How a locust's eardrum could lead to tiny microphones

Mar 31, 2006
Chironomid mosquito. The plumose antannae serve as hearing organs
Chironomid mosquito. The plumose antannae serve as hearing organs. Image: D. Robert.

Being able to hear the smallest of noises is a matter of life or death for many insects, but for the scientists studying their hearing systems understanding how insect ears can be so sensitive could lead to new microphones able to capture and analyse extremely faint sounds.

A multidisciplinary team at the University of Bristol have used funding from the Biotechnology and Biological Sciences Research Council (BBSRC) to explore the workings of the 'ears' of a locust. These are micrometre thick membranes with complex and varying structural properties. The thickness of the membrane varies at different points and this affects how it responds to sounds – and in the case of ambient noise the team have discovered the membrane oscillates by only a few nanometres. The thickness of a human hair is about 80,000 nanometres across.

Professor Daniel Robert is the research leader at Bristol: "We have found that different sound frequencies elicit very different mechanical responses in the locust hearing system. By studying these tiny nanoscale movements and understanding how sound waves are turned into mechanical responses we may be able to develop microphones based on the functions of natural hearing. These could detect very faint sounds and analyse their frequency, something that current microphones cannot pick up."

The research team is also using nanotechnology techniques to study the hearing of mosquitoes. By employing Laser Doppler Vibrometry and Atomic Force Microscopy Professor Robert's team are able to accurately measure the tiny nanoscale movements of a mosquito antenna as it responds to sound and then create a 3D map of its profile and properties.

Professor Robert explained: "Mosquitoes hear through their antenna and this comprises around 15,000 sensory cells, as many as in the human ear. We have found that just like humans, mosquitoes have the capacity for active hearing. This means that they can generate their own vibrations to amplify incoming sounds and improve the sensitivity of their hearing. They are able to stop this positive feedback when sounds create enough vibration on their own. How the mosquito does this is poorly understood but if we can gain a better understanding it could open up the way to developing tiny sensors, robust enough to work in a range of acoustic environments but able to detect nanoscale sounds at frequencies of human interest."

Professor Julia Goodfellow, BBSRC Chief Executive, commented: "The fascinating insights that this research has revealed demonstrates the importance of multidisciplinary teams in modern bioscience research. By combining the skills of biologists, physicists and engineers researchers are able to further our understanding of key basic biological processes that occur at the nanoscale."

Professor Robert is taking part in a discussion sponsored by BBSRC at the Edinburgh International Science Festival on 8 April 2006. Researchers will be available to talk to the public about nanotechnology and what it means for them and the future.

Source: Biotechnology and Biological Sciences Research Council

Explore further: Graphene imperfections key to creating hypersensitive 'electronic nose'

add to favorites email to friend print save as pdf

Related Stories

NASA scientists listen to data

Sep 05, 2014

Robert Alexander spends parts of his day listening to a soft white noise, similar to water falling on the outside of a house during a rainstorm. Every once in a while, he hears an anomalous sound and marks ...

Avatars make the Internet sign to deaf people

Aug 29, 2014

It is challenging for deaf people to learn a sound-based language, since they are physically not able to hear those sounds. Hence, most of them struggle with written language as well as with text reading ...

Unlocking the potential of simulation software

Aug 21, 2014

With a method known as finite element analysis (FEA), engineers can generate 3-D digital models of large structures to simulate how they'll fare under stress, vibrations, heat, and other real-world conditions.

Recommended for you

Engineers show light can play seesaw at the nanoscale

11 hours ago

University of Minnesota electrical engineering researchers have developed a unique nanoscale device that for the first time demonstrates mechanical transportation of light. The discovery could have major ...

Engineered proteins stick like glue—even in water

Sep 21, 2014

Shellfish such as mussels and barnacles secrete very sticky proteins that help them cling to rocks or ship hulls, even underwater. Inspired by these natural adhesives, a team of MIT engineers has designed ...

Smallest possible diamonds form ultra-thin nanothreads

Sep 21, 2014

For the first time, scientists have discovered how to produce ultra-thin "diamond nanothreads" that promise extraordinary properties, including strength and stiffness greater than that of today's strongest ...

A nanosized hydrogen generator

Sep 20, 2014

(Phys.org) —Researchers at the US Department of Energy's (DOE) Argonne National Laboratory have created a small scale "hydrogen generator" that uses light and a two-dimensional graphene platform to boost ...

User comments : 0