When we think about invertebrates, most of us picture bees, butterflies, worms, crabs or perhaps even a jellyfish. But did you know that at least two-thirds of invertebrates are active at night, meaning many are unlikely to be seen? Invertebrates carry out many of the same functions as their daytime counterparts, in some cases doing so with greater efficiency and variety.
For centuries, artificial light has been a symbol of progress. From the flickering flames of early fires to the dazzling LED displays of modern cities, light has shaped human civilisation. But while we celebrate its convenience, we often overlook the darker side of our obsession with illumination: light pollution.
Despite global efforts to combat the climate crisis and wildlife loss, light pollution remains socially accepted. It is not just a nuisance for stargazers: it’s a disruptor of ecosystems, with profound consequences for wildlife, human health and energy consumption.
Fuelled by the rapid adoption of cheap and bright LEDs, light pollution has soared by nearly 10% every year for the past decade. This represents a doubling of sky brightness every eight years. Public spaces, roads, homes and businesses are drowned in artificial light, often with little thought given to its impact.
Moths, our best-known nocturnal invertebrates, are suffering from our obsession with light. A 2021 study found that caterpillar populations were 52% lower in areas with street lights.
The winter moth is a small but essential species. In early spring its caterpillars provide a critical food source for blue tit chicks. But light pollution disorients the adult moths, disrupts mating and affects egg-laying, leading to fewer caterpillars. With declining caterpillar numbers, blue tits struggle to feed their young, causing ripple effects throughout the food chain.
Light pollution is throwing nature off balance on a wider scale: bats alter their flight patterns, dung beetles struggle to navigate, crickets chirp less and plants are affected as their natural growth cycles shift.
Even the smallest of artificial lights can disrupt natural behaviour. Fireflies and glow-worms, maybe our most charismatic nocturnal invertebrates, can mistake a single LED for a potential partner, limiting mating and reproduction. The problem is so significant that experts consider light pollution as one of the greatest threats to these special glowing beetles globally.
If we are to truly halt nature loss and protect our essential invertebrates, we must address the problems affecting all species. While light pollution continues to increase unchecked, it is our forgotten species working the night shift that will suffer the most.
Light pollution is easily preventable: turn off unnecessary lights and the problem disappears. Unlike other pollutants, there is no need for a challenging cleanup operation.
While artificial light is sometimes necessary for safety, we should prioritise lighting methods that minimise light pollution, reducing harm to the natural world while continuing to meet societal needs.
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There are a number of ways you can help reduce light pollution. One would be to join Buglife’s campaign to make it curtains for light pollution; an act as simple as closing your curtains or blinds can reduce your impact on nature.
You can also write to your local council about street lighting. It is one of the biggest causes of light pollution, and many councils are taking action, which means they are protecting wildlife as well as saving money.
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The Guardian is running the invertebrate of the year competition 2025 – and this time it’s global. Nominate your favourite invertebrate, and then, in a few weeks time, we’ll vote on which is the best.
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