Written evidence submitted by Dr Alexander Waller (INS0005)

Dr. Alexander Waller PhD MSc BSc(Hons) CBiol FRSB CChem MRSC

Visiting Professor of Environmental Ethics & Science Education American University of Sovereign Nations

Evidence for House of Commons Science & Technology Committee                           

Insect Decline and Food Security

There have been reports in the media of an insect Armageddon, a sixth mass extinction or a collapse of nature, which tend to fit more with a sudden “Catastrophian Age” rather than a prolonged “Anthropocene Epoch” [54]. The decline of insect populations and the diversity of species is being witnessed worldwide, with reports from all continents such as a 76% decline over 26 years in Germany or estimates of up to a staggering 98% over 35 years in Puerto Rica [28]. The 2019 IPBES report suggests a tentative value of 10% insects globally face extinction, although it recognises that there are gaps in knowledge of the exact numbers of endangered insect species [30]. In another 2019 review there are claims that a third of North American and European insects are at risk of extinction [43]. Dasgupta notes that:

A global review of 166 long-term surveys of insect assemblages found that on average there have been declines of terrestrial species abundance by around 9% per decade compared to increases in freshwater insect abundance by approximately 11% per decade since 1925. [14]

The 2022 Bug Matters report from number plate “splats” compares two decades of data from across theUK:

Compared to 2004, the {2022} results show a decrease in the number of insect splats in the UK of 63.7%, 5.3% greater than in 2021 (58.4%) [3]

Significantly, many of these insects such as bees and hoverflies provide an essential role in crop pollination [2,5,18,38,39].

There are various causes of this insect decline including pesticide use, habitat loss and climate change [5]. Goulson quotes UK government statistics saying that:

UK farmers applied an average of 17.4 different pesticides to each hectare of land in 2015, using a total of 16.9 thousand tons of active ingredient. [28]

Neonicotinoids in particular are extensively used across the globe and residues have been found in 75% of honey samples [35]. The 2022 State of Food Security and Nutrition in the World report shares figures from Boedeker, Watts, Clausing & Marquez (2020) stating that:

… an estimated 385 million agricultural workers are affected every year by unintentional acute pesticide poisoning. Hazards can affect the physical and mental health of workers, and adequate health and safety standards are, therefore, essential. [22]

Current evidence of insect abundance in UK and gaps in scientific knowledge

Several knowledge gaps relating to insect abundance overlap with other drivers of reductions in biodiversity generally and more broadly with planetary health. Therefore, it is vital to continually bear in mind that although concern over pollinator insect populations is important it is part of a much wider picture. For example, allowing careful management of a small group of pesticides on non-insect pollinated crops may have short term benefits it does not aid ecosystem restoration that is much more important in the long run.

One of the greatest drivers of changes in insect distribution is climate change. There are still questions on the impact of different degrees of warming on agriculture in general, relationships between biodiversity and ecosystem health and the extent that different insect populations will shift to more northern latitudes [20,34,47,55]. The impact of climate change and biodiversity loss on UK food security was considered by the House of Lords in September 2022:

It concluded climate change and biodiversity loss were among the biggest medium to long term risks to UK domestic food production, alongside other factors, including soil degradation and water quality. [44]

Climate change, pesticides and agricultural intensification are not the only causes of insect decline [16, 52]. Other potential drivers of insect declines include habitat loss, introduction of new species and transfer of diseases [1], air pollution [40,49] and even artificial light at night [6]. Therefore considering the impact of pesticides on pollinator insects should not be dealt with in a simple reductionist way.  Furthermore, as populations of species come under more and more stressors a question arises as to whether they will become more susceptible to novel diseases such as hoverflies succumbing to viruses from bees [44].

Pesticides e.g. neonicotinoids & other control measures on pollinator insects & food security

There is strong evidence that some neonicotinoids including thiamethoxam and clothianidin reduce the reproductive capacity of honeybee drones [51]. There is also evidence that exposure to imidacloprid disrupts sex allocation in some wasp species [59]. Studies have also shown that neonicotinoids and some other systemic insecticides such as fipronil have deleterious effects on butterfly populations [23,26,27]. A variety of wild bumblebee species have been shown have changes in their feeding behaviour and ovaries upon exposure to thiamethoxam [4]. Although not all neonicotinoids are proven to be harmful to bees, for example acetamiprid is claimed to be harmless, but is that proven for sub-lethal effects and population-level consequences? [53]

Some insect taxa are less well studied than others; moths for example tend to attract less attention than flagship spectacular butterflies or “sweet” honey-producing bumble bees. Yet studies in Britain have revealed that moths transport pollen from a wide variety of native and cultivated plants and some wildflowers rely almost entirely on moth pollination [9,58].

In addition to the direct effect of pesticides on pollinator species is the effect they have on the populations of natural pest predators such as ladybirds. There are also indirect effects like bioaccumulation and compounding effects of the application of pesticide mixtures [7,42,45].

Beyond the effects on pollinators or insects in general, is the question of the effects of neonicotinoids on vertebrates, particularly mammals and human health. Particularly there is a paucity of research on the direct and indirect effect of these chemicals on human health [11] Although Burke et al (2018) showed that ‘transient exposure to a neonicotinoid over the early developmental period induces long-lasting changes in behavior and brain function in mice’ [8]. In the US over the period 1999-2015 an increase was found in the trend of neonicotinoid residues on food products [13]. Have similar studies been carried out to monitor food, both home-grown and imported, on sale in UK supermarkets?

It must also be borne in mind that some alternatives to neonicotinoids, such as pyrethroids may well have similar negative impacts on non-pest insects and possibly other organisms in food chains [24,32,33]. Siviter and Muth (2020) demonstrate that ‘flupyradifurone and sulfoxaflor have significant sub-lethal impacts on beneficial insects at field-realistic levels of exposure’ [46]. There is also concern of synergistic or unclearly understood cocktail effects when several different pesticides are used in conjunction with each other [10,31].

Furthermore, the withdrawal of neonicotinoids, without adequate alternatives led to catastrophic losses in some crops such as sugar beet in the UK  [17,50] and a resurgence of beet viruses across Europe [29]. Nonetheless, with improved application quantities and timing in France there was no impact on yields despite a 42% reduction in insecticide use [41], although this data may be reflective of a honeymoon period following the EU ban. There are several tools recommended by the EU to reduce pesticides [21] and it should be remembered that insects can develop resistance to pesticides as in the case of pollen beetles and pyrethroids.

Biodiversity initiatives, e.g. reservoir popns, insect decline & coordination of UK food system

The Agriculture Bill 2019-20 allows for some payments towards habitat restoration [52]. Beetle banks, using strips of tussock-type grass mixtures in fields of cereal crops have been used in the UK since the 1980s. Hedgerow conservation, acting as a corridor for insects, delivers several co-benefits through the reduction of soil erosion from leaching and limiting low altitude wind speeds, and most relevantly they provide a habitat for an enormous variety of species [57]. In a report for DEFRA Barr, Britt, Sparks and Churchward state that:

Hedgerows, in general, are known to support a tremendous diversity of invertebrates; with over 1,500 insect species having been recorded at some time, living or feeding in hedgerows. [5]

Some studies have shown that although hedgerows can be a reservoir for pests they also act to conserve natural predators. For example, Morandin, Long and Kremen (2014) found that hedgerow presence resulted in tomato crop protection as far as between 100m and 200m within fields [36]. Similarly reductions in spray applications on field margins has been correlated with increases in butterfly species richness [41]. An added advantage of restoring hedgerows in both rural and urban environments is that they are a potential Nature based Solution for carbon storage [57].

Internationally there are several reports of the benefits to agriculture from retaining natural reservoirs such as those cited by Dasgupta:

On-farm and near-farm plant and insect biodiversity in agroforestry have been found to lead to increased yields of pollinator dependent crops: a study of coffee farms in Brazil found that farms nearest forest fragments had a 14.6% increase in production related to pollination services (De Marco and Coelho, 2004). [14]

One problem with conservation measures that involve breeding organisms for release into natural environments to restock native populations is that these individuals may not have the capacity to survive in unprotected surroundings. Davis et al (2020) recently found captive-reared monarch butterflies were weaker and paler than wild forms [15]. We cannot afford to risk losing more and more species by fooling ourselves into thinking we are doing enough by sealing off certain sites, captive breeding programmes or maintaining seed banks and gene libraries.

Genetic medication of crops for resistance to pests is now an established technology. For example, more than a decade ago the (E)-β-farnesene gene into the wheat to provide resistance to aphids [19]. This would be an advisable approach for sugar beet that is susceptible to virus yellows [17,29]. There are also physical approaches such as the use of laser-based technologies [25], semiochemical pheromones approaches using plant extracts [31] or coating fruits with physical barriers [32]. There are additional options of biological control using microorganisms  such as Bacillus thuringiensis [32].

Does insect decline pose a threat UK food security & is there cross-government attention?

According to the UK Food Security Report 2021, Food Security:

…encompasses the state of global agriculture and markets on which the UK is reliant; the sources of raw materials and foodstuffs in the UK and abroad… … and the systems of inspection that allow consumers to be confident their food is safe, authentic, and of a high standard.

The Defra 2021 Food Security report assures us that:

We work closely with our 33 agencies and arm’s length bodies on our ambition to make our air purer, our water cleaner, our land greener and our food more sustainable. Our mission is to restore and enhance the environment for the next generation, and to leave the environment in a better state than we found it.

Nice words. But how well do these 33 agencies work together? Let alone the 18 agencies of the Department for Education, the 19 agencies linked to the Department for Business & Trade, the 24 agencies that the Department of Health & Social Care work with and the 7 agencies tied to the Department for Science, Innovation and Technology. The point is that food security (or the converse: food poverty or insecurity – referring to a lack of access to enough good, healthy, and culturally appropriate food) and biodiversity or more generally planetary health should be of paramount concern to all these departments and needs strong leadership from the top to ensure this is coordinated and focused. These issues are too big for just one sector of public administration to be responsible for and departments must work cooperatively rather than antagonistically.

There is ever growing public concern over environmental issues. For example, the 2023 People’s Assembly for Nature resulted in a plan with several calls for action including:

Policy, including legislation and incentives [if required], that forces all companies involved in food production and retail to stop their negative impact on the natural environment and to actively support the restoration of nature. We want to see that the “polluter pays” principle is enforced to reduce the amount of pollutants that impact the environment and our health and to ensure that food production, processing and retail do not destroy habitats in the UK or abroad.

They also made several vision statements, emphasising the role of governance, cooperative action and education, including that nature is prioritised, and that an evidence-based nature renewal is central to lifelong education. Ultimately “politicians, charities, NGOs, scientists work together, in informed ways, to ensure thriving wildlife is kept at the front of all decisions. We understand that we need nature to thrive, to benefit all of our lives.” This clear understanding of the central importance of nature indicates a deeper appreciation that “nature” also may be less resilient to human activity than we tend to assume. Ecological time lags between environmental change and biodiversity as reported by Cornford et al (2023) [12] may well be worth investigating further in terms of how changes in pest control will impact on long term food security. It can be summed up in a precautionary approach of ban first and ask questions later. There needs to be ongoing and increased depth of sustainability education [41].

The long term food security is dependent on not only insects but so many environmental issues including general biodiversity loss, climate change, soil degradation and water quality in addition to geopolitics and international economics. The IPCC 2022 predicts the impact of an average increase of 1.5oC – 2.0oC will put pressure on food security that will become severe if the rise is greater than 2.0oC. IPBES estimates that rates of extinction are 10s to 100s of times higher than average rates over the past 10 million years. Dasgupta says that biodiversity loss is particularly damaging to soils and that ‘natural capital’ is undervalued. The Dimbleby (2021) National Food Strategy Independent Review argues that young people’s view must be seriously listened to and respected and makes clear recommendations for environmental protection and a rural land use framework. In the consultation it was seen that young people were in general unaware of the food-environment relationship and unclear of the meaning of sustainability. This lack of knowledge and understanding is a barrier to adopting sustainable diets. The government Food Strategy 2022 adopted about half the proposals recommended by Dimbleby, but needs new legislation to underpin it and enable enforcement against harmful farming practices.  Without this the consumer confidence required for genuine food security will remain lacking.

Policy solutions in UK and internationally to reduce and reverse trends in insect decline

There is a clear need for political will [41]. Questions spring to mind like: “Is the UK government really committed to reversing biodiversity decline or is it just rhetoric?” “How serious is the UK regarding the UN Decade on Restoration or the 30 x 30 CBD target?” “Why aren’t the UK one of the ENACT NbS partners?” “Will the UK insist on imported food being producted sustainably?”

Allowing emergency use of neonics for sugar beet may have resulted in sending out mixed messages to the public. Have the government forgotten that a YouGov / Avaaz survey of close to two thousand adults in 2013 indicated 71% in favour of government support for a EU pesticide ban and only 9% against it. Furthermore, in accordance with the precautionary principle, 68% were in favour of banning pesticides until it was proved they were safe for humans and animals including bees. Is there really any indication of a change in public opinion since then?

Many staple crops in the UK are wind pollinated, but these are only part of our national diet. In addition we increasingly rely on a variety of imported diversity fruit and vegetables. The Dasgupta Review notes that, “about one-third of the human diet in tropical countries is derived from insect-pollinated plants” [14]. This illustrates why insect decline cannot be addressed by one country alone and requires international cooperation and coordination of the type that led to success of the Montreal protocol tackling ozone depleting compounds.

Regarding planetary boundaries and the food system Springmann et al (2018) strongly advocated a shift towards a less meat based diet. As much farmland is currently devoted to wind pollinated crops and fodder for animals, if a more vegetarian diet was universally adopted then it is likely to lead to an even greater reliance on insect pollinated crops. In some countries the current cost of living restricts many people from buying organic food or maintaining a quality of diet. There may also be an increase in cost the produce from certain insect pollinated crops, or if produce is labelled “pesticide free”, which could in turn lead to a rise in food poverty. Importantly, Springmann et al point out that:

…no single measure is enough to keep these effects within all planetary boundaries simultaneously, and that a synergistic combination of measures will be needed to sufficiently mitigate the projected increase in environmental pressures. [48]

This combination of measures is why there must be unity between nations and national government departments as there will be a range of measures affecting agriculture, health, education, trade, etc.

Citizen science projects are one good way to engage and educate a wide sector of the community [56]. Wagner et al (2021) show exponential use of the iNaturalist online resource that aids taxonomical identifications [7]. Citizen science has been already widely beneficial in many insect research projects from bug counts to specific programmes such as exploring the effects of urbanization [37] and several field surveys [41].

There is a need for ongoing farmer education and access to full information on issues such as the Sustainable Farming Incentive or ongoing training for IPM pesticide use [33]. Landowners and agriculturalists need to be clearly aware that they are temporary privileged stewards for only their lifetime in the river of generations to come. The judge, in the case of a farmer ripping up trees on the banks of the river Lugg, referred to “industrial scale ecological vandalism”. The government needs to clamp down on habitat destruction. Although the general public are aware of the need for farmers to make a living and of the rising costs incurred by farmers there is a general knowledge gap on both sides: consumers unaware of full economic demands on the farming community and producers lack of scientific knowledge of alternative husbandry and just how important nature restoration is and how it is perceived by the wider citizenry.

25 April 2023

References are supplied in a separate document