Even crickets can’t get romantic under city lights

Artificial city lights are a “turn off” to crickets who sing love songs to their mates. A new study from the University of Haifa in Israel has found that even low levels of artificial lighting at night cause an interruption in the biological clock of male crickets. This may lead to extinction of the species, the researchers speculate. 

Artificial lighting at night (ALAN) has become a factor that negatively influences our ecological environment, especially the one close to the cities.

“The damage to the gene expression of the biological clock as a result of artificial lighting greatly disrupts the timing of vocal communication habits of the cricket, which are essential for establishing contact with the female and could endanger the existence of the cricket population,” said Prof. Eran Tauber, from the University of Haifa.

According to estimates, about a tenth of the Earth’s land surfaces are illuminated by artificial lighting, and this estimate increases to 23% if you regard the glow of the sky as part of the light pollution created by this lighting at night. According to Prof. Tauber, many animals use the timing of natural light to synchronize their behavior and the course of their lives.

For example, migratory birds use light to schedule their time of flight, and artificial light of a certain intensity may disrupt this. Another example is the animals that have different interactions with other organisms – In the case of pollinating flowers for example, insects need to “know” when to visit the plant during the day, and the plant needs to “know” when to bloom.

Any disruption of the timing of pollination that is caused by artificial lighting upsets all interactions among organisms.

When city light is brighter than 2 moons

In the current study, which was published in the International Journal of Molecular Sciences, showed that even at the lowest intensities of artificial lighting – at the level of 2 lux (1 lux is the power of a full moon) – significant changes in the expressions of genes related to male crickets’ biological clock were found.

The most significant changes were identified in eye tissues compared to tissues in other areas.

“The male crickets chirp love songs to the females when they are standing still, and this is the chirp we hear at night. The females choose the cricket they liked the most and agree to mate with him. This phenomenon has a certain timing during the 24-hour day; as soon as they are exposed to artificial light, it disrupts their biological clock and any timing of these behaviors go awry, so the crickets out of sync with their environment.

“In extreme cases, this could endanger the cricket population and even lead to the insect’s extinction,” Prof. Tauber added.

How we can help save crickets

When we install artificial lighting on roads and in parks and gardens, we need to consider the damage that could be caused to animals and plants. A study conducted in Germany estimated that street lighting caused the death of some 60 billion insects all over the world in just one summer. So turn off your lights at night. 

The results of the current study and the growing awareness of the damage of artificial lighting should be translated into public policy and intelligent urban planning to reduce the damage to the environment. The use of focused lighting at low intensities and wavelengths that do not affect the biological clock will create a safe urban environment alongside nature that thrives.