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McMahon K, Marples NM, Spurgin LG, Rowland HM, Sheldon BC, Firth JA. Social network centrality predicts dietary decisions in a wild bird population. iScience 2024; 27:109581. [PMID: 38638576 PMCID: PMC11024920 DOI: 10.1016/j.isci.2024.109581] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Revised: 12/07/2023] [Accepted: 03/25/2024] [Indexed: 04/20/2024] Open
Abstract
How individuals balance costs and benefits of group living remains central to understanding sociality. In relation to diet, social foraging provides many advantages but also increases competition. Nevertheless, social individuals may offset increased competition by broadening their diet and consuming novel foods. Despite the expected relationships between social behavior and dietary decisions, how sociality shapes individuals' novel food consumption remains largely untested in natural populations. Here, we use wild great tits to experimentally test how sociality predicts dietary decisions. We show that individuals with more social connections have higher propensity to use novel foods compared to socially peripheral individuals, and this is unrelated to neophobia, observations, and demographic factors. These findings indicate sociable individuals may offset potential costs of competition by foraging more broadly. We discuss how social environments may drive behavioral change in natural populations, and the implications for the causes and consequences of social strategies and dietary decisions.
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Affiliation(s)
- Keith McMahon
- Department of Biology, Oxford University, Oxford, UK
| | - Nicola M. Marples
- Department of Zoology, School of Natural Sciences, Trinity College Dublin, Dublin 2, Ireland
| | - Lewis G. Spurgin
- School of Biological Sciences, University of East Anglia, Norwich, UK
| | - Hannah M. Rowland
- Max Planck Institute for Chemical Ecology, Jena, Germany
- Department of Zoology, University of Cambridge, Cambridge, UK
| | | | - Josh A. Firth
- Department of Biology, Oxford University, Oxford, UK
- School of Biology, University of Leeds, Leeds, UK
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2
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Williams HJ, Sridhar VH, Hurme E, Gall GE, Borrego N, Finerty GE, Couzin ID, Galizia CG, Dominy NJ, Rowland HM, Hauber ME, Higham JP, Strandburg-Peshkin A, Melin AD. Sensory collectives in natural systems. eLife 2023; 12:e88028. [PMID: 38019274 PMCID: PMC10686622 DOI: 10.7554/elife.88028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Accepted: 11/10/2023] [Indexed: 11/30/2023] Open
Abstract
Groups of animals inhabit vastly different sensory worlds, or umwelten, which shape fundamental aspects of their behaviour. Yet the sensory ecology of species is rarely incorporated into the emerging field of collective behaviour, which studies the movements, population-level behaviours, and emergent properties of animal groups. Here, we review the contributions of sensory ecology and collective behaviour to understanding how animals move and interact within the context of their social and physical environments. Our goal is to advance and bridge these two areas of inquiry and highlight the potential for their creative integration. To achieve this goal, we organise our review around the following themes: (1) identifying the promise of integrating collective behaviour and sensory ecology; (2) defining and exploring the concept of a 'sensory collective'; (3) considering the potential for sensory collectives to shape the evolution of sensory systems; (4) exploring examples from diverse taxa to illustrate neural circuits involved in sensing and collective behaviour; and (5) suggesting the need for creative conceptual and methodological advances to quantify 'sensescapes'. In the final section, (6) applications to biological conservation, we argue that these topics are timely, given the ongoing anthropogenic changes to sensory stimuli (e.g. via light, sound, and chemical pollution) which are anticipated to impact animal collectives and group-level behaviour and, in turn, ecosystem composition and function. Our synthesis seeks to provide a forward-looking perspective on how sensory ecologists and collective behaviourists can both learn from and inspire one another to advance our understanding of animal behaviour, ecology, adaptation, and evolution.
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Affiliation(s)
- Hannah J Williams
- Max Planck Institute of Animal BehaviorKonstanzGermany
- Centre for the Advanced Study of Collective Behaviour, University of KonstanzKonstanzGermany
- Biology Department, University of KonstanzKonstanzGermany
| | - Vivek H Sridhar
- Max Planck Institute of Animal BehaviorKonstanzGermany
- Centre for the Advanced Study of Collective Behaviour, University of KonstanzKonstanzGermany
- Biology Department, University of KonstanzKonstanzGermany
| | - Edward Hurme
- Max Planck Institute of Animal BehaviorKonstanzGermany
- Centre for the Advanced Study of Collective Behaviour, University of KonstanzKonstanzGermany
- Biology Department, University of KonstanzKonstanzGermany
| | - Gabriella E Gall
- Max Planck Institute of Animal BehaviorKonstanzGermany
- Centre for the Advanced Study of Collective Behaviour, University of KonstanzKonstanzGermany
- Biology Department, University of KonstanzKonstanzGermany
- Zukunftskolleg, University of KonstanzKonstanzGermany
| | | | | | - Iain D Couzin
- Max Planck Institute of Animal BehaviorKonstanzGermany
- Centre for the Advanced Study of Collective Behaviour, University of KonstanzKonstanzGermany
- Biology Department, University of KonstanzKonstanzGermany
| | - C Giovanni Galizia
- Biology Department, University of KonstanzKonstanzGermany
- Zukunftskolleg, University of KonstanzKonstanzGermany
| | - Nathaniel J Dominy
- Zukunftskolleg, University of KonstanzKonstanzGermany
- Department of Anthropology, Dartmouth CollegeHanoverUnited States
| | - Hannah M Rowland
- Max Planck Research Group Predators and Toxic Prey, Max Planck Institute for Chemical EcologyJenaGermany
| | - Mark E Hauber
- Department of Evolution, Ecology, and Behavior, School of Integrative Biology, University of Illinois at Urbana-ChampaignUrbana-ChampaignUnited States
| | - James P Higham
- Zukunftskolleg, University of KonstanzKonstanzGermany
- Department of Anthropology, New York UniversityNew YorkUnited States
| | - Ariana Strandburg-Peshkin
- Max Planck Institute of Animal BehaviorKonstanzGermany
- Centre for the Advanced Study of Collective Behaviour, University of KonstanzKonstanzGermany
- Biology Department, University of KonstanzKonstanzGermany
| | - Amanda D Melin
- Zukunftskolleg, University of KonstanzKonstanzGermany
- Department of Anthropology and Archaeology, University of CalgaryCalgaryCanada
- Alberta Children’s Hospital Research Institute, University of CalgaryCalgaryCanada
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3
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Hofmeister NR, Stuart KC, Warren WC, Werner SJ, Bateson M, Ball GF, Buchanan KL, Burt DW, Cardilini APA, Cassey P, De Meyer T, George J, Meddle SL, Rowland HM, Sherman CDH, Sherwin WB, Vanden Berghe W, Rollins LA, Clayton DF. Concurrent invasions of European starlings in Australia and North America reveal population-specific differentiation in shared genomic regions. Mol Ecol 2023. [PMID: 37933429 DOI: 10.1111/mec.17195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 09/22/2023] [Accepted: 10/23/2023] [Indexed: 11/08/2023]
Abstract
A species' success during the invasion of new areas hinges on an interplay between the demographic processes common to invasions and the specific ecological context of the novel environment. Evolutionary genetic studies of invasive species can investigate how genetic bottlenecks and ecological conditions shape genetic variation in invasions, and our study pairs two invasive populations that are hypothesized to be from the same source population to compare how each population evolved during and after introduction. Invasive European starlings (Sturnus vulgaris) established populations in both Australia and North America in the 19th century. Here, we compare whole-genome sequences among native and independently introduced European starling populations to determine how demographic processes interact with rapid evolution to generate similar genetic patterns in these recent and replicated invasions. Demographic models indicate that both invasive populations experienced genetic bottlenecks as expected based on invasion history, and we find that specific genomic regions have differentiated even on this short evolutionary timescale. Despite genetic bottlenecks, we suggest that genetic drift alone cannot explain differentiation in at least two of these regions. The demographic boom intrinsic to many invasions as well as potential inversions may have led to high population-specific differentiation, although the patterns of genetic variation are also consistent with the hypothesis that this infamous and highly mobile invader adapted to novel selection (e.g., extrinsic factors). We use targeted sampling of replicated invasions to identify and evaluate support for multiple, interacting evolutionary mechanisms that lead to differentiation during the invasion process.
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Affiliation(s)
- Natalie R Hofmeister
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, New York, USA
- Fuller Evolutionary Biology Program, Cornell Lab of Ornithology, Ithaca, New York, USA
| | - Katarina C Stuart
- School of Biological, Earth and Environmental Sciences, Evolution & Ecology Research Centre, UNSW Sydney, Sydney, New South Wales, Australia
| | - Wesley C Warren
- Department of Animal Sciences and Surgery, Institute for Data Science and Informatics, University of Missouri, Columbia, Missouri, USA
| | - Scott J Werner
- United States Department of Agriculture, Animal and Plant Health Inspection Service, Wildlife Services, National Wildlife Research Center, Fort Collins, Colorado, USA
| | - Melissa Bateson
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, UK
| | - Gregory F Ball
- Department of Psychology, University of Maryland, College Park, Maryland, USA
| | | | - David W Burt
- Office of the Deputy Vice-Chancellor (Research and Innovation), The University of Queensland, Brisbane, Queensland, Australia
- The Roslin Institute, The Royal (Dick) School of Veterinary Studies, The University of Edinburgh, Midlothian, UK
| | - Adam P A Cardilini
- School of Life and Environmental Sciences, Deakin University, Waurn Ponds, Victoria, Australia
| | - Phillip Cassey
- Invasion Science & Wildlife Ecology Lab, University of Adelaide, Adelaide, South Australia, Australia
| | - Tim De Meyer
- Department of Data Analysis and Mathematical Modelling, Ghent University, Ghent, Belgium
| | - Julia George
- Department of Biological Sciences, Clemson University, Clemson, South Carolina, USA
| | - Simone L Meddle
- The Roslin Institute, The Royal (Dick) School of Veterinary Studies, The University of Edinburgh, Midlothian, UK
| | - Hannah M Rowland
- Max Planck Institute for Chemical Ecology, Jena, Germany
- Department of Zoology, University of Cambridge, Cambridge, UK
| | - Craig D H Sherman
- The Roslin Institute, The Royal (Dick) School of Veterinary Studies, The University of Edinburgh, Midlothian, UK
| | - William B Sherwin
- School of Biological, Earth and Environmental Sciences, Evolution & Ecology Research Centre, UNSW Sydney, Sydney, New South Wales, Australia
| | - Wim Vanden Berghe
- Department of Biomedical Sciences, University Antwerp, Antwerp, Belgium
| | - Lee Ann Rollins
- School of Biological, Earth and Environmental Sciences, Evolution & Ecology Research Centre, UNSW Sydney, Sydney, New South Wales, Australia
| | - David F Clayton
- Department of Genetics & Biochemistry, Clemson University, Clemson, South Carolina, USA
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4
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Protti-Sánchez F, Mayer U, Rowland HM. In paired preference tests, domestic chicks innately choose the colour green over red, and the shape of a frog over a sphere when both stimuli are green. Anim Cogn 2023; 26:1973-1983. [PMID: 37610527 PMCID: PMC10769926 DOI: 10.1007/s10071-023-01821-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 07/21/2023] [Accepted: 08/15/2023] [Indexed: 08/24/2023]
Abstract
Many animals express unlearned colour preferences that depend on the context in which signals are encountered. These colour biases may have evolved in response to the signalling system to which they relate. For example, many aposematic animals advertise their unprofitability with red warning signals. Predators' innate biases against these warning colours have been suggested as one of the potential explanations for the initial evolution of aposematism. It is unclear, however, whether unlearned colour preferences reported in a number of species is truly an innate behaviour or whether it is based on prior experience. We tested the spontaneous colour and shape preferences of dark-hatched, unfed, and visually naive domestic chicks (Gallus gallus). In four experiments, we presented chicks with a choice between either red (a colour typically associated with warning patterns) or green (a colour associated with palatable cryptic prey), volume-matched spheres (representing a generalised fruit shape) or frogs (representing an aposematic animal's shape). Chicks innately preferred green stimuli and avoided red. Chicks also preferred the shape of a frog over a sphere when both stimuli were green. However, no preference for frogs over spheres was present when stimuli were red. Male chicks that experienced a bitter taste of quinine immediately before the preference test showed a higher preference for green frog-shaped stimuli. Our results suggest that newly hatched chicks innately integrate colour and shape cues during decision making, and that this can be augmented by other sensory experiences. Innate and experience-based behaviour could confer a fitness advantage to novel aposematic prey, and favour the initial evolution of conspicuous colouration.
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Affiliation(s)
- Francesca Protti-Sánchez
- Max Planck Research Group Predators and Toxic Prey, Max Planck Institute for Chemical Ecology, Hans Knöll Straße 8, 07745, Jena, Germany.
| | - Uwe Mayer
- Center for Mind/Brain Sciences (CIMeC), University of Trento, Piazza Manifattura 1, 38068, Rovereto, TN, Italy
| | - Hannah M Rowland
- Max Planck Research Group Predators and Toxic Prey, Max Planck Institute for Chemical Ecology, Hans Knöll Straße 8, 07745, Jena, Germany
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5
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Varma M, Winter G, Rowland HM, Schielzeth H. Ontogeny of color development in two green-brown polymorphic grasshopper species. Ecol Evol 2023; 13:e10712. [PMID: 37928193 PMCID: PMC10620580 DOI: 10.1002/ece3.10712] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 10/17/2023] [Accepted: 10/23/2023] [Indexed: 11/07/2023] Open
Abstract
Many insects, including several orthopterans, undergo dramatic changes in body coloration during ontogeny. This variation is particularly intriguing in gomphocerine grasshoppers, where the green and brown morphs appear to be genetically determined (Schielzeth & Dieker, 2020, BMC Evolutionary Biology, 20, 63; Winter et al., 2021, Heredity, 127, 66). A better understanding of how these color morphs develop during ontogeny can provide valuable insights into the evolution and ecology of such a widespread color polymorphism. Here, we focus on the color development of two green-brown polymorphic species, the club-legged grasshopper Gomphocerus sibiricus and the steppe grasshopper Chorthippus dorsatus. By following the color development of individuals from hatching to adulthood, we found that color morph differences begin to develop during the second nymphal stage, are clearly defined by the third nymphal stage, and remain stable throughout the life of an individual. Interestingly, we also observed that shed skins of late nymphal stages are identifiable by color morphs based on their yellowish coloration, rather than the green that marks green body parts. Furthermore, by assessing how these colors are perceived by different visual systems, we found that certain potential predators can chromatically discriminate between morphs, while others may not. These results suggest that the putative genes controlling color morph are active during the early stages of ontogeny, and that green color is likely composed of two components, one present in the cuticle and one not. In addition, the effectiveness of camouflage appears to vary depending on the specific predator involved.
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Affiliation(s)
- Mahendra Varma
- Population Ecology Group, Institute of Ecology and Evolution Friedrich Schiller University Jena Jena Germany
- Max Planck Institute for Chemical Ecology Jena Germany
| | - Gabe Winter
- Population Ecology Group, Institute of Ecology and Evolution Friedrich Schiller University Jena Jena Germany
| | | | - Holger Schielzeth
- Population Ecology Group, Institute of Ecology and Evolution Friedrich Schiller University Jena Jena Germany
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6
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Kikuchi DW, Allen WL, Arbuckle K, Aubier TG, Briolat ES, Burdfield-Steel ER, Cheney KL, Daňková K, Elias M, Hämäläinen L, Herberstein ME, Hossie TJ, Joron M, Kunte K, Leavell BC, Lindstedt C, Lorioux-Chevalier U, McClure M, McLellan CF, Medina I, Nawge V, Páez E, Pal A, Pekár S, Penacchio O, Raška J, Reader T, Rojas B, Rönkä KH, Rößler DC, Rowe C, Rowland HM, Roy A, Schaal KA, Sherratt TN, Skelhorn J, Smart HR, Stankowich T, Stefan AM, Summers K, Taylor CH, Thorogood R, Umbers K, Winters AE, Yeager J, Exnerová A. The evolution and ecology of multiple antipredator defences. J Evol Biol 2023; 36:975-991. [PMID: 37363877 DOI: 10.1111/jeb.14192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 05/03/2023] [Accepted: 05/07/2023] [Indexed: 06/28/2023]
Abstract
Prey seldom rely on a single type of antipredator defence, often using multiple defences to avoid predation. In many cases, selection in different contexts may favour the evolution of multiple defences in a prey. However, a prey may use multiple defences to protect itself during a single predator encounter. Such "defence portfolios" that defend prey against a single instance of predation are distributed across and within successive stages of the predation sequence (encounter, detection, identification, approach (attack), subjugation and consumption). We contend that at present, our understanding of defence portfolio evolution is incomplete, and seen from the fragmentary perspective of specific sensory systems (e.g., visual) or specific types of defences (especially aposematism). In this review, we aim to build a comprehensive framework for conceptualizing the evolution of multiple prey defences, beginning with hypotheses for the evolution of multiple defences in general, and defence portfolios in particular. We then examine idealized models of resource trade-offs and functional interactions between traits, along with evidence supporting them. We find that defence portfolios are constrained by resource allocation to other aspects of life history, as well as functional incompatibilities between different defences. We also find that selection is likely to favour combinations of defences that have synergistic effects on predator behaviour and prey survival. Next, we examine specific aspects of prey ecology, genetics and development, and predator cognition that modify the predictions of current hypotheses or introduce competing hypotheses. We outline schema for gathering data on the distribution of prey defences across species and geography, determining how multiple defences are produced, and testing the proximate mechanisms by which multiple prey defences impact predator behaviour. Adopting these approaches will strengthen our understanding of multiple defensive strategies.
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Affiliation(s)
- David W Kikuchi
- Department of Integrative Biology, Oregon State University, Corvallis, Oregon, USA
- Evolutionary Biology, Universität Bielefeld, Bielefeld, Germany
| | | | - Kevin Arbuckle
- Department of Biosciences, Swansea University, Swansea, UK
| | - Thomas G Aubier
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
- Laboratoire Évolution & Diversité Biologique, Université Paul Sabatier Toulouse III, UMR 5174, CNRS/IRD, Toulouse, France
| | | | - Emily R Burdfield-Steel
- Institute of Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, The Netherlands
| | - Karen L Cheney
- School of Biological Sciences, The University of Queensland, St Lucia, Queensland, Australia
| | - Klára Daňková
- Department of Zoology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Marianne Elias
- Institut de Systématique, Evolution, Biodiversité, CNRS, MNHN, Sorbonne Université, EPHE, Université des Antilles, Paris, France
- Smithsonian Tropical Research Institute, Gamboa, Panama
| | - Liisa Hämäläinen
- School of Natural Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Marie E Herberstein
- School of Natural Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Thomas J Hossie
- Department of Biology, Trent University, Peterborough, Ontario, Canada
| | - Mathieu Joron
- CEFE, Université de Montpellier, CNRS, EPHE, IRD, Montpellier, France
| | - Krushnamegh Kunte
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bengaluru, India
| | - Brian C Leavell
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana, USA
| | - Carita Lindstedt
- Department of Forest Sciences, University of Helsinki, Helsinki, Finland
| | - Ugo Lorioux-Chevalier
- Laboratoire Écologie, Évolution, Interactions des Systèmes Amazoniens (LEEISA), Université de Guyane, CNRS, IFREMER, Cayenne, France
| | - Melanie McClure
- Laboratoire Écologie, Évolution, Interactions des Systèmes Amazoniens (LEEISA), Université de Guyane, CNRS, IFREMER, Cayenne, France
| | | | - Iliana Medina
- School of BioSciences, University of Melbourne, Melbourne, Victoria, Australia
| | - Viraj Nawge
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bengaluru, India
| | - Erika Páez
- Institut de Systématique, Evolution, Biodiversité, CNRS, MNHN, Sorbonne Université, EPHE, Université des Antilles, Paris, France
| | - Arka Pal
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bengaluru, India
| | - Stano Pekár
- Department of Botany and Zoology, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Olivier Penacchio
- School of Psychology and Neuroscience, University of St Andrews, St Andrews, UK
- Computer Vision Center, Computer Science Department, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Jan Raška
- Department of Zoology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Tom Reader
- School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Bibiana Rojas
- Department of Interdisciplinary Life Sciences, Konrad Lorenz Institute of Ethology, University of Veterinary Medicine, Vienna, Austria
- Department of Biology and Environmental Science, University of Jyväskylä, Jyväskylä, Finland
| | - Katja H Rönkä
- HiLIFE Helsinki Institute of Life Sciences, University of Helsinki, Helsinki, Finland
- Research Programme in Organismal & Evolutionary Biology, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - Daniela C Rößler
- Zukunftskolleg, University of Konstanz, Konstanz, Germany
- Department of Collective Behavior, Max Planck Institute of Animal Behavior, Konstanz, Germany
| | - Candy Rowe
- Institute of Biosciences, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - Hannah M Rowland
- Max Planck Research Group Predators and Toxic Prey, Max Planck Institute for Chemical Ecology, Jena, Germany
| | - Arlety Roy
- Laboratoire Écologie, Évolution, Interactions des Systèmes Amazoniens (LEEISA), Université de Guyane, CNRS, IFREMER, Cayenne, France
| | - Kaitlin A Schaal
- Institute of Integrative Biology, ETH Zurich, Zurich, Switzerland
| | | | - John Skelhorn
- Institute of Biosciences, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - Hannah R Smart
- Hawkesbury Institute of the Environment, Western Sydney University, Penrith, New South Wales, Australia
| | - Ted Stankowich
- Department of Biological Sciences, California State University, Long Beach, California, USA
| | - Amanda M Stefan
- Department of Biology, Carleton University, Ottawa, Ontario, Canada
| | - Kyle Summers
- Department of Biology, East Carolina University, Greenville, North Carolina, USA
| | | | - Rose Thorogood
- HiLIFE Helsinki Institute of Life Sciences, University of Helsinki, Helsinki, Finland
- Research Programme in Organismal & Evolutionary Biology, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - Kate Umbers
- Hawkesbury Institute of the Environment, Western Sydney University, Penrith, New South Wales, Australia
- School of Science Western Sydney University, Penrith, New South Wales, Australia
| | - Anne E Winters
- Centre for Ecology and Conservation, University of Exeter, Penryn, UK
| | - Justin Yeager
- Grupo de Biodiversidad Medio Ambiente y Salud, Universidad de Las Américas, Quito, Ecuador
| | - Alice Exnerová
- Department of Zoology, Faculty of Science, Charles University, Prague, Czech Republic
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7
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Exnerová A, Kang C, Rowland HM, Kikuchi DW. Evolution of multiple prey defences: From predator cognition to community ecology. J Evol Biol 2023; 36:961-966. [PMID: 37449469 DOI: 10.1111/jeb.14196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Accepted: 06/07/2023] [Indexed: 07/18/2023]
Affiliation(s)
- Alice Exnerová
- Department of Zoology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Changku Kang
- Department of Agricultural Biotechnology, Seoul National University, Seoul, South Korea
- Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, South Korea
| | - Hannah M Rowland
- Max Planck Research Group Predators and Toxic Prey, Max Planck Institute for Chemical Ecology, Jena, Germany
| | - David W Kikuchi
- Department of Integrative Biology, Oregon State University, Corvallis, Oregon, USA
- Evolutionary Biology, Universität Bielefeld, Bielefeld, Germany
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8
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Heyworth HC, Pokharel P, Blount JD, Mitchell C, Petschenka G, Rowland HM. Antioxidant availability trades off with warning signals and toxin sequestration in the large milkweed bug ( Oncopeltus fasciatus). Ecol Evol 2023; 13:e9971. [PMID: 37038513 PMCID: PMC10082154 DOI: 10.1002/ece3.9971] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 03/13/2023] [Accepted: 03/17/2023] [Indexed: 04/12/2023] Open
Abstract
In some aposematic species the conspicuousness of an individual's warning signal and the concentration of its chemical defense are positively correlated. Several mechanisms have been proposed to explain this phenomenon, including resource allocation trade-offs where the same limiting resource is needed to produce both the warning signal and chemical defense. Here, the large milkweed bug (Oncopeltus fasciatus: Heteroptera, Lygaeinae) was used to test whether allocation of antioxidants, that can impart color, trade against their availability to prevent self-damage caused by toxin sequestration. We investigated if (i) the sequestration of cardenolides is associated with costs in the form of changes in oxidative state; and (ii) oxidative state can affect the capacity of individuals to produce warning signals. We reared milkweed bugs on artificial diets with increasing quantities of cardenolides and examined how this affected signal quality (brightness and chroma) across different instars. We then related the expression of warning colors to the quantity of sequestered cardenolides and indicators of oxidative state-oxidative lipid damage (malondialdehyde), and two antioxidants: total superoxide dismutase and total glutathione. Bugs that sequestered more cardenolides had significantly lower levels of the antioxidant glutathione, and bugs with less total glutathione had less luminant orange warning signals and reduced chroma of their black patches compared to bugs with more glutathione. Bugs that sequestered more cardenolides also had reduced red-green chroma of their black patches that was unrelated to oxidative state. Our results give tentative support for a physiological cost of sequestration in milkweed bugs and a mechanistic link between antioxidant availability, sequestration, and warning signals.
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Affiliation(s)
- H. Cecilia Heyworth
- Predators and Toxic Prey Research GroupMax Planck Institute for Chemical EcologyJenaGermany
- Centre for Ecology and Conservation, College of Life and Environmental SciencesUniversity of ExeterExeterUK
| | - Prayan Pokharel
- Department of Applied Entomology, Institute of PhytomedicineUniversity of HohenheimStuttgartGermany
| | - Jonathan D. Blount
- Centre for Ecology and Conservation, College of Life and Environmental SciencesUniversity of ExeterExeterUK
| | - Christopher Mitchell
- Centre for Ecology and Conservation, College of Life and Environmental SciencesUniversity of ExeterExeterUK
| | - Georg Petschenka
- Department of Applied Entomology, Institute of PhytomedicineUniversity of HohenheimStuttgartGermany
| | - Hannah M. Rowland
- Predators and Toxic Prey Research GroupMax Planck Institute for Chemical EcologyJenaGermany
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9
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Blount JD, Rowland HM, Mitchell C, Speed MP, Ruxton GD, Endler JA, Brower LP. The price of defence: toxins, visual signals and oxidative state in an aposematic butterfly. Proc Biol Sci 2023; 290:20222068. [PMID: 36651049 PMCID: PMC9845971 DOI: 10.1098/rspb.2022.2068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
In a variety of aposematic species, the conspicuousness of an individual's warning signal and the quantity of its chemical defence are positively correlated. This apparent honest signalling is predicted by resource competition models which assume that the production and maintenance of aposematic defences compete for access to antioxidant molecules that have dual functions as pigments and in protecting against oxidative damage. To test for such trade-offs, we raised monarch butterflies (Danaus plexippus) on different species of their milkweed host plants (Apocynaceae) that vary in quantities of cardenolides to test whether (i) the sequestration of cardenolides as a secondary defence is associated with costs in the form of oxidative lipid damage and reduced antioxidant defences; and (ii) lower oxidative state is associated with a reduced capacity to produce aposematic displays. In male monarchs conspicuousness was explained by an interaction between oxidative damage and sequestration: males with high levels of oxidative damage became less conspicuous with increased sequestration of cardenolides, whereas those with low oxidative damage became more conspicuous with increased levels of cardenolides. There was no significant effect of oxidative damage or concentration of sequestered cardenolides on female conspicuousness. Our results demonstrate a physiological linkage between the production of coloration and oxidative state, and differential costs of sequestration and signalling in monarch butterflies.
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Affiliation(s)
- Jonathan D. Blount
- Centre for Ecology and Conservation, College of Life and Environmental Sciences, University of Exeter, Penryn Campus, Cornwall TR10 9FE, UK
| | - Hannah M. Rowland
- Research Group Predators and Toxic Prey, Max Planck Institute for Chemical Ecology, Hans-Knöll-Straße 8, Jena, 07745, Germany
| | - Christopher Mitchell
- Centre for Ecology and Conservation, College of Life and Environmental Sciences, University of Exeter, Penryn Campus, Cornwall TR10 9FE, UK
| | - Michael P. Speed
- Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool L69 7BE, UK
| | - Graeme D. Ruxton
- School of Biology, Sir Harold Mitchell Building, Greenside Place, St Andrews, UK
| | - John A. Endler
- Centre for Integrative Ecology, School of Life and Environmental Sciences, Deakin University, Waurn Ponds, Victoria 3216, Australia
| | - Lincoln P. Brower
- Department of Biology, Sweet Briar College, Sweet Briar, VA 24595, USA
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10
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Rubiano-Buitrago P, Pradhan S, Paetz C, Rowland HM. New Structures, Spectrometric Quantification, and Inhibitory Properties of Cardenolides from Asclepias curassavica Seeds. Molecules 2022; 28:molecules28010105. [PMID: 36615300 PMCID: PMC9822358 DOI: 10.3390/molecules28010105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 12/14/2022] [Accepted: 12/20/2022] [Indexed: 12/25/2022] Open
Abstract
Cardiac glycosides are a large class of secondary metabolites found in plants. In the genus Asclepias, cardenolides in milkweed plants have an established role in plant-herbivore and predator-prey interactions, based on their ability to inhibit the membrane-bound Na+/K+-ATPase enzyme. Milkweed seeds are eaten by specialist lygaeid bugs, which are the most cardenolide-tolerant insects known. These insects likely impose natural selection for the repeated derivatisation of cardenolides. A first step in investigating this hypothesis is to conduct a phytochemical profiling of the cardenolides in the seeds. Here, we report the concentrations of 10 purified cardenolides from the seeds of Asclepias curassavica. We report the structures of new compounds: 3-O-β-allopyranosyl coroglaucigenin (1), 3-[4'-O-β-glucopyranosyl-β-allopyranosyl] coroglaucigenin (2), 3'-O-β-glucopyranosyl-15-β-hydroxycalotropin (3), and 3-O-β-glucopyranosyl-12-β-hydroxyl coroglaucigenin (4), as well as six previously reported cardenolides (5-10). We test the in vitro inhibition of these compounds on the sensitive porcine Na+/K+-ATPase. The least inhibitory compound was also the most abundant in the seeds-4'-O-β-glucopyranosyl frugoside (5). Gofruside (9) was the most inhibitory. We found no direct correlation between the number of glycosides/sugar moieties in a cardenolide and its inhibitory effect. Our results enhance the literature on cardenolide diversity and concentration among tissues eaten by insects and provide an opportunity to uncover potential evolutionary relationships between tissue-specific defense expression and insect adaptations in plant-herbivore interactions.
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Affiliation(s)
- Paola Rubiano-Buitrago
- Research Group Predators and Toxic Prey, Max Planck Institute for Chemical Ecology, Hans Knöll Straße 8, 07745 Jena, Germany
- Research Group Biosynthesis/NMR, Max Planck Institute for Chemical Ecology, Hans Knöll Straße 8, 07745 Jena, Germany
- Correspondence: (P.R.-B.); (H.M.R.)
| | - Shrikant Pradhan
- Research Group Predators and Toxic Prey, Max Planck Institute for Chemical Ecology, Hans Knöll Straße 8, 07745 Jena, Germany
| | - Christian Paetz
- Research Group Biosynthesis/NMR, Max Planck Institute for Chemical Ecology, Hans Knöll Straße 8, 07745 Jena, Germany
| | - Hannah M. Rowland
- Research Group Predators and Toxic Prey, Max Planck Institute for Chemical Ecology, Hans Knöll Straße 8, 07745 Jena, Germany
- Correspondence: (P.R.-B.); (H.M.R.)
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11
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Mohammadi S, Özdemir Hİ, Ozbek P, Sumbul F, Stiller J, Deng Y, Crawford AJ, Rowland HM, Storz JF, Andolfatto P, Dobler S. Epistatic Effects Between Amino Acid Insertions and Substitutions Mediate Toxin resistance of Vertebrate Na+,K+-ATPases. Mol Biol Evol 2022; 39:6874786. [PMID: 36472530 PMCID: PMC9778839 DOI: 10.1093/molbev/msac258] [Citation(s) in RCA: 4] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 11/10/2022] [Accepted: 11/14/2022] [Indexed: 12/13/2022] Open
Abstract
The recurrent evolution of resistance to cardiotonic steroids (CTS) across diverse animals most frequently involves convergent amino acid substitutions in the H1-H2 extracellular loop of Na+,K+-ATPase (NKA). Previous work revealed that hystricognath rodents (e.g., chinchilla) and pterocliform birds (sandgrouse) have convergently evolved amino acid insertions in the H1-H2 loop, but their functional significance was not known. Using protein engineering, we show that these insertions have distinct effects on CTS resistance in homologs of each of the two species that strongly depend on intramolecular interactions with other residues. Removing the insertion in the chinchilla NKA unexpectedly increases CTS resistance and decreases NKA activity. In the sandgrouse NKA, the amino acid insertion and substitution Q111R both contribute to an augmented CTS resistance without compromising ATPase activity levels. Molecular docking simulations provide additional insight into the biophysical mechanisms responsible for the context-specific mutational effects on CTS insensitivity of the enzyme. Our results highlight the diversity of genetic substrates that underlie CTS insensitivity in vertebrate NKA and reveal how amino acid insertions can alter the phenotypic effects of point mutations at key sites in the same protein domain.
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Affiliation(s)
- Shabnam Mohammadi
- Molecular Evolutionary Biology, Institute of Cell and Systems Biology of Animals, Universität Hamburg, Hamburg 20146, Germany.,Max Planck Institute for Chemical Ecology, Research Group Predators and Toxic Prey, Jena 07745, Germany
| | | | - Pemra Ozbek
- Department of Bioengineering, Marmara University, Göztepe, İstanbul 34722, Turkey
| | - Fidan Sumbul
- INSERM, Aix-Marseille Université, Inserm, CNRS, Marseille 13009, France
| | - Josefin Stiller
- Villum Centre for Biodiversity Genomics, University of Copenhagen, Copenhagen 2100, Denmark
| | - Yuan Deng
- Villum Centre for Biodiversity Genomics, University of Copenhagen, Copenhagen 2100, Denmark.,BGI-Shenzhen, Shenzhen 518083, China
| | - Andrew J Crawford
- Department of Biological Sciences, Universidad de los Andes, Bogotá, Colombia
| | - Hannah M Rowland
- Max Planck Institute for Chemical Ecology, Research Group Predators and Toxic Prey, Jena 07745, Germany
| | - Jay F Storz
- School of Biological Sciences, University of Nebraska, Lincoln, NE
| | - Peter Andolfatto
- Department of Biological Sciences, Columbia University, New York, NY
| | - Susanne Dobler
- Molecular Evolutionary Biology, Institute of Cell and Systems Biology of Animals, Universität Hamburg, Hamburg 20146, Germany
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12
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Skelhorn J, Rowland HM. Eyespot configuration and predator approach direction affect the antipredator efficacy of eyespots. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.951967] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Many prey species possess eyespots: paired markings that often consist of two or more concentric circles. Predators are wary of such prey because eyespots are conspicuous and/or mistaken for vertebrate eyes. Here we used naïve domestic chicks as predators of artificial moth-like prey to test the hypothesis that both eyespots configuration and predator approach direction affect the antipredator efficacy of eyespots. We found that when chicks approached prey straight on, eyespots configuration did not influence attack latency. Chicks that approached from either the left or the right, were slower to attack prey in which the central circle of the eyespot was centrally placed or shifted in the direction of the chick’s approach, compared to prey in which the central circle had been shifted away from the direction of approach. These findings suggest that eyespots composed of concentric circles may protect prey against predators approaching from a wider range of directions than eyespots composed of eccentric circles. They are also consistent with the idea that eyespots are mistaken for eyes, and are perceived to pose a lesser risk when their “gaze” is averted from the approaching predator.
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13
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Mohammadi S, Yang L, Bulbert M, Rowland HM. Defence mitigation by predators of chemically defended prey integrated over the predation sequence and across biological levels with a focus on cardiotonic steroids. R Soc Open Sci 2022; 9:220363. [PMID: 36133149 PMCID: PMC9449480 DOI: 10.1098/rsos.220363] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Accepted: 08/17/2022] [Indexed: 05/10/2023]
Abstract
Predator-prey interactions have long served as models for the investigation of adaptation and fitness in natural environments. Anti-predator defences such as mimicry and camouflage provide some of the best examples of evolution. Predators, in turn, have evolved sensory systems, cognitive abilities and physiological resistance to prey defences. In contrast to prey defences which have been reviewed extensively, the evolution of predator counter-strategies has received less attention. To gain a comprehensive view of how prey defences can influence the evolution of predator counter-strategies, it is essential to investigate how and when selection can operate. In this review we evaluate how predators overcome prey defences during (i) encounter, (ii) detection, (iii) identification, (iv) approach, (v) subjugation, and (vi) consumption. We focus on prey that are protected by cardiotonic steroids (CTS)-defensive compounds that are found in a wide range of taxa, and that have a specific physiological target. In this system, coevolution is well characterized between specialist insect herbivores and their host plants but evidence for coevolution between CTS-defended prey and their predators has received less attention. Using the predation sequence framework, we organize 574 studies reporting predators overcoming CTS defences, integrate these counter-strategies across biological levels of organization, and discuss the costs and benefits of attacking CTS-defended prey. We show that distinct lineages of predators have evolved dissecting behaviour, changes in perception of risk and of taste perception, and target-site insensitivity. We draw attention to biochemical, hormonal and microbiological strategies that have yet to be investigated as predator counter-adaptations to CTS defences. We show that the predation sequence framework will be useful for organizing future studies of chemically mediated systems and coevolution.
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Affiliation(s)
- Shabnam Mohammadi
- School of Biological Sciences, University of Nebraska, Lincoln, NE, USA
- Institut für Zell- und Systembiologie der Tiere, Universität Hamburg, Hamburg, Germany
- Max Planck Institute for Chemical Ecology, Jena, Germany
| | - Lu Yang
- Wellcome Sanger Institute, Cambridge, UK
| | - Matthew Bulbert
- Department of Biological Sciences, Macquarie University North Ryde, New South Wales, Australia
- Department of Biological and Medical Sciences, Faculty of Health and Life Sciences, University of Oxford Brookes, Oxford, UK
- Max Planck Institute for Chemical Ecology, Jena, Germany
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14
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Mohammadi S, Yang L, Bulbert M, Rowland HM. Defence mitigation by predators of chemically defended prey integrated over the predation sequence and across biological levels with a focus on cardiotonic steroids. R Soc Open Sci 2022; 9:220363. [PMID: 36133149 DOI: 10.6084/m9.figshare.c.6168216] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Accepted: 08/17/2022] [Indexed: 05/25/2023]
Abstract
Predator-prey interactions have long served as models for the investigation of adaptation and fitness in natural environments. Anti-predator defences such as mimicry and camouflage provide some of the best examples of evolution. Predators, in turn, have evolved sensory systems, cognitive abilities and physiological resistance to prey defences. In contrast to prey defences which have been reviewed extensively, the evolution of predator counter-strategies has received less attention. To gain a comprehensive view of how prey defences can influence the evolution of predator counter-strategies, it is essential to investigate how and when selection can operate. In this review we evaluate how predators overcome prey defences during (i) encounter, (ii) detection, (iii) identification, (iv) approach, (v) subjugation, and (vi) consumption. We focus on prey that are protected by cardiotonic steroids (CTS)-defensive compounds that are found in a wide range of taxa, and that have a specific physiological target. In this system, coevolution is well characterized between specialist insect herbivores and their host plants but evidence for coevolution between CTS-defended prey and their predators has received less attention. Using the predation sequence framework, we organize 574 studies reporting predators overcoming CTS defences, integrate these counter-strategies across biological levels of organization, and discuss the costs and benefits of attacking CTS-defended prey. We show that distinct lineages of predators have evolved dissecting behaviour, changes in perception of risk and of taste perception, and target-site insensitivity. We draw attention to biochemical, hormonal and microbiological strategies that have yet to be investigated as predator counter-adaptations to CTS defences. We show that the predation sequence framework will be useful for organizing future studies of chemically mediated systems and coevolution.
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Affiliation(s)
- Shabnam Mohammadi
- School of Biological Sciences, University of Nebraska, Lincoln, NE, USA
- Institut für Zell- und Systembiologie der Tiere, Universität Hamburg, Hamburg, Germany
- Max Planck Institute for Chemical Ecology, Jena, Germany
| | - Lu Yang
- Wellcome Sanger Institute, Cambridge, UK
| | - Matthew Bulbert
- Department of Biological Sciences, Macquarie University North Ryde, New South Wales, Australia
- Department of Biological and Medical Sciences, Faculty of Health and Life Sciences, University of Oxford Brookes, Oxford, UK
- Max Planck Institute for Chemical Ecology, Jena, Germany
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15
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Binns GE, Hämäläinen L, Kemp DJ, Rowland HM, Umbers KDL, Herberstein ME. Additive genetic variation, but not temperature, influences warning signal expression in Amata nigriceps moths (Lepidoptera: Arctiinae). Ecol Evol 2022; 12:e9111. [PMID: 35866015 PMCID: PMC9288930 DOI: 10.1002/ece3.9111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [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: 06/17/2022] [Accepted: 06/23/2022] [Indexed: 11/18/2022] Open
Abstract
Many aposematic species show variation in their color patterns even though selection by predators is expected to stabilize warning signals toward a common phenotype. Warning signal variability can be explained by trade‐offs with other functions of coloration, such as thermoregulation, that may constrain warning signal expression by favoring darker individuals. Here, we investigated the effect of temperature on warning signal expression in aposematic Amata nigriceps moths that vary in their black and orange wing patterns. We sampled moths from two flight seasons that differed in the environmental temperatures and also reared different families under controlled conditions at three different temperatures. Against our prediction that lower developmental temperatures would reduce the warning signal size of the adult moths, we found no effect of temperature on warning signal expression in either wild or laboratory‐reared moths. Instead, we found sex‐ and population‐level differences in wing patterns. Our rearing experiment indicated that ~70% of the variability in the trait is genetic but understanding what signaling and non‐signaling functions of wing coloration maintain the genetic variation requires further work. Our results emphasize the importance of considering both genetic and plastic components of warning signal expression when studying intraspecific variation in aposematic species.
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Affiliation(s)
- Georgina E Binns
- School of Natural Sciences, 14 Eastern Road Macquarie University North Ryde New South Wales Australia
| | - Liisa Hämäläinen
- School of Natural Sciences, 14 Eastern Road Macquarie University North Ryde New South Wales Australia
| | - Darrell J Kemp
- School of Natural Sciences, 14 Eastern Road Macquarie University North Ryde New South Wales Australia
| | - Hannah M Rowland
- Max Planck Institute for Chemical Ecology Hans Knöll Straße 8,Jena Germany
| | - Kate D L Umbers
- School of Science Western Sydney University Penrith New South Wales Australia.,Hawkesbury Institute for the Environment Western Sydney University Penrith New South Wales Australia
| | - Marie E Herberstein
- School of Natural Sciences, 14 Eastern Road Macquarie University North Ryde New South Wales Australia
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16
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Protti-Sánchez F, Corrales Parada CD, Mayer U, Rowland HM. Activation of the Nucleus Taeniae of the Amygdala by Umami Taste in Domestic Chicks (Gallus gallus). Front Physiol 2022; 13:897931. [PMID: 35694389 PMCID: PMC9178096 DOI: 10.3389/fphys.2022.897931] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Accepted: 04/11/2022] [Indexed: 11/13/2022] Open
Abstract
In chickens, the sense of taste plays an important role in detecting nutrients and choosing feed. The molecular mechanisms underlying the taste-sensing system of chickens are well studied, but the neural mechanisms underlying taste reactivity have received less attention. Here we report the short-term taste behaviour of chickens towards umami and bitter (quinine) taste solutions and the associated neural activity in the nucleus taeniae of the amygdala, nucleus accumbens and lateral septum. We found that chickens had more contact with and drank greater volumes of umami than bitter or a water control, and that chicks displayed increased head shaking in response to bitter compared to the other tastes. We found that there was a higher neural activity, measured as c-Fos activation, in response to umami taste in the right hemisphere of the nucleus taeniae of the amygdala. In the left hemisphere, there was a higher c-Fos activation of the nucleus taeniae of the amygdala in response to bitter than in the right hemisphere. Our findings provide clear evidence that chickens respond differently to umami and bitter tastes, that there is a lateralised response to tastes at the neural level, and reveals a new function of the avian nucleus taeniae of the amygdala as a region processing reward information.
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Affiliation(s)
- Francesca Protti-Sánchez
- Max Planck Institute for Chemical Ecology, Jena, Germany
- *Correspondence: Francesca Protti-Sánchez,
| | | | - Uwe Mayer
- Center for Mind/Brain Sciences (CIMeC), University of Trento, Rovereto, Italy
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17
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Rowland HM, Saccheri IJ, Skelhorn J. The peppered moth Biston betularia. Curr Biol 2022; 32:R447-R448. [DOI: 10.1016/j.cub.2022.03.071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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18
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Heinze P, Dieker P, Rowland HM, Schielzeth H. Evidence for morph-specific substrate choice in a green-brown polymorphic grasshopper. Behav Ecol 2021; 33:17-26. [PMID: 35197804 PMCID: PMC8857936 DOI: 10.1093/beheco/arab133] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 08/11/2021] [Accepted: 11/02/2021] [Indexed: 11/14/2022] Open
Abstract
Abstract
Orthopteran insects are characterized by high variability in body coloration, in particular featuring a widespread green-brown color polymorphism. The mechanisms that contribute to the maintenance of this apparently balanced polymorphism are not yet understood. To investigate whether morph-dependent microhabitat choice might contribute to the continued coexistence of multiple morphs, we studied substrate choice in the meadow grasshopper Pseudochorthippus parallelus. The meadow grasshopper occurs in multiple discrete, genetically determined color morphs that range from uniform brown to uniform green. We tested whether three common morphs preferentially choose differently colored backgrounds in an experimental arena. We found that a preference for green backgrounds was most pronounced in uniform green morphs. If differential choices improve morph-specific performance in natural habitats via crypsis and/or thermoregulatory benefits, they could help to equalize fitness differences among color morphs and potentially produce frequency-dependent microhabitat competition, though difference appear too small to serve as the only explanation. We also measured the reflectance of the grasshoppers and backgrounds and used visual modeling to quantify the detectability of the different morphs to a range of potential predators. Multiple potential predators, including birds and spiders, are predicted to distinguish between morphs chromatically, while other species, possibly including grasshoppers themselves, will perceive only differences in brightness. Our study provides the first evidence that morph-specific microhabitat choice might be relevant to the maintenance of the green-brown polymorphisms in grasshoppers and shows that visual distinctness of color morphs varies between perceivers.
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Affiliation(s)
- Pauline Heinze
- Population Ecology Group, Institute of Ecology and Evolution, Friedrich Schiller University Jena, Dornburger Straße, Jena, Germany
| | - Petra Dieker
- Population Ecology Group, Institute of Ecology and Evolution, Friedrich Schiller University Jena, Dornburger Straße, Jena, Germany
| | - Hannah M Rowland
- Research Group Predators and Toxic Prey, Max Planck Institute for Chemical Ecology, Hans-Knöll-Straße, Jena, Germany
| | - Holger Schielzeth
- Population Ecology Group, Institute of Ecology and Evolution, Friedrich Schiller University Jena, Dornburger Straße, Jena, Germany
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19
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Affiliation(s)
| | - Hannah M. Rowland
- Max Planck Inst. for Chemical Ecology Jena Germany
- Dept of Zoology, Univ. of Cambridge Cambridge UK
| | - Johanna Mappes
- Research Programme in Organismal&Evolutionary Biology, Faculty of Biological and Environmental Sciences, Univ. of Helsinki Helsinki Finland
- Dept of Biological and Environmental Sciences, Univ. of Jyväskylä Jyväskylä Finland
| | - Rose Thorogood
- Research Programme in Organismal&Evolutionary Biology, Faculty of Biological and Environmental Sciences, Univ. of Helsinki Helsinki Finland
- HiLIFE Helsinki Inst. of Life Science, Univ. of Helsinki Helsinki Finland
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20
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Heyworth HC, Skelhorn J, Rowland HM. Dietary wariness. Curr Biol 2021; 31:R1412-R1414. [PMID: 34752762 DOI: 10.1016/j.cub.2021.09.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
What causes an animal to resist trying new food or incorporating it into their diet? In this Quick guide, Heyworth et al. discuss the phenomenon known as dietary wariness.
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Affiliation(s)
- H Cecilia Heyworth
- Max Planck Institute for Chemical Ecology, Jena 07745, Germany; College of Life and Environmental Sciences, University of Exeter, Penryn TR10 9FE, UK.
| | - John Skelhorn
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
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21
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Hämäläinen L, Hoppitt W, Rowland HM, Mappes J, Fulford AJ, Sosa S, Thorogood R. Social transmission in the wild can reduce predation pressure on novel prey signals. Nat Commun 2021; 12:3978. [PMID: 34172738 PMCID: PMC8233390 DOI: 10.1038/s41467-021-24154-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2020] [Accepted: 05/21/2021] [Indexed: 02/05/2023] Open
Abstract
Social transmission of information is taxonomically widespread and could have profound effects on the ecological and evolutionary dynamics of animal communities. Demonstrating this in the wild, however, has been challenging. Here we show by field experiment that social transmission among predators can shape how selection acts on prey defences. Using artificial prey and a novel approach in statistical analyses of social networks, we find that blue tit (Cyanistes caeruleus) and great tit (Parus major) predators learn about prey defences by watching others. This shifts population preferences rapidly to match changes in prey profitability, and reduces predation pressure from naïve predators. Our results may help resolve how costly prey defences are maintained despite influxes of naïve juvenile predators, and suggest that accounting for social transmission is essential if we are to understand coevolutionary processes.
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Affiliation(s)
- Liisa Hämäläinen
- Department of Zoology, University of Cambridge, Cambridge, UK.
- Department of Biological Sciences, Macquarie University, Sydney, NSW, Australia.
- Department of Biological and Environmental Sciences, University of Jyväskylä, Jyväskylä, Finland.
| | - William Hoppitt
- School of Biological Sciences, Royal Holloway, University of London, Egham, UK
| | - Hannah M Rowland
- Department of Zoology, University of Cambridge, Cambridge, UK
- Max Planck Institute for Chemical Ecology, Jena, Germany
- Institute of Zoology, Zoological Society of London, London, UK
| | - Johanna Mappes
- Department of Biological and Environmental Sciences, University of Jyväskylä, Jyväskylä, Finland
- Research Programme in Organismal and Evolutionary Biology, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | | | - Sebastian Sosa
- Université de Strasbourg, CNRS, IPHC, UMR 7178, Strasbourg, France
| | - Rose Thorogood
- Department of Zoology, University of Cambridge, Cambridge, UK
- Research Programme in Organismal and Evolutionary Biology, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
- HiLIFE Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
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22
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Rowland HM, Burriss RP, Skelhorn J. The antipredator benefits of postural camouflage in peppered moth caterpillars. Sci Rep 2020; 10:21654. [PMID: 33303853 PMCID: PMC7728781 DOI: 10.1038/s41598-020-78686-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Accepted: 11/27/2020] [Indexed: 11/09/2022] Open
Abstract
Camouflage is the most common form of antipredator defense, and is a textbook example of natural selection. How animals’ appearances prevent detection or recognition is well studied, but the role of prey behavior has received much less attention. Here we report a series of experiments with twig-mimicking larvae of the American peppered moth Biston betularia that test the long-held view that prey have evolved postures that enhance their camouflage, and establish how food availability and ambient temperature affect these postures. We found that predators took longer to attack larvae that were resting in a twig-like posture than larvae resting flat against a branch. Larvae that were chilled or food restricted (manipulations intended to energetically stress larvae) adopted a less twig-like posture than larvae that were fed ad libitum. Our findings provide clear evidence that animals gain antipredator benefits from postural camouflage, and suggest that benefits may come at an energetic cost that animals are unwilling or unable to pay under some conditions.
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Affiliation(s)
- Hannah M Rowland
- Max Planck Research Group Predators and Toxic Prey, Max Planck Institute for Chemical Ecology, Hans Knӧll Straβe 8, 07745, Jena, Germany. .,Department of Zoology, University of Cambridge, Downing Street, Cambridge, CB2 3EJ, UK.
| | - Robert P Burriss
- Department of Psychology, The University of Basel, Missionsstrasse 62, 4055, Basel, Switzerland
| | - John Skelhorn
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Henry Wellcome Building, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK
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Hämäläinen L, Mappes J, Rowland HM, Teichmann M, Thorogood R. Social learning within and across predator species reduces attacks on novel aposematic prey. J Anim Ecol 2020; 89:1153-1164. [PMID: 32077104 PMCID: PMC7317195 DOI: 10.1111/1365-2656.13180] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [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: 04/29/2019] [Accepted: 12/05/2019] [Indexed: 11/28/2022]
Abstract
To make adaptive foraging decisions, predators need to gather information about the profitability of prey. As well as learning from prey encounters, recent studies show that predators can learn about prey defences by observing the negative foraging experiences of conspecifics. However, predator communities are complex. While observing heterospecifics may increase learning opportunities, we know little about how social information use varies across predator species. Social transmission of avoidance among predators also has potential consequences for defended prey. Conspicuous aposematic prey are assumed to be an easy target for naïve predators, but this cost may be reduced if multiple predators learn by observing single predation events. Heterospecific information use by predators might further benefit aposematic prey, but this remains untested. Here we test conspecific and heterospecific information use across a predator community with wild-caught blue tits (Cyanistes caeruleus) and great tits (Parus major). We used video playback to manipulate social information about novel aposematic prey and then compared birds' foraging choices in 'a small-scale novel world' that contained novel palatable and aposematic prey items. We expected that blue tits would be less likely to use social information compared to great tits. However, we found that both blue tits and great tits consumed fewer aposematic prey after observing a negative foraging experience of a demonstrator. In fact, this effect was stronger in blue tits compared to great tits. Interestingly, blue tits also learned more efficiently from watching conspecifics, whereas great tits learned similarly regardless of the demonstrator species. Together, our results indicate that social transmission about novel aposematic prey occurs in multiple predator species and across species boundaries. This supports the idea that social interactions among predators can reduce attacks on aposematic prey and therefore influence selection for prey defences.
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Affiliation(s)
| | - Johanna Mappes
- Department of Biological and Environmental Sciences, University of Jyväskylä, Jyväskylä, Finland
| | - Hannah M Rowland
- Department of Zoology, University of Cambridge, Cambridge, UK.,Max Planck Institute for Chemical Ecology, Jena, Germany.,Institute of Zoology, Zoological Society of London, London, UK
| | - Marianne Teichmann
- HiLIFE Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland.,Research Programme in Organismal & Evolutionary Biology, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland.,Chair of Nature Conservation & Landscape Ecology, University of Freiburg, Freiburg, Germany
| | - Rose Thorogood
- Department of Zoology, University of Cambridge, Cambridge, UK.,HiLIFE Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland.,Research Programme in Organismal & Evolutionary Biology, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
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24
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Hämäläinen L, Mappes J, Thorogood R, Valkonen JK, Karttunen K, Salmi T, Rowland HM. Predators’ consumption of unpalatable prey does not vary as a function of bitter taste perception. Behav Ecol 2019. [DOI: 10.1093/beheco/arz199] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
Many prey species contain defensive chemicals that are described as tasting bitter. Bitter taste perception is, therefore, assumed to be important when predators are learning about prey defenses. However, it is not known how individuals differ in their response to bitter taste, and how this influences their foraging decisions. We conducted taste perception assays in which wild-caught great tits (Parus major) were given water with increasing concentrations of bitter-tasting chloroquine diphosphate until they showed an aversive response to bitter taste. This response threshold was found to vary considerably among individuals, ranging from chloroquine concentrations of 0.01 mmol/L to 8 mmol/L. We next investigated whether the response threshold influenced the consumption of defended prey during avoidance learning by presenting birds with novel palatable and defended prey in a random sequence until they refused to attack defended prey. We predicted that individuals with taste response thresholds at lower concentrations would consume fewer defended prey before rejecting them, but found that the response threshold had no effect on the birds’ foraging choices. Instead, willingness to consume defended prey was influenced by the birds’ body condition. This effect was age- and sex-dependent, with adult males attacking more of the defended prey when their body condition was poor, whereas body condition did not have an effect on the foraging choices of juveniles and females. Together, our results suggest that even though taste perception might be important for recognizing prey toxicity, other factors, such as predators’ energetic state, drive the decisions to consume chemically defended prey.
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Affiliation(s)
- Liisa Hämäläinen
- Department of Zoology, University of Cambridge, Cambridge, UK
- Department of Biological and Environmental Sciences, University of Jyväskylä, Jyväskylä, Finland
| | - Johanna Mappes
- Department of Biological and Environmental Sciences, University of Jyväskylä, Jyväskylä, Finland
| | - Rose Thorogood
- Department of Zoology, University of Cambridge, Cambridge, UK
- HiLIFE Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
- Research Programme in Organismal & Evolutionary Biology, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - Janne K Valkonen
- Department of Biological and Environmental Sciences, University of Jyväskylä, Jyväskylä, Finland
| | - Kaijamari Karttunen
- Department of Biological and Environmental Sciences, University of Jyväskylä, Jyväskylä, Finland
| | - Tuuli Salmi
- Department of Biological and Environmental Sciences, University of Jyväskylä, Jyväskylä, Finland
| | - Hannah M Rowland
- Department of Zoology, University of Cambridge, Cambridge, UK
- Institute of Zoology, Zoological Society of London, Regent’s Park, London, UK
- Max Planck Institute for Chemical Ecology, Jena, Germany
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25
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Hämäläinen L, Rowland HM, Mappes J, Thorogood R. The effect of social information from live demonstrators compared to video playback on blue tit foraging decisions. PeerJ 2019; 7:e7998. [PMID: 31720117 PMCID: PMC6836752 DOI: 10.7717/peerj.7998] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [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: 06/27/2019] [Accepted: 10/07/2019] [Indexed: 12/17/2022] Open
Abstract
Video playback provides a promising method to study social interactions, and the number of video playback experiments has been growing in recent years. Using videos has advantages over live individuals as it increases the repeatability of demonstrations, and enables researchers to manipulate the features of the presented stimulus. How observers respond to video playback might, however, differ among species, and the efficacy of video playback should be validated by investigating if individuals' responses to videos are comparable to their responses to live demonstrators. Here, we use a novel foraging task to compare blue tits' (Cyanistes caeruleus) responses to social information from a live conspecific vs video playback. Birds first received social information about the location of food, and were then presented with a three-choice foraging task where they could search for food from locations marked with different symbols (cross, square, plain white). Two control groups saw only a foraging tray with similar symbols but no information about the location of food. We predicted that socially educated birds would prefer the same location where a demonstrator had foraged, but we found no evidence that birds copied a demonstrator's choice, regardless of how social information was presented. Social information, however, had an influence on blue tits' foraging choices, as socially educated birds seemed to form a stronger preference for a square symbol (against two other options, cross and plain white) than the control birds. Our results suggest that blue tits respond to video playback of a conspecific similarly as to a live bird, but how they use this social information in their foraging decisions, remains unclear.
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Affiliation(s)
| | - Hannah M Rowland
- Department of Zoology, University of Cambridge, Cambridge, UK.,Institute of Zoology, Zoological Society of London, London, UK.,Max Planck Institute for Chemical Ecology, Jena, Germany
| | - Johanna Mappes
- Department of Biological and Environmental Sciences, University of Jyväskylä, Jyväskylä, Finland
| | - Rose Thorogood
- Department of Zoology, University of Cambridge, Cambridge, UK.,HiLIFE Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland.,Research Programme in Organismal & Evolutionary Biology, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
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Hämäläinen L, Mappes J, Rowland HM, Thorogood R. Social information use about novel aposematic prey is not influenced by a predator's previous experience with toxins. Funct Ecol 2019. [DOI: 10.1111/1365-2435.13395] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
| | - Johanna Mappes
- Department of Biological and Environmental Science University of Jyväskylä Jyväskylä Finland
| | - Hannah M. Rowland
- Department of Zoology University of Cambridge Cambridge UK
- Max Planck Institute for Chemical Ecology Jena Germany
- Institute of Zoology Zoological Society of London London UK
| | - Rose Thorogood
- Department of Zoology University of Cambridge Cambridge UK
- HiLIFE Helsinki Institute of Life Sciences, University of Helsinki Helsinki Finland
- Research Programme in Organismal & Evolutionary Biology, Faculty of Biological and Environmental Sciences University of Helsinki Helsinki Finland
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27
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Eacock A, Rowland HM, van’t Hof AE, Yung CJ, Edmonds N, Saccheri IJ. Adaptive colour change and background choice behaviour in peppered moth caterpillars is mediated by extraocular photoreception. Commun Biol 2019; 2:286. [PMID: 31396566 PMCID: PMC6677728 DOI: 10.1038/s42003-019-0502-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2018] [Accepted: 06/13/2019] [Indexed: 12/26/2022] Open
Abstract
Light sensing by tissues distinct from the eye occurs in diverse animal groups, enabling circadian control and phototactic behaviour. Extraocular photoreceptors may also facilitate rapid colour change in cephalopods and lizards, but little is known about the sensory system that mediates slow colour change in arthropods. We previously reported that slow colour change in twig-mimicking caterpillars of the peppered moth (Biston betularia) is a response to achromatic and chromatic visual cues. Here we show that the perception of these cues, and the resulting phenotypic responses, does not require ocular vision. Caterpillars with completely obscured ocelli remained capable of enhancing their crypsis by changing colour and choosing to rest on colour-matching twigs. A suite of visual genes, expressed across the larval integument, likely plays a key role in the mechanism. To our knowledge, this is the first evidence that extraocular colour sensing can mediate pigment-based colour change and behaviour in an arthropod.
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Affiliation(s)
- Amy Eacock
- Institute of Integrative Biology, University of Liverpool, Liverpool, L69 7ZB UK
- Max Planck Institute for Chemical Ecology, Hans-Knöll-Straße 8, Jena, 07745 Germany
| | - Hannah M. Rowland
- Max Planck Institute for Chemical Ecology, Hans-Knöll-Straße 8, Jena, 07745 Germany
- Department of Zoology, University of Cambridge, Downing Street, Cambridge, CB2 3EJ UK
| | - Arjen E. van’t Hof
- Institute of Integrative Biology, University of Liverpool, Liverpool, L69 7ZB UK
| | - Carl J. Yung
- Institute of Integrative Biology, University of Liverpool, Liverpool, L69 7ZB UK
| | - Nicola Edmonds
- Institute of Integrative Biology, University of Liverpool, Liverpool, L69 7ZB UK
| | - Ilik J. Saccheri
- Institute of Integrative Biology, University of Liverpool, Liverpool, L69 7ZB UK
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28
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Abstract
The colour of our skin and clothing affects how others perceive us and how we behave. Human skin colour varies conspicuously with genetic ancestry, but even subtle changes in skin colour due to diet, blood oxygenation and hormone levels influence social perceptions. In this review, we describe the theoretical and empirical frameworks in which human colour is researched. We explore how subtle skin colour differences relate to judgements of health and attractiveness. Also, because humans are one of the few organisms able to manipulate their apparent colour, we review how cosmetics and clothing are implicated in courtship and competition, both inside the laboratory and in the real world. Research on human colour is in its infancy compared with human psychophysics and colour research in non-human animals, and hence we present best-practice guidelines for methods and reporting, which we hope will improve the validity and reproducibility of studies on human coloration.This article is part of the themed issue 'Animal coloration: production, perception, function and application'.
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Affiliation(s)
- Hannah M Rowland
- Department of Zoology, University of Cambridge, Cambridge CB2 3EJ, UK .,Institute of Zoology, Zoological Society of London, London NW1 4RY, UK
| | - Robert P Burriss
- Faculty of Psychology, Basel University, Basel 4055, Switzerland
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29
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Eacock A, Rowland HM, Edmonds N, Saccheri IJ. Colour change of twig-mimicking peppered moth larvae is a continuous reaction norm that increases camouflage against avian predators. PeerJ 2017; 5:e3999. [PMID: 29158965 PMCID: PMC5691783 DOI: 10.7717/peerj.3999] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [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: 07/28/2017] [Accepted: 10/17/2017] [Indexed: 01/15/2023] Open
Abstract
Camouflage, and in particular background-matching, is one of the most common anti-predator strategies observed in nature. Animals can improve their match to the colour/pattern of their surroundings through background selection, and/or by plastic colour change. Colour change can occur rapidly (a few seconds), or it may be slow, taking hours to days. Many studies have explored the cues and mechanisms behind rapid colour change, but there is a considerable lack of information about slow colour change in the context of predation: the cues that initiate it, and the range of phenotypes that are produced. Here we show that peppered moth (Biston betularia) larvae respond to colour and luminance of the twigs they rest on, and exhibit a continuous reaction norm of phenotypes. When presented with a heterogeneous environment of mixed twig colours, individual larvae specialise crypsis towards one colour rather than developing an intermediate colour. Flexible colour change in this species has likely evolved in association with wind dispersal and polyphagy, which result in caterpillars settling and feeding in a diverse range of visual environments. This is the first example of visually induced slow colour change in Lepidoptera that has been objectively quantified and measured from the visual perspective of natural predators.
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Affiliation(s)
- Amy Eacock
- Institute of Integrative Biology, University of Liverpool, Liverpool, United Kingdom
| | - Hannah M. Rowland
- Predators and Prey Research Group, Max Planck Institute for Chemical Ecology, Jena, Germany
| | - Nicola Edmonds
- Institute of Integrative Biology, University of Liverpool, Liverpool, United Kingdom
| | - Ilik J. Saccheri
- Institute of Integrative Biology, University of Liverpool, Liverpool, United Kingdom
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30
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Henderson LJ, Ryan MR, Rowland HM. Perch, Perca fluviatilis show a directional preference for, but do not increase attacks toward, prey in response to water-borne cortisol. PeerJ 2017; 5:e3883. [PMID: 29018617 PMCID: PMC5629957 DOI: 10.7717/peerj.3883] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [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: 04/13/2017] [Accepted: 09/12/2017] [Indexed: 11/20/2022] Open
Abstract
In freshwater environments, chemosensory cues play an important role in predator-prey interactions. Prey use a variety of chemosensory cues to detect and avoid predators. However, whether predators use the chemical cues released by disturbed or stressed prey has received less attention. Here we tested the hypothesis that the disturbance cue cortisol, in conjunction with visual cues of prey, elevates predatory behavior. We presented predators (perch, Perca fluviatilis) with three chemosensory choice tests and recorded their location, orientation, and aggressive behavior. We compared the responses of predators when provided with (i) visual cues of prey only (two adjacent tanks containing sticklebacks); (ii) visual and natural chemical cues of prey vs. visual cues only; and (iii) visual cues of prey with cortisol vs. visual cues only. Perch spent a significantly higher proportion of time in proximity to prey, and orientated toward prey more, when presented with a cortisol stimulus plus visual cues, relative to presentations of visual and natural chemical cues of prey, or visual cues of prey only. There was a trend that perch directed a higher proportion of predatory behaviors (number of lunges) toward sticklebacks when presented with a cortisol stimulus plus visual cues, relative to the other chemosensory conditions. But they did not show a significant increase in total predatory behavior in response to cortisol. Therefore, it is not clear whether water-borne cortisol, in conjunction with visual cues of prey, affects predatory behavior. Our results provide evidence that cortisol could be a source of public information about prey state and/or disturbance, but further work is required to confirm this.
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Affiliation(s)
- Lindsay J Henderson
- Centre for Behaviour and Evolution, Newcastle University, Newcastle upon Tyne, United Kingdom.,Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary & Life Sciences, The University of Glasgow, Glasgow, United Kingdom
| | - Mary R Ryan
- Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary & Life Sciences, The University of Glasgow, Glasgow, United Kingdom
| | - Hannah M Rowland
- Predators and Prey Research Group, Max Planck Institute for Chemical Ecology, Jena, Germany
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31
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Cuthill IC, Allen WL, Arbuckle K, Caspers B, Chaplin G, Hauber ME, Hill GE, Jablonski NG, Jiggins CD, Kelber A, Mappes J, Marshall J, Merrill R, Osorio D, Prum R, Roberts NW, Roulin A, Rowland HM, Sherratt TN, Skelhorn J, Speed MP, Stevens M, Stoddard MC, Stuart-Fox D, Talas L, Tibbetts E, Caro T. The biology of color. Science 2017; 357:357/6350/eaan0221. [DOI: 10.1126/science.aan0221] [Citation(s) in RCA: 353] [Impact Index Per Article: 50.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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32
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Hämäläinen L, Rowland HM, Mappes J, Thorogood R. Can video playback provide social information for foraging blue tits? PeerJ 2017; 5:e3062. [PMID: 28344901 PMCID: PMC5363260 DOI: 10.7717/peerj.3062] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [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: 01/13/2017] [Accepted: 02/03/2017] [Indexed: 11/20/2022] Open
Abstract
Video playback is becoming a common method for manipulating social stimuli in experiments. Parid tits are one of the most commonly studied groups of wild birds. However, it is not yet clear if tits respond to video playback or how their behavioural responses should be measured. Behaviours may also differ depending on what they observe demonstrators encountering. Here we present blue tits (Cyanistes caeruleus) videos of demonstrators discovering palatable or aversive prey (injected with bitter-tasting Bitrex) from coloured feeding cups. First we quantify variation in demonstrators' responses to the prey items: aversive prey provoked high rates of beak wiping and head shaking. We then show that focal blue tits respond differently to the presence of a demonstrator on a video screen, depending on whether demonstrators discover palatable or aversive prey. Focal birds faced the video screen more during aversive prey presentations, and made more head turns. Regardless of prey type, focal birds also hopped more frequently during the presence of a demonstrator (compared to a control video of a different coloured feeding cup in an empty cage). Finally, we tested if demonstrators' behaviour affected focal birds' food preferences by giving individuals a choice to forage from the same cup as a demonstrator, or from the cup in the control video. We found that only half of the individuals made their choice in accordance to social information in the videos, i.e., their foraging choices were not different from random. Individuals that chose in accordance with a demonstrator, however, made their choice faster than individuals that chose an alternative cup. Together, our results suggest that video playback can provide social cues to blue tits, but individuals vary greatly in how they use this information in their foraging decisions.
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Affiliation(s)
- Liisa Hämäläinen
- Department of Zoology, University of Cambridge , Cambridge , United Kingdom
| | - Hannah M Rowland
- Department of Zoology, University of Cambridge, Cambridge, United Kingdom; Institute of Zoology, Zoological Society of London, London, United Kindgom
| | - Johanna Mappes
- Centre of Excellence in Biological Interactions, Department of Biological and Environmental Science, University of Jyväskylä , Jyväskylä , Finland
| | - Rose Thorogood
- Department of Zoology, University of Cambridge, Cambridge, United Kingdom; Department of Biosciences, University of Helsinki, Helsinki, Finland
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34
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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] [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: 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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35
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Burriss RP, Troscianko J, Lovell PG, Fulford AJC, Stevens M, Quigley R, Payne J, Saxton TK, Rowland HM. Changes in Women's Facial Skin Color over the Ovulatory Cycle are Not Detectable by the Human Visual System. PLoS One 2015; 10:e0130093. [PMID: 26134671 PMCID: PMC4489916 DOI: 10.1371/journal.pone.0130093] [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] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Accepted: 05/15/2015] [Indexed: 11/18/2022] Open
Abstract
Human ovulation is not advertised, as it is in several primate species, by conspicuous sexual swellings. However, there is increasing evidence that the attractiveness of women's body odor, voice, and facial appearance peak during the fertile phase of their ovulatory cycle. Cycle effects on facial attractiveness may be underpinned by changes in facial skin color, but it is not clear if skin color varies cyclically in humans or if any changes are detectable. To test these questions we photographed women daily for at least one cycle. Changes in facial skin redness and luminance were then quantified by mapping the digital images to human long, medium, and shortwave visual receptors. We find cyclic variation in skin redness, but not luminance. Redness decreases rapidly after menstrual onset, increases in the days before ovulation, and remains high through the luteal phase. However, we also show that this variation is unlikely to be detectable by the human visual system. We conclude that changes in skin color are not responsible for the effects of the ovulatory cycle on women's attractiveness.
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Affiliation(s)
- Robert P. Burriss
- Department of Psychology, Northumbria University, Newcastle, NE1 8ST, United Kingdom
| | - Jolyon Troscianko
- Centre for Ecology & Conservation, University of Exeter, Penryn Campus, Penryn, TR10 9FE, United Kingdom
| | - P. George Lovell
- Division of Psychology, Abertay University, Dundee, DD1 1HG, United Kingdom
- School of Psychology & Neuroscience, University of St Andrews, St Andrews, KY16 9JP, United Kingdom
| | - Anthony J. C. Fulford
- MRC International Nutrition Group, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, United Kingdom
- Department of Zoology, University of Cambridge, Cambridge, CB2 3EJ, United Kingdom
| | - Martin Stevens
- Centre for Ecology & Conservation, University of Exeter, Penryn Campus, Penryn, TR10 9FE, United Kingdom
| | - Rachael Quigley
- Department of Zoology, University of Cambridge, Cambridge, CB2 3EJ, United Kingdom
| | - Jenny Payne
- Department of Zoology, University of Cambridge, Cambridge, CB2 3EJ, United Kingdom
| | - Tamsin K. Saxton
- Department of Psychology, Northumbria University, Newcastle, NE1 8ST, United Kingdom
| | - Hannah M. Rowland
- Department of Zoology, University of Cambridge, Cambridge, CB2 3EJ, United Kingdom
- Institute of Zoology, Zoological Society of London, London, NW1 4RY, United Kingdom
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36
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Rowland HM, Ruxton GD, Skelhorn J. Bitter taste enhances predatory biases against aggregations of prey with warning coloration. Behav Ecol 2013. [DOI: 10.1093/beheco/art013] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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37
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Blount JD, Rowland HM, Drijfhout FP, Endler JA, Inger R, Sloggett JJ, Hurst GDD, Hodgson DJ, Speed MP. How the ladybird got its spots: effects of resource limitation on the honesty of aposematic signals. Funct Ecol 2012. [DOI: 10.1111/j.1365-2435.2012.01961.x] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Ihalainen E, Rowland HM, Speed MP, Ruxton GD, Mappes J. Prey community structure affects how predators select for Mullerian mimicry. Proc Biol Sci 2012; 279:2099-105. [PMID: 22237908 DOI: 10.1098/rspb.2011.2360] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Müllerian mimicry describes the close resemblance between aposematic prey species; it is thought to be beneficial because sharing a warning signal decreases the mortality caused by sampling by inexperienced predators learning to avoid the signal. It has been hypothesized that selection for mimicry is strongest in multi-species prey communities where predators are more prone to misidentify the prey than in simple communities. In this study, wild great tits (Parus major) foraged from either simple (few prey appearances) or complex (several prey appearances) artificial prey communities where a specific model prey was always present. Owing to slower learning, the model did suffer higher mortality in complex communities when the birds were inexperienced. However, in a subsequent generalization test to potential mimics of the model prey (a continuum of signal accuracy), only birds that had foraged from simple communities selected against inaccurate mimics. Therefore, accurate mimicry is more likely to evolve in simple communities even though predator avoidance learning is slower in complex communities. For mimicry to evolve, prey species must have a common predator; the effective community consists of the predator's diet. In diverse environments, the limited diets of specialist predators could create 'simple community pockets' where accurate mimicry is selected for.
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Affiliation(s)
- Eira Ihalainen
- Department of Biological and Environmental Science, Centre of Excellence in Evolutionary Research, University of Jyväskylä, PO Box 35, FI-40014 University of Jyväskylä, Finland.
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Rowland HM, Mappes J, Ruxton GD, Speed MP. Mimicry between unequally defended prey can be parasitic: evidence for quasi-Batesian mimicry. Ecol Lett 2010; 13:1494-502. [DOI: 10.1111/j.1461-0248.2010.01539.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Skelhorn J, Rowland HM, Speed MP, De Wert L, Quinn L, Delf J, Ruxton GD. Size-dependent misclassification of masquerading prey. Behav Ecol 2010. [DOI: 10.1093/beheco/arq159] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Rowland HM, Hoogesteger T, Ruxton GD, Speed MP, Mappes J. A tale of 2 signals: signal mimicry between aposematic species enhances predator avoidance learning. Behav Ecol 2010. [DOI: 10.1093/beheco/arq071] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Rowland HM, Wiley E, Ruxton GD, Mappes J, Speed MP. When more is less: the fitness consequences of predators attacking more unpalatable prey when more are presented. Biol Lett 2010; 6:732-5. [PMID: 20444759 DOI: 10.1098/rsbl.2010.0207] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
In 1879, Fritz Müller hypothesized that mimetic resemblance in which defended prey display the same warning signal would share the costs of predator education. Although Müller argued that predators would need to ingest a fixed number of prey with a given visual signal when learning to avoid unpalatable prey, this assumption lacks empirical support. We report an experiment which shows that, as the number of unpalatable prey presented to them increased, avian predators attacked higher numbers of those prey. We calculated that, when predators increase attacks, the fitness costs incurred by unpalatable prey can be substantial. This suggests that the survival benefits of mimicry could be lower than Müller proposed. An important finding is, however, that these costs decline in importance as the total number of available prey increases.
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Saxton TK, Little AC, Rowland HM, Gao T, Roberts SC. Trade-offs between markers of absolute and relative quality in human facial preferences. Behav Ecol 2009. [DOI: 10.1093/beheco/arp107] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Rowland HM. From Abbott Thayer to the present day: what have we learned about the function of countershading? Philos Trans R Soc Lond B Biol Sci 2009; 364:519-27. [PMID: 19000972 DOI: 10.1098/rstb.2008.0261] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Of the many visual characteristics of animals, countershading (darker pigmentation on those surfaces exposed to the most lighting) is one of the most common, and paradoxically one of the least well understood. Countershading has been hypothesized to reduce the detectability of prey to visually hunting predators, and while the function of a countershaded colour pattern was proposed over 100 years ago, the field has progressed slowly; convincing evidence for the protective effects of countershading has only recently emerged. Several mechanisms have been invoked for the concealing function of countershading and are discussed in this review, but the actual mechanisms by which countershading functions to reduce attacks by predators lack firm empirical testing. While there is some subjective evidence that countershaded animals match the background on which they rest, no quantitative measure of background matching has been published for countershaded animals; I now present the first such results. Most studies also fail to consider plausible alternative explanations for the colour pattern, such as protection from UV or abrasion, and thermoregulation. This paper examines the evidence to support each of these possible explanations for countershading and discusses the need for future empirical work.
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Affiliation(s)
- Hannah M Rowland
- School of Biological Sciences, University of Liverpool, Biosciences Building, Crown Street, Liverpool L69 7ZB, UK.
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Saxton TK, Burriss RP, Murray AK, Rowland HM, Craig Roberts S. Face, body and speech cues independently predict judgments of attractiveness. ACTA ACUST UNITED AC 2009. [DOI: 10.1556/jep.7.2009.1.4] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Rowland HM, Cuthill IC, Harvey IF, Speed MP, Ruxton GD. Can't tell the caterpillars from the trees: countershading enhances survival in a woodland. Proc Biol Sci 2008; 275:2539-45. [PMID: 18700207 DOI: 10.1098/rspb.2008.0812] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Perception of the body's outline and three-dimensional shape arises from visual cues such as shading, contour, perspective and texture. When a uniformly coloured prey animal is illuminated from above by sunlight, a shadow may be cast on the body, generating a brightness contrast between the dorsal and ventral surfaces. For animals such as caterpillars, which live among flat leaves, a difference in reflectance over the body surface may degrade the degree of background matching and provide cues to shape from shading. This may make otherwise cryptic prey more conspicuous to visually hunting predators. Cryptically coloured prey are expected to match their substrate in colour, pattern and texture (though disruptive patterning is an exception), but they may also abolish self-shadowing and therefore either reduce shape cues or maintain their degree of background matching through countershading: a gradation of pigment on the body of an animal so that the surface closest to illumination is darker. In this study, we report the results from a series of field experiments where artificial prey resembling lepidopteran larvae were presented on the upper surfaces of beech tree branches so that they could be viewed by free-living birds. We demonstrate that countershading is superior to uniform coloration in terms of reducing attack by free-living predators. This result persisted even when we fixed prey to the underside of branches, simulating the resting position of many tree-living caterpillars. Our experiments provide the first demonstration, in an ecologically valid visual context, that shadowing on bodies (such as lepidopteran larvae) provides cues that visually hunting predators use to detect potential prey species, and that countershading counterbalances shadowing to enhance cryptic protection.
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Affiliation(s)
- Hannah M Rowland
- School of Biological Sciences, University of Liverpool, Biosciences Building, Crown Street, Liverpool L69 7ZB, UK.
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Rowland HM, Speed MP, Ruxton GD, Edmunds M, Stevens M, Harvey IF. Countershading enhances cryptic protection: an experiment with wild birds and artificial prey. Anim Behav 2007. [DOI: 10.1016/j.anbehav.2007.01.030] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Rowland HM, Ihalainen E, Lindström L, Mappes J, Speed MP. Co-mimics have a mutualistic relationship despite unequal defences. Nature 2007; 448:64-7. [PMID: 17611539 DOI: 10.1038/nature05899] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2007] [Accepted: 05/02/2007] [Indexed: 11/09/2022]
Abstract
In the first clear mathematical treatment of natural selection, Müller proposed that a shared warning signal (mimicry) would benefit defended prey species by sharing out the per capita mortality incurred during predator education. Although mimicry is a mainstay of adaptationist thinking, there has been repeated debate on whether there is a mutualistic or a parasitic relationship between unequally defended co-mimic species. Here we show that the relationship between unequally defended species is mutualistic. We examined this in a 'novel world' of artificial prey with wild predators (great tit, Parus major). We kept the abundance of a highly defended prey ('model') constant and increased the density of a moderately defended prey ('defended mimic') of either perfect or imperfect mimetic resemblance to the model. Both model and defended mimic showed a net benefit from a density-dependent decrease in their per capita mortality. Even when the effect of dilution through density was controlled for, defended mimics did not induce additional attacks on the model, but we found selection for accurate signal mimicry. In comparison, the addition of fully edible (batesian) mimics did increase additional attacks on the model, but as a result of dilution this resulted in no overall increase in per capita mortality. By ignoring the effects of density, current theories may have overestimated the parasitic costs imposed by less defended mimics on highly defended models.
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Affiliation(s)
- Hannah M Rowland
- School of Biological Sciences, University of Liverpool, Biosciences Building, Crown Street, Liverpool L69 7ZB, UK.
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