• 30
  • JUN
  • 2017

Bees and neonicotinoids; pollinators meet pesticides; heroes versus villains –  they have become a cause célèbre, naturally. I don’t do causes; I do science, writes Lin Field.

And yet, unwittingly, I have found myself in one corner of this debate, apparently alongside industrial chemists and commercial farmers, and seemingly at loggerheads with an equally diverse group in the other corner.

Our latest bout concerns a paper in the current issue of Science, published yesterday. The paper reports an unusually large-scale study across three EU states: Germany, Hungary and the UK. It concerns the effects of two neonicotinoids, in the form of seed coatings of Oil Seed Rape, on three species of bees: the honey bee and two wild species, all essential pollinators.

The research is led by the Centre for Ecology & Hydrology with whom Rothamsted regularly works closely; in fact, we are currently working together on one of Rothamsted's main strategic programmes, Achieving Sustainable Agricultural Systems (ASSIST). 

The issue of bees and neonics has been long-running and inconclusive though it has still prompted regulatory restrictions with damaging consequences for agricultural economies.

The publication of this latest paper, which is critical of neonics, neatly coincides with a potentially crucial EU debate on whether to extend those restrictions on neonics. The restrictions have already cost the agriculture industry, and OSR producers in particular, many hundreds of millions of Euros. In fact, the prospect of further restrictions, without convincing evidence of their damage, prompted our position statement on neonics in May this year. 

At this point, perhaps I should make it clear that I have never personally received a penny (or a cent) from the chemicals industry. Over the past 20 years, my department has earned no more than 10% of its income from the industry, chiefly in the form of grants to support research projects and PhD studentships. And, to be frank, I’d like more grant income.

My team do the basic research that can provide the fundamental information to enable industry to design more efficient and selective pesticides; pesticides that do the job we want them to do, and no more. We are no longer in the era of ghastly DDT and Rachel Carson’s Silent Spring, which in fact stimulated my interest in agricultural science. We are well past that stage and we are not finished yet.

For instance, Rothamsted’s insecticide group is doing some valuable work to establish the selectivity of neonics; early indications suggest some neonics are not great for bees, while others have no impact whatsoever and may actually be preferable to the alternatives. The greatest risk is one-size-fits-all regulation that does not consider context and nuance. The second greatest is saying there’s no problem, when we cannot say that with any certainty.

I don’t want to drop into that trap for commentators of falling back on safely honed arguments, prejudices if you like. I try to look at each and every paper that I’m asked to review separately and afresh, drawing on 30-plus years of biochemical and molecular research and more than 250 published papers of my own, and not to succumb to bias, conscious or subconscious.

The CEH-led paper reports results from a very large study that tries to obtain data at a field scale and this is to be commended. I had high hopes for this research (or a research project of this sort); we certainly need a thorough, large-scale investigation to get to the bottom of which factor or factors seem to be harming bee populations. However, I don’t think this was it. And from the variety of “expert reactions” to the paper, it seems that there are a few others who agree with me. 

I wouldn’t argue with the authors’ contention that neonics can harm bees, and that that is worrying, very worrying. But what about the positive results in Germany? And what about the great majority of results that showed no significant impact either way? Of the 14 parameters across three countries that the authors selected, 33 of the 42 factors showed no significant effect whatsoever; 3 were positive and 6 were negative. 

I agree that, at first glance, the paper’s graph of results from all three EU states showing a negative correlation between neonic residue in nests and queen numbers (as indicative of reproductive success) looks convincing and worrying; however, closer scrutiny raises more questions than answers. If each country is looked at separately, Hungary shows a wide range of values for queen numbers with very little variation in nest residues, whereas the UK shows a wide range of residue levels but little variation in queen numbers. Overall, this is hard to interpret; it certainly suggests that refined statistical analysis is essential for making the most of the data. 

I was disappointed that there was so little convincing evidence from so much accumulated data. For me, this emphasised the profound difficulties of trying to understand what happens to these widely foraging pollinators that are subjected to a variety of competing influences, or potential influences. And what evidence that was available was presented with such incompleteness, that I found myself beginning to doubt some of the assumptions about the research that I had been willing to accept. More importantly, I don’t think this paper should encourage a hasty and ill-informed decision on neonics.

I think we need to take more time to study this latest neonics research in detail, and the vast collection of underlying data – some drawn on for the paper, and the rest that was not. The aim would not be to criticise the study but to focus instead on a description of what one really would need to do in order to unravel the whole mystery. I would call that the “ultimate neonics study”, looking at everything.

Someone needs to look at how that should be done because nobody has done it, only bits and pieces of it, which is why the argument never ends. It’s a huge challenge, but not an impossible one...and could provide the basis of a policy for governments, and regulators, to commit to.