Worker Honeybees Research Articles

Honey Bee Exposure to the Fungicide Propiconazole in Lowbush Blueberry Fields

The fungicide propiconazole is a commonly used fungicide in small fruit and tree fruit production in the U.S.A. In Maine wild blueberry production, it is used almost exclusively for mummy berry disease control. The goal of this study is to assess the risk of exposure to honey bee colonies deployed in wild blueberry fields for pollination. The study was conducted over a six-year period (2009–2014) in both the field and laboratory. Field surveys (2009–2011) measured the residues on blueberry flowers in 41 commercial fields across the blueberry growing region. A two-year study (2010–2011) determined the decay rate of propiconazole in blueberry fields after application. A laboratory study determined the contact LD50 of propiconazole to honey bee workers (2013). A field exposure/effect study was conducted over three years (2011–2013). In this study, 8–18 previously unexposed colonies were randomly assigned to one of two treatments, (1) isolated fields that were treated prior to bloom with the fungicide, propiconazole, but no other pesticides, or (2) isolated fields that were not treated with propiconazole or any other pesticides. The measures taken to evaluate effects of exposure monitored each year were (1) estimation of the exposure to colonies, measured as residues on flowers, workers, and in pollen brought back to hives; (2) colony population size (workers and brood); (3) queen status and presence; (4) queen oviposition rate; (5) supersedure rate; (6) egg hatch success; (7) mortality of developing larvae and pupae; (8) royal jelly deposition in wax comb cells; (9) worker longevity; (10) foraging activity; (11) treated bloom repellency to foragers; (12) colony overwintering success; (13) worker hypopharyngeal gland acini size; and (14) pathogen and parasite incidence and intensity. The results of these experiments and surveys showed that the propiconazole contact LD50 was 24,747 ppb. Residues of propiconazole were found to be commonly abundant on flowers in treated commercial fields after application with a mean concentration of 2083.8 ± 851.3 (se). The decay of propiconazole to non-detectable levels took about 40 days after application. The three-year hive deployment study showed that residues in treated fields were detected on flowers, pollen, and worker bees, demonstrating that exposure to this fungicide occurs even though it is applied before bloom. Also in the hive deployment study, evidence of reduced colony populations, increased supersedure, decreased queen oviposition rate, increased pathogen or parasite incidence and intensity, and increased overwintering colony loss due to propiconazole exposure was not found. However, propiconazole exposed colonies exhibited reduced worker longevity (17.3%), hypertrophy of 5 d old nurse bee hypopharyngeal acini (8.3%), and a 3.5 h repellency of foragers to treated bloom.

Joint toxic effects of thiamethoxam and flusilazole on the adult worker honey bees (Apis mellifera L.)

Insect pollinators are routinely exposed to a complex mixture of many pesticides. However, traditional environmental risk assessment is only carried out based on ecotoxicological data of single substances. In this context, we aimed to explore the potential effects when worker honey bees (Apis mellifera L.) were simultaneously challenged by thiamethoxam (TMX) and flusilazole (FSZ). Results displayed that TMX possessed higher toxicity to A. mellifera (96-h LC50 value of 0.11 mg a. i. L−1) than FSZ (96-h LC50 value of 738 mg a. i. L−1). Furthermore, the mixture of TMX and FSZ exhibited an acute synergistic impact on the pollinators. Meanwhile, the activities of SOD, caspase 3, caspase 9, and PPO, as well as the expressions of six genes (abaecin, dorsal-2, defensin-2, vtg, caspase-1, and CYP6AS14) associated with oxidative stress, immune response, lifespan, cell apoptosis, and detoxification metabolism were noteworthily varied in the individual and mixture challenges than at the baseline level. These data revealed that it is imminently essential to investigate the combined toxicity of pesticides since the toxicity evaluation from individual compounds toward honey bees may underestimate the toxicity in realistic conditions. Overall, the present results could help understand the potential contribution of pesticide mixtures to the decline of bee populations.

Fine-scale assessment of Chlorella syrup as a nutritional supplement for honey bee colonies

Habitat loss, climate change, and global agriculture have a non-negligible effect on the reduced abundance and diversity of floral resources. Malnutrition and nutritional stress are consequences of the combination of these factors with considerable impact on honey bee health and colony losses. The solution to inadequate natural sources for beekeeping is the additional feeding of honey bee colonies with food supplements. The algae Chlorella is a natural food source, with a nutrient profile similar to natural pollen, thus it has promising application in beekeeping. We evaluated Chlorella vulgaris syrup as a dietary supplement in the view of the oxidative stress that may be caused by long term administration to the colonies. Consuming Chlorella syrup did not influence the activity of digestive enzymes of summer honey bee workers, however, lipase activity insignificantly increased. After Chlorella application to colonies, we also observed insignificantly higher gene expression of antioxidant enzymes catalase and superoxid dismutase1 in adult workers; however, in larvae the expression of those genes was not affected. Surprisingly, the gene expression did not correspond with enzyme activity in adult bee abdomens. In Chlorella fed colonies, we recorded a higher concentration of vitellogenin, which plays multiple roles in honey bee physiology, i.e., antioxidant, storage protein, or immunity-related functions. Our new findings brought evidence that Chlorella did not negatively affect the digestion or oxidative balance of honey bees, thus its application as a pollen supplement can be fully recommended for maintaining the health of honey bee colonies during periods of dearth.

Effect of some bee bread quality on protein content and antioxidant system of honeybee workers

Protein content and antioxidants in both bee bread and honeybee workers were analyzed investigating the relationships between those two parameters. Results indicated significant differences between both protein and antioxidant content [total antioxidant content (TAX), glutathione (GSH) and lipid peroxidation (LPO) levels] of bee bread types. Generally, workers fed sugar syrup only (control) had significantly lower protein content, superoxide dismutase (SOD), catalase (CAT), and GSH in comparison to bees fed bee bread at all studied ages. On the other hand, LPO levels in control worker bees were significantly higher than those of bees fed fennel, maize, cucumber, clover, and broad bean bee bread. Results also showed a positive relationship between protein content and antioxidants in bee bread and between protein content and the antioxidant system of honeybees, respectively. There was a negative correlation between protein content and antioxidants. In addition, the present study showed that both the protein quantity and quality of bee bread are important for honeybees. To our knowledge, this study is the first to report the relationship between antioxidant content in bee bread and antioxidant system of honeybees. The present study showed a causal link between antioxidant system and protein content in honeybees, and the contents of both antioxidants and protein in bee bread.

Major royal jelly proteins influence the neurobiological regulation of the division of labor among honey bee workers

Age-based division of labor among workers is a fundamental life-history trait of many social insects, including the Western honey bee, Apis mellifera L. Extensive studies of the causation of the most pronounced transition from performing tasks in the nest to outside foraging indicate hormonal regulation of complex physiological changes. However, the proximate neurobiological mechanisms that cause the behavioral repertoire to change are still not understood and require novel approaches to be fully characterized. Thus, we established the first comprehensive monoclonal antibody microarray in honey bees with 16,320 antibodies to directly identify proteins in the brain that regulate the transition to foraging. Major royal jelly protein (MRJP) 1 and MRJP3 were identified as potential protein effectors and further investigated. A series of experimental manipulations of the workers' behavioral transition led to changes in MRJP1 and MRJP3 quantities in accordance with their presumed functional role. Injection of MRJPs into the brain resulted in increased task-reversal from foraging to nursing and decreased task-progression from nursing to foraging, while the latter was increased by injection with MRJP antibodies. Finally, down-regulation of MRJP1 and MRJP3 expression via RNAi injection into the brain increased the transition from in-hive nursing to outside foraging, confirming a causal role of these two proteins in the proximate regulation of behavior and life-history of honey bee workers. Interaction partners of MRJP1 and MRJP3 in the honey bee brain included other regulators of honey bee behavior and life history. Thus, our transformative methodological advancement of proteome analysis in honey bees reveals novel regulators of honey bee behavior, extends our understanding of the functional pleiotropy of MRJPs, and supports a general nutrition-based model of the regulation of the age-based division of labor in honey bees.

Comparative proteomics analysis of the head proteins of worker honey bees (Apis mellifera) in production stage of royal jelly

Honey bees can be evaluated to study their economic, developmental and immunity aspects. Apis mellifera has important organs such as the hypopharyngeal gland, mandibular gland and brain in their heads. The hypopharyngeal glands and mandibular glands cooperate to produce royal jelly essential in feeding queen honey bees and broods. Moreover, the brain is an organ that regulates the social behaviors of honey bees such as memory and learning. Therefore, this study aimed to detect differential head protein changes in one-day-old and nine-day-old worker honey bees. 153 repeatable protein spots were identified using Melanie software and statistically analyzed. Of the total protein spots, 27 responsive spots were identified using MALDI TOF-TOF mass spectrometry, of which 14 and 8 spots showed up and down regulation, respectively and five spots were expressed just in the head capsules of nine-day-old workers. All identified proteins were divided into 16 different groups involved in various growth-related processes as well as royal jelly augmentation. Nine proteins including KMT5B, TGIF2LX, Protein mono-ADP-ribosyltransferase PARP12, TCL1B4, maph-9, Vimentin-type intermediate filament-associated coiled-coil protein, HSP68, tetratricopeptide repeat domain 36 and POC1B were also identified and introduced for the first time in A. mellifera. This study provides valuable information on proteins involved in honey bee head growth and development as well as increasing royal jelly production.

Retraction: Queen cells acceptance rate and royal jelly production in worker honey bees of two Apis mellifera races.

Retraction: Queen cells acceptance rate and royal jelly production in worker honey bees of two Apis mellifera races.

Does diatomaceous earth (DE) cause mortality on Apis mellifera and Bombus terrestris?

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.

Honeybee-associated lactic acid bacteria and their probiotic potential for human use.

This study aims to identify lactic acid bacteria (LAB) isolated from honeybees (Apis mellifera workers and larvae) in detail and to determine their functional probiotic properties. A total of 11 strains were classified based on morphological and biochemical characteristics. Preliminary probiotic properties of strains, that were molecularly identified using 16S rRNA, such as antimicrobial activity, tolerance to digestive conditions, aggregation ability, were investigated. The antimicrobial properties of strains were tested against a wide range of human pathogens. All strains that showed γ-hemolysis and did not contain bacteriophages were considered safe. The strains' survivability checked for 0.3% bile and 3.0-7.8 pH contents was promising. The highest autoaggregation ranged from 14.7 to 30.76% after 4h. Tested LAB strains markedly exhibited coaggregation with Listeria monocytogenes and Escherichia coli. According to the results, tested bacteria showed significant antagonistic effects against pathogens, and positive probiotic characteristics compatible with in vitro gastrointestinal tract conditions. The results suggest that Apis mellifera LAB symbionts may have a probiotic potential, and be effective and safe candidates for human use. This study provides an addition to the development of the current knowledge by defining in detail honeybee-associated bacteria and determining their probiotic potential.

The negative effect of flumethrin stress on honey bee (Apis mellifera) worker from larvae to adults

Flumethrin is a highly effective acaricide, but its lipophilic characteristic has some negative effects, such as accumulation in bee hives and bee products. However, studies on the survival stress of honey bees subsequent to chronic flumethrin exposure are limited. To answer this question, a study was carried out on the stress to honey bee (Apis mellifera) workers from larvae to adults by chronic exposure to sublethal concentrations of flumethrin. Three flumethrin treatment groups (1, 0.1, 0.01 mg/L) and one control group (with no added flumethrin) were established and divided the worker larvae into four groups. Then, starting with 2-day-old larvae, larvae and subsequent emerged worker bees of the four groups were orally fed with the corresponding concentrations of flumethrin until all the adult worker bees died, respectively. When the concentration was at 0.01 mg/L of flumethrin, the lifespan of adult worker bees decreased, and a down-regulation of detoxification-related genes (CYP450,GSTS) was induced in 1-day-old pupae. When it is at 0.1 mg/L flumethrin, the lifespan of adult worker bees was again shortened, and down-regulation of memory-related genes (GluRA1, Nmdar1, Tyr1) in 1-day-old pupae and gene Tyr1 in 1-day-old worker bees, detoxification-related genes (CYP450,GSTS) in 1-day-old pupae, and immunity genes (Defensin1, Hymenoptaecin) in 7-day-old worker bees were observed. When the concentration is at 1 mg/L flumethrin, lighter birth weight of newly emerged honeybee was found and deficiencies in olfactory learning and memory were observed in 7-day-old worker bees. Memory-related genes (GluRA1, Nmdar1, Tyr1) were down-regulated in 1-day-old pupae and genes (Nmdar1,Tyr1)in 1-day-old worker bees, as were detoxification-related genes (CYP450,GSTS) in 1-day-old pupae and gene CPY450 in 7-day-old worker bees, and immune genes (Defensin1, Hymenoptaecin) in 7-day-old worker bees. There was no significant difference in pupal weight, capping rate, emergence rate, expression of immune-related genes of 1-day-old pupae, expression of immune-related genes and detoxification-related genes of 1-day-old worker bees, expression of memory-related genes and detoxification-related gene GSTS of 7-day-old worker bees. These data provide an ominous warning about the unintended consequences on apiaries, and underscore the need for careful control of flumethrin residues in bee hives.

Toxic evaluation of Proclaim Fit® on adult and larval worker honey bees.

Impacts to honey bees due to exposure to agricultural pesticides is one of the most serious threats to the beekeeping industry. Our research evaluated toxicity of the formulated insecticides Lufenuron+Emamectin benzoate (Proclaim Fit®) on the European honey bee Apis mellifera L. at field-realistic concentration (worst-case scenario). Newly emerged (≤24-h old) and forager (unknown age) worker bees were treated with the field recommended concentration of Proclaim Fit® using three routes of exposure including residual contact, oral, and spray within the laboratory. We also assessed the effects of Proclaim Fit® on the specific activity of some well-known detoxifying enzymes including α-esterase, β-esterase, and Glutathione S-transferase (GST) in the honey bees. In addition, toxicity of the formulation was tested on 4th instar larvae within the hive. Based on estimated median survival times (MSTs), Proclaim Fit® was highly toxic to the bees, especially when applied as spray. According to our estimated relative median potency (RMP) values, newly emerged bees were 1.72× more susceptible than foragers to Proclaim Fit® applied orally. Enzyme assays revealed the considerable involvement of the enzymes, especially GST and α-esterase, in detoxification of the Proclaim Fit®, but their activities were significantly influenced by route of exposure and age of bee. Notably, Proclaim Fit® was highly toxic to 4th instar honey bee larvae. Our results generally indicate a potent toxicity of Proclaim Fit® toward honey bees. Therefore, its application requires serious consideration and adherence to strict guidelines, especially during the flowering time of crops.

Differential resistance across paternal genotypes of honey bee brood to the pathogenic bacteriumMelissococcus plutonius

AbstractMelissococcus plutoniusis a pathogenic bacterium affecting immature stages of the western honey bee (Apis mellifera) and leads to European foulbrood (EFB) disease. Despite EFB outbreaks increasing in frequency in several countries in recent decades, there is little knowledge on the epidemiology ofM. plutoniusor on the defence mechanisms of honey bees against this pathogen. Mating of honey bee queens with multiple males (polyandry) can be such a mechanism, as it has been shown to be beneficial to colony health and fitness. It is hypothesized that a high level of polyandry was selected for in response to pathogen pressure to maximize the probability that at least some patrilines among nestmates in a colony possess a high degree of resistance to specific pathogens, ultimately protecting colonies against infections. We show thatM. plutoniusinfection provokes differential mortality among patrilines of immature honey bee workers. Such differences indicate a genetic origin of resistance against this pathogen—supporting the polyandry hypothesis—and open up avenues to improve control of EFB disease via selective breeding.

CircRNA-regulated immune responses of asian honey bee workers to microsporidian infection.

Nosema ceranae is a widespread fungal parasite for honey bees, causing bee nosemosis. Based on deep sequencing and bioinformatics, identification of circular RNAs (circRNAs) in Apis cerana workers’ midguts and circRNA-regulated immune response of host to N. ceranae invasion were conducted in this current work, followed by molecular verification of back-splicing sites and expression trends of circRNAs. Here, 10185 and 7405 circRNAs were identified in the midguts of workers at 7 days (AcT1) and 10 days (AcT2) post inoculation days post-inoculation with N. ceranae. PCR amplification result verified the back-splicing sites within three specific circRNAs (novel_circ_005123, novel_circ_007177, and novel_circ_015140) expressed in N. ceranae-inoculated midgut. In combination with transcriptome data from corresponding un-inoculated midguts (AcCK1 and AcCK2), 2266 circRNAs were found to be shared by the aforementioned four groups, whereas the numbers of specific ones were 2618, 1917, 5691, and 3723 respectively. Further, 83 52) differentially expressed circRNAs (DEcircRNAs) were identified in AcCK1 vs. AcT1 (AcCK2 vs. AcT2) comparison group. Source genes of DEcircRNAs in workers’ midgut at seven dpi were involved in two cellular immune-related pathways such as endocytosis and ubiquitin mediated proteolysis. Additionally, competing endogenous RNA (ceRNA) network analysis showed that 23 13) DEcircRNAs in AcCK1 vs. AcT1 (AcCK2 vs. AcT2) comparison group could target 18 14) miRNAs and further link to 1111 (1093) mRNAs. These target mRNAs were annotated to six cellular immunity pathways including endocytosis, lysosome, phagosome, ubiquitin mediated proteolysis, metabolism of xenobiotics by cytochrome P450, and insect hormone biosynthesis. Moreover, 284 164) internal ribosome entry site and 54 26) ORFs were identified from DEcircRNAs in AcCK1 vs. AcT1 (AcCK2 vs. AcT2) comparison group; additionally, ORFs in DEcircRNAs in midgut at seven dpi with N. ceranae were associated with several cellular immune pathways including endocytosis and ubiquitin-mediated proteolysis. Ultimately, RT-qPCR results showed that the expression trends of six DEcircRNAs were consistent with those in transcriptome data. These results demonstrated that N. ceranae altered the expression pattern of circRNAs in A. c. cerana workers’ midguts, and DEcircRNAs were likely to regulate host cellular and humoral immune response to microsporidian infection. Our findings lay a foundation for clarifying the mechanism underlying host immune response to N. ceranae infection and provide a new insight into interaction between Asian honey bee and microsporidian.

Diet and pheromones interact to shape honey bee (Apis mellifera) worker physiology

Honey bee colony health is a function of the individuals, their interactions, and the environment. A major goal of honey bee research is to understand how colonies respond to stress. Individual-level studies of the bee stress response are tractable, but their results do not always translate to the colony level. Nutritional stress is an important factor in colony declines. Nutrition studies are typically conducted on individual nurse workers (nurses), who are primarily responsible for converting pollen into brood. Nurse physiology is sensitive to both pollen and pheromones, which communicate signals among colony members. Here, we asked whether pheromones influence nurse nutrient pathways involved in brood care, and whether diet influences colony communication. We exposed caged, nurse-aged workers to different combinations of pheromones and pollen, and measured traits related to brood care. We found that pheromones enhanced pollen-dependent processes such as hypopharyngeal gland growth and mrjp1 expression, and buffered the negative effects of starvation. Pollen also enhanced how nurse phenotypes respond to pheromones. Therefore, diet and pheromones interact to influence nurse nutritional physiology and aspects of brood care. These findings have implications for studying colony function and health in an increasingly stressful climate.

Honeybee age and inoculum concentration as factors affecting the development of Nosema ceranae infection

Nosemosis is one of the most widespread honeybee diseases. Its epidemical state can be determined as panzootic. The infectious agents are the microsporidia Nosema apis and N. ceranae. Numerous substances and preparations were tested in order to find a way to combat this disease. However, methodology used in artificial infection experiments is not unique; concentrations of N. ceranae spores in inoculum vary as well as the age of honey bees when they are infected. In addition, the disease itself is still relatively poorly understood. This makes the interpretation of such research difficult. The aim of this study is to investigate the effect of bee age and inoculum concentration on the development of N. ceranae infection. Honeybee workers were collectively infected at the age of 2 and 10 days post-emergence with concentrations of 104, 5 × 104, and 105 spores/bee. While the results indicate a significant effect of both tested factors on the development of N. ceranae, the relationship is not simple, and age alters the pattern of nosemosis development in response to the given concentrations.

A Comparative Assessment of Hygienic Behavior of Carniolan (Apismelliferacarnica Pollmann) and Yemeni (Apismellifera jemenitica Ruttner) Honeybees Using Infra-Red Photography Video Recording

The use of infra-red photography video recording is very useful for conducting behavioristic studies of honeybees against many brood diseases. The removal of dead or diseased brood from capped cells by honeybee workers is a heritable trait that confers colony-level resistance. This work aimed to compare the hygienic behavior of the native (Yemeni bees, A. mellifera jemenitica) and the exotic (Carniolan bees, A. m. carnica) honeybee races in Saudi Arabia using an infra-red photography video recording. In addition, hygienic behavior towards the related and non-related combs was examined. Therefore, it is possible to obtain honeybee colonies with greater disease resistance. The pin-killing method and infra-red photography video recording were used for the evaluation of hygienic behavior in colonies of the two races. Significant differences in hygienic behavior between the two races were detected at the beginning of the experiment. Under the environmental conditions of eastern Saudi Arabia, the Yemeni honeybee colonies showed a higher number of uncapped and cleaned cells containing dead brood in either the brood comb from the same colony, or the brood comb from the same race but a different colony, or brood comb from a different race. It was concluded that the honeybee’s ability to detect and clean the dead brood from comb cells can be correlated with race and it is more efficient for the non-related individuals of the same race than from a related or another race. The outstanding performance of a few individuals in the expression of various traits indicates their usefulness in carrying out breeding programs for Varroa resistance.

Evaluation of the Biological Activities of Royal Jelly on Prostate and Breast Cancer Cells

Due to their high toxicity to healthy body cells, chemotherapy drugs used to treat cancer pose a serious threat to the organism. Recent studies have encouraged the utilization of bee products to prevent and treat the cancer. The specific food for the queen honeybee larva (Apis mellifera), royal jelly (RJ) is a yellow, milky, cremy product of the bee which is stowed from the mandibular and hypopharyngeal glands of the worker honeybee. According to the reports, RJ may have cytotoxic effects in animal models. However, RJ's cytotoxic and antioxidant properties on PC-3 prostate cancer and MCF-7 breast cancer cell lines have yet to be thoroughly investigated at the cellular level. Therefore, the antioxidant and anti-proliferative activities of RJ in PC-3 prostate cancer cells and MCF-7 breast cancer cells were evaluated to investigate a chemopreventive strategy to increase cancer therapy efficacy. WST-1 assay was used to measure cell proliferation, and levels of reactive oxygen species (ROS) and lipid peroxidation (LPO) were analyzed to look at antioxidant activities. According to the data of this research, RJ act as prooxidants in PC-3 and MCF-7 cancer cell lines by lessening cellular viability and raising ROS and LPO formation.

Revealing phosphorylation regulatory networks during embryogenesis of honey bee worker and drone (Apis mellifera).

Protein phosphorylation is known to regulate a comprehensive scenario of critical cellular processes. However, phosphorylation-mediated regulatory networks in honey bee embryogenesis are mainly unknown. We identified 6342 phosphosites from 2438 phosphoproteins and predicted 168 kinases in the honey bee embryo. Generally, the worker and drone develop similar phosphoproteome architectures and major phosphorylation events during embryogenesis. In 24 h embryos, protein kinases A play vital roles in regulating cell proliferation and blastoderm formation. At 48–72 h, kinase subfamily dual-specificity tyrosine-regulated kinase, cyclin-dependent kinase (CDK), and induced pathways related to protein synthesis and morphogenesis suggest the centrality to enhance the germ layer development, organogenesis, and dorsal closure. Notably, workers and drones formulated distinct phosphoproteome signatures. For 24 h embryos, the highly phosphorylated serine/threonine-protein kinase minibrain, microtubule-associated serine/threonine-protein kinase 2 (MAST2), and phosphorylation of mitogen-activated protein kinase 3 (MAPK3) at Thr564 in workers, are likely to regulate the late onset of cell proliferation; in contrast, drone embryos enhanced the expression of CDK12, MAPK3, and MAST2 to promote the massive synthesis of proteins and cytoskeleton. In 48 h, the induced serine/threonine-protein kinase and CDK12 in worker embryos signify their roles in the construction of embryonic tissues and organs; however, the highly activated kinases CDK1, raf homolog serine/threonine-protein kinase, and MAST2 in drone embryos may drive the large-scale establishment of tissues and organs. In 72 h, the activated pathways and kinases associated with cell growth and tissue differentiation in worker embryos may promote the configuration of rudimentary organs. However, kinases implicated in cytoskeleton organization in drone embryos may drive the blastokinesis and dorsal closure. Our hitherto most comprehensive phosphoproteome offers a valuable resource for signaling research on phosphorylation dynamics in honey bee embryos.

Increased Stress Levels in Caged Honeybee (Apis mellifera) (Hymenoptera: Apidae) Workers

Honeybees, Apis mellifera, usually live in large colonies consisting of thousands of individuals. Within the colony, workers interact with their social environment frequently. The large workforce, division of labour, and other features may promote the ecological success of honeybees. For decades, artificial mini colonies in cages within the laboratory have become the gold standard, especially in experiments related to toxicology, effects of pesticides and pathogens. Experiments using caged bees and full-sized colonies yielded contradictory results. Here, the effect of cage experiments on the stress level of individual bees is analysed. Two different stress response were targeted, the heat shock response and the mobilization of energetic resources. While no differences were found for varying group sizes of bees, very strong effects emerged by comparing caged workers with bees from natural colonies. Caged workers showed increased levels of hsp expression and reduced haemolymph titres for trehalose, the energy storage sugar. These results reveal that the lack of the social environment (e.g., lack of queen, lack of sufficient group size) induce stress in caged bees, which might act synergistically when bees are challenged by additional stressors (e.g., pesticides, pathogens) resulting in higher mortality than observed under field conditions.

Insecticide and fungicide effect on thermal and olfactory behavior of bees and their disappearance in bees’ tissues

Plant protection products may affect the behavior of organisms which are not a target of control. The effect of Karate Zeon 050 CS (λ-Cyhalothrin -based insecticide; λ-CBI) and Amistar 250 SC (Azoxystrobin-based fungicide; ABF) was determined on Apis mellifera worker attraction towards their own colony odour, along with temperature preferences. Bees exposed to pesticides prefer the environment with the odour of their nest less often than the control group, and that insecticide-treated bees chose warmer environments than the control insects. The observed differences in the bees, especially with attraction towards their own colony, were dependent on the time of day. Chromatographic analyses indicated that λ-Cyhalothrin elimination was half that of Azoxystrobin in bee organisms, and both agents retarded each other’s clearance. Mathematical modeling estimated that despite a relatively high disappearance rate, both compounds might have been bio-accumulated at relatively high level.