Showing papers on "Varroa sensitive hygiene published in 2017"
TL;DR: Data from this and other observational cohort studies that monitor individual honey bee colonies and precisely account for sampling date will lead to a better understanding of the influence of pathogens on colony mortality and the effects of other factors on these associations.
Abstract: Honey bees are important pollinators of agricultural crops. Pathogens and other factors have been implicated in high annual losses of honey bee colonies in North America and some European countries. To further investigate the relationship between multiple factors, including pathogen prevalence and abundance and colony health, we monitored commercially managed migratory honey bee colonies involved in California almond pollination in 2014. At each sampling event, honey bee colony health was assessed, using colony population size as a proxy for health, and the prevalence and abundance of seven honey bee pathogens was evaluated using PCR and quantitative PCR, respectively. In this sample cohort, pathogen prevalence and abundance did not correlate with colony health, but did correlate with the date of sampling. In general, pathogen prevalence (i.e., the number of specific pathogens harbored within a colony) was lower early in the year (January-March) and was greater in the summer, with peak prevalence occurring in June. Pathogen abundance in individual honey bee colonies varied throughout the year and was strongly associated with the sampling date, and was influenced by beekeeping operation, colony health, and mite infestation level. Together, data from this and other observational cohort studies that monitor individual honey bee colonies and precisely account for sampling date (i.e., day of year) will lead to a better understanding of the influence of pathogens on colony mortality and the effects of other factors on these associations.
59 citations
TL;DR: The authors' data confirm that reduced mite reproductive success seems to be a key factor for natural survival of infested A. mellifera colonies, and suggest learning more from nature, i.e., identifying the obviously efficient mechanisms favored by natural selection.
Abstract: 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.
59 citations
TL;DR: This study provides clear evidence that the exposure to sublethal doses of Imidacloprid could exert a significantly negative effect on health and survival of honey bees, and suggests that Vg could be a useful biomarker for measuring levels of energy stress and sublethal effects of pesticides on honey bees.
Abstract: There has been growing concern over declines in populations of honey bees and other pollinators which are a vital part to our food security. It is imperative to identify factors responsible for accelerated declines in bee populations and develop solutions for reversing bee losses. While exact causes of colony losses remain elusive, risk factors thought to play key roles are ectoparasitic mites Varroa destructor and neonicotinoid pesticides. The present study aims to investigate effects of a neonicotinoid pesticide Imidacloprid and Varroa mites individually on survivorship, growth, physiology, virus dynamics and immunity of honey bee workers. Our study provides clear evidence that the exposure to sublethal doses of Imidacloprid could exert a significantly negative effect on health and survival of honey bees. We observed a significant reduction in the titer of vitellogenin (Vg), an egg yolk precursor that regulates the honey bees development and behavior and often are linked to energy homeostasis, in bees exposed to Imidacloprid. This result indicates that sublethal exposure to neonicotinoid could lead to increased energy usage in honey bees as detoxification is a energy-consuming metabolic process and suggests that Vg could be a useful biomarker for measuring levels of energy stress and sublethal effects of pesticides on honey bees. Measurement of the quantitative effects of different levels of Varroa mite infestation on the replication dynamic of Deformed wing virus (DWV), an RNA virus associated with Varroa infestation, and expression level of immune genes yields unique insights into how honey bees respond to stressors under laboratory conditions.
53 citations
TL;DR: The different VSH responses between the two selected resistant honey bee populations lead to conclude that more than one mechanism of resistance may evolve in response to the selection pressure by varroa mites.
Abstract: The parasitic mite Varroa destructor is a serious threat for western honey bee colonies and beekeepers are compelled to control it to keep their colonies healthy. Yet, by controlling varroa no resistance to the parasite can evolve. As a trial, honey bee colonies have been left untreated in isolated locations to allow development of resistance or tolerance to the mite. These colonies developed an ability to live without control measures against varroa, although the traits responsible for this resistance or tolerance are still unclear. Two of these resistant populations have been studied to test the involvement of specific varroa mite targeted hygienic behaviour varroa sensitive hygiene (VSH) in the acquired resistance. Individual mites were manually introduced into just capped brood cells, after which the brood combs were placed in colonies of the two resistant populations and in control colonies in which varroa had always been controlled. We followed the development of the mites, including possible remova...
46 citations
TL;DR: This study studied the effects of pollen on the survival of infested bees, and observed that a pollen rich diet can compensate the deleterious effects of mite parasitization, and characterized the pollen compounds responsible for the observed positive effects.
Abstract: Parasites and pathogens of the honey bee (Apis mellifera) are key factors underlying colony losses, which are threatening the beekeeping industry and agriculture as a whole. To control the spread and development of pathogen infections within the colony, honey bees use plant resins with antibiotic activity, but little is known about the properties of other substances, that are mainly used as a foodstuff, for controlling possible diseases both at the individual and colony level. In this study, we tested the hypothesis that pollen is beneficial for honey bees challenged with the parasitic mite Varroa destructor associated to the Deformed Wing Virus. First, we studied the effects of pollen on the survival of infested bees, under laboratory and field conditions, and observed that a pollen rich diet can compensate the deleterious effects of mite parasitization. Subsequently, we characterized the pollen compounds responsible for the observed positive effects. Finally, based on the results of a transcriptomic analysis of parasitized bees fed with pollen or not, we developed a comprehensive framework for interpreting the observed effects of pollen on honey bee health, which incorporates the possible effects on cuticle integrity, energetic metabolism and immune response.
45 citations
TL;DR: The discovery of compounds that alter the host choice of Varroa mites (from nurse to forager) in laboratory tests are reviewed, and any semiochemical-based methods are still in the experimental stage and need validation in the field.
Abstract: Honey bees and their ectoparasite Varroa destructor communicate through chemical signals among themselves, but they also eavesdrop on each other’s chemical cues. We summarize semiochemicals of honey bees and Varroa, and their roles in honey bee-Varroa interactions. We also give an overview of current Varroa control methods, which can be classified into three categories: (1) chemical control methods with acaricides, (2) biotechnical intervention, and (3) bee breeding programs. Widely used synthetic chemical acaricides are failing due to the emergence of resistant mites. Therefore, new methods are being sought for Varroa control, and methods that target the semiochemical interactions between bees and mites are among the candidates. We review our discovery of compounds that alter the host choice of Varroa mites (from nurse to forager) in laboratory tests. Any semiochemical-based methods are still in the experimental stage and need validation in the field.
41 citations
TL;DR: This finding of within-colony parasite diversity provides empirical evidence that the spread of V. destructor is not accomplished solely by vertical transmission but that horizontal transmission (natural or human-mediated) must occur regularly.
Abstract: Varroa destructor is an obligate ectoparasitic mite and the most important biotic threat currently facing honey bees (Apis mellifera). We used neutral microsatellites to analyze previously unreported fine scale population structure of V. destructor, a species characterized by extreme lack of genetic diversity owing to multiple bottleneck events, haplodiploidy, and primarily brother-sister matings. Our results surprisingly indicate that detectable hierarchical genetic variation exists between apiaries, between colonies within an apiary, and even within colonies. This finding of within-colony parasite diversity provides empirical evidence that the spread of V. destructor is not accomplished solely by vertical transmission but that horizontal transmission (natural or human-mediated) must occur regularly.
36 citations
TL;DR: Combining OA applications with artificial broodless colony conditions achieved either by brood removal or queen caging as an effective management strategy for varroa mites is recommended.
Abstract: Few studies of honey bee colonies exist where varroa mite control is achieved by integrating broodless conditions, through either total brood removal or queen caging, in combination with oxalic acid (OA) applications. We observed significant varroa mortality after total brood removal or caging the queens and OA applications in broodless colonies, as well as in colonies with brood that received four consecutive OA applications. In laboratory tests, we recorded higher mortality of caged bees exposed to Apistan® compared to oxalic acid or untreated control bees. However, this mortality is not believed to negatively impact the colony. We therefore recommend combining OA applications with artificial broodless colony conditions achieved either by brood removal or queen caging as an effective management strategy for varroa mites.
35 citations
TL;DR: The effects of the neonicotinoid thiamethoxam on honey bee, Apis mellifera carnica, pupae infested with Varroa destructor mites were analyzed at the molecular level and observed a major difference in immune response toVarroa infestation between white-eyed pupae and brown- eyed pupae.
Abstract: Varroa destructor is one of the most common parasites of honey bee colonies and is considered as a possible co-factor for honey bee decline. At the same time, the use of pesticides in intensive agriculture is still the most effective method of pest control. There is limited information about the effects of pesticide exposure on parasitized honey bees. Larval ingestion of certain pesticides could have effects on honey bee immune defense mechanisms, development and metabolic pathways. Europe and America face the disturbing phenomenon of the disappearance of honey bee colonies, termed Colony Collapse Disorder (CCD). One reason discussed is the possible suppression of honey bee immune system as a consequence of prolonged exposure to chemicals. In this study, the effects of the neonicotinoid thiamethoxam on honey bee, Apis mellifera carnica, pupae infested with Varroa destructor mites were analyzed at the molecular level. Varroa-infested and non-infested honey bee colonies received protein cakes with or without thiamethoxam. Nurse bees used these cakes as a feed for developing larvae. Samples of white-eyed and brown-eyed pupae were collected. Expression of 17 immune-related genes was analyzed by real-time PCR. Relative gene expression in samples exposed only to Varroa or to thiamethoxam or simultaneously to both Varroa and thiamethoxam was compared. The impact from the consumption of thiamethoxam during the larval stage on honey bee immune related gene expression in Varroa-infested white-eyed pupae was reflected as down-regulation of spaetzle, AMPs abaecin and defensin-1 and up-regulation of lysozyme-2. In brown-eyed pupae up-regulation of PPOact, spaetzle, hopscotch and basket genes was detected. Moreover, we observed a major difference in immune response to Varroa infestation between white-eyed pupae and brown-eyed pupae. The majority of tested immune-related genes were upregulated only in brown-eyed pupae, while in white-eyed pupae they were downregulated.
35 citations
TL;DR: The costs and benefits associated with hygienic behavior are reviewed, extending preceding reviews on this subject from the late 1990s and the benefits seem to largely outweigh its costs for both colonies and bee breeders.
Abstract: The hygienic behavior of honey bee workers contributes to the social immunity of colonies. The ability of workers to detect and remove unhealthy or dead brood prevents the transmission of brood diseases inside the colony. Over the last five decades, this trait has been extensively studied and improved in several research and breeding programs. Given the strong interest for hygienic behavior, we here review the costs and benefits associated with this trait, extending preceding reviews on this subject from the late 1990s. Since the 1990s, there have been no major new insights on the efficiency of this behavior against American foulbrood and chalkbrood. However, the number of publications on hygienic behavior against the mite Varroa destructor has considerably increased, fueling the debate regarding the efficiency of hygienic behavior against this parasite. Breeding programs have shown that selection for a specific trait might also impact other traits. Thus, we also review the cost of trade-offs between hygi...
33 citations
TL;DR: The results provide valuable insights into the tolerance mechanisms that contribute to the survival of A. m.
Abstract: Varroa destructor is an ectoparasitic pest of honeybees, and a threat to the survival of the apiculture industry. Several studies have shown that unlike European honeybees, African honeybee populations appear to be minimally affected when attacked by this mite. However, little is known about the underlying drivers contributing to survival of African honeybee populations against the mite. We hypothesized that resistant behavioral defenses are responsible for the survival of African honeybees against the ectoparasite. We tested this hypothesis by comparing grooming and hygienic behaviors in the African savannah honeybee Apis mellifera scutellata in Kenya and A. mellifera hybrids of European origin in Florida, USA against the mite. Grooming behavior was assessed by determining adult mite infestation levels, daily mite fall per colony and percentage mite damage (as an indicator of adult grooming rate), while hygienic behavior was assessed by determining the brood removal rate after freeze killing a section of the brood. Our results identified two additional undescribed damaged mite categories along with the six previously known damage categories associated with the grooming behavior of both honeybee subspecies. Adult mite infestation level was approximately three-fold higher in A. mellifera hybrids of European origin than in A. m. scutellata, however, brood removal rate, adult grooming rate and daily natural mite fall were similar in both honeybee subspecies. Unlike A. mellifera hybrids of European origin, adult grooming rate and brood removal rate did not correlate with mite infestation levels on adult worker honeybee of A. m. scutellata though they were more aggressive towards the mites than their European counterparts. Our results provide valuable insights into the tolerance mechanisms that contribute to the survival of A. m. scutellata against the mite.
TL;DR: These results show that insecticide sensitivity is dynamic throughout the 5 months test and underscore the importance of controlling for as many of these variables as possible in order to accurately determine the effects of each of these factors as they act alone or in concert with others.
Abstract: Since Varroa mites may cause devastating losses of honey bees through direct feeding, transmitting diseases, and increasing pathogen susceptibility, chemical and mechanical practices commonly are used to reduce mite infestation. While miticide applications are typically the most consistent and efficacious Varroa mite management method, miticide-induced insecticide synergism in honey bees, and the evolution of resistance in Varroa mites are reasonable concerns. We treated colonies with the miticide amitraz (Apivar®), used IPM practices, or left some colonies untreated, and then measured the effect of different levels of mite infestations on the sensitivity of bees to phenothrin, amitraz, and clothianidin. Sensitivity to all insecticides varied throughout the year among and within treatment groups. Clothianidin sensitivity decreased with increasing mite levels, but no such correlation was seen with phenothrin or amitraz. These results show that insecticide sensitivity is dynamic throughout the 5 months test. In-hive amitraz treatment according to the labeled use did not synergize sensitivity to the pesticides tested and this should alleviate concern over potential synergistic effects. Since IPM practices were largely ineffective at reducing Varroa mite infestation, reliance on chemical methods of Varroa mite management is likely to continue. However, miticides must be used judiciously so the long term effectiveness of these compounds can be maximized. These data demonstrate the complex and dynamic variables that contribute to honey bee colony health. The results underscore the importance of controlling for as many of these variables as possible in order to accurately determine the effects of each of these factors as they act alone or in concert with others.
TL;DR: It is found that acaricide exposure prior to grooming delayed grooming and reduced the overall duration of grooming behavior, adding to a list of other sublethal behavioral consequences of acaricides that may subvert a comprehensive approach to Varroa control in managed colonies.
Abstract: Varroa destructor is currently one of the main threats for western apiculture. Today, synthetic acaricides (specifically coumaphos, amitraz, and tau-fluvalinate) are the most common methods to control Varroa infestations. These compounds, however, are frequently related to a wide range of side effects in the host, as well as a long half-life inside the hive matrices (wax and honey). The western honey bee, Apis mellifera, exhibits natural defense mechanisms against the mite such as grooming behavior, which is a sequence of bodily movements where the host scrapes its legs across its body surface to remove the mite. We tested the effects of synthetic acaricides on the performance of grooming behavior by adult honey bee workers. We found that acaricide exposure prior to grooming delayed grooming and reduced the overall duration of grooming behavior. Our data add to a list of other sublethal behavioral consequences of acaricides that may subvert a comprehensive approach to Varroa control in managed colonies.
TL;DR: It is discussed that the trigger for grooming behavior may be density-dependent: grooming may be only beneficial at high mite infestation levels, and other resistance mechanisms than grooming are more likely to explain the varroa resistance of two resistant A. mellifera populations.
Abstract: The ectoparasitic mite Varroa destructor is an important cause of high colony losses of the honey bee Apis mellifera. In The Netherlands, two resistant A. mellifera populations developed naturally after ceasing varroa control. As a result, mite infestation levels of the colonies of these populations are generally between 5–10%. However, the mechanisms behind mite resistance are still unclear. Since grooming behavior is a typical resistance trait that occurs in A. mellifera, we compared grooming between colonies of these two resistant populations and control colonies that had been treated against varroa twice a year in previous years. Grooming was investigated by measuring mite fall in broodless colonies in the field and in small cages with a fixed number of mites and bees in the lab. Furthermore, grooming was investigated at the individual level by measuring the effectiveness to remove dust by individual bees from the resistant and control colonies. We found that the grooming behavior of resistant colonie...
TL;DR: Under contrasting natural conditions, environment seems a predominant driver on Varroa destructor infestation level in honey bee colonies.
TL;DR: A beekeeping case study where a beekeeper’s profit function is used to evaluate the economic impact of adopting colonies selected for hygienic behavior using marker-assisted selection (MAS) into an apiary shows a net profit gain from an MAS colony of between 2% and 5% when Varroa mites are effectively treated.
Abstract: Over the past decade in North America and Europe, winter losses of honey bee (Hymenoptera: Apidae) colonies have increased dramatically. Scientific consensus attributes these losses to multifactorial causes including altered parasite and pathogen profiles, lack of proper nutrition due to agricultural monocultures, exposure to pesticides, management, and weather. One method to reduce colony loss and increase productivity is through selective breeding of queens to produce disease-, pathogen-, and mite-resistant stock. Historically, the only method for identifying desirable traits in honey bees to improve breeding was through observation of bee behavior. A team of Canadian scientists have recently identified markers in bee antennae that correspond to behavioral traits in bees and can be tested for in a laboratory. These scientists have demonstrated that this marker-assisted selection (MAS) can be used to produce hygienic, pathogen-resistant honey bee colonies. Based on this research, we present a beekeeping case study where a beekeeper's profit function is used to evaluate the economic impact of adopting colonies selected for hygienic behavior using MAS into an apiary. Our results show a net profit gain from an MAS colony of between 2% and 5% when Varroa mites are effectively treated. In the case of ineffective treatment, MAS generates a net profit benefit of between 9% and 96% depending on the Varroa load. When a Varroa mite population has developed some treatment resistance, we show that MAS colonies generate a net profit gain of between 8% and 112% depending on the Varroa load and degree of treatment resistance.
TL;DR: Clinical trials showed that the acaricide is efficacious and safe for colonies, and is ready-to-use, safe for users and suitable for organic farming.
Abstract: A new veterinary medicinal product called Varterminator for varroa mite control has been developed. The medicine is made of a gel containing formic acid (FA) and is able to produce a passive evaporation of FA and to guarantee a high degree of safety for the bee colony. To verify the efficacy of the treatment and the effect on eggs, larvae, adult bees and queens, clinical trials were performed in several apiaries spread throughout Italy, under different climatic and regional conditions. The average acaricide efficacy rate was more than 95%, with a maximum level of 99%. With regard to safety, no adverse reactions were observed on larvae, adult bees and queens when compared to untreated colonies. One adverse reaction was noted, however, a high mortality of eggs. The eggs were quickly replaced by the queen in a few days, without affecting the wellbeing of the colony. The results showed that the acaricide is efficacious and safe for colonies. The medicine can be used with brood, throughout the season of the be...
TL;DR: A cross-sectional study carried out in Galicia, NW Spain, in order to estimate the magnitude of honey bee colony losses and to identify potential risk factors involved found Nosema ceranae was found to be the only risk factor strongly associated with colony loss.
Abstract: A cross-sectional study was carried out in Galicia, NW Spain, in order to estimate the magnitude of honey bee colony losses and to identify potential risk factors involved. A total of 99 samples from 99 apiaries were collected in spring using simple random sampling. According to international guidelines, the apiaries were classified as affected by colony loss or asymptomatic. Each sample consisted of worker bees, brood and comb-stored pollen. All worker bees and brood samples were analysed individually in order to detect the main honey bee pathogens. Moreover, the presence of residues of the most prevalent agrotoxic insecticides and acaricides was assessed in comb-stored pollen. The general characteristics of the apiaries and sanitary information regarding previous years was evaluated through questionnaires, while the vegetation surrounding the apiaries sampled was assessed by palynological analysis of comb-stored pollen. The colony loss prevalence was 53.5% (CI95%=43.2-63.9) and Nosema ceranae was found to be the only risk factor strongly associated with colony loss. The decision tree also pointed out the impact of the Varroa mite presence while variables such as apiary size, the incorrect application of Varroa mite treatments, and the presence of Acarapis woodi and Kashmir bee virus (KBV) were identified as possible co-factors.
TL;DR: Varroa Sensitive Hygiene (VSH) is a useful resistance trait that honey bee breeders could increase in different populations with cost-effective and reliable tests and variances can be used to estimate the number of repeated tests required to detect true differences between colonies.
Abstract: Varroa Sensitive Hygiene (VSH) is a useful resistance trait that honey bee (Apis mellifera) breeders could increase in different populations with cost-effective and reliable tests. We investigated ...
TL;DR: Fertility and reproductive rate of Varroa mite in capped brood cells of the native honey bee subspecies were investigated and compared with an exotic honeybee subspecies, A. m.
TL;DR: Wu et al. as mentioned in this paper showed that honey bees reared in brood comb containing high levels of pesticide residues exhibit increased brood mortality and shorter adult longevity, which may be attributed to chronic exposure to a suite of agrochemicals.
Abstract: Honey bees (Apis mellifera L.) provide essential pollination services for agricultural production worldwide. Recent declines in honey bee populations have been attributed to a multitude of potential stressors, such as pest pressure, nutritional stress, and exposure to pesticides (vanEngelsdorp et al. 2009b). One possible explanation for bee decline is the accumulation of pesticide residues in honey bee brood comb, resulting in chronic exposure to a suite of agrochemicals which may detrimentally influence honey bee health. Wu et al. (2011) demonstrated that bees reared in brood comb containing high levels of pesticide residues exhibit increased brood mortality and shorter adult longevity.
01 Jan 2017
TL;DR: The case of natural selection of honeybees in France against varroa is described and it is found that the reproduction of the mite and/or thevarroa sensitive hygiene are probably key factors in the survival of those bees.
Abstract: After varroa invaded Europe in the mid of twentieth century, a few populations of honeybee colonies have been found to survive the mite. This chapter describes the case of natural selection of honeybees in France against varroa. Different hypotheses have been tested to explain this phenomenon, such as resistance of the bees to the mite or to the associated viruses and the lower virulence of the mites. We found that the reproduction of the mite and/or the varroa sensitive hygiene are probably key factors in the survival of those bees. Other varroa resistant honeybee populations have been found in several other countries and are also described as well as the putative mechanisms of survival. Finally, we discuss the interest of those bees for scientists and beekeepers in the framework of honeybee selection and describe the successful approaches lead by scientists for honeybee selection on a specific trait.
TL;DR: Under conditions where FWM populations are similar between RHB and USL, attributes that contribute to mite resistance in RHB may not keep Varroa population levels below that of USL.
Abstract: Varroa (Varroa destructor Anderson and Trueman) is an external parasite of honey bees (Apis mellifera L.) and a leading cause of colony losses worldwide. Varroa populations can be controlled with miticides, but mite-resistant stocks such as the Russian honey bee (RHB) also are available. Russian honey bee and other mite-resistant stocks limit Varroa population growth by affecting factors that contribute to mite reproduction. However, mite population growth is not entirely due to reproduction. Numbers of foragers with mites (FWM) entering and leaving hives also affect the growth of mite populations. If FWM significantly contribute to Varroa population growth, mite numbers in RHB colonies might not differ from unselected lines (USL). Foragers with mites were monitored at the entrances of RHB and USL hives from August to November, 2015, at two apiary sites. At site 1, RHB colonies had fewer FWM than USL and smaller phoretic mite populations. Russian honey bee also had fewer infested brood cells and lower percentages with Varroa offspring than USL. At site 2, FWM did not differ between RHB and USL, and phoretic mite populations were not significantly different. At both sites, there were sharp increases in phoretic mite populations from September to November that corresponded with increasing numbers of FWM. Under conditions where FWM populations are similar between RHB and USL, attributes that contribute to mite resistance in RHB may not keep Varroa population levels below that of USL.
01 Jun 2017
TL;DR: Residues of all tested insecticides persisted after the application was highly toxic to A. mellifera, focusing on the indirect application hazards to the honey bees.
Abstract: Study on persistence toxicity of different insecticides focusing newer compounds (imidacloprid, flipronil, and indoxacarb), conventional insecticides (dimethoate and cypermenthrin) and botanical insecticide (azadirachtin) to Apis mellifera was conducted on sunflower. Fipronil recorded higher residual toxicity to honey bees with a PT50 value of 5.83 days. It was followed by imidacloprid (5.74 days), cypermethrin (4.38 days), dimethoate (2.56 days) and indoxacarb (2.02 days). The order of relative persistence of insecticides was: fipronil 45 g a.i./ha > imidacloprid 20 g a.i./ha > cypermethrin 65 g a.i./ha > dimethoate 200 g a.i./ha > indoxacarb 44 g a.i./ha. Residues of all tested insecticides persisted after the application was highly toxic to A. mellifera. Findings focus on the indirect application hazards to the honey bees.
TL;DR: The results of this study suggest that co-infestations with V. destructor and DWV in feral honey bees have more serious consequences than co-infections with Nosema sp.
Abstract: Feral bees colonizing large forest habitats without human intervention are also affected by diseases. Infected bees that survive several seasons constitute an interesting object of scientific inquiry. Little is known about the health and status of feral honey bee populations. The pathogens infesting/infecting bee colonies and the biochemical status of unhealthy bees need to be studied to prevent the global decline in bee populations. Honey bees inhabiting hollow trees in forest reserves of north-eastern Poland, infected with Nosema ceranae or infested with Varroa destructor and/or infected with the deformed wing virus (DWV), were analyzed. Differences in the analyzed biochemical parameters were noted in groups infected/infested with various pathogens relative to the control group. The most significant variations were observed in antioxidant parameters: lower total antioxidant status (TAS) (excluding group N. ceranae), lower activity of superoxide dismutase (SOD) and peroxidase (POX) (excluding group N. ce...
07 Jun 2017
Journal Article•
TL;DR: The results revealed that among chemicals, Taufluvalinate (2 strips per colony) was found highly effective against the V. destructor mite followed by Formic acid 85% @ 2 ml per colony but in case of botanicals green leaf extract mixture @ 150ml/colony was foundhighly effective against Varroa mite.
Abstract: The present investigation was carried out to evaluate the chemicals (Formic acid, Oxalic acid and Taufluvalinate) and botanicals (Artemesia annua, Matricaria chamomilla, Juglans regia and mixture A. annua + M. chamomilla + J. regia) under Complete Randomised Block Design (RCBD) for management of V. destructor during 2016 at Faculty of Agriculture, Wadura SKUAST-Kashmir. The results revealed that among chemicals, Taufluvalinate (2 strips per colony) was found highly effective against the V. destructor mite followed by Formic acid 85% @ 2 ml per colony but in case of botanicals green leaf extract mixture @ 150ml/colony was found highly effective against Varroa mite followed by M. chamomilla. The order of efficacy of treatments was Taufluvalinate (78.93%) > Formic acid (74.83%) > Oxalic acid (72.16 %) > GLE mixture (67.10 %) > M. chamomilla (63.83%) > A. annua (61.87%) > J. regia (58.34 %). Bio leaf extracts need to be integrated in such a way that there may be no hazard to the bees, moreover further studies on these extracts need to be explored.
TL;DR: One interesting observation is that at the time of collapse, Varroa mite populations were not at International Journal of Current Microbiology and Applied Sciences ISSN: 2319-7706 Volume 6 Number 2 (2017) pp. 1574-1579.
Abstract: The ectoparastic mite, Varroa destructor is considered as one of the most serious pest, causing tremendous damage to honey bee (Apis mellifera L) and great economic loss to the beekeeping industry (Anderson and Trueman, 2000;Al-Abbadi and Nazer, 2003). Parasitism can result in a loss of up to 25% of adult weight, severe deformations of the wing and reduced longevity of workers and drones (Kanga and James, 2002). Colonies infested with Varroa destructor have significantly reduced worker bee populations and eventually die, if left without controlling (Sammataro, 1997). The Varroa mite has a negative effect on honey production as well as other bee products and can facilitate the horizontal transmission of Deformed Wing Virus, Sac Brood Virus and Kashmir Bee Virus from nurse bees to larvae through larval food and via brood to adults (Chen et al., 2004). It can also be transmitted vertically by drones via semen and by queens via virus infected eggs (Yue et al., 2006, 2007). In addition, there is evidence for horizontal miteto-mite transmission of viruses (BowenWalker et al., 1999; Chen et al., 2005). One interesting observation is that at the time of collapse, Varroa mite populations were not at International Journal of Current Microbiology and Applied Sciences ISSN: 2319-7706 Volume 6 Number 2 (2017) pp. 1574-1579 Journal homepage: http://www.ijcmas.com
TL;DR: There is a need for constant monitoring of bee pests and diseases in honeybee colonies in the country for early detection and to provide data on the status of bee health, and all stakeholders in the beekeeping value chain should be enlightened on their role in pest and disease transmission.
Abstract: Varroa mite (Varroa destructor Anderson and Trueman) is a major global threat to the western honey bee (Apis mellifera L.). The ectoparasite has been implicated in the spread of honeybee viruses. Beekeeping plays a major role in transmission of the mite. The study aimed at assessing levels of Varroa infestation, bee viruses and bacteria incidences in domesticated honeybee colonies. Samples of adult honey bees, bee brood and Varroa mites were collected from Baringo, Narok, Kwale, Magarini, Voi, Ijara, Busia and Siaya in Kenya. Ten hives in each site were inspected for the presence of Varroa mites on adult bees using the icing sugar technique and forceps in sealed brood cells. The number of mites observed were recorded per site. Ribonucleic acid was extracted from the mites, brood and adult bees and a polymerase chain reaction was performed to detect the black queen cell virus. Pooled RNA samples of brood and adult bees were used in next generation sequencing on a 454 GS FLX platform to detect bee v...