AsianScientist (Dec. 5, 2019) – Many Hollywood movies paint a compelling picture of the apocalypse of mankind. However, what is, in fact, closer to reality is the insect apocalypse. Dubbed the ‘windshield phenomenon’ by entomologists, the decline in insect population is becoming an increasingly pertinent concern.

According to a United Nations (UN) Environment study, more than 40 percent of insect species are declining and a third are endangered. Predicted by experts, the decline in insects may lead to a ‘bottom-up trophic cascade’ phenomenon, where the effects of the insect collapse are accumulated through the food chain, thus severely harming or even wiping out animals and mankind.



Dwindling insect population

If the loss of biodiversity of insects is so catastrophic, why are people unaware of it? As insects are legion, inconspicuous and difficult to track, their disappearance has been challenging to monitor. Unknown to many, the rate of extinction among insects is eight times faster than that of mammals, birds and reptiles. The plummeting insect biodiversity can be attributed to the wide use of insecticides, fragmentation of habitats and climate change.

The wide use of insecticides has been lamented as one of the contributing factors to the mass extinction of insects. While targeting harmful pests, pesticides may destroy beneficial insects like bees and butterfly pollinators. In addition, pesticide exposure can cause sub-lethal effects on plants. Phenoxy herbicides, including 2,4-dichlorophenoxyacetic acid (2,4-D), can injure nearby trees and shrubs if they drift or volatilize onto leaves. This creates further damage on the ecosystem, as plants play a fundamental role in the ecosystem and are essential for many insects’ survival.

While many lament about the unbearable heat, insects are likely to be more affected by it. Insects in tropical regions may have a narrow tolerance for temperatures, and suffer population declines as a result of global warming. Climate change has brought about unprecedented threats, from extreme weather events and sea level rise, to invasive alien species, agricultural intensification and increasing waste and pollution.

In an interview with The Guardian, Professor Dave Goulson from the University of Sussex said, “In the future, the decline of insects can be hugely accelerated by the impacts of climate change, under realistic climate projections. When we consider all the other adverse factors affecting wildlife, all likely to increase as the human population grows, the future for biodiversity on planet Earth looks bleak.”

The fragmentation of habitats is evident around the world. Based on a study coordinated by the Food and Agriculture Organization of the United Nations, the United States Agency for International Development and the World Bank, 60 percent of its grasslands are degraded due to overgrazing by livestock, invasion by alien species or conversion to agriculture. This results in a rapid decline of native flora and fauna, which are home to hundreds of insect species. This trend is prevalent in Asia, with eight of the top ten most plastic-polluted rivers in the world. Such an example is the Citarum river in Indonesia. Known for its murky, polluted waters, the river has lost a vast part of its biodiversity, including aquatic insects, walking catfish, common carp and minnows.



Loss of gems in our ecosystem

Many people think of insects as pests. This could not be further from the truth—they do not realize that without insects, we are doomed.

Insects create the biological foundation for all terrestrial ecosystems. They play an indispensable role in pollinating plants, including many of those that humans rely on for food. Insects are key players in breaking dead matter down into the building blocks for new life, controlling weeds and providing raw materials for medicines. Entomophily, or the pollination by insects, often occurs on plants that have developed colored petals and a strong scent to attract insects.

Many insects, especially beetles, are scavengers, feeding on dead animals and fallen trees, thereby recycling nutrients back into the soil. As decomposers, insects help to create humus, the nutrient-rich layer of soil that helps plants grow. Burrowing bugs, such as beetles and ants, provide channels for water, benefiting plants.

“One of the key findings of the assessment is that rich biodiversity and ecosystem services in Asia-Pacific are incredibly vital for human well-being and the region’s sustainable development,” says Sonali Senaratna Sellamuttu, a well-known environmental researcher based in Southeast Asia.

Throughout East Asia and Southeast Asia, insects play a crucial role in traditional Chinese medicine. For example, an extract from Polyrhachis vicina Roger, more commonly known as the Chinese Black Mountain ant, has been used as a functional ingredient in various tonics or health foods. Throughout China and across Southeast Asia, blister beetles are known for their defensive secretion of a blistering agent, cantharidin, which is often used to reduce burning pain sensations commonly associated with urinary tract infections, insect bites and kidney problems.



Crawling back from the brink of extinction

However, not all hope is lost. Scientific advancements have enabled us to slow down or even reverse our march towards an insect apocalypse. Genome editing can be used to reduce crop losses and chemical pesticide sprays. CRISPR-Cas9 gene editing technology has been harnessed to enhance the inheritance of the gene drive tool via sexual reproduction. This enables plant species to spread quickly, increasing crop yield and negating our need to use excessive chemicals and pesticides.

To many, insects’ downsides—bites, stings and diseases—have led to a manifestation of a ‘good riddance’ mentality towards them. However, it is crucial to recognize the overarching ecological benefits that insects have to offer, and work to protect them in the same way we protect pandas, rhinos and exotic birds. Strategies such as genetic engineering are stepping stones towards mitigating the effects of our damage on insect biodiversity. However, a paradigm shift in mindset towards insects is vital, so that we are compelled to take action by relieving the stresses on insects, and combating the challenges posed by climate change.



This article won second place in the Science Centre Singapore Youth Writing Prize at the 2019 Asian Scientist Writing Prize.

Click here to see photos of the the prize presentation ceremony held on December 4, 2019.

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Copyright: Asian Scientist Magazine; Photo: Shutterstock.

Disclaimer: This article does not necessarily reflect the views of AsianScientist or its staff.