The evolution of simplicity in advertisement calls of African clawed frogs (Xenopus)
-
1
Columbia University, Biological Sciences, United States
Temporal patterns of male advertisement calls in African clawed frogs (genus Xenopus) range from single clicks (“click-type”) to complex, biphasic trills of clicks. Within a clade, call types vary considerably and are informative for species identity. Click-type calls are rare, occurring in just two species within a single clade and one species in a different clade. Despite their simplicity, click-type calls are derived; parsimony suggests that the ancestral call was a moderately complex, burst-type call (Tobias et al., 2011). To gain insight into the evolution of click-type calls, we have examined how the vocal organ and the hindbrain vocal pattern-generating circuit produce calls in the distantly related click-type species, X. borealis and X. boumbaensis. Using two reduced preparations, the fictively vocalizing isolated brain (Rhodes et al., 2007) and the sound-producing isolated larynx (Tobias and Kelley, 1987), we show that these species have achieved a click-type advertisement call via different modifications of central and peripheral components of the vocal circuit. X. borealis produces fictive vocal patterns comprised of nerve activity (compound action potentials or CAPs) whose temporal patterns closely match the temporal patterns of actual male calls. The X. borealis isolated larynx is capable of converting a single nerve stimulus into a single muscle tension transient and a click. In contrast, X. boumbaensis brains produce fictive vocal patterns that are short bursts. Their isolated vocal organ requires nerve stimulus doublets to produce a single tension transient and click of sound; single stimuli are ineffective. Click production in X. boumbaensis relies on a highly potentiating vocal neuromuscular synapse to produce clicks. Thus the output of the hindbrain vocal pattern generator in X. boumbaensis is an ancestral burst pattern; the laryngeal neuromuscular synapse filters this pattern into a single click. In contrast, the X. borealis vocal pattern generator has been modified to produce single CAPs and the vocal synapse has also been modified to follow this pattern. Thus, evolution of click-type calls in Xenopus has reconfigured homologous structures in different ways to produce the same call phenotype.
Acknowledgements
We thank Columbia University and NIH NS23684 (DBK) for financial support.
References
Rhodes, H., Yu, H. Yamaguchi, A. 2007. Xenopus vocalizations are controlled by a sexually differentiated hindbrain central pattern generator. J. Neurosci. 27(6): 1485-1497.
Tobias, M.L., and Kelley, D.B. 1987. Vocalizations by a sexually dimorphic isolated larynx: peripheral constraints on behavioral expression. J. Neurosci. 7: 3191-3197.
Tobias, M.L., Evans, B.J. and Kelley, D.B. 2011. Evolution of advertisement calls in African clawed frogs. Behaviour 148(4): 519-549.
Keywords:
vocal behavior,
Xenopus
Conference:
Tenth International Congress of Neuroethology, College Park. Maryland USA, United States, 5 Aug - 10 Aug, 2012.
Presentation Type:
Poster (but consider for Participant Symposium)
Topic:
Communication
Citation:
Leininger
E and
Kelley
DB
(2012). The evolution of simplicity in advertisement calls of African clawed frogs (Xenopus).
Conference Abstract:
Tenth International Congress of Neuroethology.
doi: 10.3389/conf.fnbeh.2012.27.00404
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:
01 May 2012;
Published Online:
07 Jul 2012.
*
Correspondence:
Dr. Elizabeth Leininger, Columbia University, Biological Sciences, New York, New York, 10027, United States, ecl2107@columbia.edu