Bijensterfte neemt wereldwijd en in Nederland alarmerend toe. Deze website beoogt kennis en ontwikkelingen in wetenschap en beleid rond de vele oorzaken van bijensterfte inzichtelijk en toegankelijk te maken voor een breed publiek. Aanleiding was de brief in NRC van 2 mei 2009. We beogen verifieerbare, traceerbare informatie te bieden met bronvermeldingen en links naar de primaire bronnen uit de wetenschappelijke literatuur.

- Uitleg probleem neonicotine insecticiden (o.a. imidacloprid)
- Effects of neonicotinoid pesticide pollution of Dutch surface water on non-target species abundance
- Volg de meest actuele ontwikkelingen via Twitter

European ombudsman investigates whether the European Commission should do more to combat increased bee mortality

The European Ombudsman, P. Nikiforos Diamandouros, has opened an investigation into whether the European Commission has taken appropriate measures to combat increased bee mortality in the EU, which is potentially linked to certain insecticides. This follows a complaint from the Austrian Ombudsman Board, alleging that the Commission has failed to take into account new scientific evidence arguing in favour of restricting the use of these insecticides. The Ombudsman has asked the Commission to submit an opinion by 30 June 2012.

Neural effects of insecticides in the honey bee

Abstract – During their foraging activity, honey bees are often exposed to direct and residual contacts with pesticides, especially insecticides, all substances specifically designed to kill, repel, attract or perturb the vital functions of insects. Insecticides may elicit lethal and sublethal effects of different natures that may affect various biological systems of the honey bee. The first step in the induction of toxicity by a chemical is the interaction between the toxic compound and its molecular target. The action on the molecular target can lead to the induction of observable or non-visible effects. The toxic substance may impair important processes involved in cognitive functions, behaviour or integrity of physiological functions. This review is focused on the neural effects of insecticides that have repercussions on (a) cognitive functions, including learning and memory, habituation, olfaction and gustation, navigation and orientation; (b) behaviour, including foraging and (c) physiological functions, including thermoregulation and muscle activity.

The Harvard Study on imidacloprid and CCD - a commentary by Randy Oliver

Re this study, at first glance it appears to support the hypothesis that chronic exposure to field realistic doses of imidacloprid during summer and fall can lead to late winter collapse of the treated colonies.

New study from Harvard first to link imidacloprid directly to Colony Collapse Disorder

[Press release Harvard School of Public Health] Imidacloprid, one of the most widely used neonicotinoid pesticides, has been named as the likely culprit in the sharp worldwide decline in honey bee colonies since 2006. Researchers at the Harvard School of Public Health say their new research provides "convincing evidence" of the link between imidacloprid and colony collapse disorder. "It apparently doesn't take much of the pesticide to affect the bees," says Alex Lu, associate professor of environmental exposure biology at Harvard's Department of Environmental Health, "Our experiment included pesticide amounts below what is normally present in the environment."

Aerial powdering of bees inside mobile cages and the extent of neonicotinoid cloud surrounding corn drillers

Sudden losses of bees have been observed in spring during maize sowing. The death of bees has been correlated with the use of neonicotinoid-coated seed and the toxic particulates emitted by pneumatic drilling machines. The contamination of foragers in flight over the ploughed fields has been hypothesized. The airborne contamination has been proven, both with bees inside fixed cages around the field and in free flight near the driller. A new trial involving mobile cages has been established and consists of making rapid passes with single bees inside cages fixed to an aluminium bar. The bar was moved by two operators at different distances from the working drilling machine. A single pass was shown as sufficient to kill all the bees exposed to exhaust air on the emission side of the drill, when bees were subsequently held in high relative humidity. The extent of toxic cloud around driller was evaluated at the height of 0.5, 1.8 and 3.5 m and proved to be about 20 m in diameter, with an ellipsoidal shape. The shape may be influenced by working speed of the drill and environmental parameters, and is easily shown by adding talc powder to the seed in the machine hopper. A new driller equipment was evaluated consisting of two tubes inclined towards the soil that direct the exhaust air towards the ground. The survival rate of the bees was not substantially increased using the modified drill and was lower than 50%. Chemical analyses show up to 4000 ng of insecticide in single bees with an average content around 300 ng. Similar quantities were observed at increased distances from the modified or unmodified drillers. This new evaluation of bee mortality in the field is an innovative biological test to verify the hypothetical efficiency (or not) of driller modifications.

Tijdschrift Entomologische Berichten: themanummer bijen

Het tijdschrift Entomologische Berichten heeft ter gelegenhed van "2012 Jaar van de Bij" een speciaal themanummer over bijen uitgebracht dat niet alleen voor insectendeskundigen maar ook voor een breder publiek interessant is. Hierin passeren in zo'n 150 pagina's en 20 artikelen zeer uiteenlopende bijenonderwerpen de revue. Enkele voorbeelden:
• Oorzaken van de achteruitgang van wilde bijen in Noordwest-Europa
• Het ondergrondse leven van de gewone sachembij
• Slaapgedrag en slaapgezelschappen van solitaire bijen
• Nesthulp voor bijen en wespen

De stukken zijn toegankelijk geschreven en geheel is rijk geïllustreerd met zeer fraaie foto's. Een aanrader voor iedereen die nieuwsgierig is naar de vele facetten van het bijenleven!

Honderd wilde bijensoorten zelf herkennen met behulp van je smartphone

Zomer 2011 heeft ecoloog Dr. Arie Koster een digitale zoekkaart ontwikkeld voor het snel en gemakkelijk herkennen van wilde bijen in Nederland:

Hier is zeer positief op gereageerd. Er is ook opbouwende kritiek gekomen die zoveel mogelijk in de zoekkaart website is verwerkt. Er bleek bij veel gebruikers behoefte te zijn aan een mobiele versie die je in het veld kan gebruiken. Daarom is er nu een versie van de zoekkaart die speciaal voor mobieltjes is ontworpen:

Met deze handige mobiele zoekkaart kun je ca. 100 soorten wilde bijen opzoeken. Aan de hand van een aantal goed waarneembare kenmerken zoals kleuren, beharing, antennes en de vorm van het achterlijf kun je in enkele stappen vaststellen welke bij of hommel je ziet waarna je bij foto's uitkomt die je kunt vergelijken met de bij die je ziet in het veld.

Parasite-insecticide interactions: a case study of Nosema ceranae and fipronil synergy on honeybee

New study in Nature - Scientific Reports finds strong evidence for pesticide + pathogen hypothesis as key explanation for bee disorders.

ABSTRACT: In ecosystems, a variety of biological, chemical and physical stressors may act in combination to induce illness in populations of living organisms. While recent surveys reported that parasite-insecticide interactions can synergistically and negatively affect honeybee survival, the importance of sequence in exposure to stressors has hardly received any attention. In this work, Western honeybees (Apis mellifera) were sequentially or simultaneously infected by the microsporidian parasite Nosema ceranae and chronically exposed to a sublethal dose of the insecticide fipronil, respectively chosen as biological and chemical stressors. Interestingly, every combination tested led to a synergistic effect on honeybee survival, with the most significant impacts when stressors were applied at the emergence of honeybees. Our study presents significant outcomes on beekeeping management but also points out the potential risks incurred by any living organism frequently exposed to both pathogens and insecticides in their habitat.

Imidacloprid in Melon Guttation Fluid: A Potential Mode of Exposure for Pest and Beneficial Organisms

ABSTRACT ELISA techniques were used to detect imidacloprid in guttation fluid of young cantaloupe plants in Arizona. Imidacloprid was detected at up to 4.1 micro g/ml (ppm) in a coincidental guttation collection 3 d after a top label rate soil application and at 37 micro g/ml one d after a separate top label rate soil application study. These imidacloprid titers exceed reported median oral toxicities for several insect species by factors of 10 or more. Pesticides in guttation fluid are a relatively unexplored route of exposure for both pest and beneficial insects, and could represent an important risk for both of these groups in guttation-prone environments.

Ecologically Appropriate Xenobiotics Induce Cytochrome P450s in Apis mellifera

Background: Honey bees are exposed to phytochemicals through the nectar, pollen and propolis consumed to sustain the colony. They may also encounter mycotoxins produced by Aspergillus fungi infesting pollen in beebread. Moreover, bees are exposed to agricultural pesticides, particularly in-hive acaricides used against the parasite Varroa destructor. They cope with these and other xenobiotics primarily through enzymatic detoxificative processes, but the regulation of detoxificative enzymes in honey bees remains largely unexplored.
Methodology/Principal Findings: We used several approaches to ascertain effects of dietary toxins on bee susceptibility to synthetic and natural xenobiotics, including the acaricide tau-fluvalinate, the agricultural pesticide imidacloprid, and the naturally occurring mycotoxin aflatoxin. We administered potential inducers of cytochrome P450 enzymes, the principal biochemical system for Phase 1 detoxification in insects, to investigate how detoxification is regulated. The drug phenobarbital induces P450s in many insects, yet feeding bees with phenobarbital had no effect on the toxicity of taufluvalinate, a pesticide known to be detoxified by bee P450s. Similarly, no P450 induction, as measured by tau-fluvalinate tolerance, occurred in bees fed xanthotoxin, salicylic acid, or indole-3-carbinol, all of which induce P450s in other insects.
Only quercetin, a common pollen and honey constituent, reduced tau-fluvalinate toxicity. In microarray comparisons no change in detoxificative gene expression was detected in phenobarbital-treated bees. However, northern blot analyses of guts of bees fed extracts of honey, pollen and propolis showed elevated expression of three CYP6AS P450 genes. Diet did not influence tau-fluvalinate or imidacloprid toxicity in bioassays; however, aflatoxin toxicity was higher in bees consuming sucrose or high-fructose corn syrup than in bees consuming honey.
Conclusions/Significance: These results suggest that regulation of honey bee P450s is tuned to chemicals occurring naturally in the hive environment and that, in terms of toxicological capacity, a diet of sugar is not equivalent to a diet of honey.

Honey bees (Apis mellifera) reared in brood combs containing high levels of pesticide residues exhibit increased susceptibility to Nosema (Microsporidia) infection.

Abstract: Nosema ceranae and pesticide exposure can contribute to honey bee health decline. Bees reared from brood comb containing high or low levels of pesticide residues were placed in two common colony environments. One colony was inoculated weekly with N. ceranae spores in sugar syrup and the other colony received sugar syrup only. Worker honey bees were sampled weekly from the treatment and control colonies and analyzed for Nosema spore levels. Regardless of the colony environment (spores+syrup added or syrup only added), a higher proportion of bees reared from the high pesticide residue brood comb became infected with N. ceranae, and at a younger age, compared to those reared in low residue brood combs. These data suggest that developmental exposure to pesticides in brood comb increases the susceptibility of bees to N. ceranae infection.

Assessment of the Environmental Exposure of Honeybees to Particulate Matter Containing Neonicotinoid Insecticides Coming from Corn Coated Seeds

ABSTRACT: Since seed coating with neonicotinoid insecticides was introduced in the late 1990s, European beekeepers have reported severe colony losses in the period of corn sowing (spring). As a consequence, seed-coating neonicotinoid insecticides that are used worldwide on corn crops have been blamed for honeybee decline. In view of the currently increasing crop production, and also of corn as a renewable energy source, the correct use of these insecticides within sustainable agriculture is a cause of concern. In this paper, a probable - but so far underestimated - route of environmental exposure of honeybees to and intoxication with neonicotinoid insecticides, namely, the atmospheric emission of particulate matter containing the insecticide by drilling machines, has been quantitatively studied. Using optimized analytical procedures, quantitative measurements of both the emitted particulate and the consequent direct contamination of single bees approaching the drilling machine during the foraging activity have been determined. Experimental results show that the environmental release of particles containing neonicotinoids can produce high exposure levels for bees, with lethal effects compatible with colony losses phenomena observed by beekeepers.

Sub-Lethal Effects of Imidacloprid Exposure on Honey Bee Queen Egg-Laying and Activity

Wu, J., V. Krischik and M. Spivak, Department of Entomology, University of Minnesota; St. Paul, MN 55108
Abstract for the 2012 American Bee Research Conference, February 7-8 2012 Greenbelt.

Pesticides such as neonicotinoid insecticides have been implicated as a contributing factor to honey bee losses. The objective of this study is to examine sub-lethal effects of imidacloprid on honey bee queen egg-laying and activity. Observation hives, containing about 1500 bees and a laying queen on newly drawn comb, were given 80 ml of sugar syrup with various imidacloprid treatments (0, 20, 50, 100 ppb) every other day. A total of 16 observation hives, or 4 colonies per treatment, were set-up in July and August of 2011. Queen egg-laying rate and activity were recorded in 15-minute intervals and quantified over 3 weeks. After 3 weeks, colonies were quantified for total adult and brood population, nectar and pollen stores, presence of disease, and weight of newly emerged bees. Preliminary results show that queen laying rates were affected at each imidacloprid treatment dose (20, 50, and 100 ppb). This study will be repeated in the summer of 2012. The findings will improve our understanding of known imidacloprid studies on honey bee colonies and workers. In addition, this study will highlight the need to focus future risk assessment studies on sub-lethal effects of neonicotinyl insecticides on honey bee queen health and behavior.

A Quantitative Model of Honey Bee Colony Population Dynamics

Since 2006 the rate of honey bee colony failure has increased significantly. As an aid to testing hypotheses for the causes of colony failure we have developed a compartment model of honey bee colony population dynamics to explore the impact of different death rates of forager bees on colony growth and development. The model predicts a critical threshold forager death rate beneath which colonies regulate a stable population size. If death rates are sustained higher than this threshold rapid population decline is predicted and colony failure is inevitable. The model also predicts that high forager death rates draw hive bees into the foraging population at much younger ages than normal, which acts to accelerate colony failure. The model suggests that colony failure can be understood in terms of observed principles of honey bee population dynamics, and provides a theoretical framework for experimental investigation of the problem.

Worldwide honey bee colony losses continue

International Bee Research Association Press Release 1 February 2012
Since 2006 there has been concern worldwide about losses of honey bee colonies, especially the phenomenon of “Colony Collapse Disorder” in the USA. Information about the extent of these losses has,to date, been patchy, unsystematic and difficult to compare year on year and from country to country. Today, for the first time, the results of systematic surveys in Europe, north America, China, Israel and Turkey are published together in the Journal of Apicultural Research.

Pesticide exposure in honey bees results in increased levels of the gut pathogen Nosema

Abstract: Global pollinator declines have been attributed to habitat destruction, pesticide use, and climate change or some combination of these factors, and managed honey bees, Apis mellifera, are part of worldwide pollinator declines. Here we 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. We clearly demonstrate an increase in pathogen growth within individual bees reared in colonies exposed to one of the most widely used pesticides worldwide, imidacloprid, at below levels considered harmful to bees. The finding that individual bees with undetectable levels of the target pesticide, after being reared in a sub-lethal pesticide environment within the colony, had higher Nosema is significant. 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.

Multiple Routes of Pesticide Exposure for Honey Bees Living Near Agricultural Fields

Populations of honey bees and other pollinators have declined worldwide in recent years. A variety of stressors have been implicated as potential causes, including agricultural pesticides. Neonicotinoid insecticides, which are widely used and highly toxic to honey bees, have been found in previous analyses of honey bee pollen and comb material. However, the routes of exposure have remained largely undefined. We used LC/MS-MS to analyze samples of honey bees, pollen stored in the hive and several potential exposure routes associated with plantings of neonicotinoid treated maize. Our 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. We 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, although whether exposure was oral (consuming pollen) or by contact (soil/planter dust) is unclear. We 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. These results have implications for a wide range of large-scale annual cropping systems that utilize neonicotinoid seed treatments.

2012 het Jaar van de Bij

Op 1 januari 2012 gaat in de uitzending van Vara Vroege Vogels het Jaar van de Bij officieel van start. Vijf organisaties: KNNV, Bijenstichting, EIS Nederland, NBV en IVN hebben de handen ineengeslagen. Een heel jaar is er aandacht voor wilde- en honingbijen. Publiek en overheden krijgen via de nieuwe website volop informatie, handreikingen en goede voorbeelden om bijvriendelijk te handelen.

Current toxicological risk assessment can lead to serious underestimates of actual risk of neonicotinoids

The traditional approach to toxicity testing is to consider dose (concentration)-effect relationships at arbitrarily fixed exposure durations which are supposed to reflect ‘acute’ or ‘chronic’ time scales. This approach measures the proportion of all exposed individuals responding by the end of different exposure times. Toxicological databases established in this way are collections of endpoint values obtained at fixed times of exposure. As such these values cannot be linked to make predictions for the wide range of exposures encountered by humans or in the environment. Thus, current toxicological risk assessment can be compromised by this approach to toxicity testing, as will be demonstrated in this paper, leading to serious underestimates of actual risk. This includes neonicotinoid insecticides and certain metallic compounds, which may require entirely new approaches.

Europarlement neemt risico's met gezondheid van de bij

[Persbericht van Groen Links Europa]
STRAATSBURG, 15 november - De bijenpopulatie is schrikbarend aan het afnemen, terwijl meer dan tachtig procent van ons groente en fruit afhankelijk is van bestuiving door de bij. Vandaag stemde het Europees Parlement in met een zeer zwak voorstel van de landbouwcommissie over de bij. GroenLinks-Europarlementariër Bas Eickhout stelde een alternatieve resolutie op om aan te geven dat het voorstel van de landbouwcommissie een stap terug in de tijd zet en meer opkomt voor de belangen van de farmaceutische industrie dan van de bij.

Urgent call for EU-wide action to halt bee deaths

On 15 November 2011 the EU parliament voted for a resolution on honeybee health. Rising bee mortality could have a serious impact on Europe's food production and environmental stability, as most plants are pollinated by bees, warned MEPs on Tuesday. Parliament's resolution calls on the EU to step up investment in research on new medicines and coordinate its efforts to protect what is fast becoming an endangered species.

Franse rechter verklaart toelating Thiamethoxam illegaal - in Nederland ruim toegelaten

Op 3 oktober 2011 vernietigde de Franse "Raad van State" (Le Conseil d'Etat, de hoogste bestuursrechter) het toelatingsbesluit 2010 voor Cruiser 350, een gewasbeschermingsmiddel van Syngenta met als werkzame stof Thiamethoxam, een insectenzenuwgif uit de neonicotinegroep. In insecten en planten wordt thiamethoxam omgezet in clothianidine, een ander zeer omstreden neonicotine (Nauen et al., 2003). De zaak was aanhangig gemaakt door Union Nationale de l'Apiculture Française (UNAF), de grootste Franse imkerbond. De rechter heeft nu geoordeeld dat niet vaststaat dat deze middelen veilig zijn voor bijen en dat voorlopige toelating in afwachting van vollediger onderzoek illegaal is. Daarmee is tevens vastgesteld dat feitelijk niet voldaan is aan de Europese toelatingseisen waardoor de uitspraak ook voor andere landen gevolgen kan hebben.

Kwartmiljoen bezoekers

Op 5 september 2011 telden wij de kwartmiljoenste bezoeker van deze website. Sinds de oprichting op 5 mei 2009 heeft deze website 260303 unieke bezoekers getrokken (telling tot en met 30 sept 2011). Momenteel bezoeken maandelijks ca. 12000 mensen en zoekrobots deze website. De bezoekers zijn afkomstig uit de hele wereld, het grootste percentage komt uit Nederland.

New directions in crop protection

Current Biology, Volume 21, Issue 17, 13 September, 2011
The spread of herbicide-resistant weeds, progress in genomics, climate change and the continuing worries about pollinator decline are forcing companies to rethink their approach to crop protection. Michael Gross reports.

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