Tel Aviv University neuroethologist Amir Ayali, who took part in the cricket study. Photo: Jonathan Blum

Israeli researchers have found that light pollution interrupts the nocturnal chirping used by male crickets to lure females to come and mate — possibly inhibiting reproduction and endangering the survival of the species.

For the study, researchers at Tel Aviv University and the Open University of Israel exposed field crickets to different levels of artificial light at night and observed its impact on two behaviors: chirping and locomotion.

The male field cricket is a nocturnal insect which can be heard chirping during late summer nights, signaling for females to mate with them. The chirping sound normally starts at sunset, continues during the night, and ends in the morning. But light pollution makes crickets chirp in the daytime, the researchers found.

“The distinction between day and night, light and darkness, is a major foundation of life on earth. But humans, as creatures of the day who fear the dark, disrupt this natural order: they produce artificial light that drives away the darkness,” explained Keren Levy of Tel Aviv University, who led the study along with her colleague Amir Ayali and the Open University’s Anat Barnea.

“Our study demonstrates that crickets whose light-dark cycle is disrupted behave like teenagers on vacation: active or asleep according to their own inner clock or without any rhythm,” Levy said. “This disruption can impair the crickets’ reproductive process and even threaten the population’s survival.”

The researchers emphasized that artificial light at night negatively impacts animals and plants, affecting natural behaviors that have developed over millions of years of evolution. Today, more than 80 percent of the global population lives under light pollution, with the exposure increasing by 5 percent annually.

As part of the study, published in the Proceedings of the Royal Society B journal, as well as in Nature, the researchers observed dozens of crickets from egg to adult stage, which they exposed to four types of light conditions. Crickets exposed to 12 hours of light followed by 12 hours of darkness began to chirp when the lights went out, and stopped when the lights were turned back on.

Meanwhile, crickets subjected to partial lighting in dark periods lost their natural rhythms and their synchronization with the environment — with 80 percent followed their own individual cycle, and 5 percent losing all rhythm. Out of the crickets exposed to constant light in a 24-hour cycle, 71 percent developed their own cycles, and the remainder lost all rhythm.

“Our results are in accord with many other studies demonstrating the severe impacts of low levels of artificial light at night on nature,” Levy said. “We ask, you, therefore, to help protect our environment and surroundings by turning off the lights in your backyards, on the terrace, in parking lots, and wherever possible. Help us bring the night and the Milky Way back into our lives and enable nightly coexistence with the creatures around us.”