Tropilaelaps mercedesae parasitism changes behavior and gene expression in honey bee workers

Tropilaelaps mercedesae is one of the most problematic honey bee parasites and has become more threatening to the beekeeping industry. Tropilaelaps can easily parasitize immature honey bees (larvae and pupae) and have both lethal and sublethal effects on the individual worker bees. Our study for the first time experimentally assessed the effects of T. mercedesae on olfactory learning, flight ability, homing ability as well as transcriptional changes in parasitized adult honey bees. T. mercedesae infestation had negative impacts on olfactory associated function, flight ability, and homing rate. The volume of the mushroom body significantly increased in infested honey bees, which may be correlated to the lower sucrose responsiveness as well as lower learning ability in the infested bees. The gene expression involved in immune systems and carbohydrate transport and metabolism were significantly different between infested bees and non-infested bees. Moreover, genes function in cell adhesion play an essential role in olfactory sensory in honey bees. Our findings provide a comprehensive understanding of European honey bees in response to T. mercedesae infestation, and could be used to further investigate the complex molecular mechanisms in honey bees under parasitic stress.

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Multi-tiered Analyses of Honey Bees That Resist or Succumb to Parasitic Mites and Viruses

10.21203/rs.3.rs-291062/v1 ◽

2021 ◽

Author(s):

Daniel B. Weaver ◽

Brandi L. Cantarel ◽

Christine Elsik ◽

Dawn L. Lopez ◽

Jay Evans

Keyword(s):

Gene Expression ◽

Honey Bee ◽

Honey Bees ◽

Host Responses ◽

Negative Effects ◽

Pollination Services ◽

Deformed Wing Virus ◽

Mortality And Morbidity ◽

The Individual ◽

Parasitic Mites

Abstract Background Varroa destructor mites, and the numerous viruses they vector to their honey bee hosts, are among the most serious threats to honey bee populations, causing mortality and morbidity to both the individual honey bee and colony, the negative effects of which convey to the pollination services provided by honey bees worldwide. Here we use a combination of targeted assays and deep RNA sequencing to determine host and microbial changes in resistant and susceptible honey bee lineages. We focus on three study sets. The first involves field sampling of sympatric western bees, some derived from resistant stock and some from stock susceptible to mites. The second experiment contrasts three colonies more deeply, two from susceptible stock from the southeastern U.S. and one from mite-resistant bee stock from Eastern Texas. Finally, to decouple the effects of mites from those of the viruses they vector, we experimentally expose honey bees to DWV in the laboratory, measuring viral growth and host responses. Results We find strong differences between resistant and susceptible bees in terms of both viral loads and bee gene expression. Interestingly, lineages of bees with naturally low levels of the mite-vectored Deformed wing virus, also carried lower levels of viruses not vectored by mites. By mapping gene expression results against current ontologies and other studies, we describe the impacts of mite parasitism, as well as viruses on bee health against two genetic backgrounds. We identify numerous genes and processes seen in other studies of stress and disease in honey bee colonies, though we find novel genes and new patterns of expression too. Conclusions We provide evidence that honey bees surviving in the face of parasitic mites do so through their abilities to resist the presence of devastating viruses vectored by these mites. By revealing responses to viral infection and mite parasitism in different lineages, our data identify candidate proteins for the evolution of mite tolerance and virus resistance.

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Identification of long noncoding RNAs reveals the effects of dinotefuran on the brain in Apis mellifera (Hymenopptera: Apidae)

BMC Genomics ◽

10.1186/s12864-021-07811-y ◽

2021 ◽

Vol 22 (1) ◽

Author(s):

Minjie Huang ◽

Jie Dong ◽

Haikun Guo ◽

Minghui Xiao ◽

Deqian Wang

Keyword(s):

Immune Response ◽

Honey Bee ◽

Honey Bees ◽

Transforming Growth Factor ◽

Sublethal Effects ◽

Inflammatory Responses ◽

Noncoding Rnas ◽

Enrichment Analysis ◽

Long Noncoding Rnas ◽

Gene Set Enrichment Analysis

Abstract Background Dinotefuran (CAS No. 165252–70-0), a neonicotinoid insecticide, has been used to protect various crops against invertebrate pests and has been associated with numerous negative sublethal effects on honey bees. Long noncoding RNAs (lncRNAs) play important roles in mediating various biological and pathological processes, involving transcriptional and gene regulation. The effects of dinotefuran on lncRNA expression and lncRNA function in the honey bee brain are still obscure. Results Through RNA sequencing, a comprehensive analysis of lncRNAs and mRNAs was performed following exposure to 0.01 mg/L dinotefuran for 1, 5, and 10 d. In total, 312 lncRNAs and 1341 mRNAs, 347 lncRNAs and 1458 mRNAs, and 345 lncRNAs and 1155 mRNAs were found to be differentially expressed (DE) on days 1, 5 and 10, respectively. Gene set enrichment analysis (GSEA) indicated that the dinotefuran-treated group showed enrichment in carbohydrate and protein metabolism and immune-inflammatory responses such as glycine, serine and threonine metabolism, pentose and glucuronate interconversion, and Hippo and transforming growth factor-β (TGF-β) signaling pathways. Moreover, the DE lncRNA TCONS_00086519 was shown by fluorescence in situ hybridization (FISH) to be distributed mainly in the cytoplasm, suggesting that it may serve as a competing endogenous RNA and a regulatory factor in the immune response to dinotefuran. Conclusion This study characterized the expression profile of lncRNAs upon exposure to neonicotinoid insecticides in young adult honey bees and provided a framework for further study of the role of lncRNAs in honey bee growth and the immune response.

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Transcriptional Control of Honey Bee (Apis mellifera) Major Royal Jelly Proteins by 20-Hydroxyecdysone

Insects ◽

10.3390/insects9030122 ◽

2018 ◽

Vol 9 (3) ◽

pp. 122 ◽

Cited By ~ 4

Author(s):

Paul Winkler ◽

Frank Sieg ◽

Anja Buttstedt

Keyword(s):

Gene Expression ◽

Apis Mellifera ◽

Juvenile Hormone ◽

Honey Bee ◽

Honey Bees ◽

Transcriptional Control ◽

Royal Jelly ◽

Adult Worker ◽

Gene Expression Dynamics

One of the first tasks of worker honey bees (Apis mellifera) during their lifetime is to feed the larval offspring. In brief, young workers (nurse bees) secrete a special food jelly that contains a large amount of unique major royal jelly proteins (MRJPs). The regulation of mrjp gene expression is not well understood, but the large upregulation in well-fed nurse bees suggests a tight repression until, or a massive induction upon, hatching of the adult worker bees. The lipoprotein vitellogenin, the synthesis of which is regulated by the two systemic hormones 20-hydroxyecdysone and juvenile hormone, is thought to be a precursor for the production of MRJPs. Thus, the regulation of mrjp expression by the said systemic hormones is likely. This study focusses on the role of 20-hydroxyecdysone by elucidating its effect on mrjp gene expression dynamics. Specifically, we tested whether 20-hydroxyecdysone displayed differential effects on various mrjps. We found that the expression of the mrjps (mrjp1–3) that were finally secreted in large amounts into the food jelly, in particular, were down regulated by 20-hydroxyecdysone treatment, with mrjp3 showing the highest repression value.

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Effects on Some Therapeutical, Biochemical, and Immunological Parameters of Honey Bee (Apis mellifera) Exposed to Probiotic Treatments, in Field and Laboratory Conditions

Insects ◽

10.3390/insects11090638 ◽

2020 ◽

Vol 11 (9) ◽

pp. 638

Author(s):

Ivana Tlak Gajger ◽

Josipa Vlainić ◽

Petra Šoštarić ◽

Janez Prešern ◽

Jernej Bubnič ◽

...

Keyword(s):

Honey Bee ◽

Honey Bees ◽

Immunological Parameters ◽

Individual Level ◽

Sugar Syrup ◽

Novel Approach ◽

The Individual ◽

Field And Laboratory Conditions ◽

Negative Factors ◽

Bee Colonies

Several negative factors contribute to a decline in the number of insect pollinators. As a novel approach in therapy, we hypothesize that the EM® for bees could potentially have an important therapeutic and immunomodulatory effect on honey bee colonies. The aim of our study was to evaluate its impact on honey bees at the individual and colony level. This is the first appliance of the commercial probiotic mix EM® PROBIOTIC FOR BEES in honey bees as economically important social insects. The sugar syrup with 10% of probiotic was administered by spraying or feeding the honey bee colonies in the field conditions, in order to evaluate the infection levels with spores of Nosema spp. and colonies’ strength. Moreover, in laboratory-controlled conditions, in the hoarding cages, adult workers have been fed with sugar syrup supplemented with 2.5, 5, and 10% of EM® for bees for biochemical and immunological analyses of hemolymph, and with 5 and 10% for measuring the size of hypopharyngeal glands. It was found that following the EM® for bees administration the Nosema spp. spore counts in colonies were significantly reduced, and colonies’ strength was increased. The results at the individual level showed significant positive physiological changes in treated groups of adult bees, revealing at the same time a higher mortality rate when feeding sugar syrup supplemented with the probiotic.

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Honey Bee Viruses, Colony Health, and Antiviral Defense

Proceedings ◽

10.3390/proceedings2020050016 ◽

2020 ◽

Vol 50 (1) ◽

pp. 16

Author(s):

Katie F. Daughenbaugh ◽

Alex J. McMenamin ◽

Laura M. Brutscher ◽

Fenali Parekh ◽

Michelle L. Flenniken

Keyword(s):

Gene Expression ◽

Heat Shock ◽

Honey Bee ◽

Honey Bees ◽

Antiviral Defense ◽

Deformed Wing Virus ◽

Antiviral Responses ◽

Model Virus ◽

Virus Abundance

Honey bee colony losses are influenced by multiple abiotic and biotic factors, including viruses. To investigate the effects of RNA viruses on honey bees, we infected bees with a model virus (Sindbis-GFP) in the presence or absence of double-stranded RNA (dsRNA). In honey bees, dsRNA is the substrate for sequence-specific RNA interference (RNAi)-mediated antiviral defense and is a trigger of sequence-independent\antiviral responses. Transcriptome sequencing identified more than 200 differentially expressed genes, including genes in the RNAi, Toll, Imd, JAK-STAT, and heat shock response pathways, and many uncharacterized genes. To confirm the virus limiting role of two genes (i.e., dicer and mf116383) in honey bees, we utilized RNAi to reduce their expression in vivo and determined that the virus abundance increased. To evaluate the role of the heat shock stress response in antiviral defense, bees were heat stressed post-virus infection and the virus abundance and gene expression were assessed. Heat-stressed bees had reduced virus levels and a greater expression of several heat shock protein encoding genes (hsps) compared to the controls. To determine if these genes are universally associated with antiviral defense, bees were infected with another model virus, Flock House virus (FHV), or deformed wing virus and the gene expression was assessed. The expression of dicer was greater in bees infected with either FHV or Sindbis-GFP compared to the mock-infected bees, but not in the deformed wing virus-infected bees. To further investigate honey bee antiviral defense mechanisms and elucidate the function of key genes (dicer, ago-2, mf116383, and hsps) at the cellular level, primary honey bee larval hemocytes were transfected with dsRNA or infected with the Lake Sinai virus 2 (LSV2). These studies indicate that mf116383 and hsps mediate dsRNA detection and that MF116383 is involved in limiting LSV2 infection. Together, these results further our understanding of honey bee antiviral defense, particularly dsRNA-mediated antiviral responses, at both the individual bee and cellular levels.

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Time-restricted foraging under natural light/dark condition shifts the molecular clock in the honey bee, Apis mellifera

10.1101/242289 ◽

2018 ◽

Author(s):

Rikesh Jain ◽

Axel Brockmann

Keyword(s):

Honey Bee ◽

Molecular Clock ◽

Honey Bees ◽

Molecular Mechanisms ◽

Clock Genes ◽

Natural Light ◽

Dark Condition ◽

Flight Chamber ◽

Foraging Time ◽

Phase Differences

AbstractHoney bees have a remarkable sense of time and individual honey bee foragers are capable to adjust their foraging activity with respect to the time of food availability. Although, there is plenty of experimental evidence that foraging behavior is guided by the circadian clock, nothing is known about the underlying cellular and molecular mechanisms. Here we present a first study exploring whether the time-restricted foraging under natural light-dark condition affects the molecular clock in honey bees. In an enclosed flight chamber (12m × 4m × 4m), food was presented either for 2 hours in the morning or 2 hours in the afternoon for several consecutive days and daily cycling of the two major clock genes, cryptochrome2 (cry2) and period (per), were analyzed in three different tissues involved in feeding-related behaviors: brain, antennae and subesophageal ganglion (SEG). We found that morning and afternoon trained foragers showed significant phase-differences in the cycling of both clock genes in all three tissues. Furthermore, the phase-differences were more pronounced when the feeder was scented with the general plant odor linalool. Our results clearly demonstrate that foraging time functions as a strong circadian Zeitgeber in honey bees. More surprisingly our results suggest that foraging time might have the potential to override the entrainment effect of the light-dark cycle.

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Age-Dependent Honey Bee Appetite Regulation Is Mediated by Trehalose and Octopamine Baseline Levels

Insects ◽

10.3390/insects12100863 ◽

2021 ◽

Vol 12 (10) ◽

pp. 863

Author(s):

İrem Akülkü ◽

Saleh Ghanem ◽

Elif Filiztekin ◽

Guntima Suwannapong ◽

Christopher Mayack

Keyword(s):

Honey Bee ◽

Honey Bees ◽

Appetite Regulation ◽

Feedback Mechanisms ◽

Age Dependent ◽

Energetic State ◽

Baseline Levels ◽

The Individual ◽

The Brain ◽

Higher Sensitivity

There are multiple feedback mechanisms involved in appetite regulation, which is an integral part of maintaining energetic homeostasis. Older forager honey bees, in comparison to newly emerged bees and nurse bees, are known to have highly fluctuating hemolymph trehalose levels, higher appetite changes due to starvation, and higher octopamine levels in the brain. What remains unknown is if the hemolymph trehalose and octopamine levels interact with one another and how this varies as the bee ages. We manipulated trehalose and octopamine levels across age using physiological injections and found that nurse and forager bees increase their appetite levels due to increased octopamine levels in the brain. This is further enhanced by lower trehalose levels in the hemolymph. Moreover, nurse bees with high octopamine levels in the brain and low trehalose levels had the same appetite levels as untreated forager bees. Our findings suggest that the naturally higher levels of octopamine as the bee ages may result in higher sensitivity to fluctuating trehalose levels in the hemolymph that results in a more direct way of assessing the energetic state of the individual. Consequently, forager bees have a mechanism for more precise regulation of appetite in comparison to newly emerged and nurse bees.

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Transcriptome-level assessment of the impact of deformed wing virus on honey bee larvae

Scientific Reports ◽

10.1038/s41598-021-94641-3 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Zih-Ting Chang ◽

Yu-Feng Huang ◽

Yue-Wen Chen ◽

Ming-Ren Yen ◽

Po-Ya Hsu ◽

...

Keyword(s):

Gene Expression ◽

Honey Bee ◽

Larval Stage ◽

Honey Bees ◽

Pupal Stage ◽

Deformed Wing Virus ◽

Expression Levels ◽

The Impact ◽

Honey Bee Larvae ◽

Gene Expression Levels

AbstractDeformed wing virus (DWV) prevalence is high in honey bee (Apis mellifera) populations. The virus infects honey bees through vertical and horizontal transmission, leading to behavioural changes, wing deformity, and early mortality. To better understand the impacts of viral infection in the larval stage of honey bees, artificially reared honey bee larvae were infected with DWV (1.55 × 1010 copies/per larva). No significant mortality occurred in infected honey bee larvae, while the survival rates decreased significantly at the pupal stage. Examination of DWV replication revealed that viral replication began at 2 days post inoculation (d.p.i.), increased dramatically to 4 d.p.i., and then continuously increased in the pupal stage. To better understand the impact of DWV on the larval stage, DWV-infected and control groups were subjected to transcriptomic analysis at 4 d.p.i. Two hundred fifty-five differentially expressed genes (DEGs) (fold change ≥ 2 or ≤ -2) were identified. Of these DEGs, 168 genes were downregulated, and 87 genes were upregulated. Gene Ontology (GO) analysis showed that 141 DEGs (55.3%) were categorized into molecular functions, cellular components and biological processes. One hundred eleven genes (38 upregulated and 73 downregulated) were annotated by KO (KEGG Orthology) pathway mapping and involved metabolic pathways, biosynthesis of secondary metabolites and glycine, serine and threonine metabolism pathways. Validation of DEGs was performed, and the related gene expression levels showed a similar tendency to the DEG predictions at 4 d.p.i.; cell wall integrity and stress response component 1 (wsc1), cuticular protein and myo-inositol 2-dehydrogenase (iolG) were significantly upregulated, and small conductance calcium-activated potassium channel protein (SK) was significantly downregulated at 4 d.p.i. Related gene expression levels at different d.p.i. revealed that these DEGs were significantly regulated from the larval stage to the pupal stage, indicating the potential impacts of gene expression levels from the larval to the pupal stages. Taken together, DWV infection in the honey bee larval stage potentially influences the gene expression levels from larvae to pupae and reduces the survival rate of the pupal stage. This information emphasizes the consequences of DWV prevalence in honey bee larvae for apiculture.

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Feeding by Tropilaelaps mercedesae on pre- and post-capped brood increases damage to Apis mellifera colonies

Scientific Reports ◽

10.1038/s41598-019-49662-4 ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 4

Author(s):

Patcharin Phokasem ◽

Lilia I. de Guzman ◽

Kitiphong Khongphinitbunjong ◽

Amanda M. Frake ◽

Panuwan Chantawannakul

Keyword(s):

Apis Mellifera ◽

Honey Bee ◽

Honey Bees ◽

Brood Production ◽

Deformed Wing Virus ◽

Larval Stages ◽

Queen Cell ◽

Tropilaelaps Mercedesae ◽

Management Approaches ◽

Mite Infestations

Abstract Tropilaelaps mercedesae parasitism can cause Apis mellifera colony mortality in Asia. Here, we report for the first time that tropilaelaps mites feed on both pre- and post-capped stages of honey bees. Feeding on pre-capped brood may extend their survival outside capped brood cells, especially in areas where brood production is year-round. In this study, we examined the types of injury inflicted by tropilaelaps mites on different stages of honey bees, the survival of adult honey bees, and level of honey bee viruses in 4th instar larvae and prepupae. The injuries inflicted on different developing honey bee stages were visualised by staining with trypan blue. Among pre-capped stages, 4th instar larvae sustained the highest number of wounds (4.6 ± 0.5/larva) while 2nd-3rd larval instars had at least two wounds. Consequently, wounds were evident on uninfested capped brood (5th-6th instar larvae = 3.91 ± 0.64 wounds; prepupae = 5.25 ± 0.73 wounds). Tropilaelaps mite infestations resulted in 3.4- and 6-fold increases in the number of wounds in 5th-6th instar larvae and prepupae as compared to uninfested capped brood, respectively. When wound-inflicted prepupae metamorphosed to white-eyed pupae, all wound scars disappeared with the exuviae. This healing of wounds contributed to the reduction of the number of wounds (≤10) observed on the different pupal stages. Transmission of mite-borne virus such as Deformed Wing Virus (DWV) was also enhanced by mites feeding on early larval stages. DWV and Black Queen Cell Virus (BQCV) were detected in all 4th instar larvae and prepupae analysed. However, viral levels were more pronounced in scarred 4th instar larvae and infested prepupae. The remarkably high numbers of wounds and viral load on scarred or infested developing honey bees may have caused significant weight loss and extensive injuries observed on the abdomen, wings, legs, proboscis and antennae of adult honey bees. Together, the survival of infested honey bees was significantly compromised. This study demonstrates the ability of tropilaelaps mites to inflict profound damage on A. mellifera hosts. Effective management approaches need to be developed to mitigate tropilaelaps mite problems.

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Gut and Colony Microbiota of Honey Bees Apis mellifera: Social Immunity, Opportunistic Disease and Survival Overwinter.

10.21203/rs.3.rs-757584/v1 ◽

2021 ◽

Author(s):

Kirk E. Anderson ◽

Patrick Maes

Keyword(s):

Gene Expression ◽

Bacterial Diversity ◽

Honey Bee ◽

Environmental Conditions ◽

Honey Bees ◽

Microbial Interactions ◽

Social Immunity ◽

Immune Gene ◽

Opportunistic Disease ◽

Fungal Load

Abstract BackgroundOverwintering is a major contributor to honey bee colony loss and involves changes in environmental conditions, host physiology and group behavior that influence disease susceptibility. Honey bees possess a secretory head gland that interfaces with the extended colony environment on many levels, producing pro-oxidants, antioxidants and antimicrobial peptides. With the coming of winter, colonies produce a long-lived (diutinus) worker phenotype that survives until environmental conditions improve. We used a known-age worker cohort to investigate microbiome integrity and social gene expression of diutinus workers overwinter. We provide additional context by contrasting host-microbial interactions from warm outdoor and cold indoor overwintering environments. ResultsWe produce the first evidence that social immune gene expression is associated with the core hindgut and colony microbiota in honey bees, and highlight the midgut as a target of opportunistic disease overwinter. We discovered a distinct physiological and microbiological trajectory for diutinus workers that differs drastically from younger, short-lived workers in the colony. Diutinus bees were associated with decreased fungal load and decreased bacterial diversity, and increased core microbiota and longevity. Colonies overwintered indoors maintained a stable or improved microbiota structure and complimentary gene expression overwinter. In contrast, workers from colonies overwintered outdoors in warm southern conditions possessed changes co-occurring throughout the alimentary tract microbiota that suggest opportunistic disease progression and resistance in diutinus workers, but susceptibility to opportunistic disease in younger workers that emerged during the winter, including increases in Enterobacteriaceae, fungal load and bacterial diversity abundance. ConclusionsOur results highlight social selection pressures that shaped the colony and hindgut microbiome with evolution to a perennial life history. The results are consistent with a “group level” explanation of social immunity, including host associations with the colony microbiota, and a social immune response by long-lived diutinus workers to accompany microbial opportunism. The cost/benefit ratio associated with limited expression of the diutinus phenotype may be a strong determinant of colony survival overwinter. The relationship of colony and gut microbiota with social immune function highlights the range of host-microbial interaction associated with the honey bee superorganism, and its potential influence on colony health, disease resistance and gut integrity.

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