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Barnett JB, Varela BJ, Jennings BJ, Lesbarrères D, Pruitt JN, Green DM. Habitat disturbance alters color contrast and the detectability of cryptic and aposematic frogs. Behav Ecol 2021. [DOI: 10.1093/beheco/arab032] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
Animals use color both to conceal and signal their presence, with patterns that match the background, disrupt shape recognition, or highlight features important for communication. The forms that these color patterns take are responses to the visual systems that observe them and the environments within which they are viewed. Increasingly, however, these environments are being affected by human activity. We studied how pattern characteristics and habitat change may affect the detectability of three frog color patterns from the Bocas del Toro archipelago in Panama: Beige-Striped Brown Allobates talamancae and two spotted morphs of Oophaga pumilio, Black-Spotted Green and Black-Spotted Red. To assess detectability, we used visual modeling of conspecifics and potential predators, along with a computer-based detection experiment with human participants. Although we found no evidence for disruptive camouflage, we did find clear evidence that A. talamancae stripes are inherently more cryptic than O. pumilio spots regardless of color. We found no evidence that color pattern polytypism in O. pumilio is related to differences in the forest floor between natural sites. We did, however, find strong evidence that human disturbance affects the visual environment and modifies absolute and rank order frog detectability. Human-induced environmental change reduces the effectiveness of camouflage in A. talamancae, reduces detectability of Black-Spotted Green O. pumilio, and increases chromatic contrast, but not detectability, in Black-Spotted Red O. pumilio. Insofar as predators may learn about prey defenses and make foraging decisions based on relative prey availability and suitability, such changes may have wider implications for predator–prey dynamics.
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Affiliation(s)
- James B Barnett
- Department of Psychology, Neuroscience and Behaviour, McMaster University, Hamilton, ON, Canada
- Redpath Museum, McGill University, Montreal, QC, Canada
| | | | - Ben J Jennings
- The College of Health, Medicine and Life Sciences, Brunel University London, Kingston Lane, Uxbridge, UK
| | | | - Jonathan N Pruitt
- Department of Psychology, Neuroscience and Behaviour, McMaster University, Hamilton, ON, Canada
| | - David M Green
- Redpath Museum, McGill University, Montreal, QC, Canada
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2
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Goedert D, Clement D, Calsbeek R. Evolutionary trade‐offs may interact with physiological constraints to maintain color variation. ECOL MONOGR 2020. [DOI: 10.1002/ecm.1430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Debora Goedert
- Department of Biological Sciences Dartmouth College Hanover03755 New Hampshire USA
- Ministry of Education of Brazil CAPES Foundation Brasília DF95616Brazil
| | - Dale Clement
- Department of Biological Sciences Dartmouth College Hanover03755 New Hampshire USA
| | - Ryan Calsbeek
- Department of Biological Sciences Dartmouth College Hanover03755 New Hampshire USA
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3
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Briolat ES, Burdfield‐Steel ER, Paul SC, Rönkä KH, Seymoure BM, Stankowich T, Stuckert AMM. Diversity in warning coloration: selective paradox or the norm? Biol Rev Camb Philos Soc 2019; 94:388-414. [PMID: 30152037 PMCID: PMC6446817 DOI: 10.1111/brv.12460] [Citation(s) in RCA: 74] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Revised: 07/25/2018] [Accepted: 07/27/2018] [Indexed: 01/03/2023]
Abstract
Aposematic theory has historically predicted that predators should select for warning signals to converge on a single form, as a result of frequency-dependent learning. However, widespread variation in warning signals is observed across closely related species, populations and, most problematically for evolutionary biologists, among individuals in the same population. Recent research has yielded an increased awareness of this diversity, challenging the paradigm of signal monomorphy in aposematic animals. Here we provide a comprehensive synthesis of these disparate lines of investigation, identifying within them three broad classes of explanation for variation in aposematic warning signals: genetic mechanisms, differences among predators and predator behaviour, and alternative selection pressures upon the signal. The mechanisms producing warning coloration are also important. Detailed studies of the genetic basis of warning signals in some species, most notably Heliconius butterflies, are beginning to shed light on the genetic architecture facilitating or limiting key processes such as the evolution and maintenance of polymorphisms, hybridisation, and speciation. Work on predator behaviour is changing our perception of the predator community as a single homogenous selective agent, emphasising the dynamic nature of predator-prey interactions. Predator variability in a range of factors (e.g. perceptual abilities, tolerance to chemical defences, and individual motivation), suggests that the role of predators is more complicated than previously appreciated. With complex selection regimes at work, polytypisms and polymorphisms may even occur in Müllerian mimicry systems. Meanwhile, phenotypes are often multifunctional, and thus subject to additional biotic and abiotic selection pressures. Some of these selective pressures, primarily sexual selection and thermoregulation, have received considerable attention, while others, such as disease risk and parental effects, offer promising avenues to explore. As well as reviewing the existing evidence from both empirical studies and theoretical modelling, we highlight hypotheses that could benefit from further investigation in aposematic species. Finally by collating known instances of variation in warning signals, we provide a valuable resource for understanding the taxonomic spread of diversity in aposematic signalling and with which to direct future research. A greater appreciation of the extent of variation in aposematic species, and of the selective pressures and constraints which contribute to this once-paradoxical phenomenon, yields a new perspective for the field of aposematic signalling.
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Affiliation(s)
- Emmanuelle S. Briolat
- Centre for Ecology & Conservation, College of Life & Environmental SciencesUniversity of ExeterPenryn Campus, Penryn, Cornwall, TR10 9FEU.K.
| | - Emily R. Burdfield‐Steel
- Centre of Excellence in Biological Interactions, Department of Biological and Environmental ScienceUniversity of JyväskyläJyväskylä, 40014Finland
| | - Sarah C. Paul
- Centre for Ecology & Conservation, College of Life & Environmental SciencesUniversity of ExeterPenryn Campus, Penryn, Cornwall, TR10 9FEU.K.
- Department of Chemical EcologyBielefeld UniversityUniversitätsstraße 25, 33615, BielefeldGermany
| | - Katja H. Rönkä
- Centre of Excellence in Biological Interactions, Department of Biological and Environmental ScienceUniversity of JyväskyläJyväskylä, 40014Finland
- Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental SciencesUniversity of HelsinkiHelsinki, 00014Finland
| | - Brett M. Seymoure
- Department of BiologyColorado State UniversityFort CollinsCO 80525U.S.A.
- Department of Fish, Wildlife, and Conservation BiologyColorado State UniversityFort CollinsCO 80525U.S.A.
| | - Theodore Stankowich
- Department of Biological SciencesCalifornia State UniversityLong BeachCA 90840U.S.A.
| | - Adam M. M. Stuckert
- Department of BiologyEast Carolina University1000 E Fifth St, GreenvilleNC 27858U.S.A.
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Durso AM, French SS. Stable isotope tracers reveal a trade‐off between reproduction and immunity in a reptile with competing needs. Funct Ecol 2017. [DOI: 10.1111/1365-2435.13002] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Andrew M. Durso
- Department of Biology & The Ecology Center Utah State University Logan UT USA
| | - Susannah S. French
- Department of Biology & The Ecology Center Utah State University Logan UT USA
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Grant T, Rada M, Anganoy-Criollo M, Batista A, Dias PH, Jeckel AM, Machado DJ, Rueda-Almonacid JV. Phylogenetic Systematics of Dart-Poison Frogs and Their Relatives Revisited (Anura: Dendrobatoidea). SOUTH AMERICAN JOURNAL OF HERPETOLOGY 2017. [DOI: 10.2994/sajh-d-17-00017.1] [Citation(s) in RCA: 77] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Affiliation(s)
- Taran Grant
- Department of Zoology, Institute of Biosciences, University of São Paulo, 05508-090, São Paulo, SP, Brazil
- Amphibian Collection, Museum of Zoology of the University of São Paulo, 04263-000, São Paulo, SP, Brazil
| | - Marco Rada
- Department of Zoology, Institute of Biosciences, University of São Paulo, 05508-090, São Paulo, SP, Brazil
| | - Marvin Anganoy-Criollo
- Department of Zoology, Institute of Biosciences, University of São Paulo, 05508-090, São Paulo, SP, Brazil
| | - Abel Batista
- Universidad Autónoma de Chiriquí, David, Republic of Panama
- Los Naturalistas, David 0426-01459, Chiriquí, Panama
| | - Pedro Henrique Dias
- Department of Zoology, Institute of Biosciences, University of São Paulo, 05508-090, São Paulo, SP, Brazil
| | - Adriana Moriguchi Jeckel
- Department of Zoology, Institute of Biosciences, University of São Paulo, 05508-090, São Paulo, SP, Brazil
| | - Denis Jacob Machado
- Department of Zoology, Institute of Biosciences, University of São Paulo, 05508-090, São Paulo, SP, Brazil
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Arenas LM, Stevens M. Diversity in warning coloration is easily recognized by avian predators. J Evol Biol 2017; 30:1288-1302. [PMID: 28338250 PMCID: PMC5518184 DOI: 10.1111/jeb.13074] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Revised: 01/14/2017] [Accepted: 03/10/2017] [Indexed: 11/29/2022]
Abstract
Warning coloration is a widespread strategy to alert predators about prey unprofitability. The success of this strategy partly depends on predators being able to learn and recognize certain signals as indicators of toxicity, and theory predicts that this is easier if signals converge on similar colours. However, the diversity in warning signal form is astonishing, contradicting predictions. Here, we quantified ladybird signal diversity with respect to avian vision, measuring how unique and discernible each signal is from one another. In addition, we measured signal conspicuousness against a series of backgrounds, namely an average green, average brown, and where we collected each species, to determine whether signals are more contrasting against the ladybirds' local substrates than compared to average ones. This allowed us to establish whether there are local adaptations in conspicuousness that promote signal diversity. We found that while ladybird signals are unique and recognizable, specialist species are more contrasting against the background they are most commonly found on. However, overall our study suggests that warning signals have evolved to be effective against a wide range of natural backgrounds, partly explaining the success of this strategy in nature.
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Affiliation(s)
- L M Arenas
- Department of Zoology, University of Cambridge, Cambridge, UK.,Centre for Ecology & Conservation, College of Life & Environmental Sciences, University of Exeter, Penryn, Cornwall, UK
| | - M Stevens
- Centre for Ecology & Conservation, College of Life & Environmental Sciences, University of Exeter, Penryn, Cornwall, UK
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7
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Rojas B. Behavioural, ecological, and evolutionary aspects of diversity in frog colour patterns. Biol Rev Camb Philos Soc 2016; 92:1059-1080. [DOI: 10.1111/brv.12269] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Revised: 02/26/2016] [Accepted: 02/29/2016] [Indexed: 02/03/2023]
Affiliation(s)
- Bibiana Rojas
- Centre of Excellence in Biological Interactions, Department of Biology and Environmental Sciences; University of Jyvaskyla; PO Box 35 Jyväskylä FI 40001 Finland
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Flores EE, Stevens M, Moore AJ, Rowland HM, Blount JD. Body size but not warning signal luminance influences predation risk in recently metamorphosed poison frogs. Ecol Evol 2015; 5:4603-16. [PMID: 26668726 PMCID: PMC4670055 DOI: 10.1002/ece3.1731] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Revised: 08/19/2015] [Accepted: 08/22/2015] [Indexed: 01/05/2023] Open
Abstract
During early development, many aposematic species have bright and conspicuous warning appearance, but have yet to acquire chemical defenses, a phenotypic state which presumably makes them vulnerable to predation. Body size and signal luminance in particular are known to be sensitive to variation in early nutrition. However, the relative importance of these traits as determinants of predation risk in juveniles is not known. To address this question, we utilized computer‐assisted design (CAD) and information on putative predator visual sensitivities to produce artificial models of postmetamorphic froglets that varied in terms of body size and signal luminance. We then deployed the artificial models in the field and measured rates of attack by birds and unknown predators. Our results indicate that body size was a significant predictor of artificial prey survival. Rates of attack by bird predators were significantly higher on smaller models. However, predation by birds did not differ between artificial models of varying signal luminance. This suggests that at the completion of metamorphosis, smaller froglets may be at a selective disadvantage, potentially because predators can discern they have relatively low levels of chemical defense compared to larger froglets. There is likely to be a premium on efficient foraging, giving rise to rapid growth and the acquisition of toxins from dietary sources in juvenile poison frogs.
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Affiliation(s)
- Eric E Flores
- Centre for Ecology and Conservation College of Life & Environmental Sciences University of Exeter Penryn UK ; Sistema Nacional de Investigacion de Panama (SNI) Panama
| | - Martin Stevens
- Centre for Ecology and Conservation College of Life & Environmental Sciences University of Exeter Penryn UK
| | - Allen J Moore
- Centre for Ecology and Conservation College of Life & Environmental Sciences University of Exeter Penryn UK ; Department of Genetics University of Georgia 30602 Athens Georgia
| | | | - Jonathan D Blount
- Centre for Ecology and Conservation College of Life & Environmental Sciences University of Exeter Penryn UK
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Summers K, Speed MP, Blount JD, Stuckert AMM. Are aposematic signals honest? A review. J Evol Biol 2015; 28:1583-99. [DOI: 10.1111/jeb.12676] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Revised: 06/08/2015] [Accepted: 06/11/2015] [Indexed: 01/22/2023]
Affiliation(s)
- K. Summers
- Department of Biology; East Carolina University; Greenville NC USA
| | - M. P. Speed
- Department of Evolution, Ecology, and Behaviour; University of Liverpool; Liverpool UK
| | - J. D. Blount
- Centre for Ecology and Conservation, Biosciences; University of Exeter; Penryn UK
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Reproduction is associated with a tissue-dependent reduction of oxidative stress in eusocial female Damaraland mole-rats (Fukomys damarensis). PLoS One 2014; 9:e103286. [PMID: 25068591 PMCID: PMC4113376 DOI: 10.1371/journal.pone.0103286] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Accepted: 06/29/2014] [Indexed: 01/06/2023] Open
Abstract
Oxidative stress has been implicated as both a physiological cost of reproduction and a driving force on an animal's lifespan. Since increased reproductive effort is generally linked with a reduction in survival, it has been proposed that oxidative stress may influence this relationship. Support for this hypothesis is inconsistent, but this may, in part, be due to the type of tissues that have been analyzed. In Damaraland mole-rats the sole reproducing female in the colony is also the longest lived. Therefore, if oxidative stress does impact the trade-off between reproduction and survival in general, this species may possess some form of enhanced defense. We assessed this relationship by comparing markers of oxidative damage (malondialdehyde, MDA; protein carbonyls, PC) and antioxidants (total antioxidant capacity, TAC; superoxide dismutase, SOD) in various tissues including plasma, erythrocytes, heart, liver, kidney and skeletal muscle between wild-caught reproductive and non-reproductive female Damaraland mole-rats. Reproductive females exhibited significantly lower levels of PC across all tissues, and lower levels of MDA in heart, kidney and liver relative to non-reproductive females. Levels of TAC and SOD did not differ significantly according to reproductive state. The reduction in oxidative damage in breeding females may be attributable to the unusual social structure of this species, as similar relationships have been observed between reproductive and non-reproductive eusocial insects.
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11
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Morphological differentiation among populations of Rhinella marina (Amphibia: Anura) in western Mexico. Evol Ecol 2013. [DOI: 10.1007/s10682-013-9667-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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