Have you noticed fewer insects around your porch light or fewer splattered bugs on your windshield? You're not alone. Scientists are calling this a new crisis—the "insect apocalypse"—and artificial light at night is a major cause.
Light pollution is growing rapidly worldwide due to the widespread use of LEDs. Satellite data shows outdoor lighting expanding by over 2% each year, with brightness increasing almost 10%. Insects, which have evolved over millions of years under natural light cycles, are now struggling to survive.
How does artificial light harm insects? Dr. Avalon Owens from Harvard University explains four main ways. First, it causes disorientation—fireflies, for instance, can't synchronize their flashing, reducing their mating signals by up to 70%. Second, it creates fatal attraction—moths and other insects are drawn to lights, exhausting themselves or falling prey to predators. A single streetlamp can kill hundreds of insects each night. Third, navigation is disrupted—native bees lose their celestial cues, making it harder to find food. Fourth, visual confusion occurs—artificial polarized light tricks aquatic insects into laying eggs on wrong surfaces, reducing their populations.
In Colorado, this is a serious issue. Our state is home to over 1,500 native bee species, including the Western bumblebee, which has declined by 84%. The Rocky Mountain Apollo butterfly has retreated higher into the mountains as artificial lights disrupt its habitat. Remember how the glow of fireflies intrigued you as a child? Fireflies along the Colorado River have diminished so much that many young residents have never seen their glowing displays.
Our aquatic insects are also suffering. Salmonfly hatches, once so prevalent they darkened the sky, have decreased by nearly half in areas with increased development and lighting. These insects are vital food for fish and birds. Even high-altitude insects like the ice crawler, living on glaciers, have lost nearly 30% of their habitat due to expanding light pollution.
Why does this matter? Insects pollinate 80% of wild plants and 75% of our crops. They decompose waste and support food webs that sustain birds, fish, and mammals. In Colorado, declining pollinators mean farmers now hand-pollinate crops, and butterfly populations have dropped by over 50% since 1990.
The ecological consequences are profound. Without insects, our forests, streams, and farms suffer. Our economy, worth billions, depends on these tiny creatures. Their decline threatens the very foundation of Colorado’s natural beauty and food security.
But there’s hope. Some lighting ordinances have helped boost insect diversity. Your support of simple dark sky guidelines of smart lighting can make a difference. Use outdoor lighting when and where it is necessary, lower the intensity of lights; very bright lights cause diminished vision; use warm colors instead of blue spectrum light; and shade light sources directing down, not up or sideways.
Next time you see fewer insects around your home, remember: it’s a warning. Smart Light outdoors can boost local insect activity by over 30%. Protecting these small but essential creatures helps ensure a vibrant, healthy Colorado for generations to come.
Music written and produced by Kenny Mihelich. Western Slope Skies is produced by the Colorado Mesa University Astronomy Club, the Western Slope Dark Sky Coalition, and KVNF Community Radio. This feature was written and shared by Kate Fedback, in association with the Western Slope Dark Sky Coalition.