Farmers urged to take action and help reverse the ‘insect apocalypse’

Finding solutions to the ‘insect apocalypse’ was the subject of the session led by Vicki Hird, head of farming and supply chains at Sustain, and Dave Goulson, professor of biology at the University of Sussex, taking place on day two of the Oxford Real Farming Conference 2023.

Ms Hird began by highlighting that, although invertebrates are at the heart of our food system, their value is widely unrecognised in modern society. In fact, their importance has so far been judged in terms of how much damage they do, which became the main focus of research work and how invertebrates are looked upon, she pointed out.

However, due to the growing pool of evidence from longitudinal studies, the wider community is beginning to recognise the issues posed by the large-scale decline of these small but mighty creatures, Ms Hird said.

She then introduced the session’s guest speaker, Dave Goulson, who is a leading researcher of invertebrates specializing in bee ecology, as well as the author of several books.

Often referred to as an “activist researcher”, Prof. Goulson has taken to the role of bridging the gap between researchers, campaigners, and policy makers for the benefit of the insect world.

Answering Ms Hird’s question of whether there is an impending insect apocalypse, Prof. Goulson confirmed that insects are indeed declining. However, he also emphasized that there are huge knowledge gaps when it comes to the insect world, and there are estimated to be three to four million species still waiting to be discovered.

He added that only very few insect species are regularly counted, monitored and studied. However, the majority of seem to be declining with a few exceptions. To illustrate the severity of the issue, Prof. Goulson quoted the following facts:

• Butterflies declined in abundance over the last 50 years
• Hoverfly and wild bee ranges have declined by 30% since 1990
• The biomass of flying insects in a German nature reserve reportedly declined by 76%
• Insects have been in decline for at least the last 80 years
• Global data analysis shows a 1-2% decline in insect species per year

Reminiscing on the old days when car windscreens used to get covered in flying insects in the summer, Ms Hird remarked the decline of invertebrates also has a knock-on effect on species that feed on them, such as bats and birds, as well as on the crops and nature that relies on them.

She then asked Prof Goulson to share the main message of his Sunday Times best-selling book, Silent Earth, with the audience. The professor explained that insects form a big chunk of our biodiversity making up 70% of all species on Earth, and essentially glue the whole ecosystem together by being pollinators, food to many animals, as well as important biocontrol and recycling agents, amongst other things.

“Our fate is inextricably intertwined with that of the insects, whether we like them or not,” he said. “And so we need to change direction.”

Factors contributing to the insect apocalypse

Prof Goulson pointed out that insects are one of the oldest creatures on the planet and have been around for 480 million years, surviving five mass extinction events. However, a combination of man-made factors significantly impacted their survival, including:

• Intensification of farming
• Pesticide use
• Habitat loss
• Fertilisers
• Light pollution
• Invasive species
• Diseases

He explained that insects are remarkably adaptive creatures and could probably weather a few of the above challenges. However, when faced with all of these factors at once, adaptability becomes almost impossible.

Ms Hird added that due to invertebrates possessing a large surface area to volume ratio, any sustained change in temperature and humidity has a magnified impact on populations.

Steering the discussion towards solving the insect apocalypse, she inquired about ways farmers and the general public can get involved and help invertebrates get back on their feet.

In response, Prof Goulson said everyone can do their share in mitigating the crisis, regardless of who they are or what they do, because insects live all around us. Moreover, unlike many endangered animals, insects could recover quickly if only “we provided them with somewhere to live and stop poisoning them,” he added.

The professor stressed the importance of reducing insect exposure to pesticides, as it’s one of the major drivers of the decline in species abundance. He mentioned the EU has already rolled out plans to halve pesticide use in the near future, while the UK continues to see an increase in the number of sprays applied per field.

Specifically, the number of pesticide products has increased by 70% in the UK since 1990, and in particular, the selection of sprays for treating OSR has tripled since 1988.

While integrated pest management (IPM) seems to be the obvious choice when it comes to reducing pesticide use, there is unclear guidance as to how farmers should incorporate it into their systems, Prof Goulson said.

Moreover, fertilisers also have a profound effect on insects and the environment in general, although they tend to be left out of the equation, the professor noted. He explained the nitrification of soils and rivers as a result of fertiliser use has a substantial impact on biodiversity as it applies selective pressure to native species.

Producing food while looking after nature

Part of the long-term solution to the insect apocalypse is setting aside the least productive pieces of land to be reclaimed by wildlife and nature, Prof Goulson said. To demonstrate that farming with nature doesn’t have to result in yield penalty, he shared the results of a study conducted at the UK Centre for Ecology and Hydrology in 2015.

Over the span of five years, researchers applied the following three treatments on a 1,000-acre farm that previously functioned as an intensive production system:

• Treatment 1: business as usual
• Treatment 2: 3% land removed to wildlife habitats
• Treatment 3: 8% land removed to wildlife habitats

Changes to crop production was monitored with the use of yield maps and related to the regional average at the end of the study. Due to the increase in pollination and other ecosystem services, the fields integrating wildlife strips yielded higher after a three-year period than control fields, as shown on the graph below:

Changes to crop yield under different treatment conditions. The dashed line represents the regional average (Pywell et al, 2015)

Adding to the discussion, a member of the audience spoke of an ongoing study that established wildflower strips through the middle of arable fields as well as along the edges, saying researchers have already recorded marked increases in production.

Commenting on the above study, Prof Goulson said: “If we can show that we can still produce lots of food while looking after nature better, then everybody wins.”

With land that’s unsuitable for producing food, he said there are options for rewilding, supporting biodiversity, capturing carbon, and providing recreational tourism. He added that farming vast areas of a single crop not only depletes soil health, but also disproportionately benefits a small number of insect species.

Echoing Prof Goulson words about the urgent need for change, Ms Hird said: “We need to be acting as citizens and bugging our politicians, local authorities and government to do things differently and to support growers and farmers in doing the same.”

Lastly, Ms Hird highlighted the role the everyday gardener can play in supporting invertebrate species. Given that homogenisation of landscapes is a major factor in the decline of insects, she suggested leaving gardens ever so slightly messy to create additional habitats for insects.

Citizen science programmes and generating public engagement are also an important part of the picture, Prof Goulson said, and can often provide powerful data alongside educating the public.

With her closing words, Ms Hird encouraged the audience to become ambassadors for bugs to friends and family and “get everybody rebugging” if they can.