A new ecological study has shown that man-made sounds can have a serious impact on insects.
In previous research, the effects of sound on animal communication were proven in other organisms like birds, whales, and frogs.
Three researchers looked at male bow-winged grasshoppers, Chorthippus biguttulus, which call to females by rubbing their hind legs against their front wings.
The team captured 188 males, half from quiet locations and half from beside busy roads, and recorded their mating calls. The song is usually made up of two phrases which last for two seconds and become louder at the end.
They found that the songs of grasshoppers living beside noisy roads are different from those inhabiting quieter places.
“Bow-winged grasshoppers produce songs that include low and high frequency components,” said study lead author Ulrike Lampe at Germany’s University of Bielefeld.
“We found that grasshoppers from noisy habitats boost the volume of the lower-frequency part of their song, which makes sense since road noise can mask signals in this part of the frequency spectrum.”
Traffic noise could therefore be detrimental to breeding in this species of grasshopper.
“Increased noise levels could affect grasshopper courtship in several ways,” Lampe said.
“It could prevent females from hearing male courtship songs properly, prevent females from recognizing males of their own species, or impair females’ ability to estimate how attractive a male is from his song.”
Next, the scientists hope to understand this mechanism, and whether the males alter their behavior as larvae or if the different songs arise from genetics.
The findings were published in the British Ecological Society’s journal Functional Ecology on Nov. 13.
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