We have all seen the headlines about the alarming decline in insect populations. But while the plight of butterflies and bees during the day is well-known, two-thirds of all insects are active after dusk and the struggles of our nocturnal invertebrates remain largely unseen.

Just like their day-flying relatives, these nocturnal insects perform essential services such as pollination, recycling nutrients, providing natural pest control, and serve as a food source for other animals. Insects are more active in the warmer months, but nights are shorter, so it is especially important to protect night-flying insects from artificial light in summer.

Artificial light at night disrupts the feeding, navigating and life cycles of night-time insects. Many insects like ground beetles will only emerge to forage and feed in the dark, and others like dung beetles navigate using the moon and stars, and even the Milky Way. Light pollution causes these celestial navigators to become disorientated, leading to wasted energy, increased predation risk, and failure to reproduce.

Some insect species, like many moths, can see colour at night, particularly, green, blue and UV light, which they use to identify a flower under moonlight. The trade-off for this adaptation is that insects with night vision see fewer frames per second slowing their reactions and their vision is probably quite blurry. The benefits of night vision are lost when artificial light allows animals who hunt and forage during the day to be active at night.

As mammals with vision adapted to daylight, we light up the night to make it feel more pleasant and safe. Low-energy lights have made lighting cheaper, encouraging us to use decorative lights in gardens and on buildings that dispel the night for us but may prevent a night-time insect from completing its life cycle. A light shining on trees, a pond or river could prevent generations of insects emerging, removing a food source for bats, birds and small mammals.

Most of the UK now experiences skyglow obscuring the natural night sky. The glow from roads and buildings may seem faint to us as we are not well adapted to seeing at night, but shines brightly for the large eyes of insects. Fortunately, light pollution is a problem that can literally be

solved by a flick of a switch. Once a light is turned off, that pollution is gone, unlike other pollution that is so difficult to remove from the environment.

Conservation charity Buglife advises that the simplest action is to prevent light spilling out of our buildings into the environment by remembering to draw curtains and blinds at dusk. Avoid outdoor lighting whenever possible, fit timers and motion sensors, and direct lights away from vegetation and water.

Support local councils to adopt switch-off schemes for street lighting, keeping lighting to the minimum required for safety, and encourage them to refuse planning permission for unnecessary floodlighting.

By preserving the darkness, we can secure the future of our night-time insects, one dark hour at a time.