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

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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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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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

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Reduced Postcapping Period in Honey Bees Surviving Varroa destructor by Means of Natural Selection

Insects ◽

10.3390/insects9040149 ◽

2018 ◽

Vol 9 (4) ◽

pp. 149 ◽

Cited By ~ 8

Author(s):

Melissa Oddie ◽

Bjørn Dahle ◽

Peter Neumann

Keyword(s):

Natural Selection ◽

Reproductive Success ◽

Honey Bee ◽

Varroa Destructor ◽

Common Garden ◽

Colony Losses ◽

Susceptible Population ◽

Key Factor ◽

Worker Brood ◽

Colony Survival

The ectoparasitic mite Varroa destructor is a key factor for colony losses in European honey bee subspecies (Apis mellifera), but it is also known that some host populations have adapted to the mite by means of natural selection. The role of a shorter host brood postcapping period in reducing mite reproductive success has been investigated in other surviving subspecies, however its role in the adaptation of European honey bee populations has not been addressed. Here, we use a common garden approach to compare the length of the worker brood postcapping period in a Norwegian surviving honey bee population with the postcapping period of a local susceptible population. The data show a significantly shorter postcapping period in the surviving population for ~10% of the brood. Since even small differences in postcapping period can significantly reduce mite reproductive success, this mechanism may well contribute to natural colony survival. It appears most likely that several mechanisms acting together produce the full mite-surviving colony phenotype.

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Advances and perspectives in selecting resistance traits against the parasitic mite Varroa destructor in honey bees

Genetics Selection Evolution ◽

10.1186/s12711-020-00591-1 ◽

2020 ◽

Vol 52 (1) ◽

Cited By ~ 1

Author(s):

Matthieu Guichard ◽

Vincent Dietemann ◽

Markus Neuditschko ◽

Benjamin Dainat

Keyword(s):

Honey Bee ◽

Environmental Effects ◽

Honey Bees ◽

Varroa Destructor ◽

Selection Strategy ◽

Pollination Services ◽

Colony Losses ◽

New Host ◽

Parasitic Mite ◽

Resistance Traits

Abstract Background In spite of the implementation of control strategies in honey bee (Apis mellifera) keeping, the invasive parasitic mite Varroa destructor remains one of the main causes of colony losses in numerous countries. Therefore, this parasite represents a serious threat to beekeeping and agro-ecosystems that benefit from the pollination services provided by honey bees. To maintain their stocks, beekeepers have to treat their colonies with acaricides every year. Selecting lineages that are resistant to infestations is deemed to be a more sustainable approach. Review Over the last three decades, numerous selection programs have been initiated to improve the host–parasite relationship and to support honey bee survival in the presence of the parasite without the need for acaricide treatments. Although resistance traits have been included in the selection strategy of honey bees, it has not been possible to globally solve the V. destructor problem. In this study, we review the literature on the reasons that have potentially limited the success of such selection programs. We compile the available information to assess the relevance of selected traits and the potential environmental effects that distort trait expression and colony survival. Limitations to the implementation of these traits in the field are also discussed. Conclusions Improving our knowledge of the mechanisms underlying resistance to V. destructor to increase trait relevance, optimizing selection programs to reduce environmental effects, and communicating selection outcomes are all crucial to efforts aiming at establishing a balanced relationship between the invasive parasite and its new host.

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Three Decades of Selecting Honey Bees that Survive Infestations by the Parasitic Mite Varroa destructor: Outcomes, Limitations and Strategy

10.20944/preprints202003.0044.v1 ◽

2020 ◽

Cited By ~ 3

Author(s):

Matthieu Guichard ◽

Vincent Dietemann ◽

Markus Neuditschko ◽

Benjamin Dainat

Keyword(s):

Honey Bees ◽

Varroa Destructor ◽

Control Strategies ◽

Pollination Services ◽

Colony Losses ◽

New Host ◽

Parasite Relationship ◽

Parasitic Mite ◽

Selected Traits ◽

Colony Survival

Despite the implementation of control strategies, the invasive parasitic mite Varroa destructor remains one of the principal causes of honey bee (Apis mellifera) colony losses in numerous countries. For this reason, the parasite represents a serious threat to beekeeping and to agro-ecosystems that benefit from the pollination services provided by honey bees. Numerous selection programmes have been initiated over the last three decades with the aim of promoting the establishment of balance in the host–parasite relationship and, thus, helping European honey bees to survive in the presence of the parasite without the need for acaricide treatments. Such programmes have focused on either selective breeding for putative resistance traits or natural selection. To date, no clear overview of these attempts has been available, which has prevented building on past successes or failures and, therefore, hindered the development of a sustainable strategy for solving the V. destructor problem. In the present study, we review past and current selection strategies, report on their outcomes and discuss their limitations. Based on this state-of-the-art knowledge, we propose a strategy for increasing response to selection and colony survival against V. destructor infestations. Developing in-depth knowledge regarding the selected traits, optimising selection programmes and communicating their outcomes are all crucial to our efforts to establish a balanced relationship between the invasive parasite and its new host.

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

Insects ◽

10.3390/insects10010015 ◽

2019 ◽

Vol 10 (1) ◽

pp. 15 ◽

Cited By ~ 2

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.

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A New Strain of Virus Discovered in China Specific to the Parasitic Mite Varroa destructor Poses a Potential Threat to Honey Bees

Viruses ◽

10.3390/v13040679 ◽

2021 ◽

Vol 13 (4) ◽

pp. 679

Author(s):

Gongwen Chen ◽

Shuai Wang ◽

Shuo Jia ◽

Ye Feng ◽

Fuliang Hu ◽

...

Keyword(s):

Honey Bee ◽

Honey Bees ◽

Varroa Destructor ◽

Molecular Mechanisms ◽

Evolutionary Dynamics ◽

Apis Cerana ◽

Potential Threat ◽

Chinese Strain ◽

Illumina Hiseq ◽

Varroa Mites

The ectoparasitic mite, Varroa destructor, feeds directly on honey bees and serves as a vector for transmitting viruses among them. The Varroa mite causes relatively little damage to its natural host, the Eastern honey bee (Apis cerana) but it is the most devastating pest for the Western honey bee (Apis mellifera). Using Illumina HiSeq sequencing technology, we conducted a metatranscriptome analysis of the microbial community associated with Varroa mites. This study led to the identification of a new Chinese strain of Varroa destructor virus-2 (VDV-2), which is a member of the Iflaviridae family and was previously reported to be specific to Varroa mites. A subsequent epidemiological investigation of Chinese strain of VDV-2 (VDV-2-China) showed that the virus was highly prevalent among Varroa populations and was not identified in any of the adult workers from both A. mellifera and A.cerana colonies distributed in six provinces in China, clearly indicating that VDV-2-China is predominantly a Varroa-adapted virus. While A. mellifera worker pupae exposed to less than two Varroa mites tested negative for VDV-2-China, VDV-2-China was detected in 12.5% of the A. mellifera worker pupae that were parasitized by more than 10 Varroa mites, bringing into play the possibility of a new scenario where VDV-2 could be transmitted to the honey bees during heavy Varroa infestations. Bioassay for the VDV-2-China infectivity showed that A. cerana was not a permissive host for VDV-2-China, yet A. mellifera could be a biological host that supports VDV-2-China’s replication. The different replication dynamics of the virus between the two host species reflect their variation in terms of susceptibility to the virus infection, posing a potential threat to the health of the Western honey bee. The information gained from this study contributes to the knowledge concerning genetic variabilities and evolutionary dynamics of Varroa-borne viruses, thereby enhancing our understanding of underlying molecular mechanisms governing honey bee Varroosis.

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Using Citizen Science to Scout Honey Bee Colonies that Naturally Survive Varroa destructor Infestations

Insects ◽

10.3390/insects12060536 ◽

2021 ◽

Vol 12 (6) ◽

pp. 536

Author(s):

Arrigo Moro ◽

Alexis Beaurepaire ◽

Raffaele Dall’Olio ◽

Steve Rogenstein ◽

Tjeerd Blacquière ◽

...

Keyword(s):

Citizen Science ◽

Honey Bee ◽

Honey Bees ◽

Varroa Destructor ◽

Control Strategies ◽

Conservation Status ◽

Free Living ◽

Successful Recruitment ◽

Mite Control ◽

Colony Survival

Citizen Science contributes significantly to the conservation of biodiversity, but its application to honey bee research has remained minimal. Even though certain European honey bee (Apis mellifera) populations are known to naturally survive Varroa destructor infestations, it is unclear how widespread or common such populations are. Such colonies are highly valuable for investigating the mechanisms enabling colony survival, as well as for tracking the conservation status of free-living honey bees. Here, we use targeted Citizen Science to identify potentially new cases of managed or free-living A. mellifera populations that survive V. destructor without mite control strategies. In 2018, a survey containing 20 questions was developed, translated into 13 languages, and promoted at beekeeping conferences and online. After three years, 305 reports were collected from 28 countries: 241 from managed colonies and 64 from free-living colonies. The collected data suggest that there could be twice as many naturally surviving colonies worldwide than are currently known. Further, online and personal promotion seem to be key for successful recruitment of participants. Although the survivor status of these colonies still needs to be confirmed, the volume of reports and responses already illustrate how effectively Citizen Science can contribute to bee research by massively increasing generated data, broadening opportunities for comparative research, and fostering collaboration between scientists, beekeepers, and citizens. The success of this survey spurred the development of a more advanced Citizen Science platform, Honey Bee Watch, that will enable a more accurate reporting, confirmation, and monitoring of surviving colonies, and strengthen the ties between science, stakeholders, and citizens to foster the protection of both free-living and managed honey bees.

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Identification of new viruses specific to the honey bee mite Varroa destructor

10.1101/610170 ◽

2019 ◽

Cited By ~ 1

Author(s):

Salvador Herrero ◽

Sandra Coll ◽

Rosa M. González-Martínez ◽

Stefano Parenti ◽

Anabel Millán-Leiva ◽

...

Keyword(s):

Honey Bee ◽

Honey Bees ◽

Varroa Destructor ◽

Large Scale ◽

Rna Viruses ◽

Colony Losses ◽

Multiple Factors ◽

The Usa ◽

Pathogenic Viruses ◽

The Impact

AbstractLarge-scale colony losses among managed Western honey bees have become a serious threat to the beekeeping industry in the last decade. There are multiple factors contributing to these losses but the impact of Varroa destructor parasitism is by far the most important, along with the contribution of some pathogenic viruses vectored by the mite. So far, more than 20 viruses have been identified infecting the honey bee, most of them RNA viruses. They may be maintained either as covert infections or causing severe symptomatic infections, compromising the viability of the colony. In silico analysis of available transcriptomic data obtained from mites collected in the USA and Europe as well as additional investigation with new samples collected locally allowed the description of three novel RNA viruses. Our results showed that these viruses were widespread among samples and that they were present in the mites and in the bees but with differences in the relative abundance and prevalence. However, we have obtained strong evidence showing that these three viruses were able to replicate in the mite, but not in the bee, suggesting that they are selectively infecting the mite. To our knowledge, this is the first demonstration of Varroa-specific viruses, which open the door to future applications that might help controlling the mite through biological control approaches.

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Varroa destructor: how does it harm Apis mellifera honey bees and what can be done about it?

Emerging Topics in Life Sciences ◽

10.1042/etls20190125 ◽

2020 ◽

Vol 4 (1) ◽

pp. 45-57 ◽

Cited By ~ 6

Author(s):

Amélie Noël ◽

Yves Le Conte ◽

Fanny Mondet

Keyword(s):

Apis Mellifera ◽

Honey Bee ◽

Honey Bees ◽

Varroa Destructor ◽

Abiotic Factors ◽

Apis Cerana ◽

Management Strategies ◽

Special Focus ◽

Asian Honey Bee ◽

The Individual

Since its migration from the Asian honey bee (Apis cerana) to the European honey bee (Apis mellifera), the ectoparasitic mite Varroa destructor has emerged as a major issue for beekeeping worldwide. Due to a short history of coevolution, the host–parasite relationship between A. mellifera and V. destructor is unbalanced, with honey bees suffering infestation effects at the individual, colony and population levels. Several control solutions have been developed to tackle the colony and production losses due to Varroa, but the burden caused by the mite in combination with other biotic and abiotic factors continues to increase, weakening the beekeeping industry. In this synthetic review, we highlight the main advances made between 2015 and 2020 on V. destructor biology and its impact on the health of the honey bee, A. mellifera. We also describe the main control solutions that are currently available to fight the mite and place a special focus on new methodological developments, which point to integrated pest management strategies for the control of Varroa in honey bee colonies.

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