Insects have a tough time making sense of our modern world. Human activity causes all kinds of problems for the 6-legged creatures among us. I've written in the past about the visual obstacles insects must overcome. Light reflected off a shiny car hood looks like water to a dragonfly, and certain jewel beetle males mistake beer bottles for mates.
New research suggests that man-made noise can pose a problem to insects, too. Scientists at the University of Bielefeld in Germany discovered that grasshoppers will change their tune if they live alongside busy roads. It's the first study to confirm that noisy habitats affect insect communication.
The researchers collected a total of 188 male bow-winged grasshoppers (Chorthippus biguttulus) from both quiet and noisy habitats. Male grasshoppers produce sound to attract mates. The team took the male grasshoppers back to their lab, and introduced them to a pretty young female of their species, inducing them to "sing" their courtship song. They recorded almost 1,000 grasshopper songs, and then analyzed them.
The grasshoppers that lived alongside busy roads with lots of traffic noise boosted the volume of the lower-frequency parts of their courtship songs. Road noise can masks lower-frequency sounds, so it appears the grasshoppers are compensating for the noise in their habitat.
Source: Grasshoppers change their tune to stay tuned over traffic noise, Eurekalert, November 13, 2012