It’s always fascinating to see how moths and other flying insects bounce off the streetlights at night, get caught in a spiral dance around a room light or are attracted to a flame. It’s called positive photo praxis and it’s the ultraviolet part of the light they are attracted to which they take for the moon and stars so that they can navigate at night. At that distance the light emitted is effectively parallel, and theories say that moths and night insects adjust their flight by keeping the light at a constant angle. However, when faced with an artificial light source their attempts to keep flying are hampered because they are so close to it that they end up flying in circles to maintain that constant angle!
Artificial Light At Night (ALAN) in our towns and cities has had an impact on the population of moths and other night time insects. Even the football stadiums and shopping centres have bright lights at night. By being over attracted to the light the moths become exhausted, fall to the ground, becoming easy prey for rats, bats, toads and even spiders who have learned to congregate by lampposts and indulge in a feast. Research has shown that in areas of artificial light the numbers of caterpillars can be halved. Less moths means less caterpillars in the food chain, less pollinators for the plants, and even less food for the rats, toads, foxes etc. Such an intricate balance. Whilst there are other factors like use of pesticides and climate change which have an effect, dealing with light pollution is much simpler. You don’t have to turn off all the lights but think about what wave lengths the light is and use different filters. Moths and other night insects are not attracted to yellow light, and it would be possible to have timers to dim streetlights in the early hours and fit motion sensors rather than have lights on all night. LED lights have a lower level of ultraviolet, but high-pressure sodium discharge lamps have an even lower level.
The twelfth century Sufi Poet, Farid ud-Din Attar, wrote the “The Conference of the Birds” which was a fable for the human condition. It includes a story of the moths which I paraphrase here.
There was a community of moths content in the darkness of night, with the moon and stars to guide them as they lived out their lives, pollinating the plants, finding mates, and seeking out the plants to lay their caterpillars. One moth reported that they had seen a light in the distance, different to the moon and stars- a candlelight that flickered in the window of a palace. The leader of the moths said that they knew nothing of the light and sent another moth to investigate. This one flew close to the flame, could feel its heat and the way the light compelled him to come closer. The moth pulled back and returned to tell the community. The leader said that he didn’t understand the nature of the flame. A third moth flies to see the light and is so enamoured of it that he is totally consumed and burnt. The leader sees the blaze of the moth and says, “He knows the truth we seek.”
Many people view this as a metaphor for spiritual enlightenment, but I also see it as a metaphor for our environmental enlightenment. We need to take the step back and understand what the nature of the flame is – the effect we are having on our environment- before those flames embrace us. Putting a timer or motion detector on your outside lights at night will make a difference, and exploring what filters we can put on our streetlights so we can both see our way and does not affect the inhabitants of the night who are endangered by our town environments.