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PLEASE, BEE REASONABLE: THE BUZZ AROUND INSECTICIDES – Evan Brenton-Rule

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Headlines and interest group commentary on neonicotinoids

 

In a paper published this year, the Entomological Society of New Zealand identifies the effects of insecticides and pathogens on honey bees as a “critical issue facing New Zealand entomology” [1]. The paper echoes widespread public and scientific concern regarding the ‘plight of pollinators’ worldwide. Bees have become an emotive topic, subject to increasing politicisation. They provide enormous economic benefits in the form of pollination services to agriculture, as well as New Zealand’s growing apiculture industry. Media, and unfortunately scientists, have muddied the public perception of the problems facing bees through the sensationalising of issues and reporting of unsupported data [2]. The well-publicised phenomenon of colony collapse disorder in North America is a spectre in the public consciousness. Mass bee poisoning events through incorrect insecticide use have made headlines [3]. This increased public awareness has prompted calls from lobbyists [4] to ban insecticide use both overseas and in New Zealand. A new generation of insecticides known as neonicotinoids have become the focus of this debate. Framing the issue in such a narrow, polemic manner is foolish and counterproductive. A caveat of the Entomological Society paper was that further research is needed before measures such as banning insecticides are seriously considered. Such an evidence-based approach to regulation should be followed by New Zealand decision-makers.

NEW ZEALAND’S BEES

Pollinators including honey bees provide pollination services to the world economy worth ~$NZ245 billion per year [5]. In New Zealand it was conservatively estimated in 1987 to be ~$NZ2.2 billion per year [6]. Several of our important crop species including: kiwifruit, onions, pipfruit, berryfruit, avocados, canola and carrot crops are almost solely reliant on honey bee pollination [7]. Besides pollination services, apiculture in New Zealand represents a multimillion dollar industry in its own right. New Zealand honey exports have grown 30% per year in the past decade, reaching NZ$145million in 2013 [8]. New Zealand manuka honey is the world’s most expensive and receives a significant premium over other products. Both pollination services and the apiculture industry provide significant incentives to take a serious approach towards bee health.

honey export volumes, values and prices 2002-2013

Honey export volumes, values and prices: 2002-2013

 

THE PERCEIVED PROBLEM

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Honey bee landing on milk thistle. Photo credit: Fir0002

Bee numbers in the developed world appear to be decreasing. In North America, honey bee losses have been particularly acute. There has been a decline from six million hives in the 1940s to 2.3 million today. Mass loss of honey bees from hives has been characterised as colony collapse disorder (CCD). Hypotheses explaining CCD are varied and there is a lack of consensus. The scientific literature points to pathogens, habitat-loss, inadequate bee nutrition, climate change, low genetic diversity, insecticide use and poor bee husbandry practices as causative factors [9]. In Western Europe well-publicised mass bee fatalities due to incorrect insecticide use have made headlines [10] and provided ammunition for commentators in the blogosphere [11].

In New Zealand, anecdotal evidence suggests annual losses of 30-40% of hives by some New Zealand’s apiarists [12]. At present losses are blamed primarily on the effect of the Varroa mite; which increases bee susceptibility to a range of pathogens. However, the New Zealand Bee Keepers Association is also concerned about the use of neonicotinoids on honey bees [13].

ALL ABUZZ OVER INSECTICIDES

In recent years a series of high-impact studies showing deleterious effects of neonicotinoid insecticides on bees have been published. Some of these effects include: significant loss of queens [14], interference with foragers’ ability to navigate back to the hive [15] and synergistic deleterious effects of insecticides on bee colonies at low dosages [16].

Studies such as these, as well as media coverage and public pressure have prompted intergovernmental bodies such as the European Food Safety Authority (EFSA) to become involved. As of December 2013 the EU, acting on EFSA recommendations, has restricted field uses of three neonicotinoid insecticides. Unsurprisingly these actions elicited a strong response from neonicotinoid manufacturers. Syngenta called the risk assessment conducted by the EFSA, hurried and inadequate”. Bayer stated it does not believe the EFSA’s reports “alter the quality and validity” of previous risk assessments by the EU.

Domestic agencies have also waded in. In the United Kingdom, the Department for Environment, Food and Rural Affairs has concluded that there is a “growing body of evidence” that neonicotinoids do not exert an effect under conditions where bees can forage naturally. This suggests that studies in the lab that have linked neonicotinoids to an impact on bee health at less-than-lethal doses “did not replicate realistic conditions, but extreme scenarios”.

Closer to home, a report was released by the Australian Pesticides and Veterinary Medicines Authority (APVMA) in February of this year on neonicotinoids and the health of honey bees in Australia. The APVMA concluded the introduction of neonicotinoids has led to an overall reduction in the risks to the agricultural environment from the application of insecticides. The reasons given were extensive, but can be reduced to the following:

  1. Previous generation insecticides are significantly more toxic to mammals;
  2. The physicochemical properties of some neonicotinoids means they are used to coat crop seeds, which protects the seed and plant while they are growing. Consequently this means farmers apply fewer insecticides to the environment;
  3. Alternative application methods have a higher potential to introduce insecticides into the environment; and
  4. In Australia honey bee populations are not in decline despite extensive use of neonicotinoid insecticides.

However, potential risks of neonicotinoids are also identified. In particular, the physicochemical properties of neonicotinoids that allow them to translocate from the seed to the growing plant mean they have high stability in plant tissue and soil. Particularly worrying is that neonicotinoids may contaminate nectar and pollen which is a main food source for bees [17]. Neonicotinoids therefore could represent a larger environmental threat than other less mobile, less persistent insecticides.

Given the work occurring internationally and the importance of honey bees to New Zealand, the question arises: What action should we take?

insecticidecompilation

Popular neonicotinoid products. You might even recognise some from your garden at home.

THE NEED FOR EVIDENCE-BASED REGULATION

New Zealand’s environmental regulatory regime is well-developed. The legislature does a relatively good job of incorporating science into policy, regulation and operational decision-making. Such an evidence-based approach to regulation should apply to the debate regarding neonicotinoid use and bees. However, how ‘precautionary’ should that approach be?

Precautionary Approach? Other solutions

The precautionary approach had its genesis in international environmental law and dictates that lack of scientific evidence of harm is no reason not to legislate against harm occurring. The principle has long been accepted to apply in the areas of food safety and plant and animal protection [18]. Further, it is enshrined in the Convention on Biological Diversity 1992, to which New Zealand is a party. It is also a fundamental purpose of the HSNO Act [19]. Should the precautionary approach apply to neonicotinoid use in New Zealand? In resource management case law, it has been made clear that the weight given to the precautionary approach depends on circumstances involved [20].

Circumstances

As this article has demonstrated, many published studies have convincingly described sublethal effects of neonicotinoids on bees in laboratory conditions. However, to this author’s knowledge, no adverse effects to bee colonies has ever been observed in field studies at field-realistic exposures [21]. Additionally, an enormous body of literature attributes decline in bee health not solely to insecticides, but to pathogens, habitat-loss, inadequate bee nutrition, climate change, low genetic diversity and poor bee husbandry practices.

Although the precautionary approach is potentially applicable in this scenario it is not appropriate to apply in favour of banning neonicotinoids; the circumstances do not recommend it. Instead, a twofold approach should be pursued:

  1. First, there is clear evidence Varroa decimates New Zealand honey bee colonies [22]. Research should be undertaken both to understand bee pathogens’ impacts and combat the effect they have on New Zealand bee populations.
  2. Second, if any measures banning insecticides are to be considered, extensive field research and risk-analyses are required. A first step would involve testing what impacts sub-lethal effects observed in the lab have in the natural environment.

BEING REASONABLE

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Honey bee carrying pollen. Photo credit: Muhammed Mahdi Karim.

Misinformation and sensationalist media coverage has heightened public awareness of the challenges facing bees. The
‘plight of pollinators’ is not a minor issue, nor is it being treated as such.  Intergovernmental and domestic agencies around the world are approaching the problem with due seriousness. The effects of banning neonicotinoids are at present murky. Indeed, other insecticides more harmful to bees and mammals could be reintroduced. Causative factors of bee decline in the developed world are not yet fully elucidated. However diseases, not insecticides, are likely the primary cause of the losses. Framing the debate to focus on neonicotinoids is an irresponsible approach by commentators that delivers political capital whilst attenuating efforts to deal with the problem holistically.  The potential application of a precautionary approach to neonicotinoids should be rejected in New Zealand given the possible negative trade-offs. Overly parochial views of lobbyists should be dismissed by decision-makers in favour of evidence-based regulation. If evidence suggests change in the risk management of any substance is required, then the regulatory system should respond accordingly.

 

[1] Lester PJ, Brown SDJ, Edwards ED, Holwell GI, Pawson SM, Ward DF & Watts CH (2014) Critical issues facing New Zealand entomology. New Zealand Entomologist 37: 1-13.

[2] Maini S, Medrzycki P & Porrini C (2010) The puzzle of honey bee losses: A brief review. Bulletin of Insectology 63: 153-160.

[3] http://www.theguardian.com/environment/2008/may/23/wildlife.endangeredspecies

[4] see https://www.greens.org.nz/bees + http://tvnz.co.nz/world-news/nz-should-follow-eu-ban-bee-harming-pesticides-greens-5422307 + http://organicnz.org.nz/node/690

[5] Gallia N, Salles JM, Settele J et al. (2009) Economic valuation of the vulnerability of world agriculture confronted with pollinator decline. Ecological Economics 68: 810-821.

[6] Matheson AG & Schrader M (1987) The value of honey bees to New Zealand’s primary production. Ministry of Agriculture and Fisheries Report.

[7] Ministry for Primary Industries 2013 apiculture monitoring programme, p 3.

[8] Ministry for Primary Industries 2013 apiculture monitoring programme, p 1.

[9] Bromenshenk JJ, Henderson CB, Wick CH, Stanford MF, Zulich AW, Jabbour RF et al. (2010) Iridovirus and microsporidian linked to honey bee colony decline. PLoS One: e13181; Evans JD & Schwarz RS (2011) Bees brought to their knees: microbes affecting honey bee health. Trends in Microbiology 19: 614-620; Henry M, Beguin M, Requier F, Rollin O, Odoux JF, Aupinel P et al. (2012) A common pesticide decreases foraging success and survival in honey bees. Science 336: 348-350; Cresswell JE (2011) A meta-analysis of experiments testing the effects of neonicotinoid insecticide (Imidacloprid) on honey bees. Ecotoxicology 20: 149-157; Winfree R, Bartomeus I & Cariveau DP (2011) Native Pollinators in Anthropogenic Habitats. Annual Review of Ecology Evolution and Systematics 42: 1-22.

[10] http://www.theguardian.com/environment/2008/may/23/wildlife.endangeredspecies

[11] http://ecowatch.com/2013/04/19/greenpeace-syngenta-pesticides-kill-bees/ http://www.theguardian.com/environment/georgemonbiot/2013/aug/05/neonicotinoids-ddt-pesticides-nature

[12] Lester PJ, Brown SDJ, Edwards ED, Holwell GI, Pawson SM, Ward DF & Watts CH (2014) Critical issues facing New Zealand entomology. New Zealand Entomologist 37: 1-13.

[13] Foster B (2013) Our science challenge. New Zealand Bee Keeper 21: 4-6.

[14] Whitehorn PR, O’Connor S, Wackers FL & Goulson D (2012) Neonicotinoid Pesticide Reduces Bumble Bee Colony Growth and Queen Production. Science 336: 351–352.

[15] Henry M, Beguin M, Requier F, Rollin O, Odoux JF, Aupinel P et al. (2012) A common pesticide decreases foraging success and survival in honey bees. Science 336: 348-350.

[16] Gill RJ, Ramos-Rodriguez O & Raine NE (2012) Combined pesticide exposure severely affects individual – and colony – level traits in bees. Nature 491: 105-109.

[17] Rortais A, Arnold G, Halm MP & Touffet-Briens F (2005) Modes of honeybees exposure to systemic insecticides: estimated amounts of contaminated pollen and nectar consumed by different categories of bees. Apidologie 36: 71-83.

[18] (New Zealand v Japan; Australia v Japan) Provisional Measures ITLOS Case Nos 3 & 4, 27 August 1999; EC Measures Concerning Meat and Meat Products (Hormones) WTO DOC WT/DS26/AB/R (1998) (Report of Appellate Body); New Zealand Pork Industry Board v Director-General of Ministry for Primary Industries [2013] NZSC 154.

[19] Section 7, Hazardous Substances and New Organisms Act 1996.

[20] McIntyre v Christchurch City Council (1996) NZRMA 289 (PT).

[21] Blacquiere T, Smagghe G, van Gestel CAM & Mommaerts V (2012) Neonicotinoids in bees: a review on concentrations, side-effects and risk assessment. Ecotoxicology 21: 973-992.

[22] Howlett BG & Donovan BJ (2010) A review of New Zealand’s deliberately introduced bee fauna: current status and potential impacts. New Zealand Entomologist 33: 92-101.

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