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Lefeuvre M, Rutkowska J. Zebra finch song parameters are affected by the breeding status of the male, but not temperature variability. Physiol Behav 2024; 281:114581. [PMID: 38734358 DOI: 10.1016/j.physbeh.2024.114581] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2024] [Revised: 05/06/2024] [Accepted: 05/08/2024] [Indexed: 05/13/2024]
Abstract
Bird song is a crucial feature for mate choice and reproduction. Song can potentially communicate information related to the quality of the mate, through song complexity, structure or finer changes in syllable characteristics. It has been shown in zebra finches that those characteristics can be affected by various factors including motivation, hormone levels or extreme temperature. However, although the literature on zebra finch song is substantial, some factors have been neglected. In this paper, we recorded male zebra finches in two breeding contexts (before and after pairing) and in two ambient temperature conditions (stable and variable) to see how those factors could influence song production. We found strong differences between the two breeding contexts: compared to their song before pairing, males that were paired had lower song rate, syllable consistency, frequency and entropy, while surprisingly the amplitude of their syllables increased. Temperature variability had an impact on the extent of these differences, but did not directly affect the song parameters that we measured. Our results describe for the first time how breeding status and temperature variability can affect zebra finch song, and give some new insights into the subtleties of the acoustic communication of this model species.
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Affiliation(s)
- Maëlle Lefeuvre
- Jagiellonian University, Doctoral School of Exact and Natural Sciences, Cracow, Poland; Jagiellonian University, Faculty of Biology, Institute of Environmental Sciences, Cracow, Poland.
| | - Joanna Rutkowska
- Jagiellonian University, Faculty of Biology, Institute of Environmental Sciences, Cracow, Poland
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2
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Schlicht L, Schlicht E, Santema P, Kempenaers B. A dawn and dusk chorus will emerge if males sing in the absence of their mate. Proc Biol Sci 2023; 290:20232266. [PMID: 37989244 PMCID: PMC10688385 DOI: 10.1098/rspb.2023.2266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Accepted: 10/23/2023] [Indexed: 11/23/2023] Open
Abstract
The spring dawn and dusk chorus of birds is a widespread phenomenon, yet its origin remains puzzling. We propose that a dawn and dusk chorus will inevitably arise if two criteria are met: (1) females leave their roost later in the morning and go to roost earlier in the evening than their mate, and (2) males sing more when separated from their mate. Previous studies on blue tits (Cyanistes caeruleus) support the first criterion. We here report that males sing at a higher rate whenever they are separated from their mate and that song rate increases with the duration of female absence. These findings can explain the existence of the dawn and dusk chorus in blue tits, and they can explain why the dawn chorus is more pronounced than the dusk chorus, as is typically observed. An exhaustive literature search provides support for both criteria of the 'absent mate' hypothesis in several passerine birds. We found no evidence contradicting the hypothesis. The new hypothesis is not inconsistent with many of the existing hypotheses about dawn singing, but may be a more general explanation for the occurrence of a dawn and dusk chorus. We describe how the 'absent mate' hypothesis leads to testable predictions about daily and seasonal variation in song output.
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Affiliation(s)
- Lotte Schlicht
- Max Planck Institute for Biological Intelligence, Eberhard Gwinner Str, 82319 Seewiesen, Germany
| | - Emmi Schlicht
- Max Planck Institute for Biological Intelligence, Eberhard Gwinner Str, 82319 Seewiesen, Germany
| | - Peter Santema
- Max Planck Institute for Biological Intelligence, Eberhard Gwinner Str, 82319 Seewiesen, Germany
- Edward Grey Institute, Department of Biology, University of Oxford, Oxford, UK
| | - Bart Kempenaers
- Max Planck Institute for Biological Intelligence, Eberhard Gwinner Str, 82319 Seewiesen, Germany
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3
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Crino OL, Falk S, Katsis AC, Kraft FLOH, Buchanan KL. Mitochondria as the powerhouses of sexual selection: Testing mechanistic links between development, cellular respiration, and bird song. Horm Behav 2022; 142:105184. [PMID: 35596967 DOI: 10.1016/j.yhbeh.2022.105184] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 04/21/2022] [Accepted: 04/22/2022] [Indexed: 11/04/2022]
Abstract
The developmental environment can affect the expression of sexually selected traits in adulthood. The physiological mechanisms that modulate such effects remain a matter of intense debate. Here, we test the role of the developmental environment in shaping adult mitochondrial function and link mitochondrial function to expression of a sexually selected trait in males (bird song). We exposed male zebra finches (Taeniopygia guttata) to corticosterone (CORT) treatment during development. After males reached adulthood, we quantified mitochondrial function from whole red blood cells and measured baseline CORT and testosterone levels, body condition/composition, and song structure. CORT-treated males had mitochondria that were less efficient (FCRL/R) and used a lower proportion of maximum capacity (FCRR/ETS) than control males. Additionally, CORT-treated males had higher baseline levels of CORT as adults compared to control males. Using structural equation modelling, we found that the effects of CORT treatment during development on adult mitochondrial function were indirect and modulated by baseline CORT levels, which are programmed by CORT treatment during development. Developmental treatment also had an indirect effect on song peak frequency. Males treated with CORT during development sang songs with higher peak frequency than control males, but this effect was modulated through increased CORT levels and by a decrease in FCRR/ETS. CORT-treated males had smaller tarsi compared to control males; however, there were no associations between body size and measures of song frequency. Here, we provide the first evidence supporting links between the developmental environment, mitochondrial function, and the expression of a sexually selected trait (bird song).
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Affiliation(s)
- Ondi L Crino
- Research School of Biology, Australian National University, Canberra, ACT, Australia; Centre for Integrative Ecology, School of Life and Environmental Sciences, Deakin University, Geelong, Victoria, Australia.
| | - Steph Falk
- School of Biological Science Monash University, Melbourne, VIC, Australia; Institute of Immunology and Epigenetics, Max Planck Institute, Baden-Württemberg, Germany
| | - Andrew C Katsis
- Centre for Integrative Ecology, School of Life and Environmental Sciences, Deakin University, Geelong, Victoria, Australia; College of Science and Engineering, Flinders University, Adelaide, SA, Australia
| | - Fanny-Linn O H Kraft
- Centre for Integrative Ecology, School of Life and Environmental Sciences, Deakin University, Geelong, Victoria, Australia; Department of Zoology, Stockholm University, Stockholm, Sweden
| | - Katherine L Buchanan
- Centre for Integrative Ecology, School of Life and Environmental Sciences, Deakin University, Geelong, Victoria, Australia
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James LS, Fan R, Sakata JT. Behavioural responses to video and live presentations of females reveal a dissociation between performance and motivational aspects of birdsong. ACTA ACUST UNITED AC 2019; 222:jeb.206318. [PMID: 31331939 DOI: 10.1242/jeb.206318] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Accepted: 07/15/2019] [Indexed: 12/13/2022]
Abstract
Understanding the regulation of social behavioural expression requires insight into motivational and performance aspects. While a number of studies have independently assessed these aspects of social behaviours, few have examined how they relate to each other. By comparing behavioural variation in response to live or video presentations of conspecific females, we analysed how variation in the motivation to produce courtship song covaries with variation in performance aspects of courtship song in male zebra finches (Taeniopygia guttata). In agreement with previous reports, we observed that male zebra finches were less motivated to produce courtship songs to videos of females than to live presentations of females. However, we found that acoustic features that reflect song performance were not significantly different between songs produced in response to videos of females, and those produced in response to live females. For example, songs directed at video presentations of females were just as fast and stereotyped as songs directed at live females. These experimental manipulations and correlational analyses reveal a dissociation between motivational and performance aspects of birdsong and suggest a refinement of neural models of song production and control. In addition, they support the efficacy of videos to study both motivational and performance aspects of social behaviours.
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Affiliation(s)
- Logan S James
- Department of Biology, McGill University, Montreal, QC H3A 1B1, Canada
| | - Raina Fan
- Department of Biology, McGill University, Montreal, QC H3A 1B1, Canada
| | - Jon T Sakata
- Department of Biology, McGill University, Montreal, QC H3A 1B1, Canada
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Zsebők S, Herczeg G, Blázi G, Laczi M, Nagy G, Szász E, Markó G, Török J, Garamszegi LZ. Short- and long-term repeatability and pseudo-repeatability of bird song: sensitivity of signals to varying environments. Behav Ecol Sociobiol 2017. [DOI: 10.1007/s00265-017-2379-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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7
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Fedurek P, Slocombe KE, Enigk DK, Emery Thompson M, Wrangham RW, Muller MN. The relationship between testosterone and long-distance calling in wild male chimpanzees. Behav Ecol Sociobiol 2016; 70:659-672. [PMID: 27182103 PMCID: PMC4864005 DOI: 10.1007/s00265-016-2087-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Long-distance calling is a common behaviour in animals that has various important social functions. At a physiological level, calling is often mediated by gonadal hormones such as testosterone (T), particularly when its function is linked to intra-sexual competition for mates or territory. T also plays an important role in the development of vocal characteristics associated with dominance in humans. However, the few available studies of T and vocal behaviour in non-human primates suggest that in primates T has less influence on call production than in other animals. We tested this hypothesis by studying the relationship between T concentrations and pant hooting in wild male chimpanzees (Pan troglodytes schweinfurthii) of the Kanyawara community in the Kibale National Park, Uganda. We found three kinds of correlation. Hourly T averages were positively associated with hourly rates of pant-hooting. Monthly T levels were likewise correlated with monthly rates of pant hooting after controlling for other influences such as fission-fusion rates. Finally, males with high T levels had higher peak frequency at the start of the call climax. These results suggest that T affects the production of pant-hoots in chimpanzees. This implies that the pant-hoot call plays a role in male-male competition. We propose that even in cognitively sophisticated species, endocrine mechanisms can contribute to regulating vocal production.
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Affiliation(s)
- Pawel Fedurek
- Institute of Biology, University of Neuchâtel, Switzerland
| | | | - Drew K. Enigk
- Department of Anthropology, University of New Mexico
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8
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Narango DL, Rodewald AD. Urban-associated drivers of song variation along a rural–urban gradient. Behav Ecol 2015. [DOI: 10.1093/beheco/arv197] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
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Baldo S, Mennill DJ, Guindre-Parker S, Gilchrist HG, Love OP. The Oxidative Cost of Acoustic Signals: Examining Steroid Versus Aerobic Activity Hypotheses in a Wild Bird. Ethology 2015. [DOI: 10.1111/eth.12424] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Sarah Baldo
- Department of Biological Sciences; University of Windsor; Windsor ON Canada
| | - Daniel J. Mennill
- Department of Biological Sciences; University of Windsor; Windsor ON Canada
| | | | - Hugh Grant Gilchrist
- National Wildlife Research Centre; Environment Canada; Carleton University; Ottawa ON Canada
| | - Oliver P. Love
- Department of Biological Sciences; University of Windsor; Windsor ON Canada
- Great Lakes Institute for Environmental Research; University of Windsor; Windsor ON Canada
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11
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Casagrande S, Pinxten R, Zaid E, Eens M. Carotenoids, birdsong and oxidative status: administration of dietary lutein is associated with an increase in song rate and circulating antioxidants (albumin and cholesterol) and a decrease in oxidative damage. PLoS One 2014; 9:e115899. [PMID: 25549336 PMCID: PMC4280127 DOI: 10.1371/journal.pone.0115899] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Accepted: 11/29/2014] [Indexed: 12/21/2022] Open
Abstract
Despite the appealing hypothesis that carotenoid-based colouration signals oxidative status, evidence supporting the antioxidant function of these pigments is scarce. Recent studies have shown that lutein, the most common carotenoid used by birds, can enhance the expression of non-visual traits, such as birdsong. Nevertheless, the underlying physiological mechanisms remain unclear. In this study we hypothesized that male European starlings (Sturnus vulgaris) fed extra lutein increase their song rate as a consequence of an improved oxidative status. Although birdsong may be especially sensitive to the redox status, this has, to the best of our knowledge, never been tested. Together with the determination of circulating oxidative damage (ROMs, reactive oxygen metabolites), we quantified uric acid, albumin, total proteins, cholesterol, and testosterone, which are physiological parameters potentially sensitive to oxidation and/or related to both carotenoid functions and birdsong expression. We found that the birds fed extra lutein sang more frequently than control birds and showed an increase of albumin and cholesterol together with a decrease of oxidative damage. Moreover, we could show that song rate was associated with high levels of albumin and cholesterol and low levels of oxidative damage, independently from testosterone levels. Our study shows for the first time that song rate honestly signals the oxidative status of males and that dietary lutein is associated with the circulation of albumin and cholesterol in birds, providing a novel insight to the theoretical framework related to the honest signalling of carotenoid-based traits.
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Affiliation(s)
- Stefania Casagrande
- Department of Biology, Ethology Group, University of Antwerp, Campus Drie Eiken, Antwerp, Belgium
- * E-mail:
| | - Rianne Pinxten
- Department of Biology, Ethology Group, University of Antwerp, Campus Drie Eiken, Antwerp, Belgium
- Institute for Education and Information Sciences, Research Unit Didactica, University of Antwerp, Antwerp, Belgium
| | - Erika Zaid
- Department of Biology, Ethology Group, University of Antwerp, Campus Drie Eiken, Antwerp, Belgium
| | - Marcel Eens
- Department of Biology, Ethology Group, University of Antwerp, Campus Drie Eiken, Antwerp, Belgium
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12
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Seki Y, Hessler NA, Xie K, Okanoya K. Food rewards modulate the activity of song neurons in Bengalese finches. Eur J Neurosci 2013; 39:975-983. [PMID: 24341509 DOI: 10.1111/ejn.12457] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Revised: 11/11/2013] [Accepted: 11/18/2013] [Indexed: 01/04/2023]
Abstract
Vocal learning, a critical component of speech acquisition, is a rare trait in animals. Songbirds are a well-established animal model in vocal learning research; male birds acquire novel vocal patterns and have a well-developed 'song system' in the brain. Although this system is unique to songbirds, anatomical and physiological studies have reported similarities between the song system and the thalamo-cortico-basal ganglia circuit that is conserved among reptiles, birds, and mammals. Here, we focused on the similarity of the neural response between these two systems while animals were engaging in operant tasks. Neurons in the basal ganglia of vertebrates are activated in response to food rewards and reward predictions in behavioral tasks. A striatal nucleus in the avian song system, Area X, is necessary for vocal learning and is considered specialized for singing. We found that the spiking activity of singing-related Area X neurons was modulated by food rewards and reward signals in an operant task. As previous studies showed that Area X is not critical for general cognitive tasks, the role of Area X in general learning might be limited and vestigial. However, our results provide a new viewpoint to investigate the independence of the vocal learning system from neural systems involved in other cognitive tasks.
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Affiliation(s)
- Yoshimasa Seki
- Japan Science and Technology Agency, ERATO, Okanoya Emotional Information Project, Wako, 3510198, Japan; Laboratory for Biolinguistics, RIKEN Brain Science Institute, Wako, 3510198, Japan; Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, 1538902, Japan
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Nemeth E, Pieretti N, Zollinger SA, Geberzahn N, Partecke J, Miranda AC, Brumm H. Bird song and anthropogenic noise: vocal constraints may explain why birds sing higher-frequency songs in cities. Proc Biol Sci 2013; 280:20122798. [PMID: 23303546 PMCID: PMC3574330 DOI: 10.1098/rspb.2012.2798] [Citation(s) in RCA: 101] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2012] [Accepted: 12/13/2012] [Indexed: 11/12/2022] Open
Abstract
When animals live in cities, they have to adjust their behaviour and life histories to novel environments. Noise pollution puts a severe constraint on vocal communication by interfering with the detection of acoustic signals. Recent studies show that city birds sing higher-frequency songs than their conspecifics in non-urban habitats. This has been interpreted as an adaptation to counteract masking by traffic noise. However, this notion is debated, for the observed frequency shifts seem to be less efficient at mitigating noise than singing louder, and it has been suggested that city birds might use particularly high-frequency song elements because they can be produced at higher amplitudes. Here, we present the first phonetogram for a songbird, which shows that frequency and amplitude are strongly positively correlated in the common blackbird (Turdus merula), a successful urban colonizer. Moreover, city blackbirds preferentially sang higher-frequency elements that can be produced at higher intensities and, at the same time, happen to be less masked in low-frequency traffic noise.
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Affiliation(s)
- Erwin Nemeth
- Communication and Social Behaviour Group, Max Planck Institute for Ornithology, 82319 Seewiesen, Germany.
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14
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Apfelbeck B, Kiefer S, Mortega KG, Goymann W, Kipper S. Testosterone affects song modulation during simulated territorial intrusions in male black redstarts (Phoenicurus ochruros). PLoS One 2012; 7:e52009. [PMID: 23284852 PMCID: PMC3524101 DOI: 10.1371/journal.pone.0052009] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2012] [Accepted: 11/07/2012] [Indexed: 12/26/2022] Open
Abstract
Although it has been suggested that testosterone plays an important role in resource allocation for competitive behavior, details of the interplay between testosterone, territorial aggression and signal plasticity are largely unknown. Therefore, we investigated if testosterone acts specifically on signals that communicate the motivation or ability of individuals to engage in competitive situations in a natural context. We studied the black redstart, a territorial songbird species, during two different life-cycle stages, the early breeding phase in spring and the non-breeding phase in fall. Male territory holders were implanted with the androgen receptor blocker flutamide (Flut) and the aromatase inhibitor letrozole (Let) to inhibit the action of testosterone and its estrogenic metabolites. Controls received a placebo treatment. Three days after implantation birds were challenged with a simulated territorial intrusion (STI). Song was recorded before, during and after the challenge. In spring, both treatment groups increased the number of elements sung in parts of their song in response to the STI. However, Flut/Let-implanted males reacted to the STI with a decreased maximum acoustic frequency of one song part, while placebo-implanted males did not. Instead, placebo-implanted males sang the atonal part of their song with a broader frequency range. Furthermore, placebo-, but not Flut/Let-implanted males, sang shorter songs with shorter pauses between parts in the STIs. During simulated intrusions in fall, when testosterone levels are naturally low in this species, males of both treatment groups sang similar to Flut/Let-implanted males during breeding. The results suggest that song sung during a territorial encounter is of higher competitive value than song sung in an undisturbed situation and may, therefore, convey information about the motivation or quality of the territory holder. We conclude that testosterone facilitates context-dependent changes in song structures that may be honest signals of male quality in black redstarts.
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Affiliation(s)
- Beate Apfelbeck
- Abteilung für Verhaltensneurobiologie, Max-Planck-Institut für Ornithologie, Seewiesen, Germany.
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Maddison CJ, Anderson RC, Prior NH, Taves MD, Soma KK. Soft song during aggressive interactions: seasonal changes and endocrine correlates in song sparrows. Horm Behav 2012; 62:455-63. [PMID: 22902893 DOI: 10.1016/j.yhbeh.2012.08.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2012] [Revised: 07/26/2012] [Accepted: 08/01/2012] [Indexed: 01/21/2023]
Abstract
It is well known that songbirds produce high amplitude songs ("broadcast songs"). Songbirds also produce low amplitude songs ("soft songs") during courtship or territorial aggression in the breeding season. Soft songs are important social signals but have been studied far less than broadcast songs. To date, no studies have examined seasonal changes in soft song or its endocrine regulation. Here, in male song sparrows, we examined soft songs during a simulated territorial intrusion in the breeding season and non-breeding season. We also measured plasma testosterone and dehydroepiandrosterone (DHEA) levels in subjects immediately after the aggressive encounter. The total number of songs produced (broadcast+soft songs) did not vary between seasons. However, there was a dramatic increase in the percentage of soft song in the non-breeding season. Further, the percentage of soft song was negatively correlated with plasma testosterone levels in the non-breeding season. There were seasonal differences in the acoustic structure of two major elements of soft song, trills and buzzes. The minimum frequency of trills was lower in the non-breeding season, and the element repetition rate of buzzes was lower in the non-breeding season. To our knowledge, this is the first study to (1) examine soft songs outside of the breeding season and (2) to identify endocrine correlates of soft songs, which are important social signals in songbirds.
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Affiliation(s)
- Chris J Maddison
- Department of Psychology, University of British Columbia, Vancouver BC, Canada
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16
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Nemeth E, Zollinger SA, Brumm H. Effect Sizes and the Integrative Understanding of Urban Bird Song. Am Nat 2012. [DOI: 10.1086/665994] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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17
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Ritschard M, van Oers K, Naguib M, Brumm H. Song Amplitude of Rival Males Modulates the Territorial Behaviour of Great Tits During the Fertile Period of Their Mates. Ethology 2012. [DOI: 10.1111/j.1439-0310.2011.01999.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Ręk P, Osiejuk TS, Budka M. Functionally similar acoustic signals in the corncrake (Crex crex) transmit information about different states of the sender during aggressive interactions. Horm Behav 2011; 60:706-12. [PMID: 21983228 DOI: 10.1016/j.yhbeh.2011.09.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2011] [Revised: 09/13/2011] [Accepted: 09/14/2011] [Indexed: 11/16/2022]
Abstract
We combined playback experiments with hormonal manipulations to study the information content of acoustic signals during aggressive interactions between male corncrakes. During territorial conflicts, fights are uncommon, but the intensity of signaling usually increases. Such signals can be temporally and contextually associated with many aggressive behaviors and most likely function as threats or as indicators of the sender's quality or motivation. However, such correlational data are unsatisfactory for the proper interpretation of the function and information content of signals. Experimental tests are required to determine whether signals and aggressive behaviors are controlled by common or independent mechanisms. In our experiment, we assigned subjects to four groups: testosterone-implanted birds, flutamide-implanted birds, birds with empty implants, and non-captured control birds. Males produced two types of calls (quiet soft calls and loud broadcast calls), both of which are known to be reliable predictors of aggressive escalation. When testosterone action was blocked with flutamide, males significantly limited the amount of time spent close to the playback speaker and stopped responding to playback with soft calls. Broadcast calling was unaffected by the blockage of testosterone. Conversely, increased levels of testosterone neither affected calling nor the time spent near the speaker, indicating a permissive, rather than a graded effect of androgens. We concluded that, despite the seemingly similar function, both signals may transmit information about different states of the sender; soft calls seem to imply a threat of force, while broadcast calls appear to be more similar to an announcement, which is only indirectly associated with a male's aggressive behavior.
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Affiliation(s)
- Paweł Ręk
- Department of Behavioural Ecology, Institute of Environmental Biology, Faculty of Biology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznań, Poland.
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Brumm H, Ritschard M. Song amplitude affects territorial aggression of male receivers in chaffinches. Behav Ecol 2011. [DOI: 10.1093/beheco/arq205] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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