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Demartsev V, Haddas-Sasson M, Ilany A, Koren L, Geffen E. Male rock hyraxes that maintain an isochronous song rhythm achieve higher reproductive success. J Anim Ecol 2022. [PMID: 36097377 DOI: 10.1111/1365-2656.13801] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Accepted: 07/26/2022] [Indexed: 11/29/2022]
Abstract
Rhythmic stability (nonrandom temporal structure) is required for many neural and physiological functions, whereas rhythmic irregularities can indicate genetic or developmental deficiencies. Therefore, rhythmic courtship or contest signals are widespread in nature as honest advertisement displays. Examination of bird songs revealed the pervasiveness of categorical rhythmic patterns that can be described as small integer ratios between sequential inter-call intervals. As similar rhythmic profiles are prevalent in human music, it was suggested that a shared functionality could drive both animal songs and human musical rhythms, facilitating synchrony between signallers and enabling easy identification of performance errors. Here we examined whether the rhythmic structure and the rhythmic stability of vocal displays are related to reproductive success in male rock hyraxes (Procavia capensis), which presents an unusual case of a terrestrial singing mammal. We combined long-term parentage analysis of 13 male hyraxes (22 male/years) with an analysis of an audio library of 105 hyrax songs. Male annual reproductive success was determined by the number of offspring that survived to the age of 1 year. The frequency of singing events was used to determine the seasonal singing effort for each male. Songs were analysed for rhythmic structure, focusing on the presence of categorical rhythms and the contribution of rhythmic stability to annual reproductive success. We found that male hyraxes that sing more frequently tend to have more surviving offspring and that the rhythmic profile of hyrax songs is predominantly isochronous with sequential vocal element pairs nearly equally spaced. The ratio of isochronous vocal element transitions (on-integer) to element transitions that deviate from an isochronous pattern (off-integer) in hyrax songs is positively correlated with male reproductive success. Our findings support the notion that isochronous rhythmic stability can serve as an indication of quality in sexually selected signals and is not necessarily driven by the need for multiple caller synchronization. The relative scarcity of nonisochronous rhythmic categories in individually performed hyrax songs raises the question of whether such rhythmic categories could be a product of collective, coordinated signalling, while being selected against in individual performance.
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Affiliation(s)
- Vlad Demartsev
- Department of Biology, University of Konstanz, Konstanz, Germany.,Department for the Ecology of Animal Societies, Max Plank Institute for Animal Behavior, Konstanz, Germany
| | | | - Amiyaal Ilany
- Faculty of Life Sciences, Bar Ilan University, Ramat-Gan, Israel
| | - Lee Koren
- Faculty of Life Sciences, Bar Ilan University, Ramat-Gan, Israel
| | - Eli Geffen
- School of Zoology, Tel Aviv University, Tel Aviv, Israel
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Vanderhoff EN, Bernal Hoverud N. Perspectives on Antiphonal Calling, Duetting and Counter-Singing in Non-primate Mammals: An Overview With Notes on the Coordinated Vocalizations of Bamboo Rats (Dactylomys spp., Rodentia: Echimyidae). Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.906546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Temporally coordinated interactive vocalizations are important means of communication between individuals in various animal taxa. In mammals, interactive calling and singing can be highly synchronized to create either overlapping or antiphonal duets while in others, competitors antagonistically vocalize, engaging in counter-singing. Among non-primate mammals these vocalizations are considered rare and poorly understood. We provide an overview of antiphonal calling, duetting and counter-singing in non-primate mammals. Many of these coordinated vocalizations play a role in social interactions and allow mammals to convey information to other members of the social unit in visually inaccessible environments. South American Bamboo rats Dactylomys spp. are arboreal bamboo specialists found in dense bamboo thickets in Bolivia, Peru, Ecuador, Brazil and Colombia. These nocturnal rodents are rarely seen but can be easily heard because of their loud and distinctive staccato vocalizations. We provide some evidence that Bamboo rats engage in duetting, and as such they provide another case of a mammalian species, in which to investigate temporally coordinated interactive singing. We urge researchers to work toward common definitions of temporally coordinated vocalizations and to search for more mammals that utilize such vocalizations.
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Sivalinghem S, Mason AC. Function of structured signalling in the black widow spider Latrodectus hesperus. Anim Behav 2021. [DOI: 10.1016/j.anbehav.2021.07.015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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Weissman YA, Demartsev V, Ilany A, Barocas A, Bar-Ziv E, Koren L, Geffen E. A crescendo in the inner structure of snorts: a reflection of increasing arousal in rock hyrax songs? Anim Behav 2020. [DOI: 10.1016/j.anbehav.2020.06.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Demartsev V, Gordon N, Barocas A, Bar-Ziv E, Ilany T, Goll Y, Ilany A, Geffen E. The "Law of Brevity" in animal communication: Sex-specific signaling optimization is determined by call amplitude rather than duration. Evol Lett 2019; 3:623-634. [PMID: 31867122 PMCID: PMC6906988 DOI: 10.1002/evl3.147] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Revised: 10/10/2019] [Accepted: 10/22/2019] [Indexed: 11/25/2022] Open
Abstract
The efficiency of informational transfer is one of the key aspects of any communication system. The informational coding economy of human languages is often demonstrated by their almost universal fit to Zipf's “Law of Brevity,” expressing negative relationship between word length and its usage frequency. Animal vocal systems, however, provided mixed results in their adherence to this relationship, potentially due to conflicting evolutionary pressures related to differences in signaling range and communicational needs. To examine this potential parallel between human and animal vocal communication, and also to explore how divergent, sex‐specific, communicational settings affect signaling efficiency within a species, we examined the complete vocal repertoire of rock hyraxes (Procavia capensis). As male and female hyraxes differ in their sociality levels and male hyraxes vocal repertoire is dominated by sexual advertisement songs, we hypothesized that sex‐specific vocal repertoires could be subjected to different signaling optimization pressures. Our results show that the sexes differ in repertoire size, call usage, and adherence to coding efficiency principles. Interestingly, the classic call length/call usage relationship is not consistently found in rock hyraxes. Rather, a negative relationship between call amplitude and call usage is found, suggesting that the efficiency of the vocal repertoire is driven by call amplitude rather than duration. We hypothesize that, in contrast to human speech that is mainly intended for short distance, the need for frequent long‐range signaling shapes an animal's vocal repertoire efficiency according to the cost of call amplitude rather than call length. However, call duration may be a secondary factor affecting signaling efficiency, in cases where amplitude is under specific selection pressures, such as sexual selection.
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Affiliation(s)
- Vlad Demartsev
- Department of Biology University of Konstanz Konstanz 78464 Germany.,School of Zoology Tel Aviv University Tel Aviv 6997801 Israel
| | - Naomi Gordon
- School of Zoology Tel Aviv University Tel Aviv 6997801 Israel
| | - Adi Barocas
- San Diego Zoo's Institute for Conservation Research Escondido California 92027.,Wildlife Conservation Research Unit Department of Zoology University of Oxford Abingdon OX13 5QL United Kingdom
| | - Einat Bar-Ziv
- Mitrani Department of Desert Ecology Ben-Gurion University Midreshet Ben-Gurion 8499000 Israel
| | | | - Yael Goll
- School of Zoology Tel Aviv University Tel Aviv 6997801 Israel
| | - Amiyaal Ilany
- Faculty of Life Sciences Bar-Ilan University Ramat-Gan 5290002 Israel
| | - Eli Geffen
- School of Zoology Tel Aviv University Tel Aviv 6997801 Israel
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Weissman YA, Demartsev V, Ilany A, Barocas A, Bar-Ziv E, Geffen E, Koren L. Social context mediates testosterone's effect on snort acoustics in male hyrax songs. Horm Behav 2019; 114:104535. [PMID: 31129283 DOI: 10.1016/j.yhbeh.2019.05.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/14/2018] [Revised: 03/25/2019] [Accepted: 05/18/2019] [Indexed: 11/20/2022]
Abstract
Testosterone affects physical and motivational states, both of which may strongly influence vocalization structure and acoustics. The loud complex calls (i.e., songs) of male rock hyraxes (Procavia capensis) are used as honest signals for advertising physical and social states. The snort, a low frequency, noisy element of the song, encodes information on the singer's age and social rank via harshness, as measured by jitter (i.e., acoustic frequency stability) and duration; suggesting that the snort concomitantly advertises both vocal stability and aggression. Our past findings revealed that testosterone levels are related to both vocal elements and social status of male hyraxes, suggesting that hormonal mechanisms mediate the motivation for aggressive and courtship behaviors. Here we examined whether long-term androgen levels are related to snort acoustics and song structure by comparing levels of testosterone in hair with acoustic and structural parameters. We found that songs performed by individuals with higher testosterone levels include more singing bouts and longer, smoother snorts, but only in those songs induced by external triggers. It is possible that hyraxes with higher levels of testosterone possess the ability to perform higher-quality singing, but only invest in situations of high social arousal and potential benefit. Surprisingly, in spontaneous songs, hyraxes with high testosterone were found to snort more harshly than low-testosterone males. The context dependent effects of high testosterone on snort acoustics suggest that the aggressive emotional arousal associated with testosterone is naturally reflected in the jittery hyrax snort, but that it can be masked by high-quality performance.
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Affiliation(s)
- Yishai A Weissman
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 52900, Israel
| | - Vlad Demartsev
- School of Zoology, Tel Aviv University, Tel Aviv 69978, Israel
| | - Amiyaal Ilany
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 52900, Israel
| | - Adi Barocas
- San Diego Zoo's Institute for Conservation Research, Escondido, CA 92027, USA; Wildlife Conservation Research Unit, Department of Zoology, University of Oxford, Oxford, UK
| | - Einat Bar-Ziv
- School of Zoology, Tel Aviv University, Tel Aviv 69978, Israel; Mitrani Dept. of Desert Ecology, Ben-Gurion University of the Negev, 8499000, Israel
| | - Eli Geffen
- School of Zoology, Tel Aviv University, Tel Aviv 69978, Israel
| | - Lee Koren
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 52900, Israel.
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Demartsev V, Kershenbaum A, Ilany A, Barocas A, Weissman Y, Koren L, Geffen E. Lifetime changes in vocal syntactic complexity of rock hyrax males are determined by social class. Anim Behav 2019. [DOI: 10.1016/j.anbehav.2019.05.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Weissman YA, Demartsev V, Ilany A, Barocas A, Bar-Ziv E, Shnitzer I, Geffen E, Koren L. Acoustic stability in hyrax snorts: vocal tightrope-walkers or wrathful verbal assailants? Behav Ecol 2018. [DOI: 10.1093/beheco/ary141] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Yishai A Weissman
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, Israel
| | - Vlad Demartsev
- School of Zoology, Tel Aviv University, Tel Aviv, Israel
| | - Amiyaal Ilany
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, Israel
| | - Adi Barocas
- San Diego Zoo’s Institute for Conservation Research, Escondido, CA, USA
- Department of Zoology, Wildlife Conservation Research Unit, University of Oxford, Oxford, UK
| | - Einat Bar-Ziv
- Mitrani Department of Desert Ecology, Ben-Gurion University of the Negev, Israel
| | - Inbar Shnitzer
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, Israel
| | - Eli Geffen
- School of Zoology, Tel Aviv University, Tel Aviv, Israel
| | - Lee Koren
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, Israel
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