducting the bioassay experiments, the experimental colonies were homogenized in terms of queen age, population (adults and brood), and honey storage. Also, the initial infestation rate of colonies with Varroa mites was evaluated for adult and brood. The results showed that the extract of 50% of P. ferulacea was relatively favorable acaricidal properties. So that, there was no significant difference with oxalic acid and Apistan treatments in terms of mite mortality percentage in the first time of spraying. Also, the result showed that the bee's mortality percentage was not more than 7% in any of the times of spraying with the 50% extract of the P. ferulacea, and there was observed a significant difference compared to the oxalic acid and Apistan treatments in terms of bee's mortality percentage (P<0.01). The queen superseding was not observed in any of the experimental treatments. According to the findings of the present research, the concentration of 50% of the extract P. ferulaceous can be suggested as a suitable alternative to synthetic acaricides and organic acids to control the Varroa mite in honey bee colonies. [ABSTRACT FROM AUTHOR]

Insecticide toxicity to insect herbivores has long been known to vary across different host plants; this phenomenon has been widely documented in both foliage-feeders and sap-feeders. Species-specific phytochemical content of hostplant tissues is assumed to determine the pattern of induction of insect enzymes that detoxify insecticides, but specific phytochemicals have rarely been linked to host plant-associated variation in pesticide toxicity. Moreover, no studies to date have examined the effects of nectar source identity and phytochemical composition on the toxicity of insecticides to pollinators. In this study, we compared LD50 values for the insecticide bifenthrin, a frequent contaminant of nectar and pollen in agroecosystems, in the western honey bee, Apis mellifera, consuming three phytochemically different monofloral honeys: Nyssa ogeche (tupelo), Robinia pseudoacacia (black locust), and Fagopyrum esculentum (buckwheat). We found that bifenthrin toxicity (LD50) values for honey bees across different honey diets is linked to their species-specific phytochemical content. The profiles of phenolic acids and flavonoids of buckwheat and locust honeys are richer than is the profile of tupelo honey, with buckwheat honey containing the highest total content of phytochemicals and associated with the highest bifenthrin LD50 in honey bees. The vector fitting in the ordination analysis revealed positive correlations between LD50 values and two honey phytochemical richness estimates, Chao1 and Abundance-based Coverage Estimator (ACE). These findings suggest unequal effects among different phytochemicals, consistent with the interpretation that certain compounds, including ones that are rare, may have a more pronounced effect in mitigating pesticide toxicity. [ABSTRACT FROM AUTHOR]

Recent studies have provided new insights into the role of the microbiome in shaping host behavior. However, the relationship between the temporal division of labor among honey bees (Apis mellifera) and their gut microbial community has not been widely studied. Therefore, we aimed to evaluate the link between the gut microbiome and division of labor in honey bees by examining the microbial absolute abundance and relative composition of 7‐day‐old nurse bees and 28‐day‐old forager bees from a natural hive, as well as those of worker bees of the same 14‐day‐old age showing different behaviors in a manipulated hive. We found that forager bees had fewer core bacteria, particularly gram‐positive fermentative genera such as Lactobacillus and Bifidobacterium, with Bifidobacterium asteroides being the most sensitive to host behavioral tasks. Our results showed that forager bees have lower gut community stability compared to nurse bees, suggesting that their gut community is more susceptible to invasion by non‐core members. Furthermore, a pollen limitation experiment using caged honey bees indicated that dietary changes during behavioral shifts may be a driving factor in honey bee microbial diversity. This study contributes to a greater understanding of the interaction between the gut microbiome and behavioral tasks and provides a foundation for future assays. [ABSTRACT FROM AUTHOR]

Simple Summary: Metabolic changes in adult honey bee brains associated with the seasons and aging in honey bees (Apis mellifera) were assessed using nuclear magnetic resonance (NMR) spectroscopy. Brains were dissected from newly emerged, 14-day– old, and 28-day– old bees that were collected over the summer, as well as brood nest bees collected in the fall, winter, and spring. Changes in the brain metabolome indicated that worker bees undergo adaptations throughout their lives, with notable shifts occurring between newly emerged and older individuals. Furthermore, the seasons affected the honey bee brain metabolome, highlighting differences in metabolic responses to changes in the environment and resource availability. While previous studies have reported differences in the metabolome of whole bodies between summer and winter bees, or in the brains of forager bees infected with a virus, the present study has revealed the metabolome of the honey bee brain as it ages. Several potential markers were identified for assessing aging of the bee brain, such as the potential neurotransmitter β-alanine and neurotransmitter-precursors/intermediates, phenylalanine, tyrosine, tryptophan, and O-phosphocholine. Honey bees (Apis mellifera) provide a useful model for studying aging because of the differences in longevity between the relatively short-lived summer and long-lived winter bees, as well as bees lacking signs of cognitive senescence as they age. Bee brains were dissected from newly emerged, 14-day–, and 28-day– old bees in mid- and late summer, as well as brood nest bees in fall, winter, and spring, before, during, and after overwintering, respectively. Brains were examined with nuclear magnetic resonance (NMR) spectroscopy to analyze their metabolome. Nine variable importance in projection (VIP) variables were identified, primarily amino acids and choline derivatives. Differences in metabolite concentrations were found with different ages of summer bees, mostly between newly emerged and 14-day– old bees, such as a decrease in phenylalanine and an increase in β-alanine, but there were also changes in older adults, such as o-phosphocholine that declined in 28-day– old bees. Differences in brood nest bees were observed, including a decline in tryptophan and an increase in β-alanine. These may provide distinct metabolomic signatures with age and season. Such research holds promise for a better understanding of the complex interplays between bee physiology, development, and aging, which has implications for improving bee health and management. [ABSTRACT FROM AUTHOR]

Honey bees (Apis mellifera L.) are the premier agricultural pollinators with direct ecological value and are key to some agro-economies. Major factors have negatively impacted honey bee health in the past 2 decades with Varroa (Varroa destructor Anderson and Trueman) infestation rising as a principal predictor of colony mortality. A key strategy deployed in Varroa management is breeding for resistant honey bee populations that can maintain comparable levels of productivity as nonresistant populations. In this study, we examine one such population, Hilo honey bees, within the context of a common garden contrast with a commercial population in a stationary honey production operation. We compare colony survival, health, yield, and profit outcomes to show how this specific breeding population retains a profit value in honey production operations while maintaining higher survival and lower Varroa infestation levels than the commercial population. This information can be used by commercial beekeepers to make best management practice decisions and inspire further work examining what trade-offs, if any, are present in this Varroa- resistant population. [ABSTRACT FROM AUTHOR]

Introduction: Honey bees need nutrients such as protein, carbohydrates, lipids, minerals, and vitamins. Among nutrients, vitamins are particularly important for their roles in brood rearing, hypopharyngeal gland development, ovary development, longevity, bee immunity, bee weight, and flight muscle development. The vitamins stored in the body of the bees are vitally important in strengthening the immune system, normal growth, and development of broods, producing royal jelly, longevity of bees, and especially wintering quality of honey bees. Among the vitamins required by the honey bees, the most important are thiamine and riboflavin. Pollen quality depends on the supply of vitamins required by honey bees. Most pollen grains are poor and deficient in thiamine and riboflavin. This study aimed to investigate the effect of thiamine and riboflavin on population growth, functional traits, and fat and protein reserves of the bee body in Iranian honey bee colonies. Materials and methods: An experiment was conducted in a completely randomized design with four treatments and seven repetitions from April 2022 to September 2023 in the climatic conditions of Kurdistan province, Iran. Experimental treatments included the sugar syrup (control), thiamine (1500 ppm), riboflavin (1500 ppm), and the combination of thiamine and riboflavin (1500 ppm). From the beginning of 14 April 2023, experimental treatments were fed with the mentioned concentrations of vitamins thiamine, riboflavin, and their combination of 0.5 liters every other day for 45 days and 15 days without feeding. Then, traits such as honey production, pollen collection, population (adults and broods), and protein and fat content of carcass were measured in experimental treatments. Results and discussion: The results of the effect of thiamine, riboflavin, and their combination on the population of adult bees showed that the addition of thiamine and riboflavin in the bees' nutrition was significantly effective in the increase of adult bees' population in the investigated periods as well as the average of the entire period (P<0.05). A comparison of the averages of the experimental treatments revealed that the highest and lowest adult bee populations were associated with the treatments fed the vitamin combination and the control group, respectively. The results of the effect of thiamine, riboflavin, and their combination on the population of broods showed that the addition of thiamine and riboflavin in the diet of bee colonies during the studied periods did not have a significant effect on the increase in the population of newborns, but it showed a significant effect on the average of the entire period (P<0.05). The results of the mean comparison showed that the highest population of broods in the studied honey bee colonies was related to the treatments fed with the combination of thiamine and riboflavin, and the lowest population of broods was related to the control treatment. The results of the effect of thiamine and riboflavin on honey and pollen production traits showed that the use of vitamins and their combination in honey bee nutrition caused a significant increase in honey and pollen production traits of experimental treatments (P<0.05). The results of the mean comparison showed that the highest and lowest amounts of honey and pollen production of the studied honey bee colonies were observed in the treatment fed with the combination of vitamins and the control group, respectively. The effect of thiamine and riboflavin on the carcass protein and fat showed that the use of thiamine, riboflavin, and their combination in feeding the colonies had a significant effect on the amount of carcass protein and fat (P<0.01). A comparison of treatments showed that honey bees in the treatment fed the vitamin combination had the highest carcass protein and fat, and honey bees in the control treatment had the lowest carcass fat and protein. Conclusions: Based on the results of the present experiment, it could be concluded that the use of thiamine and riboflavin, and their combination in feeding honey bees had a positive effect on population growth, functional traits, and fat and protein reserves of the bees' body in the colonies and improved the performance and increased the economic efficiency of the colony. [ABSTRACT FROM AUTHOR]

Türkiye, with its rich flora diversity, holds a significant share in global honey production. However, honey bee populations, essential for agricultural ecosystems, face multifaceted threats such as climate change, habitat degradation, diseases, parasites, and exposure to pesticides. Alongside the increasing global food demand driven by population growth, there is a pressing need for a substantial increase in honey production. In this context, advances in machine learning algorithms offer tools to predict future food needs and production levels. The objective of this work is to develop a predictive model using machine learning techniques to predict Türkiye's honey output in the next years. To achieve this goal, a range of machine learning algorithms including K-Nearest Neighbor, Random Forest, Linear Regression, and Gaussian Naive Bayes were employed. Following investigations, Linear Regression emerged as the most effective method for predicting honey production levels (R2= 0.97). [ABSTRACT FROM AUTHOR]

Circular RNAs (circRNAs) are a class of non-coding RNAs (ncRNAs) that can participate in biological processes such as gene expression, growth, and development. However, little has been explored about the function of circRNAs in the development of Apis cerana larval guts. By using our previously gained deep sequencing data from the guts of A. cerana worker larvae at 4-, 5-, and 6-day-old (Ac4, Ac5, and Ac6 groups), the expression pattern and regulatory role of circular RNAs (circRNAs) during the development process was comprehensively investigated, with a focus on differentially expressed circRNAs (DEcircRNAs) relevant to immunity pathways and developmental signaling pathways, followed by validation of the binding relationships among a key competing endogenous RNA (ceRNA) axis. Here, 224 (158) DEcircRNAs were detected in the Ac4 vs. Ac5 (Ac5 vs. Ac6) comparison group. It's suggested that 172 (123) parental genes of DEcircRNAs were involved in 26 (20) GO terms such as developmental process and metabolic process and 138 (136) KEGG pathways like Hippo and Wnt signaling pathways. Additionally, ceRNA network analysis indicated that 21 (11) DEcircRNAs could target seven (three) DEmiRNAs, further targeting 324 (198) DEmRNAs. These DEmRNAs can be annotated to 33 (26) GO terms and 168 (200) KEGG pathways, including 12 (16) cellular and humoral immune pathways (endocytosis, lysosome, Jak-STAT, etc.) and 10 (nine) developmental signaling pathways (Hippo, mTOR, Hedgehog, etc.). Interestingly, DEcircRNAs in these two comparison groups could target the same ace-miR-6001-y, forming complex subnetworks. The results of PCR and Sanger sequencing confirmed the back- splicing sites within four randomly selected DEcircRNAs. RT-qPCR detection of these four DEcircRNAs verified the reliability of the used transcriptome data. The results of dual-luciferase reporter assay verified the binding relationships between novel_circ_001627 and ace-miR-6001-y and between ace-miR-6001-y and apterous-like. Our data demonstrated that DEcircRNAs were likely to modulate the developmental process of the A. cerana worker larval guts via regulation of parental gene transcription and ceRNA network, and novel_circ_001627/ace-miR-6001-y/apterous-like was a potential regulatory axis in the larval gut development. Findings from this work offer a basis and a candidate ceRNA axis for illustrating the circRNA-modulated mechanisms underlying the A. cerana larval guts. [ABSTRACT FROM AUTHOR]

The mite Varroa destructor Anderson and Trueman (Mesostigmata: Varroidae) has a dramatic impact on beekeeping and is one of the main causes of honey bee colony losses. This ectoparasite feeds on honey bees' liquid tissues, through a wound created on the host integument, determining weight loss and a reduction of lifespan, as well as the transmission of viral pathogens. However, despite its importance, the mite feeding strategy and the host regulation role by the salivary secretions have been poorly explored. Here, we contribute to fill this gap by identifying the salivary components of V. destructor, to study their functional importance for mite feeding and survival. The differential expression analysis identified 30 salivary gland genes encoding putatively secreted proteins, among which only 15 were found to be functionally annotated. These latter include proteins with putative anti‐bacterial, anti‐fungal, cytolytic, digestive and immunosuppressive function. The three most highly transcribed genes, coding for a chitin‐binding domain protein, a Kazal domain serine protease inhibitor and a papain‐like cysteine protease were selected to study their functional importance by reverse genetics. Knockdown (90%–99%) by RNA interference (RNAi) of the transcript of a chitin‐binding domain protein, likely interfering with the immune reaction to facilitate mite feeding, was associated with a 40%–50% decrease of mite survival. This work expands our knowledge of the host regulation and nutritional exploitation strategies adopted by ectoparasites of arthropods and allows the identification of potential targets for RNAi, paving the way towards the development of new strategies for Varroa mite control. [ABSTRACT FROM AUTHOR]

The Entomological Society of America (ESA) Student Debates is an annual student competition at the ESA Annual Meeting organized by Student Debates Subcommittee (SDS) members of the ESA Student Affairs Committee. In conjunction with the 2023 ESA Annual Meeting theme, 'Insects and influence: Advancing entomology's impact on people and policy', the theme of this year's student debate was 'Addressing emerging issues in entomology'. With the aid of ESA membership, the SDS selected the following debate topics: (1) Should disclosure of artificial intelligence large language models in scientific writing always be required? and (2) Is it more important to prioritize honey bee or native pollinator health for long-term food security within North America? Four student teams from across the nation, composed of 3–5 student members and a professional advisor, were assigned a topic and stance. Over the course of 5 months, all team members researched and prepared for their assigned topic before debating live with an opposing team at the 2023 ESA Annual Meeting in National Harbor, Maryland. SDS members additionally prepared and presented introductions for each debate topic to provide unbiased backgrounds to the judges and audience for context in assessing teams' arguments. The result was an engaging discussion between our teams, judges, and audience members on emerging issues facing entomology and its impact on people and policy, such as scientific communication and food security, that brought attention to the complexities involved when debating topics concerning insects and influence. [ABSTRACT FROM AUTHOR]

The study aimed to estimate the economic efficiency and productivity of bees honey production in Dakahlia Governorate due to the economic, nutritional and agricultural importance of bee-keeping and honey production. The research was based on a field sample of 80 apiaries in Dakahlia Governorate in the Belqas and Manzala. The results of the study showed that there was a statistically significant decrease in the number of wood cells in Dakahlia Governorate -were about 4.59 thousand cells annually, representing 5.69% of its annual average, which amounted to be 80.59 thousand cells. It was also shown that there was a statistically significant decrease in cell productivity about 0.05 kg annually. For the hive,, there was a statistically significant decrease in the production of honey by bees in Dakahlia Governorate about 29.64 tons annually, or about 6.58% of the annual average, which was estimated at about 450.29 tons during the study period. The average net return of the hive was about 684 L.E per hive in the sample. It increased to reach its maximum in the third capacity, where it reached about 842 L.E per hive, followed by the second capacity, where it was about 725 L.E per hive. The net return of the hive decreased to reach its lowest in the first capacity, where it reached About 374 L.E per cell. While it turns out that the profitability of spend or invested pound in the second and third bee-keeping capacity is greater than that of the first bee-keeping capacity, this means that by increasing the bee- keeping capacity or the number of hives, the profitability of the spend or invested pound increases, and this is consistent with economic logic and increased capacity savings. Therefore, the study recommends, according to the obtained results, the following: The use of pesticides must be rationalized to some extent, as approximately 93% of the total sample indicated the use of pesticides in spraying crops, which leads to poisoning of the insect while collecting nectar, which negatively affects the production of honey bees. Working to provide pure, high-production honey bee queens, as about 69% of the total sample indicated the difficulty of obtaining pure queens. It is necessary to activate the role of agricultural extension in the field of honey bee breeding, as about 85% of the total sample indicated the absence of the role of agricultural extension in the field of honey bee breeding [ABSTRACT FROM AUTHOR]

Varroosis is a disease that can be observed in all life stages of honey bees and causes serious clinical findings in infested hives. This study aimed to investigate and compare the efficiency of thyme oil, Cinnamomum verum, Melaleuca viridiflora, Syzygium aromaticum essential oils, and amitraz against Varroosis in the field. After the essential oils were dissolved in glycerin, they were impregnated on strips and applied by placing them between frames. Amitraz was applied by fumigation. Positive and phoretic Varroa negative control groups were also included. Treatments were applied once a week for four weeks during the autumn season. The rates of acaricide efficacy and weekly mite count per bottom frame were determined for each of the treatments. According to the results, the highest effectiveness against Varroosis was detected in the amitraz treatment group at 81.3%. The C. verum treatment group had the highest efficacy of all the essential oil treatment groups at 73.5%. The efficacies in thyme oil, M. viridiflora, and S. aromaticum essential oils treatment groups were 71.9%, 71.3%, and 67.4%, respectively. According to the findings of the study, natural extracts can be used instead of chemical drugs in the fight against Varroosis. No toxicity or unnatural death was observed in honey bees throughout the study. [ABSTRACT FROM AUTHOR]

Fungi are increasingly recognized to play diverse roles within honey bee hives, acting as pathogens, mutualists, and commensals. Pollen products, essential for hive nutrition, host significant fungal communities with potential protective and nutritional benefits. In this study, we profile the fungal communities and antifungal properties of three pollen products from healthy and stressed hives: fresh pollen collected by forager bees from local plants; stored pollen packed into the comb inside the hive; and bee bread, which is stored pollen following anaerobic fermentation used for bee and larval nutrition. Using amplicon sequencing, we found significant differences in fungal community composition, with hive health and sample type accounting for 8.8% and 19.3% of variation in beta diversity, respectively. Pollen and bee bread extracts had species-specific antimicrobial activity and inhibited the fungal hive pathogens Ascosphaera apis, Aspergillus flavus , and Aspergillus fumigatus , and the bacterial hive pathogen Paenibacillus larvae. Activity was positively correlated with phenolic and antioxidant content and was diminished in stressed hives. The plant source of pollen determined by amplicon sequencing differed in stressed hives, suggesting altered foraging behaviour. These findings illustrate the complex interplay between honey bees, fungal communities, and hive products, which should be considered in hive management and conservation. [ABSTRACT FROM AUTHOR]

Simple Summary: There is a global need for targeted, environmentally friendly, sustainable alternatives to pesticides. In the apicultural industry, the parasitic mite Varroa destructor poses a serious threat to honey bee health. Like many other agricultural pests, Varroa are primarily managed via pesticides. Whilst these pesticides can effectively control mites, they can also harm bee health, contaminate bee products and pose toxicity risks to beekeepers during application. As a first step to assessing public support for a new biotechnology that could provide a non-toxic alternative to pesticides, beekeepers' perspectives on a novel Varroa control method designed to inhibit protein production, called RNA interference (RNAi), were investigated. The majority of beekeepers surveyed were open to using RNAi treatments against Varroa, particularly as it provided a non-toxic alternative to current pesticide options. The major concerns raised were the unknown long-term effects of the RNAi treatment on bee health, potential effects on non-target species that interact with beehives and concern that an uninformed public that might prevent them from accessing a new tool to combat Varroa. Surveys such as ours can inform scientists and regulatory authorities on how best to introduce novel biotechnologies for commercial use. Current Varroa mite management strategies rely heavily on the use of pesticides, adversely affecting honey bee health and leaving toxic residues in hive products. To explore the likelihood of RNAi technology being utilised as an alternative control method for pests like Varroa, the opinions of beekeepers on the use of this new biotechnology were obtained using a mixed-methodology approach. In-person surveys and focus groups using the Q method were conducted to discover the willingness of beekeepers to utilise Varroa-targeting RNAi treatments in their hives, and to gain feedback to inform decisions before the implementation of this new technology. Overall, the beekeepers saw potential in RNAi being used to control Varroa in their hives and were eager to have access to an alternative to pesticide treatments. Participants raised concerns about unknown long-term effects on bees and other non-target species, and the potential of an uninformed public preventing them from accessing a new Varroa treatment. While further research and discussion is needed before RNAi treatments for Varroa become commercially available, RNAi technology presents a promising, species-specific and non-toxic solution for Varroa management. [ABSTRACT FROM AUTHOR]

Simple Summary: This study highlights the significant impact of acetamiprid, a neonicotinoid insecticide, on the survival and formation of olfactory appetitive learning and memory in Apis mellifera jemenitica. The insecticide exhibits deleterious effects on honey bees through both topical and oral exposure routes. This information holds significant value for devising comprehensive strategies aimed at better enhancing honey bee foraging activities within agricultural landscapes treated with chemicals. By understanding the specific impacts of insecticides against honey bees, we can develop targeted approaches to mitigate adverse effects, preserve honey bee populations, and sustain pollination services that are crucial for ecosystem health and agricultural productivity. The honey bee, a significant crop pollinator, encounters pesticides through various routes of exposure during foraging and flower visitation. Considering the potential threat of pesticide poisoning, the indigenous Saudi bee Apis mellifera jemenitica is susceptible to the risks associated with acetamiprid, a neonicotinoid insecticide. This study investigates the acetamiprid-induced effects on the survival, olfactory learning, and memory formation of A. m. jemenitica through two exposure routes: topical application and oral ingestion. Field-realistic and serially diluted concentrations (100, 50, 25, and 10 ppm) of acetamiprid led to notable mortality at 4, 12, 24, and 48 h after treatment, with peak mortality observed at 24 h and 48 h for both exposure routes. Bee mortality was concentration-dependent, increasing with the rising concentration of acetamiprid at the tested time intervals. Food consumption following oral exposure exhibited a concentration-dependent pattern, steadily decreasing with increasing concentrations of acetamiprid. Oral exposure resulted in a substantially higher cumulative mortality (55%) compared to topical exposure (15%), indicating a significant disparity in bee mortality between the two exposure routes. The 24 h post-treatment LC50 values for acetamiprid were 160.33 and 12.76 ppm for topical application and oral ingestion, respectively. The sublethal concentrations (LC10, LC20, and LC30) of acetamiprid were 15.23, 34.18, and 61.20 ppm, respectively, following topical exposure, and 2.85, 4.77, and 6.91 ppm, respectively, following oral exposure. The sublethal concentrations of acetamiprid significantly decreased learning during the 2nd–3rd conditioning trials and impaired memory formation at 2, 12, and 24 h following both topical and oral exposure routes, compared to the control bees. Notably, the sublethal concentrations were equally effective in impairing bee learning and memory. Taken together, acetamiprid exposure adversely affected bee survival, hindered learning, and impaired the memory retention of learned tasks. [ABSTRACT FROM AUTHOR]

Aim: Most of the world's food crops are dependent on pollinators. However, there is a great deal of uncertainty in the strength of this relationship, especially regarding the relative contributions of the honey bee (often a managed species) and wild insects to crop yields on a global scale. Previous data syntheses have likewise reached differing conclusions on whether pollinator species diversity, or only the number of pollinator visits to flowers, is important to crop yield. This study quantifies the current state of these relationships and links to a dynamic version of our analyses that updates automatically as studies become available. Location: Global. Time Period: Present. Taxa studied: Insect pollinators of global crops. Methods: Using a newly created database of 93 crop pollination studies across six continents that roughly triples the number of studies previously available, we analysed the relationship between insect visit rates, pollinator diversity, and crop yields in a series of mixed‐effects models. Results: We found that honey bees and wild insects contribute roughly equal amounts to crop yields worldwide, having similar average flower visitation rates and producing similar increases in yield per visit. We also found that pollinator species diversity was positively associated with increased crop yields even when total visits from all species are accounted for, though it was less explanatory than the total number of visits itself. Main conclusions: Our analysis suggests a middle ground where honey bees are not responsible for the vast majority of crop pollination as has often been assumed in the agricultural literature, and likewise wild insects are not vastly more important than honey bees, as recent global analyses have reported. We also conclude that while pollinator diversity is less important than the number of pollinator visits, these typically involve many species, underscoring the importance of conserving a diversity of wild pollinators. [ABSTRACT FROM AUTHOR]

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