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Overview of experimental design and workflow. (A) Crickets were exposed to either no traffic noise or one of three amplitudes of traffic noise as juveniles and reassigned noise processing as adults. (B) To broadcast traffic noise at different amplitudes across treatments, we first leveled the traffic noise recordings to increase consistency of amplitude during playback. Then, from this leveled recording, one meter from the sound source, he created three traffic noise tracks corresponding to 50 dBA, 60 dBA, and 70 dBA, respectively. Trucks still contain substantial changes in spectral content over time, reflecting diverse vehicle configurations (see Supplementary Figure 1). (C) During adulthood, 15 fitness-related traits were analyzed. credit: Ecology and evolution of BMC (2023). DOI: 10.1186/s12862-023-02190-2
As the sun sets, the sweltering heat subsides, and the night becomes calm, a sweet yet annoying sound fills the air. A rhythmic symphony of chirping crickets. But human-generated noise can mask the harmony of crickets' chirps, and researchers wonder if it drowns out the melody.
Researchers at the University of Denver evaluated the effects of human-generated noise on crickets. Invertebrates make up more than 95% of all animal species on Earth. At least 83% of the land in the continental United States is exposed to vehicle noise, and 88% of people experience noise equivalent to continuous rainfall. However, less than 4% of noise research on terrestrial organisms focuses on invertebrates.
The researchers recently published the results of their three-year study in the following journals: Ecology and evolution of BMC. Below are some key points.
- Under certain noise levels, survival to adulthood was reduced, and the number of offspring hatched depended on the combination of noise the female experienced during her juvenile and adult years.
- For example, the researchers exposed the crickets to four traffic noise levels commonly experienced in natural environments: quiet, 50 decibels, 60 decibels, and 70 decibels, noting that 55 decibels is equivalent to constant rainfall. Crickets raised in noise levels of 70 decibels (such as from busy streets or vacuum cleaners) were 35% less likely to survive to adulthood than those raised in silence.
“Noise pollution has recently been associated with declines in arthropod populations, which can have dramatic effects on entire ecological communities of interacting organisms,” said the study's lead researcher. said Robin Tinhittera, associate professor of biology at DU.
“We focused our research on field crickets because insects that use sound to communicate with each other can be affected by noise pollution. This is a group that lives close to the environment and can readily hear traffic noise.”
The researchers analyzed the effects of noise pollution on 15 traits in crickets and found that survival to adulthood and number of hatchlings were affected. Tinhtera suggests that human-generated noise acts as a stressor for crickets.
However, despite these effects, the other 13 traits measured did not change in response to noise exposure, indicating that the crickets are learning to live amidst the constant noise of humans. .
Mark Mitchell, a professor of animal medicine at Louisiana State University, praised the work, highlighting the diversity and collaboration within the research team. He pointed to the importance of this finding in understanding how human activities, such as traffic noise, affect the immune and reproductive responses of invertebrates such as crickets.
“This study provides important insights into the effects of anthropogenic activities (traffic noise) on the immune and reproductive responses of invertebrates (crickets),” he said. “This study contributes to the lack of evidence in this area and can be used to guide future planning.”
For more information:
Gabrielle T. Welsh et al, Consistent traffic noise has little effect on fitness-related characteristics in field cricket. Ecology and evolution of BMC (2023). DOI: 10.1186/s12862-023-02190-2
Magazine information:
Ecology and evolution of BMC
Provided by Morris Animal Foundation