The Experts below are selected from a list of 2640 Experts worldwide ranked by ideXlab platform

Mohamed Chahine - One of the best experts on this subject based on the ideXlab platform.

Pascal Gosselin-badaroudine - One of the best experts on this subject based on the ideXlab platform.

Jay D Evans - One of the best experts on this subject based on the ideXlab platform.

  • Predictive markers of honey bee Colony Collapse
    PloS one, 2012
    Co-Authors: Benjamin Dainat, Yanping Chen, Jay D Evans, Laurent Gauthier, Peter J Neumann
    Abstract:

    Across the Northern hemisphere, managed honey bee colonies, Apis mellifera, are currently affected by abrupt depopulation during winter and many factors are suspected to be involved, either alone or in combination. Parasites and pathogens are considered as principal actors, in particular the ectoparasitic mite Varroa destructor, associated viruses and the microsporidian Nosema ceranae. Here we used long term monitoring of colonies and screening for eleven disease agents and genes involved in bee immunity and physiology to identify predictive markers of honeybee Colony losses during winter. The data show that DWV, Nosema ceranae, Varroa destructor and Vitellogenin can be predictive markers for winter Colony losses, but their predictive power strongly depends on the season. In particular, the data support that V. destructor is a key player for losses, arguably in line with its specific impact on the health of individual bees and colonies.

  • weighing risk factors associated with bee Colony Collapse disorder by classification and regression tree analysis
    Journal of Economic Entomology, 2010
    Co-Authors: Maryann Frazier, Diana L Coxfoster, J.l. Frazier, Niko Speybroeck, Dennis Vanengelsdorp, Bach Kim Nguyen, Jay D Evans, Christopher A. Mullin, Yanping Chen
    Abstract:

    Colony Collapse disorder (CCD), a syndrome whose defining trait is the rapid loss of adult worker honey bees, Apis mellifera L., is thought to be responsible for a minority of the large overwintering losses experienced by U.S. beekeepers since the winter 2006-2007. Using the same data set developed to perform a monofactorial analysis (PloS ONE 4: e6481, 2009), we conducted a classification and regression tree (CART) analysis in an attempt to better understand the relative importance and interrelations among different risk variables in explaining CCD. Fifty-five exploratory variables were used to construct two CART models: one model with and one model without a cost of misclassifying a CCD-diagnosed Colony as a non-CCD Colony. The resulting model tree that permitted for misclassification had a sensitivity and specificity of 85 and 74%, respectively. Although factors measuring Colony stress (e.g., adult bee physiological measures, such as fluctuating asymmetry or mass of head) were important discriminating values, six of the 19 variables having the greatest discriminatory value were pesticide levels in different hive matrices. Notably, coumaphos levels in brood (a miticide commonly used by beekeepers) had the highest discriminatory value and were highest in control (healthy) colonies. Our CART analysis provides evidence that CCD is probably the result of several factors acting in concert, making afflicted colonies more susceptible to disease. This analysis highlights several areas that warrant further attention, including the effect of sublethal pesticide exposure on pathogen prevalence and the role of variability in bee tolerance to pesticides on Colony survivorship.

  • Colony losses managed Colony population decline and Colony Collapse disorder in the united states
    Journal of Apicultural Research, 2010
    Co-Authors: James D Ellis, Jay D Evans, Jeffery S. Pettis
    Abstract:

    Apis mellifera, CCD, Colony Collapse Disorder, Israeli acute paralysis virus, Nosema ceranae, pesticides, Varroa destructor, nutrition, stress Journal of Apicultural Research 49(1): 134-136 (2010) © IBRA 2010 DOI: 10.3896/IBRA.1.49.1.30 The beekeeping industry in the United States has faced a number of obstacles to healthy bee management in recent decades. These obstacles range from arthropod pests such as the tracheal mite (Acarapis woodi), Varroa destructor mites, and small hive beetles (Aethina tumida) to pathogenic diseases including RNA viruses and the microsporidian Nosema spp. According to the National Agricultural Statistics Service (2009), the number of managed honey bee colonies used for honey production in the U.S. has decreased steadily since the late 1940’s (Fig. 1). Even though it is clear that the number of managed colonies in the U.S. has declined over the last half century (Fig. 1), it has been difficult to determine actual yearly Colony losses, since beekeepers in the U.S. routinely split (divide) their existing colonies every spring to recover losses they experienced the previous winter. According to vanEngelsdorp et al. (2008), surveyed beekeepers losing ~22% (95% CI: 15.9 – 27.5%) of their colonies during the 2007-8 winter, felt that this level of loss was “normal”. Despite the replacement of lost colonies through splitting, there was a net loss (-5.81%) in the total number of honey producing colonies from 2007 to 2008 (calculated from data provided by NASS, 2009), thus suggesting that “splitting” colonies is not sufficient to maintain the sustainability of beekeeping in the U.S. This probably has been exacerbated by the introduction of V. destructor into the U.S. Before its introduction, the total number of honey producing colonies in the U.S. decreased on average 0.06% ± 0.5 (mean ± s.e.) per year while the rate of decline increased to 1.5% ± 0.7 afterwards. Arguably, this decline reflects both the biological loss of existing colonies and the fact that some beekeepers chose to leave the industry in the face of extra expenses and the efforts needed to combat mite infestations, a trend documented in Europe (Potts et al., 2010). In fall of 2006, some beekeepers in the U.S. reported losing 30-90% of their colonies and the symptoms associated with the dead colonies did not match those produced by known bee pests / pathogens. Although annual losses above 30% are not uncommon for beekeepers in the U.S., the number of beekeepers reporting elevated losses appeared alarming as did the unique symptoms associated with the Colony losses. Consequently, the apiculture community in the U.S. called the new phenomenon of elevated Colony losses “Colony Collapse Disorder” or CCD. In an attempt to remove the ambiguity surrounding CCD, U.S. bee scientists defined some of the symptoms often associated with the phenomenon. In Collapsed (dead) colonies, CCD may produce the following symptoms: 1. the complete absence of adult bees in colonies with few or no dead bees in / around colonies; 2. the presence of capped brood; and 3. the presence of food stores that are not robbed by other bees or typical Colony pests. CCD symptoms often associated with collapsing (weakening) colonies may include: 1. an insufficient number of bees to maintain the amount of brood in the Colony; 2. the workforce is composed largely of younger adult bees; 3. the queen is present; and 4. the cluster of bees is reluctant to consume food provided to them by the beekeeper. It has been difficult to assess the impact of CCD in the U.S. The Apiary Inspectors of America (AIA) and USDA-ARS estimate that honey bee Colony losses for fall / winter 2006-7 and 2007-8 were 31% and 36% respectively (vanEngelsdorp et al., 2007; 2008). These loss estimates were based on telephone surveys of beekeepers, who managed between 10-18% of the 2.4 million colonies in the U.S. Nu-merous causes, including CCD, were reported as contributing to the Colony losses during the 2006-7 and 2007-8 winters (vanEngelsdorp et al. 2008). The AIA and USDA-ARS conducted a similar survey for

  • Colony losses, managed Colony population decline, and Colony Collapse Disorder in the United States
    Journal of Apicultural Research, 2010
    Co-Authors: James D Ellis, Jay D Evans, Jeffery S. Pettis
    Abstract:

    (2010). Colony losses, managed Colony population decline, and Colony Collapse Disorder in the United States. Journal of Apicultural Research: Vol. 49, Honey bee Colony losses, pp. 134-136.

  • changes in transcript abundance relating to Colony Collapse disorder in honey bees apis mellifera
    Proceedings of the National Academy of Sciences of the United States of America, 2009
    Co-Authors: Reed M Johnson, Gene E. Robinson, Jay D Evans, May R Berenbaum
    Abstract:

    Colony Collapse disorder (CCD) is a mysterious disappearance of honey bees that has beset beekeepers in the United States since late 2006. Pathogens and other environmental stresses, including pesticides, have been linked to CCD, but a causal relationship has not yet been demonstrated. Because the gut acts as a primary interface between the honey bee and its environment as a site of entry for pathogens and toxins, we used whole-genome microarrays to compare gene expression between guts of bees from CCD colonies originating on both the east and west coasts of the United States and guts of bees from healthy colonies sampled before the emergence of CCD. Considerable variation in gene expression was associated with the geographical origin of bees, but a consensus list of 65 transcripts was identified as potential markers for CCD status. Overall, elevated expression of pesticide response genes was not observed. Genes involved in immune response showed no clear trend in expression pattern despite the increased prevalence of viruses and other pathogens in CCD colonies. Microarray analysis revealed unusual ribosomal RNA fragments that were conspicuously more abundant in the guts of CCD bees. The presence of these fragments may be a possible consequence of picorna-like viral infection, including deformed wing virus and Israeli acute paralysis virus, and may be related to arrested translation. Ribosomal fragment abundance and presence of multiple viruses may prove to be useful diagnostic markers for colonies afflicted with CCD.

Diana L Coxfoster - One of the best experts on this subject based on the ideXlab platform.

  • Colony Collapse disorder ccd and bee age impact honey bee pathophysiology
    PLOS ONE, 2017
    Co-Authors: Dennis Vanengelsdorp, Kirsten S Traynor, Michael Andree, Elinor M Lichtenberg, Yanping Chen, Claude Saegerman, Diana L Coxfoster
    Abstract:

    Honey bee (Apis mellifera) colonies continue to experience high annual losses that remain poorly explained. Numerous interacting factors have been linked to Colony declines. Understanding the pathways linking pathophysiology with symptoms is an important step in understanding the mechanisms of disease. In this study we examined the specific pathologies associated with honey bees collected from colonies suffering from Colony Collapse Disorder (CCD) and compared these with bees collected from apparently healthy colonies. We identified a set of pathological physical characteristics that occurred at different rates in CCD diagnosed colonies prior to their Collapse: rectum distension, Malpighian tubule iridescence, fecal matter consistency, rectal enteroliths (hard concretions), and venom sac color. The multiple differences in rectum symptomology in bees from CCD apiaries and colonies suggest effected bees had trouble regulating water. To ensure that pathologies we found associated with CCD were indeed pathologies and not due to normal changes in physical appearances that occur as an adult bee ages (CCD colonies are assumed to be composed mostly of young bees), we documented the changes in bees of different ages taken from healthy colonies. We found that young bees had much greater incidences of white nodules than older cohorts. Prevalent in newly-emerged bees, these white nodules or cellular encapsulations indicate an active immune response. Comparing the two sets of characteristics, we determined a subset of pathologies that reliably predict CCD status rather than bee age (fecal matter consistency, rectal distension size, rectal enteroliths and Malpighian tubule iridescence) and that may serve as biomarkers for Colony health. In addition, these pathologies suggest that CCD bees are experiencing disrupted excretory physiology. Our identification of these symptoms is an important first step in understanding the physiological pathways that underlie CCD and factors impacting bee health.

  • characterization of viral sirna populations in honey bee Colony Collapse disorder
    Virology, 2014
    Co-Authors: Nor Chejanovsky, Michal Sharabi Schwager, Yossi Slabezki, Smadar Grossman, Ron Ophir, Diana L Coxfoster
    Abstract:

    Abstract Colony Collapse Disorder (CCD), a special case of Collapse of honey bee colonies, has resulted in significant losses for beekeepers. CCD-colonies show abundance of pathogens which suggests that they have a weakened immune system. Since honey bee viruses are major players in Colony Collapse and given the important role of viral RNA interference (RNAi) in combating viral infections we investigated if CCD-colonies elicit an RNAi response. Deep-sequencing analysis of samples from CCD-colonies from US and Israel revealed abundant small interfering RNAs (siRNA) of 21–22 nucleotides perfectly matching the Israeli acute paralysis virus (IAPV), Kashmir virus and Deformed wing virus genomes. Israeli colonies showed high titers of IAPV and a conserved RNAi-pattern of matching the viral genome. That was also observed in sample analysis from colonies experimentally infected with IAPV. Our results suggest that CCD-colonies set out a siRNA response that is specific against predominant viruses associated with Colony losses.

  • lack of evidence for an association between iridovirus and Colony Collapse disorder
    PLOS ONE, 2011
    Co-Authors: Rafal Tokarz, Diana L Coxfoster, Craig Street, Cadhla Firth, Ian W Lipkin
    Abstract:

    Colony Collapse disorder (CCD) is characterized by the unexplained losses of large numbers of adult worker bees (Apis mellifera) from apparently healthy colonies. Although infections, toxins, and other stressors have been associated with the onset of CCD, the pathogenesis of this disorder remains obscure. Recently, a proteomics study implicated a double-stranded DNA virus, invertebrate iridescent virus (Family Iridoviridae) along with a microsporidium (Nosema sp.) as the cause of CCD. We tested the validity of this relationship using two independent methods: (i) we surveyed healthy and CCD colonies from the United States and Israel for the presence of members of the Iridovirus genus and (ii) we reanalyzed metagenomics data previously generated from RNA pools of CCD colonies for the presence of Iridovirus-like sequences. Neither analysis revealed any evidence to suggest the presence of an Iridovirus in healthy or CCD colonies.

  • weighing risk factors associated with bee Colony Collapse disorder by classification and regression tree analysis
    Journal of Economic Entomology, 2010
    Co-Authors: Maryann Frazier, Diana L Coxfoster, J.l. Frazier, Niko Speybroeck, Dennis Vanengelsdorp, Bach Kim Nguyen, Jay D Evans, Christopher A. Mullin, Yanping Chen
    Abstract:

    Colony Collapse disorder (CCD), a syndrome whose defining trait is the rapid loss of adult worker honey bees, Apis mellifera L., is thought to be responsible for a minority of the large overwintering losses experienced by U.S. beekeepers since the winter 2006-2007. Using the same data set developed to perform a monofactorial analysis (PloS ONE 4: e6481, 2009), we conducted a classification and regression tree (CART) analysis in an attempt to better understand the relative importance and interrelations among different risk variables in explaining CCD. Fifty-five exploratory variables were used to construct two CART models: one model with and one model without a cost of misclassifying a CCD-diagnosed Colony as a non-CCD Colony. The resulting model tree that permitted for misclassification had a sensitivity and specificity of 85 and 74%, respectively. Although factors measuring Colony stress (e.g., adult bee physiological measures, such as fluctuating asymmetry or mass of head) were important discriminating values, six of the 19 variables having the greatest discriminatory value were pesticide levels in different hive matrices. Notably, coumaphos levels in brood (a miticide commonly used by beekeepers) had the highest discriminatory value and were highest in control (healthy) colonies. Our CART analysis provides evidence that CCD is probably the result of several factors acting in concert, making afflicted colonies more susceptible to disease. This analysis highlights several areas that warrant further attention, including the effect of sublethal pesticide exposure on pathogen prevalence and the role of variability in bee tolerance to pesticides on Colony survivorship.

  • Colony Collapse disorder in context
    BioEssays, 2010
    Co-Authors: Diana L Coxfoster, Mariepierre Chauzat, Geoffrey R Williams, Keith S Delaplane, Jeffery S. Pettis, David R Tarpy, Dennis Vanengelsdorp, Peter J Neumann, Richard E L Rogers
    Abstract:

    Although most of humanity relies upon foods that do not require animal pollination 1, production of 39 of the world's 57 most important monoculture crops still benefits from this ecosystem service 2. Western honey bees (Apis mellifera) are undoubtedly the single-most valuable animal pollinators to agriculture because they can be easily maintained and transported to pollinator-dependent crops. Yet, despite an almost 50% increase in world honey bee stocks over the last century, beekeepers have not kept pace with the >300% increase in pollinator-dependent crops 3. This has led to great uncertainty surrounding the recent large-scale die-offs of honey bees around the world, and has sparked enormous interest from both scientists and the general public. Although sharp regional declines in honey bee populations have occurred in the past, such as the so-called unexplainable “Isle of Wight” disease in the early 1900s 4, the magnitude and velocity of these recent declines are likely unprecedented. Often in the media (e.g. “Mobile phones responsible for disappearance of honey bee,” available at http://www.telegraph.co.uk/), and sometimes in the scientific literature (e.g. 5), these losses are inappropriately equated with “Colony Collapse Disorder” or CCD, which is characterized by the rapid disappearance of adult bees from colonies containing brood and food stores but lacking damaging levels of parasitic Varroa destructor mites or Nosema microsporidians 6. Although, we agree that CCD is indeed a significant cause for concern, we believe that it is imperative to appropriately place CCD within the greater context of other honey bee morbidities occurring worldwide. In many cases, these morbidities can be explained by known parasites or beekeeper management issues. One example is the devastation caused by beekeepers' inability to control V. destructor, which not only feeds on host haemolymph and weakens host immunity but also vectors a variety of viruses 7. In other cases, however, these morbidities are genuinely unexplainable, including those attributed to CCD sensu stricto 6. In recent winters, Colony mortality in Europe has averaged ∼20% (ranging from 1.8 to 53% among countries), with starvation and parasites believed to be the main contributors (“Proceedings of the 4th COLOSS Conference, Zagreb, Croatia, 3-4 March 2009”, available at http://www.coloss.org/publications). Colony mortality during the 2006/2007, 2007/2008, and 2008/2009 winters in the US, the only country where CCD has been documented sensu stricto, was 32% 8, 36% 9, and 29% 10, respectively. During the winter of 2008/2009, ∼10% of the 2.3 million managed honey bee colonies in the US died with “CCD-like symptoms”, and US beekeepers self-diagnosed CCD as only the 8th most important contributor to Colony mortality, behind starvation, queen-related issues, and parasites 10. The point is, honey bees die from many things. We must be careful to not synonymize CCD with all honey bee losses. There is a growing consensus that Colony mortality is the product of multiple factors, both known and unknown, acting singly or in combination 11, 12. Considering the reliance that modern agriculture places on honey bees for pollination, coordinated efforts, such as those of CANPOLIN (Canadian Pollination Initiative, http://www.uoguelph.ca/canpolin), COLOSS (Prevention of Honeybee Colony Losses, http://www.coloss.org/), and the US Department of Agriculture's Areawide and Managed Pollinator CAP (Coordinated Agricultural Project) 13, are urgently needed to understand and mitigate these losses. The first step in these efforts should be to objectively discriminate among types of Colony mortality occurring worldwide. This will permit a more informed and appropriate allocation of research efforts into CCD specifically and other causes of mortality in general.

Mary R Myerscough - One of the best experts on this subject based on the ideXlab platform.

  • poor hive thermoregulation produces an allee effect and leads to Colony Collapse
    Journal of Theoretical Biology, 2020
    Co-Authors: Zeaiter Zeaiter, Mary R Myerscough
    Abstract:

    Abstract In recent years the honey bee industry has been experiencing increased loss of hives. The accumulation of multiple stressors on a hive potentially drives hive loss in various ways, including winter loss and Colony Collapse disorder. One of these stressors is the breakdown of thermoregulation inside the hive. For pupae to develop correctly into healthy adult bees, the temperature within the hive must be regulated by the hive bees to within a narrow range that ensures optimal development. Suboptimal development in adults affects their brain and flight muscles so bees becomes inefficient foragers with shorter life spans. We model the effect of thermoregulation on hive health using a system of delay differential equations that show that thermoregulatory stress has the capacity to drive Colony loss in the model via a saddle-node bifurcation with an associated Allee effect.

  • poor hive thermoregulation produces an allee effect and leads to Colony Collapse
    bioRxiv, 2020
    Co-Authors: Zeaiter Zeaiter, Mary R Myerscough
    Abstract:

    In recent years the honey bee industry has bee experiencing increased loss of hives. The accumulation of multiple stressors on a hive potentially drives hive loss in various ways, including winter loss and Colony Collapse disorder. One of these stressors is the breakdown of thermoregulation inside the hive. For pupae to develop correctly into healthy adult bees, the temperature within the hive must be regulated by the hive bees to within a narrow range that ensures optimal development. Suboptimal development in adults affects their brain and flight muscles so bees becomes inefficient foragers with shorter life spans. We model the effect of thermoregulation on hive health using a system of delay differential equations that gives insights into how varying hive temperatures have an effect on the survival of the Colony. We show that thermoregulatory stress has the capacity to drive Colony loss in the model via a saddle-node bifurcation with an associated Allee effect.