Traffic Noise Adversely Affects Cricket Mating Behavior

New research reveals how traffic noise and other man-made sounds affect the mating behavior of crickets and potentially affecting the species' future prospects for survival. This according to a report published by Phys.org.

A study led by researchers from the Anglia Ruskin University (ARU) in Cambridge, England involved observing female field crickets (Gryllus bimaculatus) under varying acoustic conditions. Details and results of their study are published in the journal Behavioral Ecology.

Courtship Songs Affected By Man-Made Noise

Male crickets perform a courtship song but rubbing their wings together once a female cricket happens to be nearby. This courtship effort is supposedly taxing to male crickets and expends a great deal of energy to make their "song" and reveals a lot of details about the male. Therefore, the song alone helps female crickets decide on their mating choices.

Researchers paired female crickets with "silenced" male crickets that were placed in ambient noise conditions, artificial white noise environment, and traffic noise environment. The traffic noise conditions were achieved by recording ambient sounds at a ground level next to the A14 near Cambridge.

They then allowed the male crickets to freely mate with the female, using an artificial courtship song - played in the background - as the males tried to perform their "song." Male crickets in the study were either placed together with a high-quality courtship song, a low-quality courtship song, or no song used at all.

In the control setup for ambient noise, females mated with the males quicker and more frequently when high-quality courtship songs were used. Unfortunately, even high-quality courtship songs could not help the crickets in the white noise and traffic noise condition.

Furthermore, researchers discovered that the duration and frequency of these mating were no longer affected by quality or even by the fact that there was a song at all.

Affecting the Crickets' Odds for Survival

These findings indicate that anthropogenic noises could actually affect how female crickets perceived males in the context of mating. Furthermore, trying to exert and display themselves in front of a female prospect - competing against man-made noises - could affect the health and fitness of the male crickets. Over long periods of time, exposure to noise could adversely affect the species' survival.

"In the short-term, we found that males paired with high-quality songs in noisy environments are receiving no benefit over those paired with a low-quality song, or no song at all," explains Dr. Adam Bent, lead author of the study for his Ph.D. at Anglia Ruskin University. "As a result, males that produce high-quality songs may attempt to expend more energy into their calls to gain an advantage, potentially affecting that individual's survival."

He adds that female crickets might prefer lower-quality mates due to being unable to determine differences between song qualities due to the noise, leading to "a reduction or complete loss of offspring viability."

Also, since the ambient man-made noise and the crickets' courtship song have different acoustic frequencies, the noise does not mask the cricket's song. Instead, it serves as a distraction, leaving females distracted and unable to gauge their choices very well.