Insect populations might be facing some serious trouble. But the good news is, it's not a lost cause. Here's why streetlights could be the cause behind a decrease in insects, even for those that we thought were the most attracted to the lamps' illumination.
The first thing that comes to mind when thinking of moths and other similar creatures might be their love for brightness. Turn on a light outside on a hot summer day, and you're sure to be surrounded by the little buggers. But apparently, one of their biggest passions might also be a danger to the tiny species.
A recent study reported in Science Advances found a correlation between the number of streetlights and the moth caterpillar population. According to the researchers, roads in the United Kingdom with more lamposts showed up to 52 percent fewer moth caterpillars than darker patches nearby. As of now, it seems that the only difference between the adjacent streets is the amount of light.
Artificial light being not so great for nocturnal insects is no surprise. Studies have shown the brightness can interrupt mating patterns. But whether the human-made light can go so far as to contribute to a decline in population has not been studied much up until now.
The new information comes from an extensive study of 27 roads that seemed identical, except for some areas that had more light at night while others stayed dark. The researchers spent nights collecting species from bushes, trees, grasses, and other surroundings in order to count the number of insects. While all kinds of lights were correlated with smaller populations, LED lights showed the worst results.
Compared to the 52 percent fewer caterpillars found under LED lights compared to dark patches, sodium lamps had 41 percent fewer. In grassy parts, LED lights decreased the population by 33 percent. So what can we do to help? According to Douglas Boyes, an ecologist at the UK Centre for Ecology and Hydrology, there are two easy ways to better the problem: either dim the lights or install filters on LEDs.