Barbara Locke

Barbara Locke
Swedish University of Agricultural Sciences | SLU · Department of Ecology

PhD

About

72
Publications
32,034
Reads
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1,881
Citations
Citations since 2017
53 Research Items
1441 Citations
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20172018201920202021202220230100200300
20172018201920202021202220230100200300
Additional affiliations
January 2013 - present
Swedish University of Agricultural Sciences
Position
  • PostDoc Position
Education
September 2000 - December 2004
University of Guelph
Field of study

Publications

Publications (72)
Preprint
Novel transmission routes can allow infectious diseases to spread, often with devastating consequences. Ectoparasitic varroa mites vector a diversity of RNA viruses and, having switched hosts from the eastern to western honey bees (Apis cerana to Apis mellifera). They provide an opportunity to explore how novel transmission routes shape disease epi...
Article
Full-text available
Monitoring virus infections can be an important selection tool in honey bee breeding. A recent study pointed towards an association between the virus-free status of eggs and an increased virus resistance to deformed wing virus (DWV) at the colony level. In this study, eggs from both naturally surviving and traditionally managed colonies from across...
Preprint
Full-text available
The ‘suppressed in-ovo virus infection’ trait (SOV) was the first trait applied in honey bee breeding programs aimed to increase resilience to virus infections, a major threat for colony survival. By screening drone eggs for viruses, the SOV trait scores the antiviral resistance of queens and its implications for vertical transmission. In this stud...
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Full-text available
There is increasing evidence that honeybees (Apis mellifera L.) can adapt naturally to survive Varroa destructor, the primary cause of colony mortality world-wide. Most of the adaptive traits of naturally varroa-surviving honeybees concern varroa reproduction. Here we investigate whether factors in the honeybee metagenome also contribute to this su...
Article
Full-text available
The ectoparasitic mite, Varroa destructor, is unarguably the leading cause of honeybee (Apis mellifera) mortality worldwide through its role as a vector for lethal viruses, in particular, strains of the Deformed wing virus (DWV) and Acute bee paralysis virus (ABPV) complexes. Several honeybee populations across Europe have well-documented adaptatio...
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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 a...
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Full-text available
Cell recapping is a behavioural trait of honeybees (Apis mellifera) where cells with developing pupae are uncapped, inspected, and then recapped, without removing the pupae. The ectoparasitic mite Varroa destructor, unarguably the most destructive pest in apiculture world-wide, invades the cells of developing pupae to feed and reproduce. Honeybees...
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Comparative studies of genetic diversity and population structure can shed light on the ecological and evolutionary factors governing host-parasite interactions. Even though invasive parasites are considered of major biological importance, little is known about their adaptative potential when infesting the new hosts. Here, the genetic diversificati...
Article
Full-text available
The ectoparasitic mite Varroa destructor is the most significant pathological threat to the western honey bee, Apis mellifera, leading to the death of most colonies if left untreated. An alternative approach to chemical treatments is to selectively enhance heritable honey bee traits of resistance or tolerance to the mite through breeding programs,...
Preprint
Full-text available
It was brought to our attention that a preprint version of a refutation to our paper titled “Rapid parallel evolution overcomes global honey bee parasite” was posted through PeerJ recently. This is our formal response to the refutation, which can be found through this link: https://peerj.com/preprints/27938/ Here we have broken down the arguments o...
Article
Full-text available
The ectoparasitic mite, Varroa destructor, is the most severe biotic threat to honeybees (Apis mellifera) globally, usually causing colony death within a few years without treatments. While it is known that a few A. mellifera populations survive mite infestations by means of natural selection, the possible role of mite adaptations remains unclear....
Article
Full-text available
The ectoparasitic mite, Varroa destructor, is unarguably the leading cause of honeybee (Apis mellifera) mortality worldwide through its role as a vector for lethal viruses, in particular, strains of the Deformed wing virus (DWV) and Acute bee paralysis virus (ABPV) complexes. This multi-level system of host-parasite-pathogen interactions makes it d...
Article
Full-text available
The bacterial disease American Foulbrood (AFB), caused by the Gram-positive bacterium Paenibacillus larvae, is considered the most contagious and destructive infectious disease affecting honeybees world-wide. The resilient nature of P. larvae bacterial spores presents a difficult problem for the control of AFB. Burning clinically symptomatic coloni...
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Interactions between multiple stressors have been implicated in elevated honeybee colony losses. Here, we extend our landscape-scale study on the effects of placement at clothianidin seed-treated oilseed rape fields on honeybees with an additional year and new data on honeybee colony development, swarming, mortality, pathogens and immune gene expre...
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Neonicotinoids are implicated in bee declines and laboratory studies imply that they impair the bee immune system, thereby precipitating a rise in pathogen levels. To establish whether such synergisms reduce bee performance in real-world agricultural landscapes, we analysed the microbial composition of the bumblebee (Bombus terrestris) samples from...
Article
Full-text available
The parasitic mite, Varroa destructor, in combination with the viruses it vectors, is the main cause for global colony losses of the European honeybee, Apis mellifera. However, an isolated honeybee population established in 1999 on the Island of Gotland, Sweden has naturally acquired resistance to the mite, and has survived without mite control tre...
Data
Major virus read-count data. Raw read-count data for the different viruses normalised to the total for each RNA sample. Data is given on logarithmic scale. (TIF)
Data
ARV-1 read map. Reads were mapped against the near full length study specific ARV-1 genome using the CodonCode aligner software 6.0.2. The read map illustrates the nucleotide coverage by viral genomic RNA (blue) and complementary RNA (red) reads. (TIF)
Data
Genome assembly maps. Schematic representation of the genomes DWV, SBV, BQCV, LSV and ARV-1, showing the location and direction of the contigs for the NGS assemblies separately for the MR (red) and MS (blue) honeybee populations. The green bars represent the RT-PCR products produced for sequence validation by Sanger sequencing. The tips of the brow...
Data
Phylogenetic analyses and accessions. Supplementary data and information underlying the phylogenetic analyses, including the ML estimate of the optimum tree, the number of characters and taxa included in the reconstruction, as well as the accession numbers of the full-length consensus sequences for each of the viruses in the MR and MS honeybee popu...
Data
LSV genome map. Map of the genome organization for LSV1, LSV2 and LSV3, with the areas of major variability (downward arrows) and deletion (white block) between the MS and MR consensus LSV3 sequences indicated. The names of the different open reading frames (ORF) are shown. (TIF)
Data
Statistical analysis of RT-qPCR data. Welch’s pairwise t-test analysis of the differences between the MR and MS honeybee populations in the DWV, SBV, BQCV, LSV and ARV-1 titres at different points in the 2009 season. (XLSX)
Data
List of diagnostic RT-qPCR Assay primers and Sanger sequencing primers. Details of the diagnostic RT-qPCR assays used, including primer sequences, product size, linearity of the external calibration curves, Cq vs log10[target amount], over 6 orders of magnitude (r2) and the mean temperature of the main peak of the Melting Curve (Tm). (XLSX)
Data
Basic information of the sequence data. Details about the number of IonTorrent sequence reads from the pooled seasonal samples of the MR and MS honeybee populations that map to either the honeybee genome, cellular microorganisms or viruses. (XLSX)
Article
Full-text available
In eusocial insect colonies nestmates cooperate to combat parasites, a trait called social immunity. However, social immunity failed for Western honey bees (Apis mellifera) when the ectoparasitic mite Varroa destructor switched hosts from Eastern honey bees (Apis cerana). This mite has since become the most severe threat to A. mellifera world-wide....
Article
The Red Queen Hypothesis predicts that host‐parasite coevolutionary dynamics can select for host resistance through increased genetic diversity, recombination and evolutionary rates. However, in haplodiploid organisms such as the honey bee (Apis mellifera), models suggest the selective pressure is weaker than in diploids. Haplodiploid sex‐determina...
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Full-text available
Purpose of Review American foulbrood (AFB) and European foulbrood (EFB) are widely distributed and highly infectious bacterial diseases of honeybee brood causing colony losses and considerable economic strain on apiculture globally. In this review, we synthesize the most recent discoveries and achievements made towards understanding the pathogenesi...
Article
Full-text available
Deformed wing virus (DWV) is a lethal virus of honeybees (Apis mellifera) implicated in elevated colony mortality rates worldwide and facilitated through vector transmission by the ectoparasitic mite Varroa destructor. Clinical, symptomatic DWV infections are almost exclusively associated with high virus titres during pupal development, usually acq...
Article
Viral infections in managed honey bees are numerous, and most of them are caused by viruses with an RNA genome. Since RNA degrades rapidly, appropriate sample management and RNA extraction methods are imperative to get high quality RNA for downstream assays. This study evaluated the effect of various sampling-transport scenarios (combinations of te...
Article
Full-text available
The Varroa destructor mite is the largest threat to apiculture worldwide and has been responsible for devastating losses of wild honeybee populations in Europe and North America. However, Varroa mite-resistant populations of A. mellifera honeybees have been reported and documented around the world with a variety of explanations for their long-term...
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Full-text available
A well-documented population of honey bees on Gotland, Sweden is resistant to Varroa destructor mites and is able in some way to reduce the mite's reproductive success. The aim of this study was to determine the genetic and maternal contribution to the inheritance of the reduced mite reproductive success trait in this population. Four genotypic gro...
Article
Full-text available
The honey bee ectoparasitic mite, Varroa destructor, has a world-wide distribution and inflicts more damage than all other known apicultural diseases. However, Varroa-induced colony mortality is more accurately a result of secondary virus infections vectored by the mite. This means that honey bee resistance to Varroa may include resistance or toler...
Article
Full-text available
Very rapidly after Varroa destructor invaded apiaries of Apis mellifera, the devastating effect of this mite prompted an active research effort to understand and control this parasite. Over a few decades, varroa has spread to most countries exploiting A. mellifera. As a consequence, a large number of teams have worked with this organism, developing...
Article
Full-text available
Honey bee societies (Apis mellifera), the ectoparasitic mite Varroa destructor, and honey bee viruses that are vectored by the mite, form a complex system of host-parasite interactions. Coevolution by natural selection in this system has been hindered for European honey bee hosts since apicultural practices remove the mite and consequently the sele...
Article
Full-text available
Honey bee (Apis mellifera) colonies are declining, and a number of stressors have been identified that affect, alone or in combination, the health of honey bees. The ectoparasitic mite Varroa destructor, honey bee viruses that are often closely associated with the mite, and pesticides used to control the mite population form a complex system of str...
Article
Full-text available
Varroa destructor is a highly virulent ectoparasitic mite of the honey bee Apis mellifera and a major cause of colony losses for global apiculture. Typically, chemical treatment is essential to control the parasite population in the honey bee colony. Nevertheless a few honey bee populations survive mite infestation without any treatment. We used on...
Article
Full-text available
A population of European honey bees (Apis mellifera) surviving Varroa destructor mite infestation in Sweden for over 10years without treatment, demonstrate that a balanced host–parasite relationship may evolve over time. Colony-level adaptive traits linked to Varroa tolerance were investigated in this population to identify possible characteristics...
Article
Full-text available
Complete genome sequences were determined for two distinct strains of slow bee paralysis virus (SBPV) of honeybees (Apis mellifera). The SBPV genome is approximately 9.5 kb long and contains a single ORF flanked by 5'- and 3'-UTRs and a naturally polyadenylated 3' tail, with a genome organization typical of members of the family Iflaviridae. The tw...
Article
Full-text available
Male butterflies aggregate at moist soil to acquire nutrients, a phenomenon termed “mud-puddling.” We studied the attraction of free-flying Papilio glaucus and Battus philenor swallowtails to dead decoys of those two species at artificial puddles moistened with NaCl solution. Both species landed preferentially at puddles with a decoy present rather...

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Projects (2)
Project
Integrating veterinary epidemiology, population ecology and advanced biostatistical approaches to understand the drivers of disease prevalence and devise health initiatives in a range of wild and domestic animal species
Project
Hypothesis-driven research to better understand the biology and enhance control of ectoparasitic mites.