Genetically Modified Insects (S&T Committee Report)

Lord Krebs Excerpts

Tuesday 7th June 2016 Lords Chamber

[Lord Krebs (CB)]

My Lords, I too thank the noble Earl, Lord Selborne, for his excellent chairmanship of this inquiry, to which I was co-opted as a member of the committee. I would also like to echo the thanks given to my colleague from the University of Oxford Department of Zoology, Professor Mike Bonsall, for his wise and authoritative advice as our specialist adviser during the inquiry. I should perhaps also declare an interest in that Oxitec, about which we have already heard, was set up by another colleague in my department, Professor Luke Alphey, and eventually my department will benefit financially from the sale last year of Oxitec to Intrexon, a US company, for $160 million.

We have heard a great deal already about the potential benefits of the genetic modification of insects both in agriculture and in relation to the control of insect-borne diseases in human beings. I do not wish to go over that ground—rather, I want to make a single point which was put to the committee very forcefully by Professor Chris Whitty, one of our witnesses. He pointed out that we must remember that GM insects, while they have their place, will not be a magic bullet. They may be more applicable in certain situations than in others. The ways of limiting the spread of human diseases that are transmitted by insect vectors depend on three factors. You can control the number of insect vectors around, and that is what we have heard about in terms of population suppression. You can control the longevity of the insect—how long it lives—and what is known as the bite rate: how often it attacks human victims. In the case of night-flying mosquitoes that carry malaria in Africa, controlling the bite rate by distributing bed nets impregnated with insecticide is an effective strategy and may indeed be more effective than GM population suppression. However, as we heard so eloquently from the noble Viscount, Lord Ridley, and others, for day-flying mosquitoes such as Aedes aegypti, that transmit the Zika virus and dengue, using GM to suppress their population may be a powerful control strategy.

I am not going to go over the problems of the European regulatory regime which we have already heard much about. Instead, I want to talk about the risks associated with GM insects in the environment. Here I thank the noble Viscount, Lord Ridley, for his trailer. What exactly are the ecological risks? The important starting point is that no control strategy is risk-free: spraying with pesticides to reduce insect populations is not risk-free; vaccinating people against diseases is not risk-free; and GM insects are no exception. The sensible questions are therefore: what is the relative risk, how do the risks associated with GM insects compare with alternative strategies, how does the balance of risk stack up against benefits, and are the risks acceptable in light of the potential benefits?

We took evidence on the worries that people have about releasing genetically modified insects into the environment. Some of these are general concerns about the control of intellectual property, “playing God with nature”, and a lack of trust in scientists and, in particular, in business. More specifically, the risks that relate to scientific understanding were of three kinds: the possibility of the evolution of new and more virulent pathogens; the possibility of transfer of genes, for example, genes for sterility from the genetically modified mosquitoes or other pests released into the environment to other harmless or even beneficial insects; and the unforeseen impacts on ecological communities.

All of these are real possibilities and deserve proper scientific scrutiny on a case-by-case basis, which is one reason why we need field scale trials to gain proper understanding. Let me briefly elaborate on the question of unforeseen ecological impacts. Would drastically reducing the population density of insect vectors, particularly mosquitoes, have unforeseen ecological consequences? This is a reasonable question. We know, for example, that the decline in the song thrush population of the United Kingdom is probably partly as a consequence of the use of molluscicides that kill snails—one of the main food items of song thrushes. Are there comparable unforeseen consequences? That question is relevant, of course, whether the reduction in the insect population is brought about by genetic modification, the use of pesticides or habitat removal.

In seeking to answer this I went to my academic colleagues—experts on the ecological consequences of mosquito control, notably Professor Charles Godfray and Professor Owen Lewis. I asked the question: what is the point of mosquitoes? That is another way of asking what mosquitoes do for us, apart from transmitting diseases. One possible consequence would be that predators that live on mosquitoes and are beneficial or nice to have around would suffer if mosquitoes were removed. There is a salticid spider called Evarcha culicivora that feeds on engorged mosquitoes in Africa. One possible effect would be to lose the population of salticid spiders.

Another possible consequence would be what ecologists call “competitive release”—the removal or reduction in one species leads to an increase in another species that is a competitor with the one taken away. However the view of the experts from whom I sought advice is that the ecological impacts of drastic reductions in mosquito populations are likely to be minimal. There is evidence of that because where spraying or bed nets have been used to reduce anopheles populations—the mosquito population—in Africa, there have been no detectable unforeseen ecological consequences.

The only way in which to resolve these questions definitively and reduce uncertainty is to take the bold step of carrying out carefully conducted and monitored field trials. They could either be in the UK or, as has already been said, in the British Overseas Territories, such as the Cayman Islands. There is a real case for the Government to take firm leadership and say that they will carry out field scale trials to further knowledge, reduce uncertainties, and therefore indirectly feed into the regulatory regime. If the UK wishes to be a leader rather than a follower, I urge the Minister to reconsider the Government’s position on this matter.

Let me turn briefly to the question of public perception of GM technologies; we have heard a substantial amount about this from the noble Lords, Lord Fox and Lord Patel, as well as the noble Viscount, Lord Ridley. I want to make three brief points, taking lessons from GM crops and GM medicines. First, the so-called rejection of GM foods by the public is no such thing. When GM tomato paste, clearly labelled as such, was first introduced by Sainsbury’s on to our supermarket shelves in the 1990s it sold well because it was very slightly cheaper and tasted better than the comparable conventional variety. It was only after certain campaigning groups, aided by irresponsible print media such as the Daily Mail, whipped up unnecessary fear with absolutely no evidence that the supermarkets retreated and declared they would not sell GM foods of any kind.

Secondly, the last time the Government tried to test public opinion on GM foods, the consultation process was hijacked by campaigning groups and the results were misleading. In the early 2000s the Government launched a consultation called GM Nation?, which included setting up a website. More than 37,000 people logged on to the website to express their views about GM foods. Those 37,000 responses were overwhelmingly negative. However, at exactly the same time, Professor Nick Pidgeon, then of the University of East Anglia, carried out a properly designed, stratified random sample survey of public opinion, which showed something quite different. It showed that the public did not object to GM foods. So when we think that the public are frightened, we really have to wonder whether that is simply a myth.

Thirdly, although the press and campaigning groups worked hard to prevent GM foods being marketed in the UK, they said nothing about GM insulin, about which we have already heard from the noble Lord, Lord Patel, and which is taken by many diabetics. Why is that? I believe the reason is, as the noble Lord, Lord Fox, already indicated, that GM insulin has an immediate direct benefit to people in this country, while the first generation of GM crops primarily benefited producers in other countries. When I explained this to the then US Agriculture Secretary Dan Glickman, his laconic response was—I will try to do the American accent—“I see what you mean, John. What we need is the tomato with the Viagra gene”.

As the noble Lord, Lord Fox, eloquently explained, the health benefits of GM insects in controlling human diseases—we have already heard from the noble Viscount, Lord Ridley, that Zika is probably on its way to Europe, transmitted by a different species of Aedes—give us a real opportunity to take the promotion of GM technology out to the public. Perhaps we can learn useful pointers on how to do that from the lessons we learned over GM foods.

Finally, only last week the UK was ranked fourth in the good country index by its global contribution to humanity. One of the reasons why we ranked so highly was that in science and technology we rank at the very top in the world. Promoting use of GM technology judiciously, with careful thought and study of the possible risks, is a way we can further contribute to the well-being of humanity globally.