Volunteers from the Kent Wildlife Trust and Buglife in the United Kingdom have spent summers watching car number plates for almost two decades. Their quiet task records each time a vehicle rolls by and tracks how often insects get caught on windshields. Though it may seem small, the effort demonstrates the power of citizen science and collective action. A campaign with nearly 700 participants collected data from 6,358 trips in 2023, providing a robust data set for broader conclusions.
Results from the 2022 campaign already showed a striking trend: a 64% drop in the number of insects hitting vehicles across the United Kingdom over less than 20 years. This finding feeds a worrying hypothesis among scientists: a large-scale decline in insect populations is underway, signaling a potential sixth mass extinction for the planet.
Sixth mass extinction
The most reliable measurements come from long-term studies that track insect groups whose populations have been monitored for decades. The current evidence, however, indicates that declines are not confined to one region; they are a global concern.
There is a visible decline in insects in many areas, illustrated by compelling imagery and data from diverse ecosystems.
A 27-year study from Germany, published in 2017, found a 76% decrease in flying insect biomass within networks of natural areas. In Denmark, declines in insects align with reductions in bird species that rely on them for food, such as the barn swallow. In Europe, entomologists gathered to express concerns through a formal manifesto during a major congress, highlighting this unprecedented trend and urging action.
Beyond Europe, studies in tropical forests show striking losses as well. In Puerto Rico, a comparison of current insect abundance to data from 36 years ago reveals a more than 78% reduction in terrestrial insect biomass. This decline mirrors trends in other insectivorous species, including lizards, frogs, and birds.
Why are there fewer insects?
The causes are multifaceted and rooted in infrastructure and activity changes. Soil degradation, habitat loss, polluted air and water, and the fragmentation of natural landscapes all contribute. Insects depend on healthy soil, clean water, and diverse plant life. When these essentials are compromised, insect populations suffer.
Disruption of communication signals is another factor. Light pollution, chemical pollutants, and physical changes in the air interfere with the sensory systems that insects use to navigate and find mates. The increasing presence of microplastics and other tiny particles also harms insect health and behavior.
Climate change interacts with these pressures, acting as a major driver of shifts in insect abundance. The loss of insect biodiversity can lead to a less resilient ecosystem, with cascading effects on other life forms and on human well being.
Why is it important to protect them?
Insects account for a large share of the world’s animal species and provide essential ecological services. Foremost among these is pollination, a process critical to many crops and wild plants alike. It is estimated that a substantial portion of global food production depends on insects for pollination, and food security would be at risk if these species vanished.
In addition to pollination, insects help break down organic matter and recycle nutrients. They act as natural soil engineers, supporting soil health and the broader food web that sustains life on Earth. Insects also contribute to pest control, helping regulate pest populations through natural predation and parasitism in ecosystems. These roles are foundational to agriculture and biodiversity alike.
Can we do something to protect them?
Addressing major environmental problems relies on many small actions. Individuals can contribute in meaningful ways, and community projects amplify impact. Practical steps include:
-
Support citizen science efforts to expand insect knowledge and conservation in natural and urban spaces. Programs similar to SPIPOLL, urban butterfly observatories, and regional phenology networks offer accessible entry points.
-
Create urban habitats by mixing native vegetation with wild areas along borders, streets, and parks. Provide breeding and shelter spaces for many species.
-
Avoid phytosanitary products in home gardens and urban green spaces. Reduce mowing of wild plants, especially during flowering periods, to let insects feed and reproduce.
-
Choose food produced under strong agricultural practices that emphasize organic or integrated pest management and support biodiversity.
-
Seek livestock care options that do not harm decaying entomofauna or disrupt soil ecosystems.
-
Avoid introducing invasive species into agricultural or horticultural practices.
Educators and all adults share a responsibility to showcase the beauty and importance of insects to children and communities. This is a critical issue for our collective survival.
It is worth noting the importance of small, everyday acts that collectively make a difference. Attention to windshield cleanliness, for instance, subtly reflects a broader concern for the tiny creatures that share our world.
Researchers emphasize that these are not isolated observations but part of a growing, global understanding of insect declines and their far-reaching consequences for ecosystems and human life.
Reference: The Conversation article on why fewer insects are observed on car windshields today and what this means for ecosystems.