August 26, 2021
Light pollution from street lamps linked to insect loss are saying that light pollution could be contributing to the dramatic insect declines experienced in recent decades. A UK study, published in Science Advances, has found that artificial street lights disrupt the behavior of nocturnal moths, decreasing the number of caterpillars by half. LED streetlights appeared to be responsible for the largest impact. Evidence that insect populations are diminishing due to climate change, habitat loss and pesticides is growing. Many factors are involved, such as the decline in forests, heathlands, meadows and marshes, overuse of pesticides, climate change, and increased pollution of rivers and lakes. Some think that using artificial lights at night could be another factor in insect loss, though the level of impact is unclear. The study compared 26 sites with streetlights to similar stretches of unlit road close by. They found that caterpillars were reduced by approximately half in lit areas. Another experiment set up lighting in a field and found that the number of caterpillars was reduced under LED lights. The researchers behind the UK study said it is the strongest evidence yet that light pollution can have detrimental effects on local insect populations, which then affects birds and other wildlife that rely on insects for food. The researchers think that the lights might increase the risk that insects will be seen and eaten by predators, or might deter them from laying their eggs. Caterpillars born under artificial streetlights, especially LEDs, have been found to have different feeding habits. The researchers noted that insects are in trouble, and we need to reduce the sources that threaten them. A 2019 scientific review of insect numbers, for example, showed that 40% of species around the world are in “dramatic rates of decline.” Insect loss has far-reaching consequences for entire ecosystems, including plant pollination. Changes that do not compromise public safety are feasible, including dimming streetlights in the early hours, or using motion sensors color filters to eliminate the most harmful wavelengths. BBC News: Light pollution from street lamps linked to insect loss