Light pollution makes crickets chirp in the daytime and may disrupt reproductive processes, research finds

Date:
November 2, 2021
Source:
Tel-Aviv University
Summary:
Exposing male crickets to artificial light at night (ALAN)
can impair their activity cycles. According to the researchers,
nocturnal chirping is the male's way of calling females to come and
mate with him, and its disruption can interfere with reproduction
processes and even endanger the entire species.



FULL STORY ==========================================================================
A joint study conducted by researchers from Tel Aviv University and
the Open University of Israel revealed that exposing male crickets
to artificial light at night (ALAN) can impair their activity
cycles. According to the researchers, nocturnal chirping is the male's
way of calling females to come and mate with him, and its disruption
can interfere with reproduction processes and even endanger the entire
species. Previous studies worldwide have shown that light pollution is
harmful to many species of animals and plants. The researchers call
for reducing ALAN as much as possible to enable coexistence In the
night environment.


==========================================================================
The study was led by Prof. Amir Ayali and Keren Levy of the School
of Zoology and the Steinhardt Museum of Natural History at Tel Aviv
University and Prof.

Anat Barnea of the Department of Natural and Life Sciences at the Open University. Yoav Wegrzyn from Prof. Ayali's laboratory and Ronny Efronny
also took part in the study. The paper was published in Proceedings of
the Royal Society B, and also mentioned in Nature.

Keren Levy explains: "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 and allows them to continue their activities at night. Today more than 80% of the world population
live under light pollution, and the overall extent of ALAN rises by 5%
every year. ALAN negatively impacts the environment and affects natural behaviors that have developed over millions of years of evolution. ALAN
affects the length and quality of sleep of many animals, leads to high mortality, and changes the activity cycles of many creatures. For example,
dung beetles, that navigate using the Milky Way, lose their way when
light pollution increases; sea turtles hatchlings seek the brightest
surface in sight -- supposedly the sea, and reach the nearby promenade
instead; to mention just two of many examples." In the current study the researchers examined the impact of light pollution on the field cricket,
a nocturnal insect whose chirping can be heard during the nights of late
summer -- when males call for females to mate with them. Prof.

Ayali: "In nature crickets exhibit a very regular cycle of
activity. 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." The researchers
monitored dozens of crickets exposed lifelong (from egg to adult stage),
to four types of light conditions. They found that crickets exposed to
12 hours of light followed by 12 hours of darkness exhibited cyclic
activity rhythms of 24h: they began to chirp when the lights went
out and stopped when the lights were turned on again. Crickets that
experienced partial lighting in the dark periods lost their natural
rhythms and their synchronization with their environment: 80% followed
an individual inner cycle, and 5% lost all rhythm. Crickets exposed to
constant light 24/7 developed their own cycles (71%) or lost all rhythm
(29%). The findings indicated that increase of ALAN in the laboratory
induces loss of rhythmicity at both the individual and population levels.

Keren Levy: "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.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. Our findings
on ALAN-induced changes in calling song patterns may possibly impair
female attraction and reproduction in this species. Our results are
in accord with many other studies demonstrating the severe impacts
of low levels of ALAN on nature. 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. " ========================================================================== Story Source: Materials provided by Tel-Aviv_University. Note: Content
may be edited for style and length.


========================================================================== Journal Reference:
1. Keren Levy, Yoav Wegrzyn, Ronny Efronny, Anat Barnea, Amir Ayali.

Lifelong exposure to artificial light at night impacts stridulation
and locomotion activity patterns in the cricket Gryllus bimaculatus.

Proceedings of the Royal Society B: Biological Sciences, 2021;
288 (1959): 20211626 DOI: 10.1098/rspb.2021.1626 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/11/211102111005.htm

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