The hearing sensitivity improves considerably in this way. The anterior part of the swim bladder functions in specialized fish species similar to an ear drum. Up to now the effects of the different swim bladder morphologies have not been investigated in detail in cichlid fishes.
Steatocranus tinanti has a tiny reduced swim bladder. Credit: Friedrich Ladich
The behavioural biologists of the University of Vienna Tanja Schulz-Mirbach and Friedrich Ladich as well as Brian Metscher from the Department of Theoretical Biology of the University of Vienna studied the relationship between the shape of the swim bladder and its function. "These fish are perfect for such an investigation because this fish family possesses a large variety of swim bladders ranging from tiny reduced ones to large highly specialized swim bladders with extensions up to the inner ear", the bioacoustician Tanja Schulz-Mirbach explains.
Different swim bladders
Currently we know approximately 1,300 species of cichlid fishes, which live in various habitats."Using microtomographic methods in cooperation with Brian Metscher we could reconstruct swim bladder specializations in detail", Tanja Schulz-Mirbach says. Some cichlid species such as the bottom-living Steatocranus tinanti inhabit fast flowing waters in the Congo river basin and their swim bladders are widely reduced. Cichlids which live in rather calm waters possess large bladders which either lack a connection to the inner ear such as the jewel cichlid Hemichromis guttatus or which possess anterior extensions bringing the swim bladder close to the inner ears. The Malagasy species Paratilapia polleni has simple tube-like swim bladder extensions whereas the Indian cichlid Etroplus maculatus has more complex extensions consisting of a gas-filled tube and a tissue pad which touches the inner ear.
Biologists in the bioacoustic lab of Friedrich Ladich measured hearing by recording acoustically evoked potentials (similar to EEGs) from the head of animals non-invasively. "We could show that species having specialized swim bladders detect higher sound frequencies and lower sound levels than species having reduced swim bladders", Schulz-Mirbach explains. However, the jewel cichlid which has a large swim bladder but no connection to the inner ear is also able to detect frequencies up to 3 kHz but only at higher sound levels. "This means that the presence of anterior swim bladder extensions results in better hearing but the size of the swim bladder is also important", explains Schulz-Mirbach says. She will continue to investigate the importance of the habitat noise on the development of hearing and if swim bladder specializations affect inner ear anatomy.
"Relationship between swim bladder morphology and hearing abilities. A case study on Asian and African cichlids": Tanja Schulz-Mirbach, Brian Metscher, Friedrich Ladich (PLoS ONE 2012) DOI: http://dx.plos.org/10.1371/journal.pone.0042292
Contacts:Dr. Friedrich Ladich
Friedrich Ladich | EurekAlert!
Microscope measures muscle weakness
16.11.2018 | Friedrich-Alexander-Universität Erlangen-Nürnberg
Good preparation is half the digestion
16.11.2018 | Max-Planck-Institut für Stoffwechselforschung
Researchers at the University of New Hampshire have captured a difficult-to-view singular event involving "magnetic reconnection"--the process by which sparse particles and energy around Earth collide producing a quick but mighty explosion--in the Earth's magnetotail, the magnetic environment that trails behind the planet.
Magnetic reconnection has remained a bit of a mystery to scientists. They know it exists and have documented the effects that the energy explosions can...
Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.
Cultivating human cells in the Petri dish is not a big challenge today. Producing artificial tissue, however, permeated by fine blood vessels, is a much more...
Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.
In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...
On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.
When choosing materials to make something, trade-offs need to be made between a host of properties, such as thickness, stiffness and weight. Depending on the application in question, finding just the right balance is the difference between success and failure
Now, a team of Penn Engineers has demonstrated a new material they call "nanocardboard," an ultrathin equivalent of corrugated paper cardboard. A square...
09.11.2018 | Event News
06.11.2018 | Event News
23.10.2018 | Event News
16.11.2018 | Health and Medicine
16.11.2018 | Life Sciences
16.11.2018 | Life Sciences