Managed honeybee colony losses of the Eastern honeybee (Apis cerana) in China (2011–2014)

ABSTRACT Honeybee colonies are vulnerable to parasites and pathogens ranging from viruses to vertebrates. An increasingly prevalent disease of managed honeybees is caused by the microsporidian Nosema ceranae. Microsporidia are basal fungi and obligate parasites with much-reduced genomic and cellular components. A recent genome-sequencing effort for N. ceranae indicated the presence of machinery for RNA silencing in this species, suggesting that RNA interference (RNAi) might be exploited to regulate Nosema gene expression within bee hosts. Here we used controlled laboratory experiments to show that double-stranded RNA homologous to specific N. ceranae ADP/ATP transporter genes can specifically and differentially silence transcripts encoding these proteins. This inhibition also affects Nosema levels and host physiology. Gene silencing could be mediated solely by Nosema or in concert with known systemic RNAi mechanisms in their bee hosts. These results are novel for the microsporidia and provide a possible avenue for controlling a disease agent implicated in severe honeybee colony losses. Moreover, since microsporidia are pathogenic in several known veterinary and human diseases, this advance may have broader applications in the future for disease control.

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Direct Economic Impact Assessment of Winter Honeybee Colony Losses in Three European Countries

Agriculture ◽

10.3390/agriculture11050398 ◽

2021 ◽

Vol 11 (5) ◽

pp. 398

Author(s):

Despina Popovska Stojanov ◽

Lazo Dimitrov ◽

Jiří Danihlík ◽

Aleksandar Uzunov ◽

Miroljub Golubovski ◽

...

Keyword(s):

Economic Impact ◽

Management Practices ◽

Agricultural Sector ◽

Stress Factors ◽

Economic Losses ◽

Colony Losses ◽

Economic Impact Assessment ◽

Parasitic Mite ◽

Honeybee Colony ◽

Pioneer Effort

Honeybees are of great importance because of their role in pollination as well as for hive products. The population of managed colonies fluctuates over time, and recent monitoring reports show different levels of colony losses in many regions and countries. The cause of this kind of loss is a combination of various factors, such as the parasitic mite Varroa destructor, viruses, pesticides, management practices, climate change, and other stress factors. Having in mind that the economic aspect of honeybee colony losses has not been estimated, a pioneer effort was made for developing a methodology that estimates the economic impact of honeybee colony losses. Winter loss data was based on 2993 answers of the COLOSS standard questionnaire survey of honeybee winter colony losses for 2016/2017. In addition, market and financial data were used for each country. In a comparative analysis, an assessment on the economic impact of colony losses in Austria, Czechia, and Macedonia was made. The estimation considered the value of the colonies and the potential production losses of the lost colonies and of surviving but weak colonies. The direct economic impact of winter honeybee colony losses in 2016/2017 in Austria was estimated to be about 32 Mio €; in Czechia, 21 Mio €; and in Macedonia, 3 Mio €. Economic impact reflects the different value levels in the three countries, national colony populations, and the magnitude of colony losses. This study also suggests that economic losses are much higher than the subsidies, which underlines the economic importance of honeybees for the agricultural sector.

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Norwegian honey bees surviving Varroa destructor mite infestations by means of natural selection

PeerJ ◽

10.7717/peerj.3956 ◽

2017 ◽

Vol 5 ◽

pp. e3956 ◽

Cited By ~ 25

Author(s):

Melissa A.Y. Oddie ◽

Bjørn Dahle ◽

Peter Neumann

Keyword(s):

Natural Selection ◽

Reproductive Success ◽

Honey Bee ◽

Honey Bees ◽

Varroa Destructor ◽

Apis Cerana ◽

Mite Infestation ◽

Colony Losses ◽

Key Factor ◽

Colony Survival

Background Managed, feral and wild populations of European honey bee subspecies, Apis mellifera, are currently facing severe colony losses globally. There is consensus that the ectoparasitic mite Varroa destructor, that switched hosts from the Eastern honey bee Apis cerana to the Western honey bee A. mellifera, is a key factor driving these losses. For >20 years, breeding efforts have not produced European honey bee colonies that can survive infestations without the need for mite control. However, at least three populations of European honey bees have developed this ability by means of natural selection and have been surviving for >10 years without mite treatments. Reduced mite reproductive success has been suggested as a key factor explaining this natural survival. Here, we report a managed A. mellifera population in Norway, that has been naturally surviving consistent V. destructor infestations for >17 years. Methods Surviving colonies and local susceptible controls were evaluated for mite infestation levels, mite reproductive success and two potential mechanisms explaining colony survival: grooming of adult worker bees and Varroa Sensitive Hygiene (VSH): adult workers specifically detecting and removing mite-infested brood. Results Mite infestation levels were significantly lower in surviving colonies and mite reproductive success was reduced by 30% when compared to the controls. No significant differences were found between surviving and control colonies for either grooming or VSH. Discussion Our data confirm that reduced mite reproductive success seems to be a key factor for natural survival of infested A. mellifera colonies. However, neither grooming nor VSH seem to explain colony survival. Instead, other behaviors of the adult bees seem to be sufficient to hinder mite reproductive success, because brood for this experiment was taken from susceptible donor colonies only. To mitigate the global impact of V. destructor, we suggest learning more from nature, i.e., identifying the obviously efficient mechanisms favored by natural selection.

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Honeybee colony losses in Uruguay during 2013–2014

Apidologie ◽

10.1007/s13592-016-0482-2 ◽

2016 ◽

Vol 48 (3) ◽

pp. 364-370 ◽

Cited By ~ 17

Author(s):

Karina Antúnez ◽

Ciro Invernizzi ◽

Yamandú Mendoza ◽

Dennis vanEngelsdorp ◽

Pablo Zunino

Keyword(s):

Colony Losses ◽

Honeybee Colony

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Haemolymph removal by Varroa mite destabilizes the dynamical interaction between immune effectors and virus in bees, as predicted by Volterra's model

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2019.0331 ◽

2019 ◽

Vol 286 (1901) ◽

pp. 20190331 ◽

Cited By ~ 14

Author(s):

Desiderato Annoscia ◽

Sam P. Brown ◽

Gennaro Di Prisco ◽

Emanuele De Paoli ◽

Simone Del Fabbro ◽

...

Keyword(s):

Viral Evolution ◽

Colony Losses ◽

Viral Pathogen ◽

Dynamical Interaction ◽

Deformed Wing Virus ◽

Pathogen Virulence ◽

Mite Feeding ◽

Parasitic Mite ◽

Honeybee Colony ◽

Honeybee Health

The association between the deformed wing virus and the parasitic mite Varroa destructor has been identified as a major cause of worldwide honeybee colony losses. The mite acts as a vector of the viral pathogen and can trigger its replication in infected bees. However, the mechanistic details underlying this tripartite interaction are still poorly defined, and, particularly, the causes of viral proliferation in mite-infested bees. Here, we develop and test a novel hypothesis that mite feeding destabilizes viral immune control through the removal of both virus and immune effectors, triggering uncontrolled viral replication. Our hypothesis is grounded on the predator–prey theory developed by Volterra, which predicts prey proliferation when both predators and preys are constantly removed from the system. Consistent with this hypothesis, we show that the experimental removal of increasing volumes of haemolymph from individual bees results in increasing viral densities. By contrast, we do not find consistent support for alternative proposed mechanisms of viral expansion via mite immune suppression or within-host viral evolution. Our results suggest that haemolymph removal plays an important role in the enhanced pathogen virulence observed in the presence of feeding Varroa mites. Overall, these results provide a new model for the mechanisms driving pathogen–parasite interactions in bees, which ultimately underpin honeybee health decline and colony losses.

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Norwegian honey bees surviving Varroa destructor miteinfestations by means of natural selection

10.7287/peerj.preprints.2976v1 ◽

2017 ◽

Author(s):

Melissa AY Oddie ◽

Bjørn Dahle ◽

Peter Neumann

Keyword(s):

Natural Selection ◽

Reproductive Success ◽

Honey Bee ◽

Honey Bees ◽

Varroa Destructor ◽

Apis Cerana ◽

Mite Infestation ◽

Colony Losses ◽

Key Factor ◽

Colony Survival

Background: Managed, feral and wild populations of European honey bee subspecies, Apis mellifera, are currently facing severe colony losses globally. There is consensus that the ectoparasite mite Varroa destructor, that switched hosts from the Eastern honey bee Apis cerana to the Western honey bee A. mellifera, is a key factor driving these losses. For >20 years, breeding efforts have not achieved that European honey bee colonies survive infestations without the need for mite control. However, at least three populations of European honey bees have developed this by means of natural selection and have been surviving for >10 years without mite treatments. Reduced mite reproductive success has been suggested as a key factor explaining this natural survival. Here, we report a managed A. mellifera population in Norway, that has been naturally surviving consistent V. destructor infestations for >17 years. Methods: Surviving colonies and local susceptible controls were evaluated for mite infestation levels, mite reproductive success and twopotential mechanisms explaining colony survival: grooming of adult worker bees and Varroa Sensitive Hygiene (VSH): adult workers specifically detecting and removing mite-infested brood. Results: Mite infestation levels were significantly lower in surviving colonies and mite reproductive success was reduced by ~30% compared to the controls. No significant differences were found between surviving and control colonies for either grooming or VSH. Discussion: Our data confirm that reduced mite reproductive success seems to be a key factor for natural survival of infested A. mellifera colonies. However, neither grooming nor VSH seem to explain colony survival. Instead, other behaviors of the adult bees seem to be sufficient to hinder mite reproductive success, because brood for this experiment was taken from susceptible donor colonies only. To mitigate the global impact of V. destructor, we suggest learning more from nature, i.e. identifying the obviously efficient mechanisms favored by natural selection.

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Dead or Alive: Deformed Wing Virus and Varroa destructor Reduce the Life Span of Winter Honeybees

Applied and Environmental Microbiology ◽

10.1128/aem.06537-11 ◽

2011 ◽

Vol 78 (4) ◽

pp. 981-987 ◽

Cited By ~ 170

Author(s):

Benjamin Dainat ◽

Jay D. Evans ◽

Yan Ping Chen ◽

Laurent Gauthier ◽

Peter Neumann

Keyword(s):

Life Expectancy ◽

Life Span ◽

Varroa Destructor ◽

Colony Losses ◽

Deformed Wing Virus ◽

Content Type ◽

Parasitic Mite ◽

Honeybee Colony ◽

Underlying Mechanisms ◽

Acute Bee Paralysis Virus

ABSTRACTElevated winter losses of managed honeybee colonies are a major concern, but the underlying mechanisms remain controversial. Among the suspects are the parasitic miteVarroa destructor, the microsporidianNosema ceranae, and associated viruses. Here we hypothesize that pathogens reduce the life expectancy of winter bees, thereby constituting a proximate mechanism for colony losses. A monitoring of colonies was performed over 6 months in Switzerland from summer 2007 to winter 2007/2008. Individual dead workers were collected daily and quantitatively analyzed for deformed wing virus (DWV), acute bee paralysis virus (ABPV),N. ceranae, and expression levels of thevitellogeningene as a biomarker for honeybee longevity. Workers from colonies that failed to survive winter had a reduced life span beginning in late fall, were more likely to be infected with DWV, and had higher DWV loads. Colony levels of infection with the parasitic miteVarroa destructorand individual infections with DWV were also associated with reduced honeybee life expectancy. In sharp contrast, the level ofN. ceranaeinfection was not correlated with longevity. In addition,vitellogeningene expression was significantly positively correlated with ABPV andN. ceranaeloads. The findings strongly suggest thatV. destructorand DWV (but neitherN. ceranaenor ABPV) reduce the life span of winter bees, thereby constituting a parsimonious possible mechanism for honeybee colony losses.

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Honeybee colony losses and threats in Scotland. (2012-2017)

10.20933/10000106 ◽

2017 ◽

Author(s):

Christopher Connolly ◽

John Durkacz

Keyword(s):

Colony Losses ◽

Honeybee Colony

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Norwegian honey bees surviving Varroa destructor miteinfestations by means of natural selection

10.7287/peerj.preprints.2976 ◽

2017 ◽

Author(s):

Melissa AY Oddie ◽

Bjørn Dahle ◽

Peter Neumann

Keyword(s):

Natural Selection ◽

Reproductive Success ◽

Honey Bee ◽

Honey Bees ◽

Varroa Destructor ◽

Apis Cerana ◽

Mite Infestation ◽

Colony Losses ◽

Key Factor ◽

Colony Survival

Background: Managed, feral and wild populations of European honey bee subspecies, Apis mellifera, are currently facing severe colony losses globally. There is consensus that the ectoparasite mite Varroa destructor, that switched hosts from the Eastern honey bee Apis cerana to the Western honey bee A. mellifera, is a key factor driving these losses. For >20 years, breeding efforts have not achieved that European honey bee colonies survive infestations without the need for mite control. However, at least three populations of European honey bees have developed this by means of natural selection and have been surviving for >10 years without mite treatments. Reduced mite reproductive success has been suggested as a key factor explaining this natural survival. Here, we report a managed A. mellifera population in Norway, that has been naturally surviving consistent V. destructor infestations for >17 years. Methods: Surviving colonies and local susceptible controls were evaluated for mite infestation levels, mite reproductive success and twopotential mechanisms explaining colony survival: grooming of adult worker bees and Varroa Sensitive Hygiene (VSH): adult workers specifically detecting and removing mite-infested brood. Results: Mite infestation levels were significantly lower in surviving colonies and mite reproductive success was reduced by ~30% compared to the controls. No significant differences were found between surviving and control colonies for either grooming or VSH. Discussion: Our data confirm that reduced mite reproductive success seems to be a key factor for natural survival of infested A. mellifera colonies. However, neither grooming nor VSH seem to explain colony survival. Instead, other behaviors of the adult bees seem to be sufficient to hinder mite reproductive success, because brood for this experiment was taken from susceptible donor colonies only. To mitigate the global impact of V. destructor, we suggest learning more from nature, i.e. identifying the obviously efficient mechanisms favored by natural selection.

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An investigation of honey bee virus prevalence in managed honey bees (Apis mellifera and Apis cerana) undergone colony losses: a case study in China

10.21203/rs.3.rs-48932/v1 ◽

2020 ◽

Author(s):

Yanchun Deng ◽

Li Zhang ◽

Xuejian Jiang ◽

Sa Yang ◽

Shuai Deng ◽

...

Keyword(s):

Apis Mellifera ◽

Honey Bee ◽

Clinical Symptoms ◽

Apis Cerana ◽

Colony Losses ◽

Queen Cell ◽

Bee Virus ◽

Paralysis Virus ◽

Bee Viruses

Abstract Objective: In the absence of known clinical symptoms, viruses were considered to be the most probable key pathogens of honey bee. Therefore, the aim of this study was to investigate the prevalence and distribution of honey bee viruses in managed Apis mellifera and Apis cerana in China. Results: We conducted a screening of 9 honey bee viruses on A. mellifera and A. cerana samples collected from 54 apiaries from 13 provinces in China. We found that the types and numbers of viruses significantly differed between A. mellifera and A. cerana. Black queen cell virus (BQCV), chronic bee paralysis virus (CBPV), Apis mellifera filamentous virus (AmFV) and Kakugo virus (DWV-C/KV) were the primary viruses found in A. mellifera colonies, whereas Chinese sacbrood bee virus (CSBV) and sacbrood bee virus (SBV) were the primary viruses found in A. cerana. The percentage infection of BQCV and CSBV were 84.6% and 61.6% in all detected samples. We first detected the occurrences of Varroa destructor virus-1(VDV-1, DWV-B) and DWV-C/KV in China but not ABPV in both A. mellifera and A. cerana.

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