Plants and animals really don't rate hard rock. That's according to a study published in the journal Ecology and Evolution. A long-time fan of AC/DC, biologist Brandon Barton tested the band's assertion that "rock and roll ain't noise pollution" and found that it is, in fact, wrong. Exposure to hard rock music disturbs plant growth and insect behavior, Barton and colleagues found, but listening to country or folk music appears to have no effect.
To find out how exactly noise pollution effects insects, biologists at Mississipi State University exposed colonies of soybean aphids and ladybugs to various genres of music, including AC/DC's Back in Black album in full volume and half volume, and a 17-track playlist of urban and industrial sounds. The team also looked at how music affects growth rates in soybean plants.
When the aphids and the soybean plants listened to the music in isolation there was no effect either on plant biomass or insect density, regardless of genre. However, when ladybirds, aphids, and soybeans were placed in containers together to create a simple ecosystem, something interesting happened.
Under control conditions (i.e. when no music played), the ladybirds reduced the density of aphids to nearly zero and, because the ladybirds were keeping the pests under control, the plants grew strong and healthy. In stark contrast, when AC/DC was played at full volume (that is, 95 to 100 decibels or roughly the same volume as a lawnmower), the population of aphids exploded and the plants' rate of growth diminished. The ladybirds were not doing their job.
Comparing the two results, the researchers noticed the aphids' population size was 40 times higher in the second group (more than 180 aphids per plant as opposed to an average of four aphids per plant) – and the plants were 25 percent smaller.
Volume does play a role, the researchers noticed. When played at half volume, the Back in Black album had a nominal effect. Perhaps more intriguingly, however, the study also shows that certain genres are more damaging than others. Even at full volume, the country mixtape and Warblefly (folk music) playlist had an insignificant effect on insect behavior. The results of rock music and urban sounds sat somewhere between those of AC/DC and country and folk. Why this is, is unclear.
The effect of music on insects is even more interesting because many species of insects don't have ears or any other form of auditory receptor. Noise pollution may have influenced the ladybugs directly through vibrations or through an as-yet-unknown indirect route but more research is needed to explain further.
While using music might seem trivial, Barton is keen to point out that it is a proof-of-concept study to examine how noise pollution can affect interactions between species.
As he explained to Newsweek, "biological disruption, even at the ladybug’s level, can affect the entire food web."