Light pollution in cities major threat to survival of crickets

By Tom Campbell via SWNS

Light pollution from major cities could threaten the survival of crickets by ruining their mating calls, scientists warned.

Male crickets exposed to artificial light at night, also known as ALAN, are losing track of when to start chirping or what rhythm to follow, according to a new study.

More than 80 percent of the world population is now living in areas with light pollution and the number of night lights is growing by five percent every year.

But light pollution has been found to harm many animal and plant species, who rely on the clear distinction between day and night.

Male crickets for example, normally start chirping at night to attract females so they can reproduce.

But now scientists in Israel have found man-made lights could be disrupting the crickets' romantic calls and chances of reproducing.

"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 lacking any rhythm whatsoever," saidDoctoral student Keren Levy and study author at Tel Aviv University.

"In fact, light pollution induced by humankind impacts the field cricket and evokes loss of synchronization within the individual, on the population level, and between the population and the environment."

The researchers exposed dozens of field crickets to four types of light conditions from the moment they were born to adulthood.

"In nature crickets exhibit a very regular cycle of activity,"said co-author Professor Amir Ayali.

"Chirping behavior, calling for females, occurs at sunset and during the night, ending in the morning.

"We exposed field crickets to different levels of lifelong ALAN and observed its impact on two fundamental behaviors: chirping and locomotion."

Those exposed to 12 hours of light followed by 12 hours of darkness followed a 24-hour rhythm.

They began chirping when the lights went out, but stopped once they had been switched back on.

In contrast, when crickets were exposed to partial lighting, 80 percent followed their own cycle and five percent lost all rhythm, the researchers found.

Being exposed to constant lighting made matters even worse, with 71 percent of the insects developing their own cycle and 29 percent falling out of rhythm.

"Our findings on ALAN-induced changes in calling song patterns may possibly impair female attraction and reproduction in this species," Levy said.

"Our results are in accord with many other studies demonstrating the severe impacts of low levels of ALAN on nature."

Crickets are not the only animals to suffer from light pollution at night however.

Dung beetles for example use the Milky Way to navigate at night, while baby sea turtles seek out the brightest surface in sight after hatching and often find themselves on a road instead of the sea.

Steps must therefore be taken to reduce ALAN and enable coexistence between humans and other animals at night.

“We ask you to help protect our environment and surroundings by turning off the lights in your backyards, on the terrace, in parking lots, and wherever possible," Levy said.

"Help us bring the night and the milky way back into our lives and enable nightly coexistence with the creatures around us."