How Climate Change Is Affecting Insects and Why It Threatens Life on Earth

KAKALI DAS

Insects are among the smallest creatures on Earth, yet they are also among the most important. They quietly support ecosystems, pollinate crops, recycle nutrients, and help maintain the balance of nature. Although they are often ignored or considered a nuisance, life as we know it would be impossible without them. From the coffee we drink and the chocolate we enjoy to apples, apricots, berries, and countless other fruits, many of the foods we depend on exist because insects pollinate plants. As climate change continues to reshape the planet, scientists are increasingly concerned about how these tiny creatures are being affected and what their decline could mean for the future of humanity.

Dr. Tim Cockerill, a zoologist and lecturer at the University of Falmouth in the United Kingdom, has spent years studying insects and their remarkable diversity. Outside his academic work, he is also a circus performer, a fire eater, and someone who has even trained fleas to perform tricks. His lifelong fascination with insects has taken him to some of the world’s most remote forests in search of species that few people have ever seen.

One of Dr. Cockerill’s most remarkable discoveries led to an insect species being named after him. The insect is called Megaphragmacockerelli, with the ending added in Latin to honour him. He discovered this tiny insect while working in the rainforest canopy of northern Borneo. Scientists climbed to the top of a rainforest tree and used a special method to collect insects living high above the ground. They released a harmless substance into the canopy that caused insects to fall into collection trays below. Later, researchers examined the collected insects under microscopes.

Among what Dr. Cockerill described as an “insect soup,” scientists found something completely unknown to science. The insect was so tiny that if it landed on a person’s hand, they would probably never notice it. After years of careful study and comparison with museum collections around the world, experts confirmed that it was a new species. Today, only one specimen of this insect has ever been found. It is preserved on a small microscope slide in the Natural History Museum, making it one of the rarest known insects.

When people think of wasps, they usually imagine the black and yellow insects that often disturb outdoor meals and picnics. However, this represents only a tiny fraction of the thousands of wasp species found across the world. Most wasps are extremely small and live hidden lives that most people never notice.

One of the most fascinating groups is known as parasitoid wasps. These insects have an extraordinary life cycle. Instead of building nests or hunting prey like larger wasps, they lay their eggs inside other insects, often caterpillars. The young wasps develop safely inside their host, feeding on it without immediately killing it. The caterpillar continues living as if nothing has happened until the wasps are fully grown. Instead of becoming a butterfly, the caterpillar eventually dies as many tiny wasps emerge from its body.

This life cycle may sound like something from a science fiction film, but it is one of the most common survival strategies in nature. Although many people find it disturbing, scientists believe there may be more species of parasitoid wasps than any other kind of animal on Earth. Their incredible diversity reminds us that much of the natural world remains hidden from human eyes.

Dr. Cockerill explains that insects have existed for around 480 million years, long before dinosaurs appeared on Earth. Over hundreds of millions of years, they have evolved together with plants, animals, and entire ecosystems. Every forest, grassland, wetland, and farm depends on insects in ways that are often invisible to us.

Flowers themselves owe much of their existence to insects. Most flowering plants evolved because insects carried pollen from one flower to another. Flowers produce nectar and colourful petals as a way of attracting insects. In return for food, insects help plants reproduce by spreading pollen. This relationship has developed over millions of years and has shaped much of the natural world that surrounds us today.

People often ask what insects do for humans. The answer is simple. They do an enormous amount. One of their greatest contributions is pollination. Many of the foods people enjoy every day depend on insects. Coffee, chocolate, berries, apples, apricots, and many other fruits would be impossible or much more difficult to produce without insect pollinators.

Scientists describe these benefits as ecosystem services. These are the valuable services that nature provides free of charge. Pollination alone is estimated to contribute about half a trillion dollars to the global economy every year. Without insects, food production would become much more expensive and less reliable.

Insects also play an important role in controlling agricultural pests. Instead of relying entirely on chemical pesticides, many farmers work with beneficial insects that naturally reduce pest populations. One example comes from citrus farms growing oranges and lemons in tropical regions, where farmers encourage colonies of weaver ants because they actively hunt insects that damage crops.

Weaver ants are remarkable builders. They use the silk produced by their own larvae to join leaves together and create nests high in the trees. Adult ants carefully carry their larvae from leaf to leaf, using them almost like living glue guns. As the ants move through the trees searching for food, they attack and remove many harmful insects that would otherwise damage citrus crops. This natural form of pest control reduces the need for chemical pesticides and demonstrates how working with nature can often be more effective than working against it.

Humans simply could not live without insects. Besides pollinating fruits, they are also essential for producing many vegetable oils that people use every day. One of the world’s most important crops is oil palm, which produces palm oil. Palm oil is found in countless products, including processed foods, cosmetics, soaps, and even biodiesel.

The pollination of oil palm depends largely on one tiny species of weevil that originally came from Guinea in West Africa. As oil palm plantations spread around the world, this small insect travelled with them and became essential for successful production. Before this weevil was introduced, workers had to pollinate every flower by hand using small paintbrushes. Imagining millions of workers carrying out this task shows just how valuable these tiny insects truly are. They quietly perform work every day that would otherwise require enormous amounts of human labour and money.

The importance of insects becomes even clearer when considering the growing threat of climate change. Scientists are trying to understand exactly how rising temperatures, changing rainfall patterns, and more frequent extreme weather events are affecting insect populations. While researchers have identified some clear trends, the full picture remains extremely complex because insects are incredibly diverse and every ecosystem functions differently.

One of the main challenges is that insects are facing several threats at the same time. Climate change is only one part of the problem. Habitat destruction, fragmentation of natural landscapes, intensive farming, the widespread use of pesticides, urbanisation, and light pollution are all placing enormous pressure on insect populations. This makes it difficult for scientists to separate the specific effects of climate change from all the other human activities that are changing the natural world.

Even so, research has revealed some worrying patterns. Scientists have observed a decline in both the abundance and diversity of insects in many parts of the world. Abundance refers to the total number of insects present, while diversity refers to the variety of different species. Although the rate of decline varies from place to place, the overall trend suggests that many insect populations are shrinking.

In many ways, insects act as nature’s early warning system. If something goes wrong in an ecosystem, insects are usually among the first organisms to show signs of stress. Because they are found almost everywhere and are closely connected to plants, animals, fungi, and microorganisms, changes in insect populations often signal that larger environmental changes are taking place.

Habitat fragmentation is another serious problem. For example, when a road is built through a forest, one large forest becomes two smaller patches. Although this may not seem like a major change, it can have significant consequences for wildlife. Smaller forest patches cannot support as many species as larger continuous forests. Animals become isolated from one another, breeding becomes more difficult, and insects lose the habitats they have depended on for thousands of years.

Modern cities also create unexpected challenges. Artificial lights attract countless insects at night, disrupting their natural behaviour. Many insects waste valuable energy flying around streetlights and buildings instead of feeding, finding mates, or laying eggs. Light pollution has quietly become another major pressure on insect populations around the world.

Dr. Tim Cockerill shared a striking example of how fragile some insect species have become. He spoke about a species of cockroach discovered only around fifteen years ago in a cave in Guinea, West Africa. The word “cockroach” often creates negative reactions because people associate it with household pests. However, there are around 4,500 species of cockroaches worldwide, and only a handful are considered pests. Most live in forests, caves, or other natural habitats where they perform valuable ecological roles.

Many cockroaches help break down rotting wood and dead plant material, returning nutrients to the soil. Others live inside caves, feeding on bat droppings and contributing to the recycling of nutrients in these unique underground ecosystems. They are an essential part of nature’s cleaning system.

The cave dwelling cockroach that Dr. Cockerill described is believed to be extinct in the wild. Today it survives only in captivity, where insect enthusiasts have managed to breed it successfully. Scientists believe that mining activities destroyed its natural habitat, leaving no suitable environment for the species to survive outside captivity. It is a powerful reminder that insects can disappear long before most people even realise they exist.

Climate change presents another serious challenge because every insect has evolved to survive within a specific range of temperatures and environmental conditions. Each species has its own preferred levels of warmth, humidity, food availability, and habitat. When those conditions change too quickly, insects may no longer be able to survive where they once flourished.

Scientists have already documented changes in several species of butterflies and dragonflies across the Northern Hemisphere. As average temperatures continue to rise, many insects are gradually shifting their geographical ranges towards cooler northern regions. They are essentially following the climate conditions that suit them best.

At first glance, moving north may seem like a simple solution. However, many species cannot move indefinitely. Others live in places where there is nowhere left to go. Mountain species face an especially difficult situation. As temperatures rise, they move higher up mountain slopes in search of cooler conditions. Eventually they reach the summit. Beyond that point, there is nowhere else to escape the warming climate, leaving them at serious risk of extinction.

Climate change can also disturb the delicate timing of natural events. Scientists refer to this as a phenological mismatch. One example involves bees and apricot trees in North America. Rising temperatures are causing apricot trees to flower earlier in the spring. However, the bees that pollinate these flowers spend the winter underground and are not emerging early enough to match the earlier flowering season.

As a result, many flowers bloom and fade before the bees become active. The bees lose an important source of food, while the trees receive less pollination. Even though both species are responding to warmer temperatures, they are not changing at the same rate. Such timing mismatches can gradually reduce crop production and weaken natural ecosystems.

Climate change is also changing the distribution of disease carrying insects such as mosquitoes. Mosquitoes thrive within certain temperature ranges. As warmer conditions spread into higher elevations and previously cooler regions, mosquitoes are expanding into new areas where they were once unable to survive.

Communities that historically lived above the mosquito zone in mountainous regions are now increasingly exposed to diseases such as malaria and dengue fever. Scientists have documented this shift in countries including Ethiopia and Colombia, where warmer temperatures have allowed mosquitoes to move uphill into areas that were previously protected by cooler climates.

Some climate projections even suggest that diseases such as dengue fever, once considered almost entirely tropical, could become more common in parts of Europe during the coming decades if warming continues. This demonstrates that the effects of climate change on insects are not limited to wildlife alone but have direct consequences for human health as well.

Extreme weather events are creating additional problems. The devastating floods in Pakistan in 2022 left vast areas covered with standing water, providing ideal breeding sites for mosquitoes. Combined with warmer temperatures, these conditions allowed mosquito populations to grow rapidly, contributing to a significant increase in malaria cases compared with previous years. Climate change therefore affects insects not only through gradual warming but also by increasing the frequency and intensity of floods, droughts, and other extreme events that alter their habitats.

Although insects generally reproduce much faster than larger animals, giving them greater potential to adapt through evolution, scientists believe that climate change is occurring faster than many species can adjust. Fruit flies and other insects may complete several generations within a single month, allowing natural selection to work relatively quickly. However, even this rapid reproduction is often not enough to keep pace with the speed of environmental change.

If insects with their short life cycles are struggling to adapt, the challenge is even greater for long lived organisms such as elephants or oak trees, which reproduce far more slowly. This is one reason why scientists often describe insects as the canaries in the coal mine. Their decline provides an early warning that much larger environmental problems may soon affect entire ecosystems and eventually human societies as well.

The decline of insects is far more than the loss of a few small creatures. It threatens many of the natural services that make life on Earth possible. Scientists describe these benefits as ecosystem services because they support both nature and human societies. Among the most important of these services are pollination, decomposition, and natural pest control. If insect populations continue to decline, people around the world will increasingly experience the consequences through food shortages, reduced agricultural productivity, and weakened ecosystems.

Pollination remains one of the most valuable services insects provide. Many crops that supply fruits, vegetables, nuts, seeds, and oils depend on insects transferring pollen from one flower to another. Without pollinators, many plants would produce fewer fruits and seeds, while some would fail to reproduce altogether. This would not only affect farmers but also reduce food availability and increase prices for consumers.

Insects are equally important in recycling nutrients. Nature constantly produces dead plants, fallen trees, animal waste, and the remains of dead animals. Without decomposers, these materials would simply accumulate. Cockroaches, termites, beetles, flies, ants, and countless other insects break down this organic matter and return valuable nutrients to the soil. Healthy soils, in turn, support forests, grasslands, and agricultural lands.

Dr. Tim Cockerill pointed out that where there are cattle, there are usually dung beetles and dung flies. These insects quickly remove and recycle animal waste, preventing it from piling up across fields. They also reduce breeding sites for harmful flies and help improve soil quality. Likewise, when a tree falls in a forest, insects begin breaking it down almost immediately, allowing nutrients locked inside the wood to return to the ecosystem. Without these natural recyclers, ecosystems would struggle to function efficiently.

The loss of insects would also weaken natural pest control. Many insects feed on species that damage crops. Farmers who work with beneficial insects often need fewer chemical pesticides, making agriculture more sustainable. If these helpful insects disappear, farmers may become increasingly dependent on pesticides, creating additional environmental problems and placing even more pressure on biodiversity.

As climate change continues to alter ecosystems, agriculture itself may need to adapt. Crops that grow well in one region today may no longer be suitable there in the future. Farmers may need to change the varieties they grow or shift cultivation to different regions as temperatures, rainfall, and seasons continue to change. Protecting insect populations will therefore become an essential part of ensuring future food security.

Fortunately, there are many practical actions that individuals, communities, and governments can take to help insects survive. One of the simplest is to make gardens, balconies, parks, and public spaces more friendly to insects. Planting native flowering plants that bloom at different times of the year provides a continuous supply of nectar and pollen for bees, butterflies, and other pollinators. Even a few flowering plants on a balcony can provide valuable food for insects living in urban areas.

Avoiding artificial grass and maintaining natural vegetation also creates better habitats. Native plants support local insect species because they have evolved together over thousands of years. Small actions by millions of people can collectively make a significant difference.

Reducing the use of pesticides is another important step. Many pesticides remain in the environment long after they are applied. Bees and other beneficial insects may collect small amounts while visiting flowers. These chemicals can accumulate in food chains and affect many different species over time. Choosing organic food, where possible, and encouraging farming methods that reduce dependence on harmful chemicals can help protect insect populations while supporting healthier ecosystems.

Conservation also requires protecting natural habitats such as forests, wetlands, grasslands, caves, and cloud forests. Many insects survive only within very specific environments. Once these habitats are destroyed through mining, deforestation, urban expansion, or pollution, entire species may disappear forever. Some may become extinct before scientists have even had the opportunity to discover and study them.

Dr. Cockerill also highlighted one of the most beautiful insects he had brought with him for demonstration, the jewel scarab beetle. These remarkable beetles appear almost metallic, shining like polished pieces of silver or green metal. Their brilliant colours are not simply beautiful but are believed to help them survive. Living in the misty cloud forests of Central America, their reflective bodies may resemble tiny droplets of water resting on leaves, helping them avoid predators.

Despite their beauty and remarkable adaptations, jewel scarabs are now under threat because the cloud forests they depend upon are disappearing. Habitat loss and climate change are shrinking these cool, moist environments, leaving the beetles with fewer places where they can survive. They represent just one example of the astonishing diversity that could be lost if action is not taken.

The world of insects is far richer and more complex than most people realise. They have shaped life on Earth for nearly 480 million years, evolving alongside flowering plants, forests, birds, mammals, and eventually humans. They pollinate crops, recycle nutrients, control pests, maintain healthy soils, and support countless food webs. Their contribution to human well being is immense, even though it often goes unnoticed.

Climate change has added another major challenge to the many pressures insects already face. Rising temperatures, shifting seasons, habitat destruction, pollution, pesticides, and extreme weather events are combining to threaten many species. Their decline serves as an early warning that ecosystems are under increasing stress.

Protecting insects is therefore not simply about conserving small creatures. It is about protecting the ecological systems that support agriculture, biodiversity, public health, and human civilisation itself. Every flower planted, every natural habitat protected, every reduction in pesticide use, and every effort to reduce greenhouse gas emissions contributes to safeguarding these remarkable animals. By protecting insects, we are ultimately protecting the future of life on Earth.

References

BBC World Service. (2024). The Climate Question: How Are Insects Being Impacted by Climate Change? BBC World Service.

Tim Cockerill. Research and public lectures on insect ecology, biodiversity, and conservation.

The Insects: Structure and Function. (2013). Cambridge University Press.

The Diversity of Life. (1992). Harvard University Press.

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