Page 73 - The Power of Light, Colour and Sound for Health and Wellness draft

periodicity, the length, timing and quality of light exposure, alter the outcome. For animals, for predators a majority use light to hunt, but for the prey darkness is their defence. Extended illumination tips the scales against the small nocturnal beasts.
We are able to seek out healthy light sources, to wear blue light excluding glasses, to block light out of our sleeping spaces, but this is a facility denied other creatures.
Take frogs and toads as an example. Mating calls are broadcast in the dark, as is the mating itself and subsequent laying of eggs. The species are being decimated by many swampy habitats being kept bright by street lighting or the glow from buildings. Fewer frogs, fewer insects eaten, ecological balance disturbed.
Baby turtles emerge from their eggs in the sand and instinctively head towards the luminescence of moonlight on the sea’s horizon. But if there is competing brightness from townscapes behind, thousands of hatchlings head in the wrong direction, and perish.
For many species of migratory birds, the clue to start the long fight lies in the angle of starlight. If this signal is misinterpreted because of street and other artifcial illumination, the birds may depart too early, or leave too late, imperilling the journey’s success And even if the departure is on time, programmed to navigating their paths by the stars, birds may become disoriented by the lights of cities and fnd themselves fying into buildings and thus being injured or killed. Others are distracted by the brightness and circle endlessly, using up limited energy sources meant to get them to their destinations, places where they never arrive, and again, like the amphibians, never breed.
Pollination of a variety of food crops depends not only in the daytime by bees, but various other insects such as moths which work the night shift. Many of these nocturnal pollinators are drawn to light, but artifcial lights may prove to be a fatal attraction. In the case of moths, they futter about till exhausted, no energy to live let alone pollinate. Bats contribute to seed distribution in their night fights, but where night is limited, so too the reach of the bats which are disinclined to move in light.
A study released by the University of Exeter in 2015 reported that artifcial night time light from sources such as street lamps impacted not only plant growth and fowering but equally the number of insects dependent on those plants for food. To exemplify, plants such as some cacti bloom only in the dark of night, and of these ones like the Queen of the Night – Selenicerus grandiforus – for just two hours. They are pollinated by
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