Are increasing honey bee colony losses attributed to<i>Varroa destructor</i>in New Zealand driven by miticide resistance?

McGruddy, Rose; Bulgarella, Mariana; Felden, Antoine; Baty, James W.; Haywood, John; Stahlmann-Brown, Philip; Lester, Philip J.

doi:10.1101/2023.03.22.533871

Cited by 4 publications

(1 citation statement)

References 68 publications

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“…In 2022 it was first detected in Australia, which has been the last major landmass previously free of the parasite and DWV (Chapman et al, 2023). In many of these countries including New Zealand, for example, the combined effects of this parasite and virus have been consistently identified as the leading cause of overwintering honey bee hive mortality (Stahlmann-Brown et al, 2022;McGruddy et al, 2023). This parasite now fits the description of a 'superpest', or a species that has the capacity to invade and adapt to environments around the globe, causing significant damage, and evading control strategies (Whitfield and Rotenberg, 2023).…”

Section: Introductionmentioning

confidence: 99%

Integrated resistance management for acaricide use on Varroa destructor

Lester

2023

Front. Bee Sci.

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The global beekeeping industry faces an escalating challenge in the form of Varroa destructor. Synthetic chemicals serve as a cornerstone for varroa management, although they face a major challenge in the form of acaricide resistance. Here, I examine acaricide resistance in varroa under the framework of Insecticide Resistance Management (IRM). I assess the potential of diverse IRM strategies, such as pesticide rotation and mixtures, refuge utilization, synergists and the integration of non-persistent chemicals. The peculiar life history of varroa, characterized by its incestuous breeding system, challenges conventional IRM strategies. There is little published evidence that pesticide rotation is beneficial for resistance management in varroa, with several studies showing resistance is maintained despite rotation. Fitness costs associated with pesticide resistance are often an essential component for IRM strategies, but there are no current data from varroa demonstrating such specific fitness costs (e.g., a reduced relative oviposition rate) associated with resistance. The single published experimental study directly examining relative fitness found that here was little or no reproductive fitness cost associated with pyrethroid resistance. More work is needed on fitness effects of the key acaricides, which would better guide the use of rotation and refuge strategies. A key prospect for future work that has been identified through simulation modeling is offered by pesticide mixtures and the role of synergists to elevate acaricide efficacy. Additional tools for varroa IRM include ‘soft’ acaricides, including oxalic acid, and biopesticides such as dsRNA. In light of the widespread prevalence of acaricide resistance and an increasing varroa problem, there is an urgent need for nuanced, data-driven varroa IRM strategies.

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Section: Introductionmentioning

confidence: 99%

Integrated resistance management for acaricide use on Varroa destructor

Lester

2023

Front. Bee Sci.

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Investigation of resistance against to flumethrin using against Varroa destructor in Türkiye

Yarsan,

Yilmaz,

Sevin

et al. 2024

Vet Res Commun

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The honeybee ectoparasite Varroa destructor is a major threat to apiculture when evaluating bee diseases and pests. While attempting to control this mite, beekeepers often depend on a small selection of authorized synthetic acaricides, such as flumethrin, which is widely used in Türkiye and globally. However, resistance to flumethrin develops due to incorrect and excessive use. In this study conducted at Ordu Beekeeping Research Institute, trial group were established including an untreated control group and group where flumethrin-based pesticides were applied. Dead varroas collected from pollen traps and live varroas collected from bees were obtained from these trial groups for molecular analysis as positive-negative controls. Varroa samples were collected from provinces representing different regions with intensive beekeeping activities such as Adana, Ankara, Bingöl, Muğla, Ordu, Şanlıurfa, Tekirdağ. Molecular methods were employed to investigate the resistance gene region for pyrethroids (specifically flumethrin) against V. destructor. In our study, individual DNA extractions were performed on dead parasites from colonies subjected to pyrethroid application (resistance negative control) and live parasites (resistance positive control). The DNA samples obtained were used in PCR reactions targeting the region encoding the 925th amino acid of the voltage-gated sodium channel (VGSC) gene, which is responsible for resistance formation. The DNA samples were subjected to gel electrophoresis to observe the amplification products of the expected target region. To examine the nucleotide sequence changes that encode leucine at the 925th amino acid, which is associated with resistance, DNA sequence analysis was applied to the amplification products. Out of 332 V. destructor parasites obtained from different provinces, 279 were analysed using molecular methods. It was observed that 31% of the samples showed sensitivity to flumethrin while 69% exhibited resistance to it. Among the resistant samples: 27% had homozygous isoleucine mutation; 28% had homozygous valine mutation; 2.8% had heterozygous isoleucine mutation; 8.5% had heterozygous valine mutation; and 2.8% had heterozygous methionine mutation, all of which were associated with flumethrin resistance. As a result, the rate of flumethrin resistance in parasites varied between 51% and 94% among different provinces.

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Stimulus-specific gene expression profiles associated with grooming behavior and Varroa destructor resistance in honey bees

Russo,

Pietronave,

Conte

et al. 2024

Front. Bee Sci.

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Grooming behavior is one of the mechanisms of social immunity in Apis mellifera. This behavior has been proposed as an active strategy of honey bees to restrain the population growth of the ectoparasitic mite Varroa destructor in honey bee colonies. The characterization of honey bee stocks with high grooming behavior is of utmost importance for honey bee breeding programs to set the background for mite resistance biomarker-based selection. In this study, we analyzed the expression level of 11 candidate genes putatively involved in grooming and hygiene behaviors in adult workers from mite-resistant (R) and mite-susceptible (S) honey bee stocks. Heads and bodies of worker bees from both stocks, previously tested for grooming response to two treatments (mite infestation and a paintbrush touch control stimulus) were assessed by qPCR. In the head, R bees exposed to mite infestation showed higher levels of Nrx1 and Dop2 and lower levels of Obp3 than S bees. At the body level, R and S bees differed in the expression levels of Nrx1, Oa1, Obp4, Obp14, Obp16, Obp18, Spf45, CYP9Q3, with no stimulus-specific pattern. Overall, our results suggest the involvement of some of the analyzed genes in the specific response to mite infestation, possibly related to the sensitivity and specificity of the R bee to this stimulus at the head level, while other genes would be involved in the non-specific motor response to irritants at the body level. The present study provides new insights into the characterization of the grooming behavior in a selected honey bee stock and increases the available information on its underlying molecular mechanisms. We discuss the putative functions and use of the assessed genes as potential tools for biomarker-assisted selection and improvement of Varroa mite control strategies in honey bee colonies.

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Are increasing honey bee colony losses attributed toVarroa destructorin New Zealand driven by miticide resistance?

Cited by 4 publications

References 68 publications

Integrated resistance management for acaricide use on Varroa destructor

Integrated resistance management for acaricide use on Varroa destructor

Investigation of resistance against to flumethrin using against Varroa destructor in Türkiye

Stimulus-specific gene expression profiles associated with grooming behavior and Varroa destructor resistance in honey bees

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