Call overlapping signals sexual status in Darwin’s frogs
- Published
- Accepted
- Subject Areas
- Animal Behavior, Zoology, Population Biology
- Keywords
- call overlap, vocal recognition, sexual recognition, call delay, female call, female vocalization, vocal interaction, male pregnancy, evoked vocal response, playback experiments
- Copyright
- © 2019 Serrano et al.
- Licence
- This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. For attribution, the original author(s), title, publication source (PeerJ Preprints) and either DOI or URL of the article must be cited.
- Cite this article
- 2019. Call overlapping signals sexual status in Darwin’s frogs. PeerJ Preprints 7:e27943v1 https://doi.org/10.7287/peerj.preprints.27943v1
Abstract
Background. In animal reproductive contexts, calling behaviour is mostly performed by males but in species in which females call, it is not known how vocal interaction occurs between sexes, particularly when sexual dimorphism in signals is low, as in cases in which call repertoire is identical but acoustic properties differ. In Darwin’s frog (Rhinoderma darwinii), a species in which males brood larvae inside their vocal sacs, females have higher dominant frequency and shorter calls and notes than males. Since in this species males persist calling after getting pregnant with larvae, different vocal interaction patterns are expected to occur among animals having dissimilar reproductive status.
Methodology. To explore the mechanisms underlying vocal recognition among the different sexual status of R. darwinii, we recorded natural duets between non-pregnant males (NPM), pregnant males (PM) and females (F) and evaluated their evoked vocal response to natural playback stimuli of each sexual status from November to February 2015-2016 in Chiloé island, Chile. Call rate, phase angles, sound pressure level (SPL), number of overlapping calls and delay of overlapping calls were measured to determine differential responses between natural duets and in response to stimuli consisting of natural calls of individuals of different sexual status.
Results. Spontaneous duet interactions occurred mainly between males and no clear differences between duets were detected. In playbacks, call ratios in response to calls of different sexual status were similar. Females decreased their SPL in response to F calls, while F and PM had longer call delays and lower call overlaps between each other. Major differences were observed in call overlap, as the occurrence of this phenomenon was larger in playback experiments than during natural duets. The number of calls overlapped during natural duets was fewer (10.9 %) than during playback experiments (36.8 %).
Conclusions. Our results suggest that in R. darwinii, PM and F signalize their sexual status by decreasing their call overlap and that NPM respond indistinctly to the other sexual status. In general, these differences in selective call overlap between Darwin's frogs arise as a novel mechanism for signal recognition between animal vocal interactions.
Author Comment
This is a submission to the second international workshop on Vocal Interactivity in-and-between Humans, Animals and Robots (VIHAR 2019).