What
the Science Shows
Since 2007, researchers have increased their efforts to find a cause for the CCD phenomena. The issue is diverse and complex, with many factors potentially contributing to the cause including parasites, pesticides and stress.
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Multiple routes of pesticide exposure for honey bees living near agricultural fields.
Study analyzed samples of honey bees, pollen stored in the hive and several potential exposure routes associated with plantings of neonicotinoid treated maize. Results demonstrate that bees are exposed to these compounds and several other agricultural pesticides in several ways throughout the foraging period. During spring, extremely high levels of clothianidin and thiamethoxam were found in planter exhaust material produced during the planting of treated maize seed. Study also found neonicotinoids in the soil of each field we sampled, including unplanted fields. Plants visited by foraging bees (dandelions) growing near these fields were found to contain neonicotinoids as well. This indicates deposition of neonicotinoids on the flowers, uptake by the root system, or both. Dead bees collected near hive entrances during the spring sampling period were found to contain clothianidin as well. Study also detected the insecticide clothianidin in pollen collected by bees and stored in the hive. When maize plants in our field reached anthesis, maize pollen from treated seed was found to contain clothianidin and other pesticides; and honey bees in our study readily collected maize pollen. These findings clarify some of the mechanisms by which honey bees may be exposed to agricultural pesticides throughout the growing season. -
RFID Tracking of Sublethal Effects of Two Neonicotinoid Insecticides on the Foraging Behavior of Apis mellifera.
Study tested an experimental design using the radiofrequency identification (RFID) method to monitor the influence of sublethal doses of insecticides on individual honeybee foragers on an automated basis. In this experimental approach the authors monitored the acute effects of sublethal doses of the neonicotinoids imidacloprid (0.15-6 ng/bee) and clothianidin (0.05-2 ng/bee) under field-like circumstances. At field-relevant doses for nectar and pollen no adverse effects were observed for either substance. Both substances led to a significant reduction of foraging activity and to longer foraging flights at doses of ≥0.5 ng/bee (clothianidin) and ≥1.5 ng/bee (imidacloprid) during the first three hours after treatment. This study demonstrates that the RFID-method is an effective way to record short-term alterations in foraging activity after insecticides have been administered once, orally, to individual bees. - Exposure to Sublethal Doses of Fipronil and Thiacloprid Highly Increases Mortality of Honeybees Previously Infected by Nosema ceranae
This study explores the effect of Nosema ceranae infection on honeybee sensitivity to sublethal doses of the insecticides fipronil and thiacloprid. Honeybee mortality and insecticide consumption were analyzed daily and the intestinal spore content was evaluated 20 days after infection. A significant increase in honeybee mortality was observed when N. ceranae-infected honeybees were exposed to sublethal doses of insecticides. Analysis of the honeybee detoxification system 10 days p.i. showed that N. ceranae infection induced an increase in glutathione-S-transferase activity in midgut and fat body. The synergistic effect of N. ceranae and insecticide on honeybee mortality, however, did not appear strongly linked to a decrease of the insect detoxification system. These data support the hypothesis that the combination of the increasing prevalence of N. ceranae with high pesticide content in beehives may contribute to colony depopulation. - Fatal powdering of bees in flight with particulates of neonicotinoids seed coating and humidity implication
The effect of direct aerial powdering was tested on foragers in free flight near the drilling machine. Bees were conditioned to visit a dispenser of sugar solution whilst a drilling machine was sowing corn along the flight path. Samples of bees were captured on the dispenser, caged and held in the laboratory. Chemical analysis showed some hundred nanograms of insecticide per bee. Nevertheless, caged bees, previously contaminated in flight, died only if kept in conditions of high humidity. After the sowing, an increase in bee mortality in front of the hives was also observed. Spring bee losses, which corresponded with the sowing of corn-coated seed, seemed to be related to the casual encountering of drilling machine during foraging flight across the ploughed fields. - Neonicotinoid insecticides translocated in guttated droplets of seed-treated maize and wheat: a threat to honeybees?
This experiment demonstrates that guttated water of plants germinated from seeds dressed with neonicotinoids contains neonicotinoids. Maize seeds treated with clothianidin (Poncho® 0.5 mg/seed and Poncho® Pro 1.25 mg/seed) resulted in neonicotinoid concentrations up to 8,000 ng mL−1 in the guttated fluid. This concentration decreases rapidly, but remained detectable over several weeks. Seeds treated with Poncho® Pro did not result in higher concentrations in guttated droplets in the first stages of plant development, but the concentration decreased more slowly. Triticale seed treated with imidacloprid contained small quantities of this active agent (up to 13 ng mL−1) in the guttated fluid the following spring after overwintering. - Sub-Lethal Effects of Pesticide Residues in Brood Comb on Worker Honey Bee (Apis mellifera) Development and Longevity
Synopsis: Researchers conducted studies to examine possible direct and indirect effects of pesticide exposure from contaminated brood comb on developing worker bees and adult worker lifespan. Results demonstrate sub-lethal effects on worker honey bees from pesticide residue exposure from contaminated brood comb. Sub-lethal effects, including delayed larval development and adult emergence or shortened adult longevity, can have indirect effects on the colony such as premature shifts in hive roles and foraging activity. - Rapid
analysis of neonicotinoid insecticides in guttation drops of corn seedlings
obtained from coated seeds
Synopsis: In the present study, guttation drops of corn plants obtained from commercial seeds coated with thiamethoxam, clothianidin, imidacloprid and fipronil have been analyzed. The young plants grown both in pots – in greenhouse – and in open field from coated seeds, produced guttation solutions containing high levels of the neonicotinoid insecticides (up to 346 mg L-1 for imidacloprid, 102 mg L-1 for clothianidin and 146 mg L-1 for thiamethoxam). These concentration levels may represent lethal doses for bees that use guttation drops as a source of water. The neonicotinoid concentrations in guttation drops progressively decrease during the first 10–15 days after the emergence of the plant from the soil. Otherwise fipronil, which is a non-systemic phenylpyrazole insecticide, was never detected into guttation drops. Current results confirm that the physiological fluids of the corn plant can effectively transfer neonicotinoid insecticides from the seed onto the surface of the leaves, where guttation drops may expose bees and other insects to elevated doses of neurotoxic insecticides. - The
impact of neonicotinoid insecticides on bumblebees, Honey bees and other
non-target invertebrates
Synopsis: This report reviews existing approvals research and independent research on the effects of neonicotinoid pesticides on Honey bees, bumblebees and other non-target invertebrates, and investigates the current approvals mechanism and its standards. - Abnormal
Foraging Behavior Induced by Sublethal Dosage of Imidacloprid in the
Honey Bee (Hymenoptera: Apidae)
Synopsis: Although sublethal dosages of insecticide to nontarget insects have never been an important issue, they are attracting more and more attention lately. It has been demonstrated that low dosages of the neonicotinoid insecticide imidacloprid may affect honey bee, Apis mellifera L., behavior. In this article, the foraging behavior of the honey bee workers was investigated to show the effects of imidacloprid. Results demonstrated that sublethal dosages of imidacloprid were able to affect foraging behavior of honey bees. - Pesticides
and honey bee toxicity – USA
Synopsis: This review examines pesticides applied to crops, pesticides used in apiculture and pesticide residues in hive products. Authors discuss the role that pesticides and their residues in hive products may play in colony collapse disorder and other colony problems. Although no single pesticide has been shown to cause colony collapse disorder, the additive and synergistic effects of multiple pesticide exposures may contribute to declining honey bee health.
- High
Levels of Miticides and Agrochemicals in North American Apiaries: Implications
for Honey Bee Health
Synopsis: Recent declines in honey bees for crop pollination threaten fruit, nut, vegetable and seed production in the United States. A broad survey of pesticide residues was conducted on samples from migratory and other beekeepers across 23 states, one Canadian province and several agricultural cropping systems during the 2007–08 growing seasons. The 98 pesticides and metabolites detected in mixtures up to 214 ppm in bee pollen alone represents a remarkably high level for toxicants in the brood and adult food of this primary pollinator. This represents over half of the maximum individual pesticide incidences ever reported for apiaries. While exposure to many of these neurotoxicants elicits acute and sublethal reductions in honey bee fitness, the effects of these materials in combinations and their direct association with CCD or declining bee health remains to be determined. See: Daily News Blog. - Effects
of sublethal concentrations of bifenthrin and deltamethrin on fecundity,
growth, and development of the honeybee Apis mellifera ligustica
Synopsis: Bifenthrin and deltamethrin have been widely used as pesticides in agriculture and forestry and are becoming an increasing risk to honeybees. The honeybee, Apis mellifera ligustica, is widely recognized as a beneficial insect of agronomic, ecological, and scientific importance. It is important to understand what effects these chemicals have on bees. Effects of two pesticides at sublethal concentrations on fecundity, growth, and development of honeybees were examined with the feeding method for a three-year period (2006–2008). It was shown that both bifenthrin and deltamethrin significantly reduced bee fecundity, decreased the rate at which bees develop to adulthood, and increased their immature periods. The toxicity of bifenthrin and deltamethrin on workers of Apis mellifera ligustica was also assessed, and the results from the present study showed that the median lethal effects of bifenthrin and deltamethrin were 16.7 and 62.8?mg/L, respectively. See Daily News Blog.
- Synergistic
Interactions Between In-Hive Miticides in Apis mellifera
Synopsis : The varroa mite, Varroa destructor Anderson & Trueman, is a devastating pest of honey bees, Apis mellifera L., that has been primarily controlled over the last 15 yr with two in-hive miticides: the organophosphate coumaphos (Checkmite+), and the pyrethroid tau-fluvalinate (Apistan). In this laboratory study, the authors observed a large increase in the toxicity of tau-fluvalinate to 3-day-old bees that had been treated previously with coumaphos, and a moderate increase in the toxicity of coumpahos in bees treated previously with tau-fluvalinate. The observed synergism may result from competition between miticides. These results suggest that honey bee mortality may occur with the application of otherwise sublethal doses of miticide when tau-fluvalinate and coumaphos are simultaneously present in the hive.
- Translocation
of Neonicotinoid Insecticides From Coated Seeds to Seedling Guttation
Drops: A Novel Way of Intoxication for Bees
Synopsis: The death of honey bees, Apis mellifera L., and the consequent colony collapse disorder causes major losses in agriculture and plant pollination worldwide. The phenomenon showed increasing rates in the past years, although its causes are still awaiting a clear answer. Here, we show that leaf guttation drops of all the corn plants germinated from neonicotinoid-coated seeds contained amounts of insecticide constantly higher than 10 mg/l, with maxima up to 100 mg/l for thiamethoxam and clothianidin, and up to 200 mg/l for imidacloprid. The concentration of neonicotinoids in guttation drops can be near those of active ingredients commonly applied in field sprays for pest control, or even higher. When bees consume guttation drops, collected from plants grown from neonicotinoid-coated seeds, they encounter death within few minutes. - Interactions between Nosema microspores and a neonicotinoid weaken honeybees (Apis mellifera) Synopsis: Global pollinators, like honeybees, are declining in abundance and diversity, which can adversely affect natural ecosystems and agriculture. The authors tested the current hypotheses describing honeybee losses as a multifactorial syndrome, by investigating integrative effects of an infectious organism and an insecticide on honeybee health. Study demonstrated that the interaction between the microsporidia Nosema and a neonicotinoid (imidacloprid) significantly weakened honeybees. In the short term, the combination of both agents caused the highest individual mortality rates and energetic stress. This provides the first evidences that interaction between an infectious organism and a chemical can also threaten pollinators, interactions that are widely used to eliminate insect pests in integrative pest management.
- Toxicities
of fipronil enantiomers to the honeybee Apis mellifera L. and enantiomeric
compositions of fipronil in honey plant flowers.
Synopsis: Fipronil is a chiral phenylpyrazole insecticide that is effective for control of a wide range of agricultural and domestic pests at low application rates. Wide application of fipronil also causes poisoning of some nontarget insects, such as honeybees. In the present study, toxicities of fipronil enantiomers and racemate to the honeybee Apis mellifera L. were determined to examine whether using formulations of single or enriched fipronil enantiomer is a possible option to reduce risks to bees. The results indicate that it is unlikely that use of formulations with single or enriched fipronil enantiomer would reduce the risk that fipronil poses to honeybees. Improved fipronil application practices (based on safest timing and bloom conditions) and reduction of overall fipronil usage seem to be more realistic options. - Is
Apis mellifera more sensitive to insecticides than other insects?
Synopsis: The goal of this review was to summarize insecticide toxicity data between A. mellifera and other insects to determine the relative sensitivity of honey bees to insecticides. It was found that, in general, honey bees were no more sensitive than other insect species across the 62 insecticides examined. In addition, honey bees were not more sensitive to any of the six classes of insecticides (carbamates, nicotinoids, organochlorines, organophosphates, pyrethroids and miscellaneous) examined. While honey bees can be sensitive to individual insecticides, they are not a highly sensitive species to insecticides overall, or even to specific classes of insecticides. However, all pesticides should be used in a way that minimizes honey bee exposure, so as to minimize possible declines in the number of bees and/or honey contamination. - Exposure
to pesticides at sublethal level and their distribution within a honey
bee (Apis mellifera) colony.
Synopsis: Honey bee colonies were exposed to pesticides used in agriculture or within bee hives by beekeepers: coumaphos; diazinon; amitraz or fluvalinate. Samples of bee workers, larvae and royal jelly were analysed. Amitraz residues in all sampled material were below the level of detection of 10 ng/g. Diazinon was not detected in any of the analysed samples. The large quantities of fluvalinate found in bee heads and larvae, the coumaphos residues in royal jelly, and additional potential sub-lethal effects on individual honey bees or brood are discussed. - The
relevance of sublethal effects in honey bee testing for pesticide risk
assessment.>
Synopsis: The option of an evaluation and assessment of possible sublethal effects of pesticides on bees has been a subject of discussion by scientists and regulatory authorities. Effects considered included learning behaviour and orientation capacity. This paper considers whether and, if so, how sublethal effects should be incorporated into risk assessment, by addressing a number of questions: The authors conclude that sublethal studies may be helpful as an optional test to address particular, compound-specific concerns, as a lower-tier alternative to semi-field or field testing, if the effects are shown to be ecologically relevant. However, available higher-tier data (semi-field, field tests) should make any additional sublethal testing unnecessary, and higher-tier data should always override data of lower-tier trials on sublethal effects. - Is
it possible to use the honey bee adult as a bioindicator for the detection
of pesticide residues in plants?
Synopsis: Pesticide residues are usually determined by physical, chemical and biological methods. Theoretically, any organism that is susceptible to a pesticide may be used for its bioassay in any environmental sample. This means that such organism may serve as a bioindicator for the detection of certain pollutants. The susceptibility of honey bees (Apis melifera L.) to many insecticides commonly used in crop protection led to an attempt to use it as a bioindicator for the determination of residues of some insecticides in plant materials, as well as to detect toxicity hazards to honey bees of some commonly used insecticides. Results of this work which have been recently published may suggest "Yes" to answer the question posed in the title of this subject.
- Risk
assessment for side-effects of neonicotinoids against bumblebees with
and without impairing foraging behavior.
Synopsis: Bombus terrestris bumblebees are important pollinators of wild flowers, and in modern agriculture they are used to guarantee pollination of vegetables and fruits. In the field it is likely that worker bees are exposed to pesticides during foraging. Within the context of ecotoxicology and insect physiology, study reports the development of a new bioassay to assess the impact of sublethal concentrations on the bumblebee foraging behavior under laboratory conditions. In general, the experiments showed that concentrations that may be considered safe for bumblebees can have a negative influence on their foraging behavior. Therefore it is recommended that behavior tests should be included in risk assessment tests for highly toxic pesticides because impairment of the foraging behavior can result in a decreased pollination, lower reproduction and finally in colony mortality due to a lack of food. - Subchronic
exposure of honeybees to sublethal doses of pesticides: effects on behavior.
Synopsis: Laboratory bioassays were conducted to evaluate the effects on honeybee behavior of sublethal doses of insecticides chronically administered orally or by contact. After exposure to fipronil, acetamiprid or thiamethoxam, behavioral functions of honeybees were tested on day 12. Fipronil, used at the dose of 0.1 ng/bee, induced mortality of all honeybees after one week of treatment. In the olfactory conditioning paradigm, fipronil-treated honeybees failed to discriminate between a known and an unknown odorant. Thiamethoxam by contact induced either a significant decrease of olfactory memory 24 h after learning at 0.1 ng/bee or a significant impairment of learning performance with no effect on memory at 1 ng/bee. The only significant effect of acetamiprid (administered orally, 0.1 microg/bee) was an increase in responsiveness to water. Data on the intrinsic toxicity of the compounds after chronic exposure have to be taken into account for evaluation of risk to honeybees in field conditions. - Comparative
sublethal toxicity of nine pesticides on olfactory learning performances
of the honeybee Apis mellifera.
Synopsis: Using a conditioned proboscis extension response (PER) assay, honeybees (Apis mellifera L.) can be trained to associate an odor stimulus with a sucrose reward. In the present study, the effects of sublethal concentrations of nine pesticides on learning performances of worker bees subjected to the PER assay were estimated and compared. Reduced learning performances were observed for bees surviving treatment with fipronil, deltamethrin, endosulfan, and prochloraz. A lack of behavioral effects after treatment with lambda-cyalothrin, cypermethrin, tau-fluvalinate, triazamate, and dimethoate was recorded. - Residues
of Pesticides in honeybee (Apis mellifera carnica) bee bread and in
pollen loads from treated apple orchards.
Synopsis: Honey bee (Apis mellifera carnica) colonies were placed in two apple orchards treated with the insecticides diazinon and thiacloprid and the fungicide difenoconazole in accordance with a Protection Treatment Plan in the spring of 2007. Possible sub-lethal effects on individual honey bees and brood are discussed. - The
Significance of the Druckrey-Küpfmüller Equation for Risk
Assessment - The Toxicity of Neonicotinoid Insecticides to Arthropods
is Reinforced by Exposure Time
Synopsis: The Druckrey-Küpfmüller equation explains why toxicity may occur after prolonged exposure to very low toxicant levels. Recently, similar dose-response characteristics have been established for the toxicity of the neonicotinoid insecticides imidacloprid and thiacloprid to arthropods. This observation is highly relevant for environmental risk assessment. Traditional approaches that consider toxic effects at fixed exposure times are unable to allow extrapolation from measured endpoints to effects that may occur at other times of exposure. Time-to-effect approaches that provide information on the doses and exposure times needed to produce toxic effects on tested organisms are required for prediction of toxic effects for any combination of concentration and time in the environment. See: Daily News Blog.
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Pesticide exposure in honey bees results in increased levels of the gut pathogen Nosema.
Study exposed honey bee colonies during three brood generations to sub-lethal doses of a widely used pesticide, imidacloprid, and then subsequently challenged newly emerged bees with the gut parasite, Nosema spp. The pesticide dosages used were below levels demonstrated to cause effects on longevity or foraging in adult honey bees. Nosema infections increased significantly in the bees from pesticide-treated hives when compared to bees from control hives demonstrating an indirect effect of pesticides on pathogen growth in honey bees. Interactions between pesticides and pathogens could be a major contributor to increased mortality of honey bee colonies, including colony collapse disorder, and other pollinator declines worldwide. -
A New Threat to Honey Bees, the Parasitic Phorid Fly Apocephalus borealis.
Study provides the first documentation that the phorid fly Apocephalus borealis, previously known to parasitize bumble bees, also infects and eventually kills honey bees and may pose an emerging threat to North American apiculture. Parasitized honey bees show hive abandonment behavior, leaving their hives at night and dying shortly thereafter. On average, seven days later up to 13 phorid larvae emerge from each dead bee and pupate away from the bee. Using DNA barcoding, study confirmed that phorids that emerged from honey bees and bumble bees were the same species. Phorid parasitism may affect hive viability since 77% of sites sampled in the San Francisco Bay Area were infected by the fly and microarray analyses detected phorids in commercial hives in South Dakota and California's Central Valley. Study concludes that understanding details of phorid infection may shed light on similar hive abandonment behaviors seen in CCD. - Iridovirus
and Microsporidian Linked to Honey Bee Colony Decline
Synopsis: In 2010 Colony Collapse Disorder (CCD), again devastated honey bee colonies in the USA, indicating that the problem is neither diminishing nor has it been resolved. Many CCD investigations, using sensitive genome-based methods, have found small RNA bee viruses and the microsporidia, Nosema apis and N. ceranae in healthy and collapsing colonies alike with no single pathogen firmly linked to honey bee losses. These findings implicate co-infection by invertebrate iridescent virus (IIV) (Iridoviridae) and Nosema with honey bee colony decline, giving credence to older research pointing to IIV, interacting with Nosema and mites, as probable cause of bee losses in the USA, Europe, and Asia. See: Daily News Blog. - Nosema
ceranae, a newly identified pathogen of Apis mellifera in the U.S. and
Asia
Synopsis: Nosemosis (Nosema disease) is one of the most serious and prevalent adult honey bee diseases worldwide. For years, Nosema apis was thought to be the only microsporidia infecting domestic bee colonies. However, recently it was discovered that N. ceranae could jump from Asian honey bees (Apis cerana) to European honey bees (Apis mellifera) that are widely used for crop pollination. The data presented in the studies demonstrated that N. ceranae infection is widespread in the U.S., China and Australia and that infection with N. ceranae was more common than infection with N. apis in European honey bees. The finding about the prevalence of N. ceranae in the U.S. and Asian bee populations in conjunction with findings in other parts of the world invites further research of the evolutionary history of N. ceranae infection in European honey bees. - Winter losses of honeybee colonies (Apis mellifera): The role of infestations
with Aethina tumida and Varroa destructor
Synopsis: Multiple infections and infestations of honeybee colonies with pathogens and parasites are inevitable due to the ubiquitous ectoparasitic mite Varroa destructor and might be one of the mechanisms underlying winter losses. Here the authors investigated the role of adult small hive beetles, Aethina tumida, alone and in combination with V. destructor for winter losses and infections with the microsporidian endoparasite Nosema ceranae. High losses occurred in all groups highly infested with V. destructor, supporting the central role of this mite in colony losses. Data suggest that A. tumida alone is unlikely to contribute to losses of overwintering honeybee colonies. - Changes
in Gene Expression Relating to Colony Collapse Disorder in honey bees,
Apis mellifera
Synopsis: Colony collapse disorder (CCD) is a mysterious disappearance of honey bees that has beset beekeepers in the United States since late in 2006. Pathogens and other environmental stresses, including pesticides, have been linked to CCD, but a causal relationship has not yet been demonstrated. Considerable variation in gene expression was associated with the geographical origin of bees, but a consensus list of 65 transcripts was identified as potential genetic markers for CCD status. Reduced expression of two genes associated with detoxification and a mixed response from genes involved in immune function were observed. Unusual ribosomal RNA fragments were also conspicuously more abundant in CCD bee guts. The presence of these fragments may be a possible consequence of picornavirus infection. Ribosomal fragment abundance and viral presence may prove useful as diagnostic markers for colonies afflicted with CCD. - Honeybee
Sacbrood virus infects adult small hive beetles, Aethina tumida (Coleoptera:
Nitidulidae)
Synopsis: The Small Hive Beetle (SHB) is a recently discovered pest that invades honey bee colonies and causes damage to comb, stored honey and pollen. A laboratory experiment was conducted to investigate whether SHB could harbor honey bee virus(es) via feeding on virus infected brood and thereby serving as a vector of viruses in honey bee colonies. Study demonstrated for the first time that SHB could become infected with honey bee Sacbrood virus (SBV) via the food-borne transmission route. This study should raise awareness among scientists, beekeepers, and regulatory personnel to the threats of SHB not only for its directly negative impact on bee health but also for its ability to transmit viral diseases in bee colonies. - Entombed
pollen: A new condition in honey bee colonies associated with increased
risk of colony mortality
Synopsis: Here we describe a new phenomenon, entombed pollen, which is highly associated with increased colony mortality. Entombed pollen appears as sunken, wax-covered cells amidst "normal", uncapped cells of stored pollen, and the pollen contained within these cells is brick red in color. The increased incidence of entombed pollen in reused wax comb suggests that there is a transmittable factor common to the phenomenon and colony mortality. In addition, there were elevated pesticide levels, notably of the fungicide chlorothalonil, in entombed pollen. Additional studies are needed to determine if there is a causal relationship between entombed pollen, chemical residues, and colony mortality. - Differential
gene expression of the honey bee Apis mellifera associated with Varroa
destructor infection.
Synopsis: The parasitic mite, Varroa destructor, is the most serious pest of the western honey bee, Apis mellifera, and has caused the death of millions of colonies worldwide. Authors investigated whether Varroa infestation induces changes in Apis mellifera gene expression, and whether there are genotypic differences in the bee’s tolerance, as first steps toward unraveling mechanisms of host response and differences in susceptibility to Varroa parasitism. Results suggest that differences in behavior, rather than in the immune system, underlie Varroa tolerance in honey bees. They provide a first step toward better understanding molecular pathways involved in this particular host-parasite relationship. - A
metagenomic survey of microbes in honey bee colony collapse disorder
Synopsis: In Colony Collapse Disorder (CCD), honey bee colonies inexplicably lose all of their workers. CCD has resulted in a loss of 50-90% of colonies in beekeeping operations across the United States. The observation that irradiated combs from affected colonies can be repopulated with naïve bees suggests an infectious basis for CCD. One organism, Israeli acute paralysis virus (IAPV) of bees, was strongly correlated with CCD. The prevalence of IAPV sequences in CCD operations, as well as the temporal and geographic overlap of CCD and importation of IAPV infected bees from Australia, indicates that IAPV is a significant marker for CCD. - Honeybee
colony collapse due to Nosema ceranae in professional apiaries
Synopsis Honeybee colony collapse is a sanitary and ecological worldwide problem. To date there has not been a consensus about its origins. This report describes the clinical features of two professional bee-keepers affecting by this syndrome. Anamnesis, clinical examination and analyses support that the depopulation in both cases was due to the infection by Nosema ceranae (Microsporidia), an emerging pathogen of Apis mellifera. No other significant pathogens or pesticides (neonicotinoids) were detected and the bees had not been foraging in corn or sunflower crops. The treatment with fumagillin avoided the loss of surviving weak colonies. This is the first case report of honeybee colony collapse due to N. ceranae in professional apiaries in field conditions reported worldwide. - Recent
Honey Bee Colony Declines
Synopsis : In 2006, commercial migratory beekeepers along the East Coast of the United States began reporting sharp declines in their honey bee colonies. Current reports indicate that beekeepers in 35 states have been affected. Recent surveys indicate that about one-half of surveyed beekeepers have experienced "abnormal" or "severe" colony losses. To date, the potential causes of CCD, as reported by the scientists who are researching this phenomenon, include but may not be limited to the following: parasites, mites, and disease loads in the bees and brood; emergence of new or newly more virulent pathogens; poor nutrition among adult bees; lack of genetic diversity and lineage of bees; level of stress in adult bees (e.g., transportation and confinement of bees, or other environmental or biological stressors); chemical residue/contamination in the wax, food stores, and/or bees; and a combination of these and/or other factors. - IAPV,
a bee-affecting virus associated with Colony Collapse Disorder can be
silenced by dsRNA ingestion
Synopsis: Colony Collapse Disorder (CCD) has been associated with Israeli acute paralysis virus (IAPV). CCD poses a serious threat to apiculture and agriculture as a whole, due to the consequent inability to provide the necessary amount of bees for pollination of critical crops. Here we report on RNAi-silencing of IAPV infection by feeding bees with double-stranded RNA, as an efficient and feasible way of controlling this viral disease. The association of CCD with IAPV is discussed, as well as the potential of controlling CCD. - Behavioral
attributes and parental care of Varroa mites parasitizing honeybee brood
Synopsis: Varroa jacobsoni, an ectoparasite of the Asian honeybee Apis cerana, has been introduced world-wide, and is currently decimating colonies of the European honeybee Apis mellifera. Study describes here how a single fertilized female, infesting a brood cell, can produce two to four adult fertilized females within the limited time span of bee development (270 h in worker and 330 h in drone cells), despite the disturbance caused by cocoon spinning and subsequent morphological changes of the bee. - Nutritional
stress due to habitat loss may explain recent honeybee colony collapses
Synopsis: In spite of the tremendous public interest in the recent large honeybee losses attributed to colony collapse disorder, there is still no definitive explanation for the phenomenon. With the hypothesis that nutritional stress due to habitat loss has played an important role in honeybee colony collapse, study analyzes the land use data in United States to show that the colony loss suffered by each state is significantly predicted by the extent of its open land relative to its developed land area. Study also discusses how increasing loss of foraging resources could be synergistically acting with emerging diseases to stress honeybee populations and the importance therefore for preserving natural areas that act as important pollinator habitats.
- Global Bee Colony Disorders and other Threats to Insect Pollinators
United Nations Environment Programme (UNEP).
Scientists working for the United Nations (UN) reveal in a report published March 10, 2011 that the collapse of honeybee colonies is now a global phenomenon that could have devastating consequences. Declines in managed bee colonies, seen increasingly in Europe and the US in the past decade, are now being observed in China, Japan and Egypt according to the report. - Effects
of neonicotinoid pesticide pollution of Dutch surface water on non-target
species abundance
MSc Thesis by Teresa C. van Dijk, 2010.
Sustainable Development Track Land use, Environment and Biodiversity (SD: LEB), Utrecht University
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