scholarly journals Evaluating toxicity of Varroa mite (Varroa destructor)-active dsRNA to monarch butterfly (Danaus plexippus) larvae

PLoS ONE ◽  
2021 ◽  
Vol 16 (6) ◽  
pp. e0251884
Author(s):  
Niranjana Krishnan ◽  
Maura J. Hall ◽  
Richard L. Hellmich ◽  
Joel R. Coats ◽  
Steven P. Bradbury
Keyword(s):  
Honey Bee ◽  
Base Pair ◽  
Varroa Destructor ◽  
Sublethal Effects ◽  
Larval Mortality ◽  
Danaus Plexippus ◽  
Monarch Butterfly ◽  
Varroa Mite ◽  
Colony Losses ◽  
Varroa Mites

Varroa mites (Varroa destructor) are parasitic mites that, combined with other factors, are contributing to high levels of honey bee (Apis mellifera) colony losses. A Varroa-active dsRNA was recently developed to control Varroa mites within honey bee brood cells. This dsRNA has 372 base pairs that are homologous to a sequence region within the Varroa mite calmodulin gene (cam). The Varroa-active dsRNA also shares a 21-base pair match with monarch butterfly (Danaus plexippus) calmodulin mRNA, raising the possibility of non-target effects if there is environmental exposure. We chronically exposed the entire monarch larval stage to common (Asclepias syriaca) and tropical (Asclepias curassavica) milkweed leaves treated with concentrations of Varroa-active dsRNA that are one- and ten-fold higher than those used to treat honey bee hives. This corresponded to concentrations of 0.025–0.041 and 0.211–0.282 mg/g leaf, respectively. Potassium arsenate and a previously designed monarch-active dsRNA with a 100% base pair match to the monarch v-ATPase A mRNA (leaf concentration was 0.020–0.034 mg/g) were used as positive controls. The Varroa mite and monarch-active dsRNA’s did not cause significant differences in larval mortality, larval or pupal development, pupal weights, or adult eclosion rates when compared to negative controls. Irrespective of control or dsRNA treatment, larvae that consumed approximately 7500 to 10,500-mg milkweed leaf within 10 to 12 days had the highest pupal weights. The lack of mortality and sublethal effects following dietary exposure to dsRNA with 21-base pair and 100% base pair match to mRNAs that correspond to regulatory genes suggest monarch mRNA may be refractory to silencing by dsRNA or monarch dsRNase may degrade dsRNA to a concentration that is insufficient to silence mRNA signaling.

scholarly journals Ecological characteristics of Varroa destructor (parasitiformes, varroidea) and its environmental capacity as a key factor for development of varroosis panzootia

2012 ◽  
Vol 46 (5) ◽  
pp. 8-14
Author(s):  
I. A. Akimov ◽  
O. P. Korzh
Keyword(s):  
Life Cycle ◽  
Honey Bee ◽  
Host Species ◽  
Varroa Destructor ◽  
Varroa Mite ◽  
Environmental Capacity ◽  
Ecological Characteristics ◽  
High Pathogenicity ◽  
Key Factor

Ecological Characteristics of Varroa destructor (Parasitiformes, Varroidae) and Its Environmental Capacity as a Key Factor for Development of Varroosis Panzootia. Akimov I. A., Korzh O. P. - By means of formalized schematic models of relationship with hosts the varroa mite uniqueness as a parasite is shown. The life cycle of this species requires the change of a host species at different stages of their development and physiological states. Thus the mite parasitizes not only a separate bee but a whole hive. The fact that the whole hive but not a single bee dies during varroosis development supports this idea. The impetus for this type of parasitism is the relative constancy of the environment in the hive supported by bees even in winter. Exactly this fact causes high pathogenicity of the varroa for the honey bee and its control complexity.

scholarly journals Neonicotinoid Clothianidin reduces honey bee immune response and contributes to Varroa mite proliferation

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Desiderato Annoscia ◽  
Gennaro Di Prisco ◽  
Andrea Becchimanzi ◽  
Emilio Caprio ◽  
Davide Frizzera ◽  
...  
Keyword(s):  
Immune Responses ◽  
Honey Bee ◽  
Honey Bees ◽  
Varroa Destructor ◽  
Negative Impact ◽  
Asymptomatic Infection ◽  
Varroa Mite ◽  
Deformed Wing Virus ◽  
Synergistic Interactions ◽  
Parasitic Mite

AbstractThe neonicotinoid Clothianidin has a negative impact on NF-κB signaling and on immune responses controlled by this transcription factor, which can boost the proliferation of honey bee parasites and pathogens. This effect has been well documented for the replication of deformed wing virus (DWV) induced by Clothianidin in honey bees bearing an asymptomatic infection. Here, we conduct infestation experiments of treated bees to show that the immune-suppression exerted by Clothianidin is associated with an enhanced fertility of the parasitic mite Varroa destructor, as a possible consequence of a higher feeding efficiency. A conceptual model is proposed to describe the synergistic interactions among different stress agents acting on honey bees.

scholarly journals Biology and Management of Varroa destructor (Mesostigmata: Varroidae) in Apis mellifera (Hymenoptera: Apidae) Colonies

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Morgan A Roth ◽  
James M Wilson ◽  
Keith R Tignor ◽  
Aaron D Gross
Keyword(s):  
Apis Mellifera ◽  
Honey Bee ◽  
Varroa Destructor ◽  
Sampling Methods ◽  
Apis Cerana ◽  
Varroa Mite ◽  
Resistance Development ◽  
Deformed Wing Virus ◽  
The Past ◽  
Asian Honey Bee

Abstract Varroa mite (Varroa destructor Anderson and Trueman) infestation of European honey bee (Apis mellifera L.) colonies has been a growing cause of international concern among beekeepers throughout the last 50 yr. Varroa destructor spread from the Asian honey bee (Apis cerana Fabricius [Hymenoptera: Apidae]) to A. mellifera populations in Europe in the 1970s, and subsequently traveled to the Americas. In addition to causing damage through feeding upon lipids of larval and adult bees, V. destructor also facilitates the spread of several viruses, with deformed wing virus being most prevalent. Several sampling methods have been developed for estimating infestation levels of A. mellifera colonies, and acaricide treatments have been implemented. However, overuse of synthetic acaricides in the past has led to widespread acaricide resistant V. destructor populations. The application of Integrated Pest Management (IPM) techniques is a more recent development in V. destructor control and is suggested to be more effective than only using pesticides, thereby posing fewer threats to A. mellifera colonies. When using IPM methods, informed management decisions are made based upon sampling, and cultural and mechanical controls are implemented prior to use of acaricide treatments. If acaricides are deemed necessary, they are rotated based on their mode of action, thus avoiding V. destructor resistance development.

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

2020 ◽  
Vol 52 (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.

scholarly journals Diagnosis of Varroa Mite (Varroa destructor) and Sustainable Control in Honey Bee (Apis mellifera) Colonies—A Review

Diversity ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 243 ◽  
Author(s):  
Aleš Gregorc ◽  
Blair Sampson
Keyword(s):  
Apis Mellifera ◽  
Organic Acids ◽  
Essential Oils ◽  
Honey Bee ◽  
Varroa Destructor ◽  
Mite Infestation ◽  
Varroa Mite ◽  
Mite Control ◽  
Bee Colonies ◽  
Reliable Methods

Determining varroa mite infestation levels in honey bee colonies and the proper method and time to perform a diagnosis are important for efficient mite control. Performing a powdered sugar shake or counting mites that drop from combs and bees onto a hive bottom board are two reliable methods for sampling varroa mite to evaluate the efficacy of an acaricide treatment. This overview summarizes studies that examine the efficacy of organic acids and essential oils, mite monitoring, and brood interruption for integrated varroa mite control in organic beekeeping.

Gene expression in honey bee (Apis mellifera) larvae exposed to pesticides and Varroa mites (Varroa destructor)

2012 ◽  
Vol 58 (8) ◽  
pp. 1042-1049 ◽  
Author(s):  
Aleš Gregorc ◽  
Jay D. Evans ◽  
Mike Scharf ◽  
James D. Ellis
Keyword(s):  
Gene Expression ◽  
Apis Mellifera ◽  
Honey Bee ◽  
Varroa Destructor ◽  
Varroa Mites

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

Insects ◽  
2018 ◽  
Vol 9 (4) ◽  
pp. 149 ◽  
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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