Bijensterfte, oorzaken en gevolgen

A mysterious problem that causes bee colonies to decline is once again taking its toll on California's beekeepers.
The problem known as colony collapse disorder is characterized by a sudden drop in a bee colony's population and the inexplicable absence of dead bees. The disorder has no known cure and appears to be cyclical. After several mild years, it has resurfaced with a vengeance, said Eric Mussen, apiculturist with the University of California at Davis.
"It never went away, but this year a substantial number of beekeepers got walloped again," said Mussen, the state's leading bee expert. "And worse than they had been hit before." Although Mussen said it is too early to tell exactly how many bees have been lost, a bee industry official said losses in the state vary from 30 percent to 80 percent.

Kamervragen aan de ministers van LNV en van VROM over bijenvolksterfte door onduurzame maisteelt gesteld op 5 maart 2010

Vragen van het lid Thieme (Partij voor de Dieren) aan de ministers van Landbouw, Natuur en Voedselkwaliteit en van Volkshuisvesting, Ruimtelijke Ordening en Milieubeheer over bijenvolksterfte door onduurzame maisteelt.

1. Kent u het bericht ‘Duurzame maisteelt raakt steeds verder uit zicht[1] ’?

2. Deelt u de mening van Dr. Van der Sluijs dat het inzetten van deflectoren op maiszaaimachines een end-of-pipe maatregel is en dat deze maatregel het probleem niet oplost? Zo neen, waarom niet?

3. Deelt u de analyse van Dr. Van der Sluijs dat een deflector de hoeveelheid gif die in het milieu komt niet verandert en dat gelet op de lange verblijftijd (tot 2 jaar) van imidacloprid in het milieu het gif uiteindelijk toch in bijenvolken terecht komt en dat dat gecombineerd met het feit dat imidacloprid een CT-gif is waarvoor de Regel van Haber geldt[2] vastgesteld moet worden dat het enige te verwachten effect van een deflector is dat de bijenvolken dan later aan chronische vergiftiging sterven in plaats van vlak na het zaaien aan acute vergiftiging (‘de wet van behoud van ellende’ zoals dit ook wel aangeduid wordt)?

Bij een recente enquete van meer dan 2000 Duitse imkers kwam naar voren dat tenminste 1 op de 4 bijenvolken deze winter niet zal overleven.

By many accounts, the honey bee population on Vancouver Island is down 90 per cent heading into the spring of 2010. After a die-off of 65 per cent in 2007 and a good recovery last year, honey bees are now teetering on the point of a catastrophe.

In Alphen aan den Rijn wordt de komende jaren bij het zaaien van bloemen en gras in de bermen voorrang gegeven aan voor bijen goede plantensoorten. Insecticiden worden niet ingezet in het openbaar gebied.

28-Jan-2010, Helmholtz Association of German Research Centres
A first-time overview of the population trends for honey bee colonies and beekeepers in Europe

Cardiff/Halle/S./Bern. The number of bee colonies in Central Europe has decreased over recent decades. In fact, the number of beekeepers has been declining in the whole of Europe since 1985. This is the result of a study that has now been published by the International Bee Research Association, which for the first time has provided an overview of the problem of bee colony decline at the European level. Until now there had only been the reports from individual countries available. As other pollinators such as wild bees and hoverflies are also in decline, this could be a potential danger for pollinator services, on which many arable crops depend, according to what an international team of scientists have written in a special edition of the Journal of Apicultural Research.

[New study by Alaux et al, 2010, Biology Letters]

ABSTRACT
The maintenance of the immune system can be costly, and a lack of dietary protein can increase the susceptibility of organisms to disease. However, few studies have investigated the relationship between protein nutrition and immunity in insects. Here, we tested in honeybees (Apis mellifera) whether dietary protein quantity (monofloral pollen) and diet diversity (polyfloral pollen) can shape baseline immunocompetence (IC) by measuring parameters of individual immunity (haemocyte concentration, fat body content and phenoloxidase activity) and glucose oxidase (GOX) activity, which enables bees to sterilize colony and brood food, as a parameter of social immunity. Protein feeding modified both individual and social IC but increases in dietary protein quantity did not enhance IC. However, diet diversity increased IC levels. In particular, polyfloral diets induced higher GOX activity compared with monofloral diets, including protein-richer diets. These results suggest a link between protein nutrition and immunity in honeybees and underscore the critical role of resource availability on pollinator health.

England's bees are vanishing faster than anywhere else in Europe, with more than half of hives dying out over the last 20 years, according to a new study.

The plight of the honey bee has been highlighted by Pembrokeshire County Council. Honey bee populations in Britain have declined at an alarming rate over the past decade with a 39% decline in Welsh bee colonies in 2009. Populations in England had declined by similar amounts.

Surveys performed in 1971-1973 and in 2004-2006 document an impoverishment of the bumblebee community in southern Ontario over the past 35 years. Bombus affinis in particular was found to have declined drastically in abundance. The loss of any bumblebee species may result in cascading impacts on native fauna and flora.

Imidacloprid can be applied as a systemic insecticide to trees by direct stem injections or by soil injections and drenches, and be indirectly introduced to aquatic systems via leaf fall or leaching, which may pose a risk to natural decomposer organisms. When applied directly to aquatic microcosms to simulate leaching from soils, imidacloprid was shown to be highly toxic to aquatic insects. Imidacloprid at realistic field concentrations in maple leaves had adverse effects on aquatic insects and earthworms. Imidacloprid at realistic concentrations in leaves can inhibit leaf litter breakdown through adverse effects on decomposer invertebrates. When imidacloprid is applied as a systemic insecticide to the soil around trees it may cause adverse effects on earthworms.

by Marianne E. Horn and Peter G. Kevan

The plight of pollinators is causing worldwide concern. Certain species of bumblebees have gone either extinct or close thereto due to habitat and resource destruction, pesticide use and pathogens.

In hives affected by Colony Colapse Disorder (CCD), first observed on sunflowers in France, there may only be a few bees around the queen, or none at all. Bees are not seen leaving the hive, and where they go is a mystery. Clinical evidence for hives collapsing due to disease pathogens such as the varroa mite, Nosema ceranae or viruses is lacking. Varroa and its proliferation in hives is clearly visible with the naked eye, but the hive does not disappear so quickly as those affected by CCD. A correlation between the varroa infestation level of an apiary and the disappearance recorded has not been demonstrated. Bees in apiaries infested by Nosema ceranae do not have the key symptom: diarrhea. The Acute Paralysis Virus is too virulent and would kill the infected bee before contaminating other hosts or vectors. An infection with the Deformed Wing Virus is clearly visible (atrophied wings and a small stomach) and does not explain the rapid collapse of hives during sunflower harvesting.

"Natura 2000 fails to strike a balance between ecological value, economic interests and other uses. This is due mainly to the wording of the precautionary principle....The strict ecological focus of Natura 2000, ...., means that in some regions - on land as well as water - entrepeneurs are at risk of losing their livelihooods". Dit schreef Minister-President Dr. Jan Peter Balkenende in een brief van 13 juli 2009 aan de President van de Europese Commissie, de heer José Manuel Barroso. Barroso ontkende dit in zijn antwoordschrijven aan Balkenende van 26 oktober 2009. LTO Noord-voorzitter Tammo Beishuizen meent echter dat Barroso heeft aangegeven dat wel degelijk rekening gehouden moet worden met sociaal-economische factoren en roept het kabinet op om hier nu werk van te maken, bijvoorbeeld door regels te versoepelen of door Natura-gebieden te schrappen. De Tweede Kamer houdt nu op verzoek van PvdD en VVD een spoeddebat over de uitvoering van het Natura 2000-beleid in Nederland.

The man credited with discovering colony collapse disorder, a strange phenomenon in which workers bees suddenly desert the hive — that has wiped out more than a third of all honeybees in the US — says this winter could be the worst yet.

The Bayer pesticide spirotetramat approved just 18 months ago must be taken off the market because it could be toxic to America's honey bees, already in steep decline.

AGD.nl 05 jan 2010 14:43

Er gaan in 2010 nieuwe eisen gelden bij het zaaien van mais, meldt het CTGB.

Aanleiding is de bijensterfte. Pneumatische (onderdruk/vacuüm) zaaimachines moeten per 1 januari 2010 zijn voorzien van zogeheten deflectoren. Deze deflectoren buigen de luchtstroom af naar de grond en reduceren zodoende de drift met meer dan 85 procent.

Tot nog toe blaast de pneumaat de lucht die vrijkomt voor het creëren van het vacuüm voor zaaien omhoog of opzij. Stof met insecticide in die lucht kan daardoor naast het maïsveld op bloeiende planten terecht komen. In 2008 leidde de combinatie van slecht gecoat maïszaad, ongunstig weer en zaaien met pneumaten in het buitenland tot hoge bijensterfte.

ABSTRACT
Global pollinators, like honeybees, are declining in abundance and diversity, which can adversely affect natural ecosystems and agriculture. Therefore, we 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. We 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. By quantifying the strength of immunity at both the individual and social levels, we showed that neither the haemocyte number nor the phenoloxidase activity of individuals was affected by the different treatments. However, the activity of glucose oxidase, enabling bees to sterilize colony and brood food, was significantly decreased only by the combination of both factors compared with control, Nosema or imidacloprid groups, suggesting a synergistic interaction and in the long term a higher susceptibility of the colony to pathogens. 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.

In navolging van Frankrijk besloot Italie op 17 september 2008 uit voorzorg een moratorium (voorlopig verbod in afwachting van meer onderzoek) in te stellen op het gebruik van gewasbeschermingsmiddelen met werkzame stoffen clothianidine, thiamethoxam, imidacloprid of fiproniel voor zaadbehandeling (clothianidine, thiamethoxam en imidacloprid zijn neonicotinoiden), omdat deze toepassing in verband is gebracht met verhoogde bijensterfte.

Een onderzoeksprogramma (APENET) onderzoekt ondermeer het effect van het verbod. Na het Italiaanse verbod daalde het aantal meldingen van hoge bijensterfte tijdens het zaaien van mais van 185 gevallen (2008) naar 3 gevallen (2009). De 3 gevallen in 2009 waren allen te herleiden tot illegale zaadbehandeling. Deze onderzoeksuitkomsten waren mede aanleiding om op 14 september 2009 het moratorium met een jaar te verlengen.
Hieronder een volledige vertaling van het Italiaanse besluit.