Bijensterfte, oorzaken en gevolgen

Thu, Jul 22, 2010, Paul Tukey, safelawns.org
It’s been almost exactly three years since some impulsive research led me to David Hackenberg. I had just watched an advertisement for grub control for lawns and the punchline stated that “one application lasts 12 months.”

Compulsively suspect of chemical pesticides, I cringed when I thought of a substance that would persist in the soil for a year. “How can that possibly be a good thing?” I said aloud to my wife before she wandered off to bed with her omnipresent here-he-goes-again expression. “I wonder what the active ingredient is?” I asked to an empty livingroom.

Abstract
The essence oft he Druckrey–Küpfmüller equation dt^n = constant(where d = daily dose and t = exposure
time-to-effect, with n>1) for chemical carcinogens is that the total dose required to produce the same effect decreases with decreasing exposure levels, even though the exposure times required to produce the same effect increase with decreasing exposure levels. Druckrey and Küpfmüller inferred that if both receptor binding and the effect are irreversible, exposure time would reinforce the effect. 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.

Source: Henk A. Tennekes, The significance of the Druckrey–Küpfmüller equation for risk assessment—The toxicity of neonicotinoid insecticides to arthropods is reinforced by exposure time, Toxicology, in press,
doi:10.1016/j.tox.2010.07.005

Stefano MAINI, Piotr MEDRZYCKI, Claudio PORRINI, Bulletin of Insectology 63 (1): 153-160, 2010

The impact of pesticides on honey bees is an issue that has been studied for many years and is now being reconsidered because controversy still exists with the relationship of insecticides and Colony Collapse Disorder (CCD). It is insufficient to explain CCD with only bee pathology studies. Research must be conducted on a wider series of causes: i) in open field and agroecosystems, to understand the fate of pesticide blends, ii) in the hives, to determine ways to enhance honey bee defence to diseases and parasites. References regarding imidacloprid and CCD in the maize agroecosystems are critically reviewed. Pesticides and the thechniques to rationally use them (in particular following the integrated pest management guidelines) represent one of the several puzzles regarding the mystery of CCD or honey bee vanishing. An appendix, i.e., a rejected letter to Science and relevant reply, is also reported.

Full paper: http://www.bulletinofinsectology.org/pdfarticles/vol63-2010-153-160maini...

C.A. Brittain, M. Vighi, R. Bommarco, J. Settele, S.G. Potts, 2010

Abstract

OIE - World Organisation for Animal Health, Paris , 28 April 2010
Arthropod parasites such as Varroa mites as well as virus and bacteria infections, pesticide exposure, and poor nutrition resulting from other environmental issues linked with human behaviour, are all concomitant factors which threaten the survival of certain bee colonies worldwide. Similarly, the causes of honey bee Colony Collapse Disorder (CCD), a recently described phenomenon leading to global extensive losses of bee colonies, are unquestionably multi-factored, concluded experts of an OIE ad hoc group on diseases of honey bees.

The Times, May 6, 2010
Can the struggling honeybee be pulled back from the brink by a hive of scientific industry?

Beliën T, Kellers J, Heylen K, Keulemans W, Billen J, Arckens L, Huybrechts R, Gobin B.

Abstract
Honey bees (Apis mellifera) are the most economically valuable pollinators of fruit crops worldwide. Taking into account bees' contributions to other flowering agricultural crops, about one-third of our total diet comes directly or indirectly from bee-pollinated plants. However, in recent years there increasingly have been worrisome alarm sounds on serious bee mortalities and mysterious disappearance of bees from beehives. Among several environmental factors (e.g. climate and bee pathogens), stress factors arising from agricultural practices can potentially play a role in bee losses.

The European Commission announced plans to create an EU Reference Laboratory in the area of bee health. Parallel to this, the first ever bee health training course for officials of Member States under the Better Training for Safer Food initiative is also starting next week.

A group of former members have split from the British Bee Keepers Association (BBKA) and criticised its 12-year-sponsorship deal with chemical companies Bayer Crop Sciences and Syngenta who produce pesticides that the group say are harmful to bees. The BBKA, a charity for the last 135 years, receives around £17,500 pounds-a-year in funding for their relationship with the chemical giants. Phil Chandler, a former BBKA member who left the organisation last year and runs website Biobees promoting sustainable and chemical-free bee keeping, said: "This has been going on for years but has only come to light in the last few years. An organisation claiming to work on behalf on bees cannot be endorsing pesticides. Pesticides kill bees, to pretend they do not have effect is ridiculous. A third of UK bee colonies have been lost over the last two years. There is strong evidence that neonicotinoids a class of pesticide first used in agriculture in the mid 1990s at exactly the time when mass bee disappearances started occurring are involved in the deaths. "

The decline in the US bee population, first observed in 2006, is continuing. Data from the US Department of Agriculture show a 29 percent drop in beehives in 2009, following a 36 percent decline in 2008 and a 32 percent fall in 2007. Winter figures will be published in April. But preliminary estimates already indicate losses of 30 to 50 percent, said David Mendes, president of the American Beekeeping Federation."There are a lot of beekeepers who are in trouble" he said."Under normal condition you have 10 percent winter losses.. this year there are 30, 40 to 50 percent losses."

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.

NEW YORK, New York, January 4, 2010 (ENS) – A pesticide 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.

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.

Nationally, there are three main reasons for the loss of wildlife on farmed land: 1. Farming has become more specialised. Historically most farms were a mix of grassland and different arable crops. 2. Farming has become much more intensive, with increased applications of fertiliser and pesticides. Herbicides and insecticides reduce numbers of wild plants and insects, thus reducing the food supply for other wildlife, such as birds and mammals. 3. Habitats have been lost through conversion to other land uses, agricultural intensification or through inappropriate or lack of management.

New research has shown that Europe’s farmland birds have declined by almost 50% in the past 25 years – a trend caused by EU-wide agricultural intensification being driven by a policy in need of urgent reform. The results bring together the most comprehensive biodiversity indicators of their kind in Europe, collated by the Pan-European Common Bird Monitoring Scheme (PECBMS) - a partnership led by scientists from the European Bird Census Council, BirdLife International, the RSPB (BirdLife in the UK) and Statistics Netherlands.

The September 2009 issue of The Internationalist presents in seven articles a comprehensive discussion on the vanishing bees.

With almost one million described species, insects eclipse all other forms of animal life on Earth, not only in sheer numbers, diversity, and biomass, but also in their importance to functioning ecosystems. However, human-induced changes to the natural environment threaten vast numbers of these organisms and the vital services they provide to ecosystems. Leading causes of insect endangerment are habitat destruction or alteration of habitat by chemical pollutants (such as pesticides). Pesticides are implicated in the decline of many native bees and some aquatic insects.

Western culture views insects and arachnids as pests and vermin that need to be controlled. They usually are not considered as something to be preserved. Accordingly, arthropods and other small organisms have not been taken seriously for conservation by policy makers and the conservation community at large. Arthropods, however, are major components of diverse ecosystems and are the major players in functioning of ecosystem processes. Arthropods are relentlessly vanishing before our eyes. They must be preserved because of their inherent values but also because we need them for human survival.

PULLMAN, Washington, July 29, 2009 (ENS) — A microscopic pathogen and pesticides embedded in old honeycombs are two major contributors to the bee disease known as colony collapse disorder, which has wiped out thousands of beehives throughout the United States and Europe over the past three years, new research at Washington State University has confirmed.

Fri, Jul 17, 2009

Having received more than 12,000 comments from concerned citizens, the Environmental Protection Agency announced yesterday it will begin reviewing the pesticide responsible for Colony Collapse Disorder of bees.

As one of the first organizations in the U.S. to begin tracking this story, SafeLawns.org has long concluded that a synthetic nicotine known as imidacloprid — used to kill grubs on lawns — is responsible for the widespread bee epidemic that has claimed more than a third of the nation’s beehives since 2006. France, Germany, Italy and several other nations have already banned the chemical, often marketed as “Merit,” that has been licensed for use in the U.S. since the 1990s, but came into widespread use in 2005 after the EPA banned diazinon.

[updated 4 December 2009] In the Netherlands, a petition to ask for measures to stop honeybee decline started in June 2009. In five months time, 40856 citizens have signed the petition. The petition has been delivered to the parliament on November 24, 2009. The text of the petition is:

The Netherlands is not the only country that started a petition to ask policy makers to take measures to stop honeybee decline. The UK Soil Association has started a petition calling on the Government to protect honeybees and ban neonicotinoid pesticides. See:
http://www.soilassociation.org/Takeaction/Savethehoneybee/tabid/434/Default.aspx

The text of the petition is:
We, the undersigned support the Soil Association in calling on Hilary Benn, the UK’s Secretary of State for Environment, Food & Rural Affairs to ban neonicotinoid pesticides with immediate effect. These pesticides have been shown to kill honeybees and are thought to be a contributory factor in the recent dramatic increase in honeybee deaths.

In a briefing paper the background of the petition is explained.