The role of otolith size in hearing – Insights from cichlid fishes
-
1
Ludwig-Maximilians-University Munich, Department Biology II, Germany
-
2
University of Vienna, Department of Behavioural Biology, Austria
-
3
Northwest A&F University, College of Animal Science and Technology, China
Otolithic end organs in fishes function as accelerometers and are involved in the senses of balance and hearing (e.g. Popper et al. 2005). Otolith mass and shape are likely decisive factors influencing otolith motion, but while it is largely unknown how different shapes affect otolith movement relative to the sensory epithelium (Popper et al. 2005), greater otolith mass is predicted to result in enhanced stimulation of sensory hair cells and improved hearing (Lychakov and Rebane 2005). What few studies exist on this topic, however, yielded contradicting results in that they did or did not find a correlation between increased otolith mass and enhanced hearing (see Kéver et al. 2014). We investigated the relationship between otolith morphology (including 3D-models of otoliths based on high-resolution microCT imaging and otolith weight) and hearing abilities in cichlids while comparing three species (Etroplus maculatus, Hemichromis guttatus, Steatocranus tinanti) with different swimbladder morphology and hearing abilities (Schulz-Mirbach et al. 2014). We predicted Etroplus maculatus—the species that displays the best hearing sensitivities—to possess larger/heavier otoliths. As swimbladder extensions in this species are connected to the lagena, we further predicted to find heavier lagenar otoliths. Compared to H. guttatus and S. tinanti, E. maculatus showed the heaviest saccular otoliths, while lagenar otoliths were significantly thinner and lighter than in the former two species, apparently contradicting the hypothesis that the lagena and its otolith are primarily involved in improved hearing abilities. Our results support the idea that there is no ‘simple’ relationship between otolith weight, ancilliary auditory structures and hearing abilities. 3D-models of inner ears and otoliths may be ideally suited for future studies modeling complex otolith motion and thus, may provide a better understanding of how otolith morphology contributes to inner ear functions.
Acknowledgements
Funding was provided by the German Academic Exchange Service (DAAD).
References
Kéver, L., Colleye, O., Herrel, A., Romans, P., and Parmentier, E. (2014). Hearing capacities and otolith size in two ophidiiform species (Ophidion rochei and Carapus acus). J. Exp. Biol. 217, 2517-2525.
Lychakov, D. V., and Rebane, Y. T. (2005). Fish otolith mass asymmetry: morphometry and influence on
acoustic functionality. Hear. Res. 201, 55-69.
Popper, A. N., Ramcharitar, J. U., and Campana, S. E. (2005). Why otoliths? Insights from inner ear physiology and fisheries biology. Mar. Freshw. Res. 56, 497-504.
Schulz-Mirbach, T., Ladich, F., Plath, M., Metscher, B. D., and Heß, M. (2014). Are accessory hearing structures linked to inner ear morphology? Insights from 3D orientation patterns of ciliary bundles in three cichlid species. Front. Zool. 11:25. doi:10.1186/1742-9994-11-25.
Keywords:
otolith motion,
hearing enhancement,
ancillary auditory structures,
ear physiology,
Otolith function
Conference:
XV European Congress of Ichthyology, Porto, Portugal, 7 Sep - 11 Sep, 2015.
Presentation Type:
Poster Presentation
Topic:
Otoliths as a tool to study fish life cycles
Citation:
Schulz-Mirbach
T,
Ladich
F,
Plath
M and
Heß
M
(2015). The role of otolith size in hearing – Insights from cichlid fishes.
Front. Mar. Sci.
Conference Abstract:
XV European Congress of Ichthyology.
doi: 10.3389/conf.fmars.2015.03.00034
Copyright:
The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers.
They are made available through the Frontiers publishing platform as a service to conference organizers and presenters.
The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated.
Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed.
For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions.
Received:
26 Oct 2015;
Published Online:
04 Nov 2015.
*
Correspondence:
Dr. Tanja Schulz-Mirbach, Ludwig-Maximilians-University Munich, Department Biology II, Planegg-Martinsried, Germany, schulz-mirbach@biologie.uni-muenchen.de