Courtship songs ruined by traffic noise: Anglia Ruskin University probes plight of field crickets
Traffic noise could be ruining the exquisite efforts of crickets to woo females with their finest courtship songs.
And it could increase the chances of lesser males with lower quality songs - let’s say, the insect equivalent of Chas ‘n’ Dave, rather than Barry White - finding a mate.
This, warn researchers at Anglia Ruskin University, could have implications for the long-term viability of the cricket population.
They studied the mating choices of female field crickets (Gryllus bimaculatus) under different acoustic conditions.
Male crickets play their courtship song when a female cricket is nearby. It contains important information about the male’s qualities, but it requires lot of energy.
The researchers paired female crickets were paired with silenced male crickets in ambient noise conditions, artificial white noise conditions and traffic noise conditions, recorded at a ground level next to the A14 near Cambridge.
Males were then allowed to court the females freely, but an artificial courtship song was played back.
In the control conditions of ambient noise, females mounted the males much sooner and more frequently when paired with a high-quality courtship song.
But amid white noise and traffic noise, the high-quality courtship song offered no advantage - even over no song at all.
Lead author Dr Adam Bent, who carried out the study as part of his PhD at ARU, said: “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. 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.
“At the same time, female crickets may choose to mate with a lower-quality male as they are unable to detect differences in mate quality due to the man-made noise, and this may lead to a reduction or complete loss of offspring viability.
“Traffic noise and the crickets’ courtship song do not share similar acoustic frequencies, so rather than masking the courtship song, we think the traffic noise serves as a distraction for the female cricket.”
Co-author Dr Sophie Mowles, senior lecturer in animal and environmental biology at Anglia Ruskin University (ARU), said: “Humans are continually changing the characteristics of environments, including through the production of anthropogenic noise.
“As mate choice is a powerful driving force for evolution through sexual selection, disruptions may cause a decline in population viability. And because anthropogenic noise is a very recent evolutionarily selection pressure, it is difficult to predict how species may adapt.”
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