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The use of invertebrate models has allowed researchers to examine the mechanisms behind alcoholism and its effects with a cost-effective system. In that respect, the honey bee is an ideal model species to study the effects of ethanol (EtOH) due to the behavioral and physiological similarities of honey bees with humans when alcohol is consumed. Although both ingestion and inhalation methods are used to dose subjects in insect EtOH model systems, there is little literature on the use of the EtOH vapor-exposure method for experiments using honey bees. The experiment presented here provides baseline data for a dose EtOH-hemolymph response curve when using EtOH vapor-inhalation dosing with honey bees (Apis mellifera). Bees were exposed to EtOH vapors for 0, 1, 2.5, or 5 min, and hemolymph was collected 1 min post EtOH exposure. Hemolymph samples were analyzed using gas chromatography (GC) for hemolymph EtOH concentration. The ethanol-hemolymph level of the bees increased linearly with exposure time. The results provide a dosing guide for hemolymph EtOH level in the honey bee model ethanol-inhalation system, and thus makes the honey bee model more robust.

Background: Temperature is one of the essential abiotic factors required for honey bee survival and pollination. Apart from its role as a major contributor to colony collapse disorder (CCD), it also affects honey bee physiology and behavior. Temperature-stress induces differential expression of genes related to protein synthesis and metabolic regulation, correlating with impaired gland function. This phenomenon has been confirmed in mandibular glands (MGs), but not in Hypopharyngeal glands (HGs), potentially affecting larval nutrition. RNA-seq analysis was performed using HGs tissue at low (23 °C), regular (26 °C), and high (29 °C) ambient temperatures. This study aims to decode molecular signatures and the pathways of the HGs tissue in response to temperature-stress and the rapid genetic changes that impact not only royal jelly (RJ) production potential but also other biological functions related to HGs and beyond. Results: From the analyzed RNA-seq data, 1,465 significantly differentially expressed genes (DEGs) were identified across all the temperature groups. Eight genes (APD-1, LOC100577569, LOC100577883, LOC113218757, LOC408769, LOC409318, LOC412162, OBP18) were commonly expressed in all groups, while 415 (28.3%) of the total genes were exclusively expressed under temperature-stress. The DEGs were categorized into 14 functional groups and significantly enriched in response to external stimuli, response to abiotic stimuli, and protein processing in the endoplasmic reticulum (ER). Pathway analysis of exclusively temperature-stressed DEGs revealed that these genes promote ECM-receptor interaction and fatty acid metabolism while reducing protein processing in the ER, which is related to royal jelly (RJ) production and overall nutrition. Although heat-shock protein 90 and gustatory receptor 10 serve as markers for stress and hypopharyngeal glands (HGs) development respectively, their expression varies under temperature-stress conditions. Conclusions: We conclude that with the recent effects of climate change and its contributing factors, honey bee pollination, and reproduction activity is on the verge of halting or experiencing a detrimental decline. Considering the impact of temperature-stress on the expression of the nutritional marker gene (GR10), silencing GR10 in HGs tissue could provide valuable insights into its significance in nutritional performance, survival, and beyond. Finally, a broader temperature range in future experiments could help derive more definitive conclusion. [ABSTRACT FROM AUTHOR]

Simple Summary: Honey bees are vulnerable to multiple stressors, including pesticide toxicity during foraging. They can be exposed to pesticides through various routes, such as oral ingestion of contaminated pollen, nectar, or water, and contact with pesticide residues on plants and environmental surfaces. Beyond individual pesticide poisoning, the combined effects of pesticide mixtures—whether synthetic or naturally occurring—can be lethal to bees, even at sublethal concentrations. This study investigates the effects of a binary mixture of two commonly used pesticides, acetamiprid (neonicotinoid) and deltamethrin (pyrethroid), on the survival and cognitive functions of the native Saudi Arabian honey bee species, Apis mellifera jemenitica. The insecticide mixture caused significantly higher mortality and impaired learning and memory formation, as assessed through lethal concentration analysis and olfactory learning paradigms via oral and topical exposure routes. These findings enhance our understanding of synergistic and antagonistic interactions between pesticides and highlight the need for cautious pesticide use to protect pollinator health and ecosystem stability. The impact of agrochemicals on pollinators, especially honey bees, has drawn significant attention due to its critical implications for worldwide food stability and ecosystems. Given the potential threat of insecticides to honey bees, bees may encounter multiple insecticides simultaneously during foraging. This study investigated the toxic effect of an insecticide mixture (IM) containing acetamiprid (neonicotinoid) and deltamethrin (pyrethroid) on the survival and cognitive appetitive performance of Apis mellifera jemenitica, a vital native pollinator in arid regions of Saudi Arabia. The lethal concentration (LC50) was determined by assessing bees' mortality rates following exposure to IM through topical and oral routes. Significant bee mortality occurred at 4–48 h post treatment with IM through both exposure routes, showing a trend of increased mortality with higher IM concentrations compared to the control bees. Throughout all tested times, topical exposure proved relatively more effective, resulting in significantly greater bee mortality compared to oral exposure to IM. Food intake declined progressively with rising IM concentrations during oral exposure. The LC50 values of IM at 24 h after treatment were 12.24 ppm for topical and 10.45 ppm for oral exposure. The corresponding LC10, LC20, and LC30 values were 3.75 ppm, 5.63 ppm, and 7.54 ppm for topical exposure and 2.45 ppm, 4.04 ppm, and 5.78 ppm for oral exposure, respectively. The combination index (CI) revealed a synergistic effect (0.43) for topical exposure and antagonistic effects (1.43) for oral exposure, highlighting differential toxicity dynamics. IM exposure significantly impaired cognitive acquisition and memory reinforcement in honey bees, as demonstrated through behavioral assays, indicating potential neurotoxic effects. Learning and memory formation significantly declined at 2, 12, and 24 h after exposure to sublethal concentrations of IM through both topical and oral routes. Thus, evaluating the interactive impact of multiple pesticides on bees' health and cognitive function is essential, particularly in regions where diverse agrochemicals are routinely utilized. [ABSTRACT FROM AUTHOR]

The bacterium Paenibacillus larvae is responsible for the devastating honey bee (Apis mellifera) disease American Foulbrood. Research into bacteriophages that infect P. larvae is growing rapidly due to increasing antibiotic resistance and restrictions on antibiotic use in beehives in some countries. In this study, we present the sequenced and annotated genomes of 26 novel P. larvae phages recently isolated in New Zealand, which brings the total number of sequenced and annotated P. larvae phages to 96. The 26 novel phages belong to the pre-existing Vegas or Harrison clusters. We performed a comprehensive genomic analysis of all 96 phage genomes, grouping them into five divergent clusters and two singletons. The majority of these phages are temperate, with the possible exception of three phages that may be lytic. All 96 of these phages encode an N-acteylmuramoyl-L-alanine amidase that serves as their lysin. The amidases are from two divergent clusters, both of which show a high degree of intra-cluster similarity. Six phages and a prophage contain the Plx1 P. larvae toxin gene, which we suggest may be mobilizable. This study expands our knowledge of P. larvae phages from around the world. [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]

This study aims to classify honey bee genotypes by integrating explainable artificial intelligence techniques, particularly decision trees, with both morphometric and molecular data. A total of 4949 samples were collected from 500 colonies across five regions in Türkiye, representing diverse subspecies and ecotypes. Morphometric data included 16 key wing characteristics, while molecular data contained 26 highly informative SSR loci. First, we used 16 morphometric wing parameters to classify bees into five regions where they originate. The decision tree algorithm resulted in a tree with wing length and O26 and L13 angles, but the classification accuracy was low (51%). Later, we included 26 molecular variables and obtained a decision tree with four SSR loci—Ap218, Ap274, Ap001, and Ap289—and achieved a high classification accuracy of 96.38%. The findings also revealed the first-ever identification of a SSR locus (Ap218) strongly associated with wing length in honey bees. Finally, we explained wing length with molecular data by modeling a regression decision tree. This tree identified Ap218, Ap223, and Ap001 as the most significant SSR loci for the wing length model. This study provides a powerful approach for differentiating honey bee genotypes while offering valuable insights into the genetic factors influencing wing morphology. The results have significant implications for the conservation and sustainable management of honey bee genetic resources, particularly in regions like Türkiye where genetic diversity is at risk. [ABSTRACT FROM AUTHOR]

Queen health and quality play a significant role in the survival, expansion, and productivity of honey bee colonies. Nevertheless, modern beekeeping practices, intensified agriculture, and climate change can leave queens vulnerable to diverse stressors. These stressors can exert a negative impact on queens, resulting in a range of morphological and physiological abnormalities. The repercussions of queen stress may not only cause direct impacts on her survival and performance, but it may also extend to the offspring of surviving queens through transgenerational mechanisms. Here, we review the current knowledge regarding the effects of major abiotic stressors (namely, nutrition, pesticides, and extreme temperatures) on queen health and their potential impacts on the queen’s progeny. Gaining insight into the effects of these factors across individual and colony levels is vital for prioritizing further research on queen and colony health. [ABSTRACT FROM AUTHOR]

Honey bee (Apis mellifera) thermoregulation plays an integral part in their behaviour and physiology and has been shown to be vulnerable to the effects of neonicotinoid insecticides. Flight muscles are a crucial source of physiological heat as well as being vital for behavioural heat regulation, and are negatively affected by neonicotinoid insecticides. In this study, we evaluated the flight efficiency and capacity of Apis mellifera scutellata under the influence of both elevated ambient temperatures and sublethal neonicotinoid exposure. The various aspects of flight; success, distance, speed, and duration, were not notably affected by these factors. However, the honey bees' ability to initiate a successful flight was significantly affected by neonicotinoid exposure. Such a reduction in honey bee flight capacity, and flight muscle function in general, especially under the increasing frequency and intensity of hot weather events, is cause for concern when considering legislation and use of these neonicotinoids in the agricultural and suburban setting. [ABSTRACT FROM AUTHOR]

High summer temperatures caused major crop losses in scarlet runner beans (Phaseolus coccineus) in Austrian agriculture. To evaluate the impact of temperature on pollination, a greenhouse experiment was conducted. Pollination of P. coccineus by Apis mellifera was studied under standard temperature conditions (22 °C) and was compared to heat stress conditions (35 °C) in the greenhouse as well as to natural insect–flower interactions in the field trial. Under heat stress conditions, workers of A. mellifera significantly decreased their flower visitation, while the duration of flower visits significantly increased compared to normal greenhouse temperatures. Heat stress leads to a foraging stop of honey bees on the flowers of runner beans within a few days. It is concluded that the raised ambient temperature that we are facing during global warming may have negative effects on pollination and fruit set of P. coccineus. [ABSTRACT FROM AUTHOR]

Genetic analysis of the honey bee spermathecal content can be particularly useful to provide an estimate of the genetic diversity and purity of the surrounding populations. Here we compared the concentration and quality of DNA extracted from queen spermatheca using four commercial kits to determine the best method to obtain DNA suitable for single nucleotide polymorphism genotyping by next-generation sequencing. The four kits were tested with different adjustments in the lysis incubation time, use of RNA-carrier, elution conditions and number of re-elutions. Only the use of QIAamp DNA Microkit with 3 h of lysis incubation, the addition of RNA-carrier and multiple re-elutions produced a DNA concentration over the required threshold. [ABSTRACT FROM AUTHOR]

Transferring adult honey bees from the combs of their hive to a new empty hive is a management strategy known as "shook swarming" that has been used by beekeepers in a variety of contexts since as early as 1796. Varroa destructor are dependent on mature brood to reproduce and shook swarming breaks the colony's brood cycle by separating the adult bees from the brood developing in the old combs. We investigated the efficacy and practicality of shook swarming to mitigate negative health effects of Varroa in honey bee colonies by reducing Varroa infestation rates. New colonies were founded via traditional splitting or the shook swarm technique either with or without comb in the new hive. All colonies were given ∼1 month to establish and then assessed for foraging activity, colony strength, and Varroa infestation rate. We observed a significant decrease in the Varroa infestation rates of colonies that experienced shook swarming compared with those that had not. Colonies established via shook swarming had lower colony strength scores but maintained similar relative foraging activity as traditional splits. Our findings indicate that shook swarming is a viable, non-chemical control strategy for managing Varroa infestations and should be considered in long-term management plans where colonies undergo shook swarming aligned with honey production and/or pollination service delivery. [ABSTRACT FROM AUTHOR]

Varroa species, commonly known as the honey bee mites, poses a significant challenge to the worldwide beekeeping industry. The aim of this study was to investigate the effect of haplotype variation on morphology of Varroa destructor. Forty-one apiaries across Bingol province (Türkiye) and its districts were visited using random sampling to examine 2440 honey bee colonies. Adult Varroa spp mites were collected from each apiary and morphometrically analysed at species level, resulting in seven mites being used to represent each apiary. Length measurements were taken of six morphometric parameters of 287 adult Varroa spp. isolates under a stereo microscope, including body length, body width, genital shield length, genital shield width, anal shield length and anal shield width. In order to analyze genetic diversity, genomic DNA was isolated from a total of 82 individual Varroa spp. isolates, and specific primers were used to amplify the mitochondrial cytochrome oxidase subunite 1 (mt-CO1) gene fragment (376 bp) by PCR followed by DNA sequence analysis. Morphometric analysis revealed that the adult Varroa spp isolates had a body width of 1691.10 ± 06.55 μm and a body length of 1125.69 ± 06.62 μm, with no significant differences between apiaries. These findings indicate that all the isolates were morphometrically identified as V. destructor. Moreover, all the sequences were highly similar to the Korean (K) haplotype of V. destructor. Six haplotypes (Hap01-Hap06) of V. destructor were identified via haplotype analysis. The haplotype groups exhibited low nucleotide diversity and were separated by 1–3 point mutations. There was no significant difference in body widths between Hap01 and other haplotypes. However, Hap03 had significantly higher body widths than Hap04 and Hap05. This indicates that haplotype differences may have an effect on morphological parameters in Varroa species. [ABSTRACT FROM AUTHOR]

The Varroa destructor represents a significant threat to honey bees, leading to substantial yield losses and declines in colony health. Defense behaviors, including grooming (auto and allogrooming), serve as crucial mechanisms against Varroa infestations, yet the genetic basis of these behaviors remains elusive. This study examines the expression levels of hymenoptaecin (hym), neurexin-1 (AmNrx1), and CYP9Q3, potentially associated with defense behavior, in colonies of the Muğla honey bee ecotype (Apis mellifera anatoliaca) subjected to a Varroa selection program. Worker bees from 23 control groups and 23 colonies under selection were evaluated by using qPCR analysis. Results reveal a significant upregulation of hym, AmNrx1, and CYP9Q3 genes in the selected group, with fold changes of 2.9, 2.95, and 3.26 respectively compared to controls (p < 0.01). This suggests that selection against Varroa induces alterations in gene expression linked to Varroa exposure behaviors. These findings advocate for the potential use of hym, AmNrx1, and CYP9Q3 genes in preselection for future Varroa-resistant programs in honey bees. Supported by previous studies, these genes may facilitate the establishment of populations with enhanced defense behaviors, such as autogrooming and allogrooming. [ABSTRACT FROM AUTHOR]

Pollination by insects is vital for global agriculture, with honey bees (Apis mellifera L.) being the most important pollinators. Honey bees are exposed to numerous stressors, including disease, pesticides, and inadequate nutrition, resulting in significant colony losses.This study investigates the use of drone brood to mitigate these problems. Drone brood, which is normally discarded during varroa mite (Varroa destructor, Anderson and Trueman) management, is rich in proteins, fats, and essential minerals. We compared drone brood with an already suggested pollen supplement (Tenebrio [Tenebrio molitor L.] flour).The results indicate that drone brood flour is a viable source of proteins, fats, and minerals and is potentially antimicrobial due to its high content of elements with known antimicrobial properties. It meets the nutritional needs of honey bees while mitigating the effects of varroa mites. The use of drone brood flour can provide high-quality beeswax, surplus of pollen, and improve bee health, which promotes sustainable beekeeping. Graphical Abstract [ABSTRACT FROM AUTHOR]

Background: The mite Varroa destructor is the most serious pest of the western honey bee (Apis mellifera) and a major factor in the global decline of colonies. Traditional control methods, such as chemical pesticides, although quick and temporarily effective, leave residues in hive products, harming bees and operators' health, while promoting pathogen resistance and spread. As a sustainable alternative, RNA interference (RNAi) technology has shown great potential for honey bee pest control in laboratory assays, but evidence of effectiveness in the field has been lacking. Methods: We investigated the efficacy and feasibility of a RNAi treatment to improve bee health under natural beekeeping conditions by integrating a honey bee diet with a mixture of dsRNA targeting V. destructor acetyl-CoA carboxylase, Na+/K+ ATPase and endochitinase genes. Results: In treated hives, we observed that the average infestation rate of phoretic Varroa mite was reduced by 33% and 42% relative to control bees fed with sucrose and GFP-dsRNA, respectively. The dsRNA treatment did not affect bee survival, and the beekeepers involved in the project found the method manageable in the apiary and non-intrusive to production activities. Conclusions: Our findings demonstrate the feasibility and effectiveness of RNAi technology in reducing Varroa mite infestations under natural rearing conditions. This study supports the potential of RNAi as a promising alternative to chemical pesticides, offering a targeted, efficient and sustainable solution for managing V. destructor in honey bee populations. [ABSTRACT FROM AUTHOR]

Bees are essential pollinators that contribute to maintaining biodiversity and increasing agricultural production. However, by foraging on agricultural crops, bees may become contaminated with compounds used for pest control. In this study, we exposed bee (Apis mellifera L.) colonies to the insecticide imidacloprid (IMD) under field conditions to assess the occurrence of oxidative stress in larvae and pupae and investigate morphological changes in the fat body and midgut of larvae and midgut of adult bees. The apiary area was divided into three groups: control, commercial formulation containing IMD (Evidence® 700WG) (IMDCF), and IMD active ingredient (Sigma–Aldrich) (IMDAI). Treatment groups were fed syrup containing 1 µg L−1 IMD, whereas the control group was fed syrup only. Compared with the control, larvae exposed to IMDCF or IMDAI for 42 days exhibited morphological changes in the external body, midgut, and fat body. The midgut of adult bees contaminated with IMDCF showed only structural remnants of the peritrophic membrane and absence of regenerative cell nests. Oxidative stress analyses revealed that IMDCF-exposed larvae had higher nitrite and carbonylated protein contents and lower catalase and superoxide dismutase activity than control individuals. In pupae, IMDAI decreased catalase activity while increasing superoxide dismutase activity. These findings indicate that IMD has the potential to significantly impact the development of bees and their colonies by disrupting vital organs responsible for normal physiological functioning and overall activities of individuals. Oxidative stress, which was detected at different stages of bee development, may induce lipid, protein, and DNA oxidation, leading to cell death. [ABSTRACT FROM AUTHOR]

Recently, it has been shown that sugar‑conditioned honey bees can be biased towards a nectarless dioecious crop as kiwifruit. The challenges for an efficient pollination service in this crop species are its nectarless flowers and its short blooming period. It is known that combined non-sugar compounds (NSCs) present in the floral products of different plants, such as caffeine and arginine, enhance olfactory memory retention in honey bees. Additionally, these NSCs presented in combination with scented food improve pollination activity in nectar crops. Here, we evaluated the effect of kiwifruit mimic-scented sugar solution (KM) on colonies located in this crop by supplementing them either with these NSCs individually (KM + CAF, KM + ARG), or combined (KM + MIX). Our results show an increase in colonies' activity after feeding for all treatments. However, the colonies supplemented with the combined mixture (KM + MIX) collected heavier kiwifruit pollen loads and showed an increasing pollen stored area in their hives compared to the KM-treated control colonies. Unexpectedly, the caffeine-treated colonies showed a decrease in the pollen foraging related responses. These results show a combined effect of NSCs that improves honey bee pollen foraging in a nectarless crop, however this activity is impaired when caffeine is used alone for a nectarless crop. [ABSTRACT FROM AUTHOR]

Due to the increase in data rate in mobile communication and the widespread use of mobile internet, electromagnetic communication systems are increasing daily. This situation causes increases in the use of more mobile communication devices and environmental non-ionizing Electromagnetic Field (EMF) levels. The rise of bee deaths and colony losses in beekeeping parallel to the increase of the EMF sources cause the concept of "electromagnetic pollution" to be considered among the reasons. Therefore, studying the effects of non-ionizing Electromagnetic Radiation (EMR) on the health of living things is one of the most significant issues today. The bees determine their direction with the Earth's magnetic field. Electromagnetic signals emitted by GSM base stations, etc. may affect the direction-finding capabilities of honey bees and constitute a stress factor. In this study, the aim was to determine the effect of EMF on honey bees and honey yield. Honey bee colonies were used, obtained from the same farm in the Trabzon region, and equalized in all respects. Moreover, these colonies were divided into five groups randomly as experiments and control groups. The experiment hives were exposed to the EMF in the frequency band of the Wi-Fi signals (2.4 GHz) and the high-voltage line (50 hz). The control hives are located far away from the EMR sources. The study was repeated in the second year to confirm the results. During the investigation, some physiological and behavioural effects of bees, such as aggressiveness, brood area, etc. were determined based on EMR exposure. Plain Language Summary: Studying the effects of non-ionizing Electromagnetic Radiation (EMR) on the health of living things is one of the most significant issues today. In this study, the aim was to determine the effect of EMF on honey bees and honey yield. Honey bee colonies were used, obtained from the same farm in the Trabzon region, and equalized in all respects. During the investigation, some physiological and behavioural effects of bees, such as aggressiveness, brood area, etc. were determined based on EMR exposure. [ABSTRACT FROM AUTHOR]

Simple Summary: Modern agriculture relies mainly on the honey bee for pollination. Therefore, it is crucial to preserve and increase bee populations. Breeding programs have a crucial role, and insemination with frozen semen bypasses many practical limitations. This study evaluates the effectiveness of a simple antibiotic-free freezing protocol by assessing semen viability using two different tools and female brood production. The drop in viability associated with cryopreservation is 37%, and both evaluation tools give similar results. Despite that loss, 5/8 queens inseminated with frozen–thawed semen produced female brood, which is similar to the results obtained with the control group inseminated with fresh semen. This demonstrates that cryopreserved semen following this protocol is capable of egg fertilization. That, in turn, is very promising as this is the first antibiotic-free protocol reported in the literature to prove effective in female brood production. The increasing reliance of modern agriculture on honey bee (Apis mellifera) pollination has driven efforts to preserve and enhance bee populations. The cryopreservation of drone semen presents a promising solution for preserving genetic diversity and supporting breeding programs without live animal transport risks. This study aimed to evaluate a one-step dilution antibiotic-free drone semen slow-freezing protocol under field conditions with in vitro and in vivo parameters. Semen viability was tested by two different mixes of dyes, and both techniques gave similar results, showing a post-thaw viability drop of 37%. Virgin queens were inseminated either with fresh or frozen–thawed semen. Survival rates until egg-laying onset and female brood production were similar for both groups; however, colonies with queens inseminated with fresh semen were more likely to go into wintering. Results suggest that frozen–thawed semen can support viable queen insemination, with potential for female brood production even without antibiotics in the diluent. This study highlights the need for further refinement of cryopreservation protocols, particularly regarding semen quality and queen longevity, to improve the feasibility of cryobanking for Apis mellifera conservation and breeding. [ABSTRACT FROM AUTHOR]

Simple Summary: The nutrition of the honey bee is an important factor essential for maintaining their health. In this study, we examined the impact of supplementary feeding on bees by analyzing the gene expression of antioxidative enzymes and vitellogenin, oxidative stress parameters, and hygienic and grooming behavior. The results of this study indicate that the applied supplement may have a positive effect in reducing oxidative stress and improving hygienic and grooming behavior in honey bees. The honey bee is an important insect pollinator that provides critical pollination services for natural and agricultural systems worldwide. However, inadequate food weakens honey bee colonies, making them vulnerable to various biotic and abiotic factors. In this study, we examined the impact of supplementary feeding on bees' genes for antioxidative enzymes and vitellogenin, oxidative stress parameters, and the hygienic and grooming behavior. The colonies were divided into two experimental groups (with ten hives each): a treatment group that received the plant-based supplement and a control group. The experiment was conducted in two seasons, spring and summer. After the treatment, in both seasons, all the monitored parameters in the treatment group differed from those in the control group. The expression levels of genes for antioxidative enzymes were significantly lower, but the vitellogenin gene transcript level was significantly higher. Values of oxidative stress parameters were significantly lower. The levels of hygienic and grooming behavior were significantly higher. Therefore, our field study indicates that the tested supplement exerted beneficial effects on bees, reflected in reduced oxidative stress and enhanced hygienic and grooming behavior. [ABSTRACT FROM AUTHOR]

Simple Summary: Honey robbing refers to a situation where, during times of food scarcity, worker bees are forced to adopt more aggressive and risky foraging strategies to ensure the survival and reproduction of their own colony. This involves invading other colonies to pillage their food resources. Such behavior poses a serious threat to both bee populations and beekeepers. This review focuses on the morphological and behavioral characteristics of honey robbers and elaborates on the timing, distribution, and causes of honey robbing. The article outlines the various harms caused by honey robbing and proposes effective prevention and control measures accordingly. Furthermore, we summarize the potential obstacles currently facing honey robbing research and lay out feasible paths for future exploration. The aim of this paper is to assist beekeepers in managing their colonies more effectively and thereby promote the sustainable development of the beekeeping industry. Honey robbing, which typically occurs during times of food scarcity, is a perilous foraging strategy for bee colonies and presents a formidable challenge in the realm of beekeeping. This article provides a comprehensive and multifaceted exploration of honey robbing, including the morphology, behavioral traits, timing, and scope of this phenomenon. This exploration elucidates the specific manifestations of honey robbing, offering readers a deeper understanding of its various facets. Next, this article investigates the root causes of honey robbing by examining both abiotic and biotic factors. The resulting harms are outlined, and corresponding preventive and control measures are suggested. Finally, the article succinctly summarizes the current obstacles in research related to honey robbing and outlines promising avenues for future exploration. The objective of this study was to elucidate the occurrence mechanism of honey robbing, ultimately aiming to contribute to the sustainable growth of the beekeeping industry. [ABSTRACT FROM AUTHOR]

The increasing prevalence of monocultures has reduced floral diversity, diminishing pollen diet variety for bees. This study examines the impact of monofloral pollen diets (hazel, rapeseed, pine, buckwheat, Phacelia, goldenrod) on the antioxidant enzyme activities in the fat body from tergite 3, tergite 5, sternite, and hemolymph of honey bees. We show that pollen from plants such as rapeseed, Phacelia, buckwheat, and goldenrod (rich in phenolic compounds and flavonoids) increases the activities of SOD, CAT, GST, and GPx in the fat body and hemolymph compared to the control group. Although it is commonly known that a monodiet is one of the stress factors for bees, the increase in the activities of these enzymes in the hemolymph and fat body of workers fed with pollen candy compared to those fed only sugar candy has a positive (although inconclusive) effect. These activities in the hemolymph and fat body of bees fed with pollen from anemophilous plants are usually lower compared to those in bees fed with candy containing 10% pollen from rapeseed, Phacelia, buckwheat, or goldenrod. Further research is needed to fully understand the complex interactions among monofloral pollen diets, antioxidant enzyme activities, and the overall physiology of honey bees. [ABSTRACT FROM AUTHOR]

Global climate change, intensive agriculture, and anthropogenic pollution adversely affect flowering plants and the vitality of bee colonies. In nutritional stress conditions, bees deplete the food reserves of their fat body to sustain colony life. Beekeepers play a critical role by providing supplemental nutrient solutions. This study examines the effects of various sugar syrups on the fat body development of worker bees (Apis mellifera macedonica). The colonies were divided into one control group and five experimental groups: one fed with 1:1 sugar/water syrup, one with 2:1 sugar/water syrup, one with inverted syrup (Apiinvert), one with HFCS (high-fructose corn syrup) (Isosweet), and one with 1:1 honey/water syrup. Fat body development was assessed through meticulous dissection, and the degrees of development were documented using a USB digital microscope (Bresser). The results indicate significant seasonal variations in fat body development, with winter depletion and recovery influenced by supplemental feeding. Apiinvert and honey/water syrup promoted higher fat body stages, while Isosweet led to elevated fifth degrees of development but raised concerns about potential toxicity due to the hydroxymethylfurfural (HMF) formation of improperly stored syrups. This study concludes that adequate supplemental feeding with easily digestible sugars is critical for promoting fat body development, enhancing winter survival, and ensuring overall colony health. These findings provide practical guidance for beekeepers to optimize feeding strategies and support resilient bee colonies. [ABSTRACT FROM AUTHOR]

BACKGROUND: The acaricide amitraz is now used intensively in many regions to control the honey bee parasite, Varroa destructor, because of the reduced efficacy of pyrethroids and coumaphos caused by resistance evolution. The continued application of amitraz in recent years exerts a very high selection pressure on mites, favouring the evolution of resistance to this acaricide. Mutations N87S and Y215H in the β2‐adrenergic‐like octopamine receptor (Octβ2R), target site of amitraz, have been already associated with resistance to amitraz in France and the USA, respectively. RESULTS: A new mutation (F290L) in the Octβ2R of V. destructor has been found in mites from Spanish apiaries. The frequency of L290 mutated alleles in colonies increased after consecutive treatments with amitraz. In a field trial, mites from colonies with higher frequency of L290 mutated allele took longer to die compared with those carrying a higher proportion of the wild‐type allele. Lower susceptibility to amitraz was found in apiaries with a high frequency of homozygous mutants. CONCLUSION: Our data indicate the association of the F290L mutation in the octopamine receptor with resistance to amitraz in Spanish populations of V. destructor. Determining the frequency of mutant mites in apiaries may be important for predicting the efficacy of amitraz treatment in the field and would help design appropriate resistance management. © 2024 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Abstract Bees are essential pollinators that contribute to maintaining biodiversity and increasing agricultural production. However, by foraging on agricultural crops, bees may become contaminated with compounds used for pest control. In this study, we exposed bee (Apis mellifera L.) colonies to the insecticide imidacloprid (IMD) under field conditions to assess the occurrence of oxidative stress in larvae and pupae and investigate morphological changes in the fat body and midgut of larvae and midgut of adult bees. The apiary area was divided into three groups: control, commercial formulation containing IMD (Evidence® 700WG) (IMDCF), and IMD active ingredient (Sigma–Aldrich) (IMDAI). Treatment groups were fed syrup containing 1 µg L−1 IMD, whereas the control group was fed syrup only. Compared with the control, larvae exposed to IMDCF or IMDAI for 42 days exhibited morphological changes in the external body, midgut, and fat body. The midgut of adult bees contaminated with IMDCF showed only structural remnants of the peritrophic membrane and absence of regenerative cell nests. Oxidative stress analyses revealed that IMDCF-exposed larvae had higher nitrite and carbonylated protein contents and lower catalase and superoxide dismutase activity than control individuals. In pupae, IMDAI decreased catalase activity while increasing superoxide dismutase activity. These findings indicate that IMD has the potential to significantly impact the development of bees and their colonies by disrupting vital organs responsible for normal physiological functioning and overall activities of individuals. Oxidative stress, which was detected at different stages of bee development, may induce lipid, protein, and DNA oxidation, leading to cell death. Graphical Abstract

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.

Pollen satisfies the nutritional requirements for developing honey bees, and without pollen, there is no brood development. Beekeepers feed colonies pollen substitutes or pollen supplements to stimulate brood rearing in the winter and early spring, or when pollen from blooming plants is scarce. The performance of honey bee colonies has been enhanced by supplementation with pollen substitutes. The current study aimed to evaluate the efficiency of three pollen substitutes in maintaining the colony strength during winter and improvement of colony performance during the winter and spring seasons. The three diets consisted of 30 g peeled white lupine flour + 20 g brewer's yeast + 20 g casein milk powder + 20 g honey + 10 g sugar powder (diet 1), 30 g fenugreek flour + 20 g brewer's yeast + 20 g casein milk powder + 20 g honey + 10 g sugar powder (diet 2), and 30 g defatted soybean flour + 20 g brewer's yeast + 20 g casein milk powder + 20 g honey + 10 g sugar powder (diet 3), and were provided to the experimental colonies in a paste form and compared with the unfed colonies. Diet 1 was the most accepted and consumed diet by honey bee workers during the winter and spring seasons. Colonies fed on diet 1 stored pollen, reared worker brood, and had adult population sizes larger than colonies fed on diet 2, diet 3, and unfed colonies. Colonies fed on diet 1, diet 2, and diet 3 produced more honey than the unfed colonies by 125.00%, 95.00%, and 70.00%, respectively. Diet 1 could be recommended to feed honey bee colonies during winter and spring to sustain the strength of the colonies and improve their productivity. [ABSTRACT FROM AUTHOR]

Honey bees rely on haplodiploidy for sex determination. Here, diploid eggs develop into females (i.e., queens and workers) and haploid eggs develop into males (i.e., drones). This system is regulated by complementary sex-determiner (csd)—a single, multi-allelic locus with very high diversity. Honey bees heterozygous at the csd locus will develop into females, while hemizygosity results in normal male development. Homozygosity at csd results in abnormal diploid males. Diploid males are usually destroyed by the workers early in development which can negatively impact the colony population, growth, and productivity. As such, maintaining genetic diversity at csd is critical for the health and productivity of honey bee populations. This is reflected in the increasing number of studies examining csd diversity in local and global populations. However, many csd alleles appear in multiple studies and have been assigned several different names, complicating cross-study comparisons. In 2020, we developed a standardized nomenclature for the hypervariable region (HVR) of honey bee csd alleles to facilitate a better understanding of csd diversity within and between populations. Here, we present an updated database including all csd sequences deposited into GenBank since our last publication. In only the last 4 years, 370 new csd sequences were deposited, including 154 novel HVR sequences. [ABSTRACT FROM AUTHOR]

Identification of the honey bee (Apis mellifera) subspecies is an important aspect of bee breeding and biodiversity conservation. The identification can be based on molecular or morphological markers. For some markers, including the cytochrome c oxidase subunit, there is a well-established methodology allowing consistent subspecies identification in different laboratories. In the case of morphological markers, identification is hindered by a lack of reference data and a standardized methodology to reuse it. There is the Morphometric Bee Data Bank in Oberursel, Germany, which provides reliable reference data for many honey bee subspecies; however, it must be expanded and updated. Moreover, there is a need for standardized protocols that allow reliable identification of unknown samples. We show here that reference data for the identification of honey bees based on geometric morphometrics can be saved in an XML file. The information in this file can be easily extracted by other users for the identification of unknown samples. We illustrate this procedure using ten samples from north India. The samples were identified as A. mellifera; next, they were identified as lineage C; and finally, most of the samples had high similarity to honey bees from Croatia and Slovenia. We explained what data is required for such identification and how it can be reused. The method described here works correctly only if the identified species or subspecies is well represented in the reference samples. Without reference data from America, we could not confirm the importation of honey bees to India from this region.

The greater wax moth Galleria mellonella (Linnaeus, 1758), is one of the principal pests in the honeycomb of the European bee Apis mellifera Linnaeus, 1758, around the world. In this experiment, the complete biological cycle of G. mellonella was determined for the first time in Panama, achieving an incubation period of 4 to 10 days with an average of 7.16 ± 1.42. The larvae went through eight larval instars with a total larval duration of ±38.63 days. The pupa period was 9.22 ± 1.40 days. The average daily oviposition varied from a maximum of 182 to a minimum of 1.8 eggs, and the maximum life span of the adult was eight days. The number of eggs hatched was 1,503 in 10 evaluation days; on day 7, the most hatching occurred with 410 newly emerged larvae. The temperature and relative humidity averages were 28 °C and 76%, respectively, and varied from 25-33 °C to 58%-86% during the evaluation period. The life cycles of females and males were similar, of 39.00 and 39.53 days, respectively. The artificial diet used in this study guaranteed the successful completion of the larval stage in the life cycle of this wax moth.