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Díaz S, Labra A. Exploring Sound Emission of the Lizard Pristidactylus valeriae. Animals (Basel) 2023; 13:3813. [PMID: 38136850 PMCID: PMC10740820 DOI: 10.3390/ani13243813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 12/03/2023] [Accepted: 12/08/2023] [Indexed: 12/24/2023] Open
Abstract
Lizards, except geckos, are generally considered voiceless organisms, although some species emit oral sounds. For most of these "vocal lizards", however, there is almost no information on the characteristics of the sounds, precluding exploration of the functionality and evolution of the sounds. Pristidactylus are known as "grunter lizards" since individuals emit oral sounds under predation risk. We explored the characteristics of the sounds emitted by P. valeriae, recording 17 adults and 1 juvenile when they were threatened and captured by a predator. Only adults emitted sounds with open mouths and displayed aggressive postures, e.g., biting attempts. These sounds correspond to hisses, which lack amplitude or frequency modulation. The lizards emitted longer hisses when threatened than when captured by the predator, which may provide honest information on individuals' ability to escape. In addition, males may experience higher distress during threats since their hisses had higher aggregate entropy than those of the females. Finally, hissing has been documented in four of the five Leiosauridae genera, the family to which Pristidactylus belongs, suggesting that sound emission is ancestral to the family.
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Affiliation(s)
- Sebastián Díaz
- Laboratorio de Ecología Geográfica, Facultad de Ciencias, Universidad de Chile, Santiago 7800003, Chile;
| | - Antonieta Labra
- Center for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, P.O. Box 1066 Blindern, NO-0316 Oslo, Norway
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Valenzuela-Sánchez A, Azat C, Cunningham AA, Delgado S, Bacigalupe LD, Beltrand J, Serrano JM, Sentenac H, Haddow N, Toledo V, Schmidt BR, Cayuela H. Interpopulation differences in male reproductive effort drive the population dynamics of a host exposed to an emerging fungal pathogen. J Anim Ecol 2021; 91:308-319. [PMID: 34704260 DOI: 10.1111/1365-2656.13603] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 10/04/2021] [Indexed: 11/28/2022]
Abstract
Compensatory recruitment is a key demographic mechanism that has allowed the coexistence of populations of susceptible amphibians with Batrachochytrium dendrobatidis (Bd), a fungus causing one of the most devastating emerging infectious disease ever recorded among vertebrates. However, the underlying processes (e.g. density-dependent increase in survival at early life stages, change in reproductive traits) as well as the level of interpopulation variation in this response are poorly known. We explore potential mechanisms of compensatory recruitment in response to Bd infection by taking advantage of an amphibian system where male reproductive traits are easy to quantify in free-living populations. The Southern Darwin's frog Rhinoderma darwinii is a vocal sac-brooding species that exhibits a high susceptibility to lethal Bd infection. Using a 7-year capture-recapture study at four populations with contrasting Bd infection status (one high prevalence, one low prevalence and two Bd-free populations), we evaluated whether Bd-positive populations exhibited a higher adult recruitment and a higher male reproductive effort than Bd-negative populations. We also estimated population growth rates to explore whether recruitment compensated for the negative impacts of Bd on the survival of adults. In addition, we evaluated a potential demographic signal of compensatory recruitment (i.e. positive relationship between the proportion of juveniles and Bd prevalence) in response to Bd infection using raw count data from 13 R. darwinii populations. The high Bd prevalence population exhibited the highest male reproductive effort and the highest recruitment among the four monitored populations. This led to a growing population during the study period despite high mortality of adult hosts. In contrast, males from the population with low Bd prevalence had a low reproductive effort and this population, which had the lowest adult recruitment, was declining during the study period despite adults having a higher survival in comparison to the high Bd prevalence population. We also found a demographic signal of compensatory recruitment in response to Bd infection in our broader analysis of 13 R. darwinii populations. Our study underlines the importance of interpopulation variation in life-history strategies on the fate of host populations after infectious disease emergence. Our results also suggest that an increase in reproductive effort can be one of the processes underlying compensatory recruitment in populations of Bd-susceptible amphibians.
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Affiliation(s)
- Andrés Valenzuela-Sánchez
- ONG Ranita de Darwin, Valdivia, Chile.,Instituto de Conservación, Biodiversidad y Territorio, Facultad de Ciencias Forestales y Recursos Naturales, Universidad Austral de Chile, Valdivia, Chile.,Sustainability Research Centre & PhD in Conservation Medicine, Life Sciences Faculty, Universidad Andres Bello, Santiago, Chile
| | - Claudio Azat
- Sustainability Research Centre & PhD in Conservation Medicine, Life Sciences Faculty, Universidad Andres Bello, Santiago, Chile
| | | | | | - Leonardo D Bacigalupe
- Instituto de Ciencias Ambientales y Evolutivas, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile
| | | | - José M Serrano
- ONG Ranita de Darwin, Valdivia, Chile.,Museo de Zoología 'Alfonso L. Herrera', Departamento Biología Evolutiva, Facultad de Ciencias, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Hugo Sentenac
- Institute of Zoology, Zoological Society of London, London, UK.,Royal Veterinary College, University of London, London, UK
| | - Natashja Haddow
- Sustainability Research Centre & PhD in Conservation Medicine, Life Sciences Faculty, Universidad Andres Bello, Santiago, Chile.,Institute of Zoology, Zoological Society of London, London, UK.,Royal Veterinary College, University of London, London, UK
| | | | - Benedikt R Schmidt
- Info fauna karch, Neuchâtel, Switzerland.,Institut für Evolutionsbiologie und Umweltwissenschaften, Universität Zürich, Zürich, Switzerland
| | - Hugo Cayuela
- Department of Ecology and Evolution, Biophore, University of Lausanne, Lausanne, Switzerland
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