To investigate how the shift towards white LED lighting is affecting insects, I turned my attention to moth caterpillars. Biological processes that are controlled by daylight and internal circadian rhythms, such as reproduction, are more likely to be disrupted or prevented by white LEDS. Insects are known to be more sensitive to shorter, bluer wavelengths of light, which are largely absent from sodium lighting. Author provided In the cold light of night A comparison of sodium lights (on the left) and white LEDs (on the right).
The more wavelengths emitted, the greater the diversity of species and biological processes that are likely to be disrupted. That’s because white LEDs emit light across the entire visible spectrum. This change in the colour of artificial light is predicted to have major consequences for wildlife. LEDs used in streetlights typically emit white light, while sodium lamps have a characteristic yellow glow – as seen in the picture below. While accurate statistics are hard to come by, a quick internet search indicates that most UK councils are well on their way to replacing all their streetlights with LEDs. In this context, there is an important change taking place in the UK: the replacement of older, less energy-efficient sodium street-lighting with white LEDs. Between 20, satellite measurements revealed that the global area polluted by artificial light grew by 2% each year, intruding ever deeper into biodiversity hotspots like tropical forests. But this pattern has become increasingly blurred. Life on Earth has evolved alongside predictable cycles of day and night. Surveying moth caterpillars Douglas Boyes. Writing for The Conversation, PhD researcher Douglas Boyes discusses why the changing colour of our streetlights could be a danger for insect populations. Comment: streetlights could be a danger for insect populations