Insect Declines: A Global Problem

We are heavily reliant on insects as pollinators for the vast majority of our crops. However, rather ironically, it is the very agricultural system for which we utilise their services that is driving huge declines of many insect species. These are the findings from a recent review published in Biological Conservation, in which authors Francisco Sánchez-Bayo and Kris Wyckhuys highlight the ‘dreadful’ state of the world’s insect biodiversity in 2019.

To assess the current health of the world’s insect life, they analysed 73 reports of insect declines over the past 40 years. What they found is alarming. Forty per cent of insect species are in rapid decline, and 30 per cent are threatened by extinction. At the current rate of loss, most insects could disappear over the course of the next century if we don’t change our ways.

Maintaining insect biodiversity for global food security is vastly important. Up to seventy per cent of the crops we consume are insect-pollinated, mostly by commercial bee colonies, which are shipped around the globe to pollinate crops. However, single species monocultures are more susceptible to rapidly spreading diseases. Honeybees themselves have been afflicted by the deformed wing virus, which spreads through parasitic mites. Therefore, it is important to protect wild pollinator diversity so they can act as a buffer for threatened commercial pollinators.

Beyond pollination, the role of insects in sustaining life cannot be understated. Sánchez-Bayo and Wyckhuys describe them as the ‘structural and functional base’ of the world’s ecosystems, important in nutrient cycling, seed dispersal, pollination, soil structure and viability, and providing a food source for a huge number of organisms.

So, what is causing the declines? You guessed it – us, and the main offender is agriculture. Farming practices have intensified over the last sixty years as the human population has continued to grow. This is a double-whammy to insects. Firstly, their habitat is being removed or degraded by the conversion of land to agriculture. Secondly, toxic pesticides (such as neonicotinoids) are being sprayed liberally onto crops, which though intended to affect unwanted beasties, often make their way into the areas surrounding farms, and ultimately harm wild insects. The authors also cite urbanisation, pollution, climate change, and human-facilitated spread of insect diseases and invasive species as significant drivers of the declines.

To halt insect declines, Sánchez-Bayo and Wyckhuys suggest that farmers need to move away from the current intensive agricultural practices, and towards more integrated approaches that make use of ‘ecological engineering’. These strategies could include planting strips of pollinator friendly habitat, or rotating crops with clover, which has been shown to boost bumblebee numbers. Such methods would allow for reduced pesticide use and promote the natural predators of herbivorous crop pests. However, farmers cannot be expected to do this on their own, and governments will need to implement policies that incentivize farmers that maximise biodiversity and reduce habitat loss.

We might need to consider changing our eating habits too. Currently, farming livestock takes up 83 per cent of land used for agriculture, but only provides 18 per cent of the calories. With demand for products derived from livestock (meat, eggs and milk) expected to double by 2050, this is clearly not the most efficient way to feed the world’s growing population. If we could shift our consumption even just a little bit more towards a plant-based diet, we could reduce the amount of habitat that is destroyed to be used for agriculture.

This review follows in the wake of reports of huge biodiversity losses in other groups of organisms. A report published by the WWF last year found that vertebrate populations (i.e. mammals, birds, reptiles etc.) have seen losses of 60% since the 1970s. Recent analyses estimate that 83% of wild mammals have vanished since the rise of human civilisation. Research published this year in the journal Science estimates that 90 frog species have gone extinct and a further 124 species have seen losses of more than 90 per cent because of chytrid fungus disease. Unfortunately, humans are implicated here too, as globalisation and the wildlife trade have been cited as the drivers of the spread of the fungus.

The situation looks bleak. Humans make up just 0.01 per cent of life on earth, but our existence continues to reap damage to biodiversity. However, the problems that face wildlife are in the public awareness now more than ever, and some positive change has already happened. In the final episode of Blue Planet II, David Attenborough called for action in reducing plastic pollution in our oceans. Since then, the UK government has opened consultations on how we can repeat the success of the 5p carrier bag charge with possible bans on other single-use plastics. The British supermarket Tesco recently announced plans to trial selling loose fruits and vegetables normally packaged in plastic. Numerous other countries, cities and companies have also pledged to ban plastics.

The public’s response to single-use plastic is required in other aspects of conservation

People are also pushing for action on climate change. Activist movement Extinction Rebellion has been organising regular demonstrations in cities around the UK to pressure the government on climate change and other environmental issues. Moreover, inspired by sixteen-year-old climate activist Greta Thunberg, schoolkids all over the world recently went on strike from class to ask world leaders to stand up and take climate change seriously.

Clearly life on Earth is in trouble. But it is also clear that the people want change, and are willing to fight to get it. We can all do our bit, whether that means participating in a large-scale demonstration, or just making small changes to our daily habits. Every small act furthers the conversation. What will you do to fight for your planet?

Originally published online by The Otterside Journal