Fruit flies are as susceptible to loud noise as teenagers attending rock concerts, scientists have learned.
The discovery that being blasted by sound has the same effect on the tiny insects as it does on humans could open up new avenues of research into hearing loss.
Although the flies “listen” with antennae rather than ears, the molecular basis of their hearing is much the same as ours.
To test the sensitivity of fruit fly hearing, scientists exposed a group of insects to a loud 120 decibel tone in the centre of the sound frequencies they can detect.
In human terms, the noise exposure was similar to being at a loud rock concert or close to a pounding jack hammer, said the scientists.
When the flies were tested after the sound blast, their hearing was found to be impaired. But a week later it was back to normal, mimicking the temporary hearing loss experienced by humans subjected to short periods of loud noise.
The scientists discovered signs of stress in the auditory nerve cells of the noise-exposed flies. In particular, the power plants called mitochondria which generate most of a cell’s energy were affected.
Genetically engineered flies with a mutation making them more susceptible to stress suffered greater hearing impairment, which still had an effect after seven days.
Lead scientist Professor Daniel Eberi, from the University of Iowa in the US, said: “As far as we know, this is the first time anyone has used an insect system as a model for noise-induced hearing loss (NIHL).
“We found that fruit flies exhibit acoustic trauma effects resembling those found in vertebrates, including inducing metabolic stress in sensory cells.”
Hearing loss due to recreational or occupational noise is a growing problem. Yet the biological and molecular mechanics of the phenomenon are still not fully understood.
Fruit flies could provide an ideal model for research into NIHL, say the researchers whose findings are reported in the journal Proceedings of the National Academy of Sciences.
Co-author Dr Kevin Christie, also from the University of Iowa, said: “The fruit fly is superior to other models in genetic flexibility, cost, and ease of testing.
“We hope eventually to use the system to look at how genetic pathways change in response to NIHL. Also, we would like to learn how the modification of genetic pathways might reduce the effects of noise trauma.”