scholarly journals RNAi and Antiviral Defense in the Honey Bee

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Laura M. Brutscher ◽  
Michelle L. Flenniken
Keyword(s):  
Honey Bee ◽  
Honey Bees ◽  
Defense Mechanism ◽  
Antiviral Defense ◽  
Virus Infections ◽  
Colony Losses ◽  
The Us ◽  
Bee Health ◽  
Honey Bee Health

Honey bees play an important agricultural and ecological role as pollinators of numerous agricultural crops and other plant species. Therefore, investigating the factors associated with high annual losses of honey bee colonies in the US is an important and active area of research. Pathogen incidence and abundance correlate with Colony Collapse Disorder- (CCD-) affected colonies in the US and colony losses in the US and in some European countries. Honey bees are readily infected by single-stranded positive sense RNA viruses. Largely dependent on the host immune response, virus infections can either remain asymptomatic or result in deformities, paralysis, or death of adults or larvae. RNA interference (RNAi) is an important antiviral defense mechanism in insects, including honey bees. Herein, we review the role of RNAi in honey bee antiviral defense and highlight some parallels between insect and mammalian immune systems. A more thorough understanding of the role of pathogens on honey bee health and the immune mechanisms bees utilize to combat infectious agents may lead to the development of strategies that enhance honey bee health and result in the discovery of additional mechanisms of immunity in metazoans.

scholarly journals Comparing Survival of Israeli Acute Paralysis Virus Infection among Stocks of U.S. Honey Bees

Insects ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 60
Author(s):  
Shilpi Bhatia ◽  
Saman S. Baral ◽  
Carlos Vega Melendez ◽  
Esmaeil Amiri ◽  
Olav Rueppell
Keyword(s):  
Honey Bee ◽  
Honey Bees ◽  
Virus Infections ◽  
Israeli Acute Paralysis Virus ◽  
Immune Genes ◽  
Starting Point ◽  
Bee Health ◽  
Honey Bee Health ◽  
Survival Differences ◽  
Paralysis Virus

Among numerous viruses that infect honey bees (Apis mellifera), Israeli acute paralysis virus (IAPV) can be linked to severe honey bee health problems. Breeding for virus resistance may improve honey bee health. To evaluate the potential for this approach, we compared the survival of IAPV infection among stocks from the U.S. We complemented the survival analysis with a survey of existing viruses in these stocks and assessing constitutive and induced expression of immune genes. Worker offspring from selected queens in a common apiary were inoculated with IAPV by topical applications after emergence to assess subsequent survival. Differences among stocks were small compared to variation within stocks, indicating the potential for improving honey bee survival of virus infections in all stocks. A positive relation between worker survival and virus load among stocks further suggested that honey bees may be able to adapt to better cope with viruses, while our molecular studies indicate that toll-6 may be related to survival differences among virus-infected worker bees. Together, these findings highlight the importance of viruses in queen breeding operations and provide a promising starting point for the quest to improve honey bee health by selectively breeding stock to be better able to survive virus infections.

scholarly journals The Gut Microbiota Can Provide Viral Tolerance in the Honey Bee

2021 ◽  
Vol 9 (4) ◽  
pp. 871
Author(s):  
Christopher Dosch ◽  
Anja Manigk ◽  
Tabea Streicher ◽  
Anja Tehel ◽  
Robert J. Paxton ◽  
...  
Keyword(s):  
Gut Microbiota ◽  
Honey Bee ◽  
Honey Bees ◽  
Negative Effects ◽  
Positive Role ◽  
Viral Pathogen ◽  
Deformed Wing Virus ◽  
Bee Health ◽  
Honey Bee Health

Adult honey bees host a remarkably consistent gut microbial community that is thought to benefit host health and provide protection against parasites and pathogens. Currently, however, we lack experimental evidence for the causal role of the gut microbiota in protecting the Western honey bees (Apis mellifera) against their viral pathogens. Here we set out to fill this knowledge gap by investigating how the gut microbiota modulates the virulence of a major honey bee viral pathogen, deformed wing virus (DWV). We found that, upon oral virus exposure, honey bee survival was significantly increased in bees with an experimentally established normal gut microbiota compared to control bees with a perturbed (dysbiotic) gut microbiota. Interestingly, viral titers were similar in bees with normal gut microbiota and dysbiotic bees, pointing to higher viral tolerance in bees with normal gut microbiota. Taken together, our results provide evidence for a positive role of the gut microbiota for honey bee fitness upon viral infection. We hypothesize that environmental stressors altering honey bee gut microbiota composition, e.g., antibiotics in beekeeping or pesticides in modern agriculture, could interact synergistically with pathogens, leading to negative effects on honey bee health and the epidemiology and impact of their viruses.

scholarly journals Pesticide–Virus Interactions in Honey Bees: Challenges and Opportunities for Understanding Drivers of Bee Declines

Viruses ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 566
Author(s):  
Gyan P. Harwood ◽  
Adam G. Dolezal
Keyword(s):  
Honey Bee ◽  
Honey Bees ◽  
Colony Losses ◽  
Challenges And Opportunities ◽  
Bee Health ◽  
Honey Bee Health ◽  
Varroa Mites ◽  
The Individual ◽  
Inadequate Nutrition ◽  
Virus Interactions

Honey bees are key agricultural pollinators, but beekeepers continually suffer high annual colony losses owing to a number of environmental stressors, including inadequate nutrition, pressures from parasites and pathogens, and exposure to a wide variety of pesticides. In this review, we examine how two such stressors, pesticides and viruses, may interact in additive or synergistic ways to affect honey bee health. Despite what appears to be a straightforward comparison, there is a dearth of studies examining this issue likely owing to the complexity of such interactions. Such complexities include the wide array of pesticide chemical classes with different modes of actions, the coupling of many bee viruses with ectoparasitic Varroa mites, and the intricate social structure of honey bee colonies. Together, these issues pose a challenge to researchers examining the effects pesticide-virus interactions at both the individual and colony level.

scholarly journals Comb Irradiation Has Limited, Interactive Effects on Colony Performance or Pathogens in Bees, Varroa destructor and Wax Based on Two Honey Bee Stocks

Insects ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 15 ◽  
Author(s):  
Lilia I. De Guzman ◽  
Michael Simone-Finstrom ◽  
Amanda M. Frake ◽  
Philip Tokarz
Keyword(s):  
Honey Bee ◽  
Honey Bees ◽  
Varroa Destructor ◽  
Adult Population ◽  
Interactive Effects ◽  
Colony Losses ◽  
Deformed Wing Virus ◽  
Bee Health ◽  
Honey Bee Health ◽  
Russian Honey Bees

Parasitic mites and pathogens compromise honey bee health. Development of sustainable and integrative methods of managing these problems will minimize their detrimental impact on honey bees. Here, we aimed to determine if the combination of using mite-resistant stocks along with gamma-irradiated combs influences colony health and productivity. The major finding concerned honey bee genotype confirming that Russian honey bees are more resistant to Varroa destructor than Italian honey bees. The effect of comb irradiation was inconsistent showing a significant increase in adult bee population and amount of stored pollen in 2015, but not in 2016. The increased amount of stored pollen was probably associated with larger adult population in colonies with irradiated combs in September 2015 regardless of honey bee stock. Nevertheless, the ability of bees to collect and store more pollen in the irradiated group does not appear to compensate the negative impacts of mite parasitism on honey bees especially in the Italian bees, which consistently suffered significant colony losses during both years. Results of viral analyses of wax, newly emerged bees, and Varroa and their pupal hosts showed common detections of Deformed wing virus (DWV), Varroa destructor virus (VDV-1), Chronic bee paralysis virus (CBPV), and Black queen cell virus (BQCV). Wax samples had on average ~4 viruses or pathogens detected in both irradiated and non-irradiated combs. Although pathogen levels varied by month, some interesting effects of honey bee stock and irradiation treatment were notable, indicating how traits of mite resistance and alternative treatments may have additive effects. Further, this study indicates that wax may be a transmission route of viral infection. In addition, pupae and their infesting mites from Italian colonies exhibited higher levels of DWV than those from Russian colonies suggesting potential DWV resistance by Russian honey bees. CBPV levels were also reduced in mites from Russian colonies in general and in mites, mite-infested pupae, and newly emerged bees that were collected from irradiated combs. However, BQCV levels were not reduced by comb irradiation. Overall, the contribution of irradiating comb in improving honey bee health and colony survival appears to be subtle, but may be useful as part of an integrated pest management strategy with the addition of using mite-resistant stocks.

scholarly journals Genomic Signatures of Honey Bee Association in an Acetic Acid Symbiont

2020 ◽  
Vol 12 (10) ◽  
pp. 1882-1894
Author(s):  
Eric A Smith ◽  
Irene L G Newton
Keyword(s):  
Honey Bee ◽  
Honey Bees ◽  
Phylogenetic Analyses ◽  
Food Stores ◽  
Genomic Changes ◽  
Eusocial Insects ◽  
Us Economy ◽  
Bee Health ◽  
Honey Bee Health ◽  
Honey Bee Queens

Abstract Recent declines in the health of the honey bee have startled researchers and lay people alike as honey bees are agriculture’s most important pollinator. Honey bees are important pollinators of many major crops and add billions of dollars annually to the US economy through their services. One factor that may influence colony health is the microbial community. Indeed, the honey bee worker digestive tract harbors a characteristic community of bee-specific microbes, and the composition of this community is known to impact honey bee health. However, the honey bee is a superorganism, a colony of eusocial insects with overlapping generations where nestmates cooperate, building a hive, gathering and storing food, and raising brood. In contrast to what is known regarding the honey bee worker gut microbiome, less is known of the microbes associated with developing brood, with food stores, and with the rest of the built hive environment. More recently, the microbe Bombella apis was identified as associated with nectar, with developing larvae, and with honey bee queens. This bacterium is related to flower-associated microbes such as Saccharibacter floricola and other species in the genus Saccharibacter, and initial phylogenetic analyses placed it as sister to these environmental bacteria. Here, we used comparative genomics of multiple honey bee-associated strains and the nectar-associated Saccharibacter to identify genomic changes that may be associated with the ecological transition to honey bee association. We identified several genomic differences in the honey bee-associated strains, including a complete CRISPR/Cas system. Many of the changes we note here are predicted to confer upon Bombella the ability to survive in royal jelly and defend themselves against mobile elements, including phages. Our results are a first step toward identifying potential function of this microbe in the honey bee superorganism.

scholarly journals Descriptive Analysis of the Varroa Non-Reproduction Trait in Honey Bee Colonies and Association with Other Traits Related to Varroa Resistance

Insects ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 492 ◽  
Author(s):  
Sonia E. Eynard ◽  
Christina Sann ◽  
Benjamin Basso ◽  
Anne-Laure Guirao ◽  
Yves Le Conte ◽  
...  
Keyword(s):  
Honey Bee ◽  
Empirical Bayes ◽  
Descriptive Analysis ◽  
Field Studies ◽  
Colony Losses ◽  
Bee Colony ◽  
Bee Health ◽  
Honey Bee Health ◽  
Varroa Resistance ◽  
Resistance Traits

In the current context of worldwide honey bee colony losses, among which the varroa mite plays a major role, the hope to improve honey bee health lies in part in the breeding of varroa resistant colonies. To do so, methods used to evaluate varroa resistance need better understanding. Repeatability and correlations between traits such as mite non-reproduction (MNR), varroa sensitive hygiene (VSH), and hygienic behavior are poorly known, due to practical limitations and to their underlying complexity. We investigate (i) the variability, (ii) the repeatability of the MNR score, and (iii) its correlation with other resistance traits. To reduce the inherent variability of MNR scores, we propose to apply an empirical Bayes correction. In the short-term (ten days), MNR had a modest repeatability of 0.4, whereas in the long-term (a month), it had a low repeatability of 0.2, similar to other resistance traits. Within our dataset, there was no correlation between MNR and VSH. Although MNR is amongst the most popular varroa resistance estimates in field studies, its underlying complex mechanism is not fully understood. Its lack of correlation with better described resistance traits and low repeatability suggest that MNR needs to be interpreted cautiously, especially when used for selection.

scholarly journals Honey Bee Viruses, Colony Health, and Antiviral Defense

Proceedings ◽  
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.

scholarly journals Chronic exposure to neonicotinoids reduces honey bee health near corn crops

Science ◽  
2017 ◽  
Vol 356 (6345) ◽  
pp. 1395-1397 ◽  
Author(s):  
N. Tsvetkov ◽  
O. Samson-Robert ◽  
K. Sood ◽  
H. S. Patel ◽  
D. A. Malena ◽  
...  
Keyword(s):  
Acute Toxicity ◽  
Honey Bee ◽  
Honey Bees ◽  
Chronic Exposure ◽  
Social Immunity ◽  
Active Season ◽  
Bee Health ◽  
Honey Bee Health ◽  
Over Time

Experiments linking neonicotinoids and declining bee health have been criticized for not simulating realistic exposure. Here we quantified the duration and magnitude of neonicotinoid exposure in Canada’s corn-growing regions and used these data to design realistic experiments to investigate the effect of such insecticides on honey bees. Colonies near corn were naturally exposed to neonicotinoids for up to 4 months—the majority of the honey bee’s active season. Realistic experiments showed that neonicotinoids increased worker mortality and were associated with declines in social immunity and increased queenlessness over time. We also discovered that the acute toxicity of neonicotinoids to honey bees doubles in the presence of a commonly encountered fungicide. Our work demonstrates that field-realistic exposure to neonicotinoids can reduce honey bee health in corn-growing regions.

scholarly journals Deformed Wing Virus Infection in Honey Bees (Apis mellifera L.)

2019 ◽  
Vol 56 (4) ◽  
pp. 636-641 ◽  
Author(s):  
Roman V. Koziy ◽  
Sarah C. Wood ◽  
Ivanna V. Kozii ◽  
Claire Janse van Rensburg ◽  
Igor Moshynskyy ◽  
...  
Keyword(s):  
Apis Mellifera ◽  
Honey Bee ◽  
Honey Bees ◽  
Rna Virus ◽  
Mandibular Glands ◽  
Deformed Wing Virus ◽  
Clinically Normal ◽  
Bee Health ◽  
Honey Bee Health ◽  
Honey Bee Workers

Deformed wing virus (DWV) is a single-stranded RNA virus of honey bees ( Apis mellifera L.) transmitted by the parasitic mite Varroa destructor. Although DWV represents a major threat to honey bee health worldwide, the pathological basis of DWV infection is not well documented. The objective of this study was to investigate clinicopathological and histological aspects of natural DWV infection in honey bee workers. Emergence of worker honey bees was observed in 5 colonies that were clinically affected with DWV and the newly emerged bees were collected for histopathology. DWV-affected bees were 2 times slower to emerge and had 30% higher mortality compared to clinically normal bees. Hypopharyngeal glands in bees with DWV were hypoplastic, with fewer intracytoplasmic secretory vesicles; cells affected by apoptosis were observed more frequently. Mandibular glands were hypoplastic and were lined by cuboidal epithelium in severely affected bees compared to tall columnar epithelium in nonaffected bees. The DWV load was on average 1.7 × 106 times higher ( P < .001) in the severely affected workers compared to aged-matched sister honey bee workers that were not affected by deformed wing disease based on gross examination. Thus, DWV infection is associated with prolonged emergence, increased mortality during emergence, and hypoplasia of hypopharyngeal and mandibular glands in newly emerged worker honey bees in addition to previously reported deformed wing abnormalities.

scholarly journals Impacts of Diverse Natural Products on Honey Bee Viral Loads and Health

2021 ◽  
Vol 11 (22) ◽  
pp. 10732
Author(s):  
Dawn L. Boncristiani ◽  
James P. Tauber ◽  
Evan C. Palmer-Young ◽  
Lianfei Cao ◽  
William Collins ◽  
...  
Keyword(s):  
Natural Products ◽  
Immune Responses ◽  
Honey Bee ◽  
Honey Bees ◽  
Food Sources ◽  
Deformed Wing Virus ◽  
Bee Health ◽  
Honey Bee Health ◽  
Living Organisms ◽  
Bee Disease

Western honey bees (Apis mellifera), a cornerstone to crop pollination in the U.S., are faced with an onslaught of challenges from diseases caused by parasites, pathogens, and pests that affect this economically valuable pollinator. Natural products (NPs), produced by living organisms, including plants and microorganisms, can support health and combat disease in animals. NPs include both native extracts and individual compounds that can reduce disease impacts by supporting immunity or directly inhibiting pathogens, pests, and parasites. Herein, we describe the screening of NPs in laboratory cage studies for their effects on honey bee disease prevention and control. Depending on the expected activity of compounds, we measured varied responses, including viral levels, honey bee immune responses, and symbiotic bacteria loads. Of the NPs screened, several compounds demonstrated beneficial activities in honey bees by reducing levels of the critical honey bee virus deformed wing virus (DWV-A and-B), positively impacting the gut microbiome or stimulating honey bee immune responses. Investigations of the medicinal properties of NPs in honey bees will contribute to a better understanding of their potential to support honey bee immunity to fight off pests and pathogens and promote increased overall honey bee health. These investigations will also shed light on the ecological interactions between pollinators and specific floral food sources.

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