Nature crisis: Why insect populations are declining

Bees clustered on a flower

Gone are the days when drivers battled with flies, gnats, bugs and wasps on their windscreens, or the occasional moth fluttering away at the headlights. Entomologists - experts who study insects – have coined the phrase ‘windscreen phenomenon’, to refer to the observation that fewer dead insects accumulate on the windshields of people’s cars since the early 2000s.

This phenomenon has been attributed to a decline in insect numbers, thanks to human activity. In Kenya however, a lack of data to substantiate the evident decline in insect numbers cripples the efforts that would be made towards salvaging these populations, as Dr George Ong’amo, and agricultural entomologist and lecturer at The University of Nairobi, explains. On the world stage however, researchers have been able to substantiate the decline.

The role of insects

The question of what the world would be without insects often comes up. For a species whose members are largely referred to as pests, and portrayed as quite the nuisance, it can be tempting for some to envision a bug-free, wasp-free world.

‘But keep the bees for their honey, oh and the butterflies because they are pretty.’ But this would only mark the beginning of tragedy in the world.

Insects hold aloft everything that we value. According to Oliver Milmann, an environmental journalist and author of the book The Insect Crisis: The Fall of the Tiny Empires That Run the World, three-quarters of all the known animals in the world are insects. He further explains that there’s roughly one million named species but there might be nearly five million or maybe 10 million, or even up to 30 million species that remain unnamed or undiscovered.

Insects play a huge role in plant pollination, dispersion of seeds as well as maintenance of the soils structure and its fertility. More importantly, insects control populations of other organisms and provide a huge food source to species such as birds.


“More than 40 per cent of insect species are declining and a third are endangered, the analysis found. The rate of extinction is eight times faster than that of mammals, birds and reptiles. The total mass of insects is falling by a precipitous 2.5 per cent a year, according to the best data available, suggesting they could vanish within a century,” reads part of  an article on The Guardian.

Reasons for the decline?

According to Milmann, habitat loss has had the greatest impact on insect populations. The environmentalist notes that a third of all forested areas have been cleared to pave way for industrialisation.

“We’ve changed much of the planet into monocultural farmland. We’ve expanded highways, urban areas, and so on, creating a landscape that’s very hostile to insects. We’ve dominated the world in a very boring way. Insects like diversity and colour and a range of different plants and we tend to like uniformity and tidiness. Culturally, we like very neatly trimmed lawns. We like fields of crops that are not diversified and have tidy edges. We dislike weeds in general. We’ve created a monotonous world that isn’t favourable to insects,” Milmann explains in part in an interview with Vox News.

Pesticide use is also a huge contributing factor to the declining insect numbers. “The demise of insects appears to have started at the dawn of the 20th century, accelerated during the 1950s and 1960s and reached alarming proportions over the last two decades. …New classes of insecticides introduced in the last 20 years have been particularly damaging as they are used routinely and persist in the environment. They sterilise the soil, killing all the grubs,” an article published by The Guardian states.

Climate change has also exacerbated the conditions that have led to the decline of insect population.

“Insects are more restricted in terms of their movement. They exist in fairly stable bands of temperature, and once that’s pushed beyond their limits, they are in big trouble,” Milmann says.

What can be done to save insects?

There is a huge need to let things be as they naturally would. As Milmann puts it, “One scientist told me that we need more of an inaction plan rather than an action plan. It’s about just letting things slide a little bit. Maybe don’t rake the leaves in your yard, or don’t apply as much or as many insecticides. Maybe let the grass grow a little bit — because insects love that.”

Dr Ong’amo explains that conservation efforts will help to restore natural habitats that can be taken up by insects, allowing them to reproduce. He further notes that conscious efforts to reduce the use of synthetic pesticides will help restore the insect populations.


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