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Jessop TS, Webb J, Dempster T, Feit B, Letnic M. Interactions between corticosterone phenotype, environmental stressor pervasiveness and irruptive movement-related survival in the cane toad. J Exp Biol 2018; 221:jeb.187930. [PMID: 30352824 DOI: 10.1242/jeb.187930] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2018] [Accepted: 10/19/2018] [Indexed: 11/20/2022]
Abstract
Animals use irruptive movement to avoid exposure to stochastic and pervasive environmental stressors that impact fitness. Beneficial irruptive movements transfer individuals from high-stress areas (conferring low fitness) to alternative localities that may improve survival or reproduction. However, being stochastic, environmental stressors can limit an animal's preparatory capacity to enhance irruptive movement performance. Thus individuals must rely on pre-existing, or rapidly induced, physiological and behavioural responses. Rapid elevation of glucocorticoid hormones in response to environmental stressors are widely implicated in adjusting physiological and behaviour processes that could influence irruptive movement capacity. However, there remains little direct evidence demonstrating that corticosterone-regulated movement performance or interaction with pervasiveness of environmental stress, confers adaptive movement outcomes. Here, we compared how movement-related survival of cane toads (Rhinella marina) varied with three different experimental corticosterone phenotypes across four increments of increasing environmental stressor pervasiveness (i.e. distance from water in a semi-arid landscape). Our results indicated that toads with phenotypically increased corticosterone levels attained higher movement-related survival compared with individuals with control or lowered corticosterone phenotypes. However, the effects of corticosterone phenotypes on movement-related survival to some extent co-varied with stressor pervasiveness. Thus, our study demonstrates how the interplay between an individual's corticosterone phenotype and movement capacity alongside the arising costs of movement and the pervasiveness of the environmental stressor can affect survival outcomes.
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Affiliation(s)
- Tim S Jessop
- Centre for Integrative Ecology, Deakin University, Victoria, 3220, Australia
| | - Jonathan Webb
- School of the Environment, University of Technology Sydney, NSW 2007, Australia
| | - Tim Dempster
- School of Biosciences, University of Melbourne, Victoria, 3010, Australia
| | - Benjamin Feit
- Department of Ecology, Swedish University of Agricultural Sciences, Uppsala, Sweden.,School of Biological, Earth and Environmental Sciences, University of New South Wales, NSW 2052, Australia
| | - Mike Letnic
- School of Biological, Earth and Environmental Sciences, University of New South Wales, NSW 2052, Australia
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Torres-Medina F, Cabezas S, Marchant TA, Wikelski M, Romero LM, Hau M, Carrete M, Tella JL, Blas J. Corticosterone implants produce stress-hyporesponsive birds. ACTA ACUST UNITED AC 2018; 221:jeb.173864. [PMID: 30111557 DOI: 10.1242/jeb.173864] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Accepted: 08/07/2018] [Indexed: 12/25/2022]
Abstract
In birds, the use of corticosterone (Cort) implants is a frequent tool aimed at simulating systemic elevations of this hormone and studying effects on biological traits (e.g. physiology, morphology, behavior). This manipulation may alter adrenocortical function, potentially changing both baseline (CortBAS) and stress-induced (CortSTRESS) plasma Cort levels. However, implant effects on the latter trait are rarely measured, disregarding downstream consequences of potentially altered stress responses. Here, we analyzed the effects of Cort implants on both CortBAS and CortSTRESS in nestling and adult European white storks, Ciconia ciconia In addition, we performed a review of 50 studies using Cort implants in birds during the last two decades to contextualize stork results, assess researchers' patterns of use and infer current study biases. High and low doses of Cort implants resulted in a decrease of both CortBAS (31-71% below controls) and CortSTRESS (63-79% below controls) in storks. Our literature review revealed that CortBAS generally increases (72% of experiments) whereas CortSTRESS decreases (78% of experiments) following implant treatment in birds. Our results challenge and expand the prevailing assumption that Cort implants increase circulating CortBAS levels because: (i) CortBAS levels show a quadratic association with implant dose across bird species, and decreased levels may occur at both high and low implant doses, and (ii) Cort implants also decrease CortSTRESS levels, thus producing stress-hyporesponsive phenotypes. It is time to work towards a better understanding of the effects of Cort implants on adrenocortical function, before addressing downstream links to variation in other biological traits.
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Affiliation(s)
- Fernando Torres-Medina
- Departamento de Biología de la Conservación, Estación Biológica de Doñana, Consejo Superior de Investigaciones Científicas (CSIC), 41092 Seville, Spain .,Department of Biology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada, S7N 5E2
| | - Sonia Cabezas
- Departamento de Biología de la Conservación, Estación Biológica de Doñana, Consejo Superior de Investigaciones Científicas (CSIC), 41092 Seville, Spain.,Department of Biology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada, S7N 5E2
| | - Tracy A Marchant
- Department of Biology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada, S7N 5E2
| | - Martin Wikelski
- Department of Migration and Immuno-Ecology, Max Planck Institute for Ornithology, 78315 Radolfzell, Germany.,Department of Biology, University of Konstanz, Universitätsstrasse 10, 78464 Konstanz, Germany
| | | | - Michaela Hau
- Department of Biology, University of Konstanz, Universitätsstrasse 10, 78464 Konstanz, Germany.,Evolutionary Physiology Group. Max Planck Institute for Ornithology, Eberhard-Gwinner-Str., 82319 Seewiesen, Germany
| | - Martina Carrete
- Departamento de Biología de la Conservación, Estación Biológica de Doñana, Consejo Superior de Investigaciones Científicas (CSIC), 41092 Seville, Spain.,Departamento de Sistemas Físicos, Químicos y Naturales, Universidad Pablo de Olavide, 41013 Seville, Spain
| | - José L Tella
- Departamento de Biología de la Conservación, Estación Biológica de Doñana, Consejo Superior de Investigaciones Científicas (CSIC), 41092 Seville, Spain
| | - Julio Blas
- Departamento de Biología de la Conservación, Estación Biológica de Doñana, Consejo Superior de Investigaciones Científicas (CSIC), 41092 Seville, Spain .,Department of Biology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada, S7N 5E2
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Arbore R, Sekii K, Beisel C, Ladurner P, Berezikov E, Schärer L. Positional RNA-Seq identifies candidate genes for phenotypic engineering of sexual traits. Front Zool 2015; 12:14. [PMID: 26146508 PMCID: PMC4490696 DOI: 10.1186/s12983-015-0106-0] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Accepted: 05/15/2015] [Indexed: 12/11/2022] Open
Abstract
INTRODUCTION RNA interference (RNAi) of trait-specific genes permits the manipulation of specific phenotypic traits ("phenotypic engineering") and thus represents a powerful tool to test trait function in evolutionary studies. The identification of suitable candidate genes, however, often relies on existing functional gene annotation, which is usually limited in emerging model organisms, especially when they are only distantly related to traditional genetic model organisms. A case in point is the free-living flatworm Macrostomum lignano (Lophotrochozoa: Platyhelminthes: Rhabditophora), an increasingly powerful model organism for evolutionary studies of sex in simultaneous hermaphrodites. To overcome the limitation of sparse functional annotation, we have performed a positional RNA-Seq analysis on different body fragments in order to identify organ-specific candidate transcripts. We then performed gene expression (in situ hybridization) and gene function (RNAi) analyses on 23 candidate transcripts, both to evaluate the predictive potential of this approach and to obtain preliminary functional characterizations of these candidate genes. RESULTS We identified over 4000 transcripts that could be expected to show specific expression in different reproductive organs (including testis, ovary and the male and female genital systems). The predictive potential of the method could then be verified by confirming organ-specific expression for several candidate transcripts, some of which yielded interesting trait-specific knock-down phenotypes that can now be followed up in future phenotypic engineering studies. CONCLUSIONS Our positional RNA-Seq analysis represents a highly useful resource for the identification of candidate transcripts for functional and phenotypic engineering studies in M. lignano, and it has already been used successfully in several studies. Moreover, this approach can overcome some inherent limitations of homology-based candidate selection and thus should be applicable to a broad range of emerging model organisms.
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Affiliation(s)
- Roberto Arbore
- />Evolutionary Biology, Zoological Institute, University of Basel, Vesalgasse 1, CH-4051 Basel, Switzerland
| | - Kiyono Sekii
- />Evolutionary Biology, Zoological Institute, University of Basel, Vesalgasse 1, CH-4051 Basel, Switzerland
| | | | - Peter Ladurner
- />Institute of Zoology and CMBI, University of Innsbruck, Innsbruck, Austria
| | - Eugene Berezikov
- />ERIBA, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Lukas Schärer
- />Evolutionary Biology, Zoological Institute, University of Basel, Vesalgasse 1, CH-4051 Basel, Switzerland
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