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Leal-Cardín M, Bracamonte SE, Aldegunde J, Magalhaes IS, Ornelas-García CP, Barluenga M. Signatures of convergence in Neotropical cichlid fish. Mol Ecol 2024; 33:e17524. [PMID: 39279721 DOI: 10.1111/mec.17524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2024] [Revised: 07/17/2024] [Accepted: 08/02/2024] [Indexed: 09/18/2024]
Abstract
Convergent evolution of similar phenotypes suggests some predictability in the evolutionary trajectories of organisms, due to strong and repeated selective pressures, and/or developmental constraints. In adaptive radiations, particularly in cichlid fish radiations, convergent phenotypes are commonly found within and across geographical settings. Cichlids show major repeated axes of morphological diversification. Recurrent changes in body patterns reveal adaption to alternative habitats, and modifications of the trophic apparatus respond to the exploitation of different food resources. Here we compare morphologically and genetically two Neotropical cichlid assemblages, the Mexican desert cichlid and the Nicaraguan Midas cichlid, with similar polymorphic body and trophic adaptations despite their independent evolution. We found a common morphological axis of differentiation in trophic structures in both cichlid radiations, but two different axes of differentiation in body shape, defining two alternative limnetic body patterns. Adaptation to limnetic habitats implied regulation of immune functions in the Midas cichlid, while morphogenesis and metabolic functions in the desert cichlid. Convergent phenotypic adaptions could be associated to divergent gene regulation.
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Affiliation(s)
- Mariana Leal-Cardín
- Department of Biodiversity and Evolutionary Biology, Museo Nacional de Ciencias Naturales, CSIC, Madrid, Spain
- University of Alcalá de Henares, Madrid, Spain
| | - Seraina E Bracamonte
- Department of Biodiversity and Evolutionary Biology, Museo Nacional de Ciencias Naturales, CSIC, Madrid, Spain
| | - Javier Aldegunde
- Department of Biodiversity and Evolutionary Biology, Museo Nacional de Ciencias Naturales, CSIC, Madrid, Spain
| | - Isabel S Magalhaes
- School of Life and Health Sciences, Centre for Integrated Research in Life and Health Sciences, University of Roehampton, London, UK
| | - Claudia Patricia Ornelas-García
- Colección Nacional de Peces, Departamento de Zoología, Instituto de Biología, Universidad Nacional Autónoma de Mexico, México City, Mexico
| | - Marta Barluenga
- Department of Biodiversity and Evolutionary Biology, Museo Nacional de Ciencias Naturales, CSIC, Madrid, Spain
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2
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Thompson KA, Brandvain Y, Coughlan JM, Delmore KE, Justen H, Linnen CR, Ortiz-Barrientos D, Rushworth CA, Schneemann H, Schumer M, Stelkens R. The Ecology of Hybrid Incompatibilities. Cold Spring Harb Perspect Biol 2024; 16:a041440. [PMID: 38151331 PMCID: PMC11368197 DOI: 10.1101/cshperspect.a041440] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2023]
Abstract
Ecologically mediated selection against hybrids, caused by hybrid phenotypes fitting poorly into available niches, is typically viewed as distinct from selection caused by epistatic Dobzhansky-Muller hybrid incompatibilities. Here, we show how selection against transgressive phenotypes in hybrids manifests as incompatibility. After outlining our logic, we summarize current approaches for studying ecology-based selection on hybrids. We then quantitatively review QTL-mapping studies and find traits differing between parent taxa are typically polygenic. Next, we describe how verbal models of selection on hybrids translate to phenotypic and genetic fitness landscapes, highlighting emerging approaches for detecting polygenic incompatibilities. Finally, in a synthesis of published data, we report that trait transgression-and thus possibly extrinsic hybrid incompatibility in hybrids-escalates with the phenotypic divergence between parents. We discuss conceptual implications and conclude that studying the ecological basis of hybrid incompatibility will facilitate new discoveries about mechanisms of speciation.
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Affiliation(s)
- Ken A Thompson
- Department of Biology, Stanford University, Stanford, California 94305, USA
- Department of Plant Biology, Carnegie Institution for Science, Stanford, California 94305, USA
| | - Yaniv Brandvain
- Department of Plant and Microbial Biology, University of Minnesota - Twin Cities, St Paul, Minnesota 55108, USA
| | - Jenn M Coughlan
- Department of Ecology & Evolutionary Biology, Yale University, New Haven, Connecticut 06511, USA
| | - Kira E Delmore
- Department of Biology, Texas A&M University, College Station, Texas 77843, USA
| | - Hannah Justen
- Department of Biology, Texas A&M University, College Station, Texas 77843, USA
| | - Catherine R Linnen
- Department of Biology, University of Kentucky, Lexington, Kentucky 40506, USA
| | - Daniel Ortiz-Barrientos
- School of Biological Sciences, The University of Queensland, Centre of Excellence for Plant Success in Nature and Agriculture, St Lucia, Queensland 4072, Australia
| | - Catherine A Rushworth
- Department of Biology and Ecology Center, Utah State University, Logan, Utah 84322, USA
| | - Hilde Schneemann
- Department of Genetics, University of Cambridge, Cambridge CB2 3EH, United Kingdom
| | - Molly Schumer
- Department of Biology, Stanford University, Stanford, California 94305, USA
- Centro de Investigaciones Científicas de las Huastecas "Aguazarca," A.C., Calnali 43240, Mexico
- Hanna H. Gray Fellow, Howard Hughes Medical Institute, Chevy Chase, Maryland 20815, USA
| | - Rike Stelkens
- Division of Population Genetics, Department of Zoology, Stockholm University, 106 91 Stockholm, Sweden
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3
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Boerma DB, Swartz SM. Roosting ecology drives the evolution of diverse bat landing maneuvers. iScience 2024; 27:110381. [PMID: 39045098 PMCID: PMC11263957 DOI: 10.1016/j.isci.2024.110381] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Revised: 04/02/2024] [Accepted: 06/24/2024] [Indexed: 07/25/2024] Open
Abstract
Bats and birds are the only living vertebrates capable of powered flight. However, bats differ from birds in that their flight required the evolution of ascending landing maneuvers that achieve their iconic head-under-heels roosting posture. We examined the evolution of landing flight in bats and tested its association with the physical properties of roosts. Bats performed four maneuvers, each correlated with patterns of peak impact force, impulse, and roosting ecology, a critical aspect of bat biology. Our findings indicate that the common ancestor of bats performed simple, four-limbed landings, similar to extant gliding mammals, and that rotationally complex landings enhancing control over impact forces coevolved multiple times with shifts to stiff, horizontal roosts. These results suggest landing biomechanics is central to bat biology: it was critical to flight adaptation in the past, mediates roost use in the present, and may affect bats' ability to respond to deforestation in the future.
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Affiliation(s)
- David B. Boerma
- Department of Biology, Pace University, New York, NY 10038, USA
- Department of Mammalogy, Division of Vertebrate Zoology, American Museum of Natural History, New York, NY 10024, USA
- Department of Ecology, Evolution, and Organismal Biology, Brown University, Providence, RI 02912, USA
| | - Sharon M. Swartz
- Department of Ecology, Evolution, and Organismal Biology, Brown University, Providence, RI 02912, USA
- School of Engineering, Brown University, Providence, RI 02912, USA
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4
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Sansalone G, Wroe S, Coates G, Attard MRG, Fruciano C. Unexpectedly uneven distribution of functional trade-offs explains cranial morphological diversity in carnivores. Nat Commun 2024; 15:3275. [PMID: 38627430 PMCID: PMC11021405 DOI: 10.1038/s41467-024-47620-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Accepted: 04/08/2024] [Indexed: 04/19/2024] Open
Abstract
Functional trade-offs can affect patterns of morphological and ecological evolution as well as the magnitude of morphological changes through evolutionary time. Using morpho-functional landscape modelling on the cranium of 132 carnivore species, we focused on the macroevolutionary effects of the trade-off between bite force and bite velocity. Here, we show that rates of evolution in form (morphology) are decoupled from rates of evolution in function. Further, we found theoretical morphologies optimising for velocity to be more diverse, while a much smaller phenotypic space was occupied by shapes optimising force. This pattern of differential representation of different functions in theoretical morphological space was highly correlated with patterns of actual morphological disparity. We hypothesise that many-to-one mapping of cranium shape on function may prevent the detection of direct relationships between form and function. As comparatively only few morphologies optimise bite force, species optimising this function may be less abundant because they are less likely to evolve. This, in turn, may explain why certain clades are less variable than others. Given the ubiquity of functional trade-offs in biological systems, these patterns may be general and may help to explain the unevenness of morphological and functional diversity across the tree of life.
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Affiliation(s)
- Gabriele Sansalone
- Institute for Marine Biological Resources and Biotechnology (CNR-IRBIM), National Research Council, Via S. Raineri 4, 98122, Messina, Italy.
- Function, Evolution and Anatomy Research Lab, Zoology Division, School of Environmental and Rural Science, University of New England, Armidale, NSW, Australia.
- Department of Life Sciences, University of Modena and Reggio Emilia, Via Campi 213D, 41125, Modena, Italy.
| | - Stephen Wroe
- Function, Evolution and Anatomy Research Lab, Zoology Division, School of Environmental and Rural Science, University of New England, Armidale, NSW, Australia
| | - Geoffrey Coates
- Function, Evolution and Anatomy Research Lab, Zoology Division, School of Environmental and Rural Science, University of New England, Armidale, NSW, Australia
| | - Marie R G Attard
- Function, Evolution and Anatomy Research Lab, Zoology Division, School of Environmental and Rural Science, University of New England, Armidale, NSW, Australia
- British Antarctic Survey, High Cross, Madingley Road, CB3 0ET, Cambridge, UK
| | - Carmelo Fruciano
- Institute for Marine Biological Resources and Biotechnology (CNR-IRBIM), National Research Council, Via S. Raineri 4, 98122, Messina, Italy.
- National Biodiversity Future Center, Piazza Marina 61, 90133, Palermo, Italy.
- Department of Biological, Geological and Environmental Sciences, University of Catania, via Androne 81, 95124, Catania, Italy.
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5
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Tan A, St. John M, Chau D, Clair C, Chan H, Holzman R, Martin CH. Multiple performance peaks for scale-biting in an adaptive radiation of pupfishes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.22.573139. [PMID: 38187684 PMCID: PMC10769438 DOI: 10.1101/2023.12.22.573139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
The physical interactions between organisms and their environment ultimately shape their rate of speciation and adaptive radiation, but the contributions of biomechanics to evolutionary divergence are frequently overlooked. Here we investigated an adaptive radiation of Cyprinodon pupfishes to measure the relationship between feeding kinematics and performance during adaptation to a novel trophic niche, lepidophagy, in which a predator removes only the scales, mucus, and sometimes tissue from their prey using scraping and biting attacks. We used high-speed video to film scale-biting strikes on gelatin cubes by scale-eater, molluscivore, generalist, and hybrid pupfishes and subsequently measured the dimensions of each bite. We then trained the SLEAP machine-learning animal tracking model to measure kinematic landmarks and automatically scored over 100,000 frames from 227 recorded strikes. Scale-eaters exhibited increased peak gape and greater bite length; however, substantial within-individual kinematic variation resulted in poor discrimination of strikes by species or strike type. Nonetheless, a complex performance landscape with two distinct peaks best predicted gel-biting performance, corresponding to a significant nonlinear interaction between peak gape and peak jaw protrusion in which scale-eaters and their hybrids occupied a second performance peak requiring larger peak gape and greater jaw protrusion. A bite performance valley separating scale-eaters from other species may have contributed to their rapid evolution and is consistent with multiple estimates of a multi-peak fitness landscape in the wild. We thus present an efficient deep-learning automated pipeline for kinematic analyses of feeding strikes and a new biomechanical model for understanding the performance and rapid evolution of a rare trophic niche.
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Affiliation(s)
- Anson Tan
- Department of Integrative Biology, University of California, Berkeley
- Museum of Vertebrate Zoology, University of California, Berkeley
| | | | - Dylan Chau
- Department of Integrative Biology, University of California, Berkeley
- Museum of Vertebrate Zoology, University of California, Berkeley
| | - Chloe Clair
- Department of Integrative Biology, University of California, Berkeley
- Museum of Vertebrate Zoology, University of California, Berkeley
| | | | - Roi Holzman
- School of Zoology, Tel Aviv University, Eilat, Israel
- Inter-University Institute for Marine Sciences, Eilat, Israel
| | - Christopher H. Martin
- Department of Integrative Biology, University of California, Berkeley
- Museum of Vertebrate Zoology, University of California, Berkeley
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Matthews DG, Dial TR, Lauder GV. Genes, Morphology, Performance, and Fitness: Quantifying Organismal Performance to Understand Adaptive Evolution. Integr Comp Biol 2023; 63:843-859. [PMID: 37422435 DOI: 10.1093/icb/icad096] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2023] [Revised: 06/06/2023] [Accepted: 06/22/2023] [Indexed: 07/10/2023] Open
Abstract
To understand the complexities of morphological evolution, we must understand the relationships between genes, morphology, performance, and fitness in complex traits. Genomicists have made tremendous progress in finding the genetic basis of many phenotypes, including a myriad of morphological characters. Similarly, field biologists have greatly advanced our understanding of the relationship between performance and fitness in natural populations. However, the connection from morphology to performance has primarily been studied at the interspecific level, meaning that in most cases we lack a mechanistic understanding of how evolutionarily relevant variation among individuals affects organismal performance. Therefore, functional morphologists need methods that will allow for the analysis of fine-grained intraspecific variation in order to close the path from genes to fitness. We suggest three methodological areas that we believe are well suited for this research program and provide examples of how each can be applied within fish model systems to build our understanding of microevolutionary processes. Specifically, we believe that structural equation modeling, biological robotics, and simultaneous multi-modal functional data acquisition will open up fruitful collaborations among biomechanists, evolutionary biologists, and field biologists. It is only through the combined efforts of all three fields that we will understand the connection between evolution (acting at the level of genes) and natural selection (acting on fitness).
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Affiliation(s)
- David G Matthews
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA
- Museum of Comparative Zoology, Harvard University, Cambridge, MA 02138, USA
| | - Terry R Dial
- Department of Biology and Ecology Center, Utah State University, Moab, UT 84322, USA
- Department of Environment and Society, Utah State University, Moab, UT 84322, USA
| | - George V Lauder
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA
- Museum of Comparative Zoology, Harvard University, Cambridge, MA 02138, USA
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7
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Ferry LA, Higham TE. Ecomechanics and the Rules of Life: a Critical Conduit Between the Physical and Natural Sciences. Integr Comp Biol 2022; 62:icac114. [PMID: 35878412 DOI: 10.1093/icb/icac114] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Nature provides the parameters, or boundaries, within which organisms must cope in order to survive. Therefore, ecological conditions have an unequivocal influence on the ability of organisms to perform the necessary functions for survival. Biomechanics brings together physics and biology to understand how an organism will function under a suite of conditions. Despite a relatively rich recent history linking physiology and morphology with ecology, less attention has been paid to the linkage between biomechanics and ecology. This linkage, however, could provide key insights into patterns and processes of evolution. Ecomechanics, also known as ecological biomechanics or mechanical ecology, is not necessarily new, but has received far less attention than ecophysiology or ecomorphology. Here, we briefly review the history of ecomechanics, and then identify what we believe are grand challenges for the discipline and how they can inform some of the most pressing questions in science today, such as how organisms will cope with global change.
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Affiliation(s)
- Lara A Ferry
- Arizona State University, School of Mathematical and Natural Sciences, New College of Interdisciplinary Arts and Sciences, Glendale, AZ, USA
| | - Timothy E Higham
- University of California Riverside, Department of Evolution, Ecology, and Organismal Biology, Riverside, CA, USA
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Studies of the Behavioral Sequences: The Neuroethological Morphology Concept Crossing Ethology and Functional Morphology. Animals (Basel) 2022; 12:ani12111336. [PMID: 35681801 PMCID: PMC9179564 DOI: 10.3390/ani12111336] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Revised: 05/19/2022] [Accepted: 05/20/2022] [Indexed: 01/25/2023] Open
Abstract
Simple Summary Behavioral sequences analysis is a relevant method for quantifying the behavioral repertoire of animals to respond to the classical Tinbergen’s four questions. Research in ethology and functional morphology intercepts at the level of analysis of behaviors through the recording and interpretation of data from of movement sequence studies with various types of imaging and sensor systems. We propose the concept of Neuroethological morphology to build a holistic framework for understanding animal behavior. This concept integrates ethology (including behavioral ecology and neuroethology) with functional morphology (including biomechanics and physics) to provide a heuristic approach in behavioral biology. Abstract Postures and movements have been one of the major modes of human expression for understanding and depicting organisms in their environment. In ethology, behavioral sequence analysis is a relevant method to describe animal behavior and to answer Tinbergen’s four questions testing the causes of development, mechanism, adaptation, and evolution of behaviors. In functional morphology (and in biomechanics), the analysis of behavioral sequences establishes the motor pattern and opens the discussion on the links between “form” and “function”. We propose here the concept of neuroethological morphology in order to build a holistic framework for understanding animal behavior. This concept integrates ethology with functional morphology, and physics. Over the past hundred years, parallel developments in both disciplines have been rooted in the study of the sequential organization of animal behavior. This concept allows for testing genetic, epigenetic, and evo-devo predictions of phenotypic traits between structures, performances, behavior, and fitness in response to environmental constraints. Based on a review of the literature, we illustrate this concept with two behavioral cases: (i) capture behavior in squamates, and (ii) the ritualistic throat display in lizards.
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McWhinnie K, Gibson J, Gislason M, Tanner E, Windmill J, Albertson RC, Parsons K. Assessing the Levels of Functional Adaptation: Finite Element Analysis Reveals Species, Hybrid, and Sexual Variation in the Biomechanics of African Cichlid Mandibles. Evol Biol 2022. [DOI: 10.1007/s11692-022-09566-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
AbstractTo understand how adaptive divergence emerges it is essential to examine the function of phenotypic traits along a continuum. For vertebrates, the mandible provides a key link with foraging and other important activities which has made it highly relevant for investigations of biomechanical change. Variation in mandible shape is known to correspond with ecology but its function is often only investigated between distinct species. However, for such divergence to occur and be maintained selection likely draws from many sources of biomechanical variation. African cichlids represent an exemplar model for understanding how such processes unfold with mandible variation existing between species, sexes, and is likely generated in nature by the potential for hybridization. We explored such mandible variation through a finite element modelling approach and predicted that hybrids and females would have reduced functional capabilities, the former in line with disruptive selection and the latter due to potential trade-offs incurred by maternal mouthbrooding in Malawian haplochromines. We revealed evidence of structural adaptations between Tropheops ‘Red Cheek’ and Labeotrophues fuelleborni that impacted the dispersion of mechanical stress in ways that matched the foraging of these species. Also, hybrids showed higher stresses relative to both species across the mandible. Sexual dimorphism in stress handling was evident despite minor differences in shape with males showing enhanced load resistance. However, in hybrids it appeared that males were disadvantaged relative to females, and displayed asymmetry in load handling. Together, these results show evidence of species and sex based biomechanical variation, that could be targeted by divergent selection.
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Galván I, Schwartz TS, Garland T. Evolutionary physiology at 30+: Has the promise been fulfilled?: Advances in Evolutionary Physiology: Advances in Evolutionary Physiology. Bioessays 2021; 44:e2100167. [PMID: 34802161 DOI: 10.1002/bies.202100167] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2021] [Revised: 10/20/2021] [Accepted: 10/22/2021] [Indexed: 12/19/2022]
Abstract
Three decades ago, interactions between evolutionary biology and physiology gave rise to evolutionary physiology. This caused comparative physiologists to improve their research methods by incorporating evolutionary thinking. Simultaneously, evolutionary biologists began focusing more on physiological mechanisms that may help to explain constraints on and trade-offs during microevolutionary processes, as well as macroevolutionary patterns in physiological diversity. Here we argue that evolutionary physiology has yet to reach its full potential, and propose new avenues that may lead to unexpected advances. Viewing physiological adaptations in wild animals as potential solutions to human diseases offers enormous possibilities for biomedicine. New evidence of epigenetic modifications as mechanisms of phenotypic plasticity that regulate physiological traits may also arise in coming years, which may also represent an overlooked enhancer of adaptation via natural selection to explain physiological evolution. Synergistic interactions at these intersections and other areas will lead to a novel understanding of organismal biology.
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Affiliation(s)
- Ismael Galván
- Department of Evolutionary Ecology, National Museum of Natural Sciences, CSIC, Madrid, Spain
| | - Tonia S Schwartz
- Department of Biological Sciences, Auburn University, Auburn, Alabama, USA
| | - Theodore Garland
- Department of Evolution, Ecology, and Organismal Biology, University of California, Riverside, California, USA
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11
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Horta-Lacueva QJB, Snorrason SS, Morrissey MB, Leblanc CAL, Kapralova KH. Multivariate analysis of morphology, behaviour, growth and developmental timing in hybrids brings new insights into the divergence of sympatric Arctic charr morphs. BMC Ecol Evol 2021; 21:170. [PMID: 34493202 PMCID: PMC8422654 DOI: 10.1186/s12862-021-01904-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Accepted: 08/18/2021] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND Studying the development of fitness related traits in hybrids from populations diverging in sympatry is a fundamental approach to understand the processes of speciation. However, such traits are often affected by covariance structures that complicate the comprehension of these processes, especially because the interactive relationships between traits of different nature (e.g. morphology, behaviour, life-history) remain largely unknown in this context. In a common garden setup, we conducted an extensive examination of a large suit of traits putatively involved in the divergence of two morphs of Arctic charr (Salvelinus alpinus), and investigated the consequences of potential patterns of trait covariance on the phenotype of their hybrids. These traits were measured along ontogeny and involved growth, yolk sac resorption, developmental timing (hatching and the onset of exogeneous feeding), head morphology and feeding behaviour. RESULTS Growth trajectories provided the strongest signal of phenotypic divergence between the two charr. Strikingly, the first-generation hybrids did not show intermediate nor delayed growth but were similar to the smallest morph, suggesting parental biases in the inheritance of growth patterns. However, we did not observe extensive multivariate trait differences between the two morphs and their hybrids. Growth was linked to head morphology (suggesting that morphological variations in early juveniles relate to simple allometric effects) but this was the only strong signal of covariance observed between all the measured traits. Furthermore, we did not report evidence for differences in overall phenotypic variance between morphs, nor for enhanced phenotypic variability in their hybrids. CONCLUSION Our study shed light on the multivariate aspect of development in a context of adaptive divergence. The lack of evidence for the integration of most traits into a single covariance structure suggested that phenotypic constraints may not always favour nor impede divergence toward ecological niches differing in numerous physical and ecological variables, as observed in the respective habitats of the two charr. Likewise, the role of hybridization as a disruptive agent of trait covariance may not necessarily be significant in the evolution of populations undergoing resource polymorphism.
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Affiliation(s)
- Quentin J-B Horta-Lacueva
- Institute of Life and Environmental Sciences, University of Iceland, Askja - Náttúrufræðihús, Sturlugötu 7, 102, Reykjavík, Iceland.
| | - Sigurður S Snorrason
- Institute of Life and Environmental Sciences, University of Iceland, Askja - Náttúrufræðihús, Sturlugötu 7, 102, Reykjavík, Iceland
| | - Michael B Morrissey
- School of Biology, University of St Andrews, Sir Harold Mitchell Building, Greenside Place, St Andrews, UK
| | - Camille A-L Leblanc
- Department of Aquaculture and Fish Biology, Hólar University, Háeyri 1, 550, Sauðárkrókur, Iceland
| | - Kalina H Kapralova
- Institute of Life and Environmental Sciences, University of Iceland, Askja - Náttúrufræðihús, Sturlugötu 7, 102, Reykjavík, Iceland
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12
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Zhang Y, Teng D, Lu W, Liu M, Zeng H, Cao L, Southcott L, Potdar S, Westerman E, Zhu AJ, Zhang W. A widely diverged locus involved in locomotor adaptation in Heliconius butterflies. SCIENCE ADVANCES 2021; 7:7/32/eabh2340. [PMID: 34348900] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Accepted: 06/17/2021] [Indexed: 06/13/2023]
Abstract
Heliconius butterflies have undergone adaptive radiation and therefore serve as an excellent system for exploring the continuum of speciation and adaptive evolution. However, there is a long-lasting paradox between their convergent mimetic wing patterns and rapid divergence in speciation. Here, we characterize a locus that consistently displays high divergence among Heliconius butterflies and acts as an introgression hotspot. We further show that this locus contains multiple genes related to locomotion and conserved in Lepidoptera. In light of these findings, we consider that locomotion traits may be under selection, and if these are heritable traits that are selected for, then they might act as species barriers.
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Affiliation(s)
- Yubo Zhang
- State Key Laboratory of Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
| | - Dequn Teng
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, China
| | - Wei Lu
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, China
| | - Min Liu
- Ministry of Education Key Laboratory of Cell Proliferation and Differentiation, Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, School of Life Sciences, Peking University, Beijing 100871, China
| | - Hua Zeng
- State Key Laboratory of Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
| | - Lei Cao
- State Key Laboratory of Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
| | - Laura Southcott
- Committee on Evolutionary Biology, University of Chicago, Chicago, IL 60637, USA
| | - Sushant Potdar
- Department of Biological Sciences, University of Arkansas, Fayetteville, AR 72701, USA
| | - Erica Westerman
- Department of Biological Sciences, University of Arkansas, Fayetteville, AR 72701, USA
| | - Alan Jian Zhu
- Ministry of Education Key Laboratory of Cell Proliferation and Differentiation, Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, School of Life Sciences, Peking University, Beijing 100871, China.
| | - Wei Zhang
- State Key Laboratory of Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China.
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, China
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13
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Zhang Y, Teng D, Lu W, Liu M, Zeng H, Cao L, Southcott L, Potdar S, Westerman E, Zhu AJ, Zhang W. A widely diverged locus involved in locomotor adaptation in Heliconius butterflies. SCIENCE ADVANCES 2021; 7:eabh2340. [PMID: 34348900 PMCID: PMC8336958 DOI: 10.1126/sciadv.abh2340] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Accepted: 06/17/2021] [Indexed: 12/30/2023]
Abstract
Heliconius butterflies have undergone adaptive radiation and therefore serve as an excellent system for exploring the continuum of speciation and adaptive evolution. However, there is a long-lasting paradox between their convergent mimetic wing patterns and rapid divergence in speciation. Here, we characterize a locus that consistently displays high divergence among Heliconius butterflies and acts as an introgression hotspot. We further show that this locus contains multiple genes related to locomotion and conserved in Lepidoptera. In light of these findings, we consider that locomotion traits may be under selection, and if these are heritable traits that are selected for, then they might act as species barriers.
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Affiliation(s)
- Yubo Zhang
- State Key Laboratory of Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
| | - Dequn Teng
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, China
| | - Wei Lu
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, China
| | - Min Liu
- Ministry of Education Key Laboratory of Cell Proliferation and Differentiation, Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, School of Life Sciences, Peking University, Beijing 100871, China
| | - Hua Zeng
- State Key Laboratory of Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
| | - Lei Cao
- State Key Laboratory of Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
| | - Laura Southcott
- Committee on Evolutionary Biology, University of Chicago, Chicago, IL 60637, USA
| | - Sushant Potdar
- Department of Biological Sciences, University of Arkansas, Fayetteville, AR 72701, USA
| | - Erica Westerman
- Department of Biological Sciences, University of Arkansas, Fayetteville, AR 72701, USA
| | - Alan Jian Zhu
- Ministry of Education Key Laboratory of Cell Proliferation and Differentiation, Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, School of Life Sciences, Peking University, Beijing 100871, China.
| | - Wei Zhang
- State Key Laboratory of Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China.
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, China
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14
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Gerullis P, Reinel CP, Schuster S. Archerfish coordinate fin maneuvers with their shots. J Exp Biol 2021; 224:jeb.233718. [PMID: 33785500 DOI: 10.1242/jeb.233718] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 03/15/2021] [Indexed: 11/20/2022]
Abstract
Archerfish down a variety of aerial prey from a range of distances using water jets that they adjust to the size and distance of their prey. We describe here that characteristic rapid fin maneuvers, most notably of the pectoral and pelvic fins, are precisely coordinated with the release of the jet. We discovered these maneuvers in two fish, the jets of which had been characterized in detail, that had been trained to shoot from fixed positions at targets at different heights and that remained stable during their shots. Based on the findings in these individuals, we examined shooting-associated fin movement in 28 further archerfish of two species that could shoot from freely chosen positions at targets at different heights. Slightly before the onset of the water jet, at a time when the shooter remains stable, the pectoral fins of all shooters switched from asynchronous low-amplitude beating to a synchronized rapid forward flap. The onset and duration of the forward and subsequent backward flap were robust across all individuals and shooting angles but depended on target height. The pelvic fins were slowly adducted at the start of the jet and stopped moving after its release. All other fins also showed a characteristic sequence of activation, some starting ∼0.5 s before the shot. Our findings suggest that shooting-related fin maneuvers are needed to stabilize the shooter, and that these maneuvers are an important component in the precise and powerful far-distance shooting in archerfish.
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Affiliation(s)
- Peggy Gerullis
- Department of Animal Physiology, University of Bayreuth, 95440 Bayreuth, Germany
| | - Caroline P Reinel
- Department of Animal Physiology, University of Bayreuth, 95440 Bayreuth, Germany
| | - Stefan Schuster
- Department of Animal Physiology, University of Bayreuth, 95440 Bayreuth, Germany
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15
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Safian D, Wiegertjes GF, Pollux BJA. The Fish Family Poeciliidae as a Model to Study the Evolution and Diversification of Regenerative Capacity in Vertebrates. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.613157] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The capacity of regenerating a new structure after losing an old one is a major challenge in the animal kingdom. Fish have emerged as an interesting model to study regeneration due to their high and diverse regenerative capacity. To date, most efforts have focused on revealing the mechanisms underlying fin regeneration, but information on why and how this capacity evolves remains incomplete. Here, we propose the livebearing fish family Poeciliidae as a promising new model system to study the evolution of fin regeneration. First, we review the current state of knowledge on the evolution of regeneration in the animal kingdom, with a special emphasis on fish fins. Second, we summarize recent advances in our understanding of the mechanisms behind fin regeneration in fish. Third, we discuss potential evolutionary pressures that may modulate the regenerative capacity of fish fins and propose three new theories for how natural and sexual selection can lead to the evolution of fin regeneration: (1) signaling-driven fin regeneration, (2) predation-driven fin regeneration, and (3) matrotrophy-suppressed fin regeneration. Finally, we argue that fish from the family Poeciliidae are an excellent model system to test these theories, because they comprise of a large variety of species in a well-defined phylogenetic framework that inhabit very different environments and display remarkable variation in reproductive traits, allowing for comparative studies of fin regeneration among closely related species, among populations within species or among individuals within populations. This new model system has the potential to shed new light on the underlying genetic and molecular mechanisms driving the evolution and diversification of regeneration in vertebrates.
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16
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Martin CH, Gould KJ. Surprising spatiotemporal stability of a multi-peak fitness landscape revealed by independent field experiments measuring hybrid fitness. Evol Lett 2020; 4:530-544. [PMID: 33312688 PMCID: PMC7719547 DOI: 10.1002/evl3.195] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 07/23/2020] [Accepted: 09/14/2020] [Indexed: 12/14/2022] Open
Abstract
The effect of the environment on fitness in natural populations is a fundamental question in evolutionary biology. However, experimental manipulations of both environment and phenotype at the same time are rare. Thus, the relative importance of the competitive environment versus intrinsic organismal performance in shaping the location, height, and fluidity of fitness peaks and valleys remains largely unknown. Here, we experimentally tested the effect of competitor frequency on the complex fitness landscape driving adaptive radiation of a generalist and two trophic specialist pupfishes, a scale-eater and molluscivore, endemic to hypersaline lakes on San Salvador Island (SSI), Bahamas. We manipulated phenotypes, by generating 3407 F4/F5 lab-reared hybrids, and competitive environment, by altering the frequency of rare transgressive hybrids between field enclosures in two independent lake populations. We then tracked hybrid survival and growth rates across these four field enclosures for 3-11 months. In contrast to competitive speciation theory, we found no evidence that the frequency of hybrid phenotypes affected their survival. Instead, we observed a strikingly similar fitness landscape to a previous independent field experiment, each supporting multiple fitness peaks for generalist and molluscivore phenotypes and a large fitness valley isolating the divergent scale-eater phenotype. These features of the fitness landscape were stable across manipulated competitive environments, multivariate trait axes, and spatiotemporal heterogeneity. We suggest that absolute performance constraints and divergent gene regulatory networks shape macroevolutionary (interspecific) fitness landscapes in addition to microevolutionary (intraspecific) competitive dynamics. This interplay between organism and environment underlies static and dynamic features of the adaptive landscape.
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Affiliation(s)
- Christopher H. Martin
- Department of Integrative BiologyUniversity of California, BerkeleyBerkeleyCalifornia94720
- Museum of Vertebrate ZoologyUniversity of California, BerkeleyBerkeleyCalifornia94720
| | - Katelyn J. Gould
- Department of BiologyUniversity of North Carolina at Chapel HillChapel HillNorth Carolina27515
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17
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St John ME, Holzman R, Martin CH. Rapid adaptive evolution of scale-eating kinematics to a novel ecological niche. J Exp Biol 2020; 223:jeb217570. [PMID: 32029459 PMCID: PMC7097200 DOI: 10.1242/jeb.217570] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Accepted: 01/29/2020] [Indexed: 01/08/2023]
Abstract
The origins of novel trophic specialization, in which organisms begin to exploit resources for the first time, may be explained by shifts in behavior such as foraging preferences or feeding kinematics. One way to investigate behavioral mechanisms underlying ecological novelty is by comparing prey capture kinematics among species. We investigated the contribution of kinematics to the origins of a novel ecological niche for scale-eating within a microendemic adaptive radiation of pupfishes on San Salvador Island, Bahamas. We compared prey capture kinematics across three species of pupfish while they consumed shrimp and scales in the lab, and found that scale-eating pupfish exhibited peak gape sizes twice as large as in other species, but also attacked prey with a more obtuse angle between their lower jaw and suspensorium. We then investigated how this variation in feeding kinematics could explain scale-biting performance by measuring bite size (surface area removed) from standardized gelatin cubes. We found that a combination of larger peak gape and more obtuse lower jaw and suspensorium angles resulted in approximately 40% more surface area removed per strike, indicating that scale-eaters may reside on a performance optimum for scale biting. To test whether feeding performance could contribute to reproductive isolation between species, we also measured F1 hybrids and found that their kinematics and performance more closely resembled generalists, suggesting that F1 hybrids may have low fitness in the scale-eating niche. Ultimately, our results suggest that the evolution of strike kinematics in this radiation is an adaptation to the novel niche of scale eating.
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Affiliation(s)
- Michelle E St John
- Department of Integrative Biology, University of California, Berkeley, Berkeley, CA 94720, USA
- Museum of Vertebrate Zoology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Roi Holzman
- School of Zoology, Tel Aviv University, Eilat 6997801, Israel
- Inter-University Institute for Marine Sciences, Eilat 8810302, Israel
| | - Christopher H Martin
- Department of Integrative Biology, University of California, Berkeley, Berkeley, CA 94720, USA
- Museum of Vertebrate Zoology, University of California, Berkeley, Berkeley, CA 94720, USA
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18
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Domenici P, Seebacher F. The impacts of climate change on the biomechanics of animals: Themed Issue Article: Biomechanics and Climate Change. CONSERVATION PHYSIOLOGY 2020; 8:coz102. [PMID: 31976075 PMCID: PMC6956782 DOI: 10.1093/conphys/coz102] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Revised: 10/24/2019] [Accepted: 11/03/2019] [Indexed: 05/09/2023]
Abstract
Anthropogenic climate change induces unprecedented variability in a broad range of environmental parameters. These changes will impact material properties and animal biomechanics, thereby affecting animal performance and persistence of populations. Climate change implies warming at the global level, and it may be accompanied by altered wind speeds, wave action, ocean circulation, acidification as well as increased frequency of hypoxic events. Together, these environmental drivers affect muscle function and neural control and thereby movement of animals such as bird migration and schooling behaviour of fish. Altered environmental conditions will also modify material properties of animals. For example, ocean acidification, particularly when coupled with increased temperatures, compromises calcified shells and skeletons of marine invertebrates and byssal threads of mussels. These biomechanical consequences can lead to population declines and disintegration of habitats. Integrating biomechanical research with ecology is instrumental in predicting the future responses of natural systems to climate change and the consequences for ecosystem services such as fisheries and ecotourism.
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Affiliation(s)
- Paolo Domenici
- IAS-CNR, Località Sa Mardini, Torregrande, Oristano, 09170 Italy
| | - Frank Seebacher
- School of Life and Environmental Sciences A08, University of Sydney, Sydney, NSW 2006, Australia
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19
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Raffini F, Schneider RF, Franchini P, Kautt AF, Meyer A. Diving into divergence: Differentiation in swimming performances, physiology and gene expression between locally‐adapted sympatric cichlid fishes. Mol Ecol 2019; 29:1219-1234. [DOI: 10.1111/mec.15304] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2019] [Revised: 10/24/2019] [Accepted: 11/08/2019] [Indexed: 12/25/2022]
Affiliation(s)
- Francesca Raffini
- Lehrstuhl für Zoologie und Evolutionsbiologie Department of Biology University of Konstanz Konstanz Germany
- International Max Planck Research School (IMPRS) for Organismal Biology Max‐Planck‐Institut für Ornithologie Radolfzell Germany
- Max Planck Institute for Ornithology Radolfzell Germany
| | - Ralf F. Schneider
- Lehrstuhl für Zoologie und Evolutionsbiologie Department of Biology University of Konstanz Konstanz Germany
- International Max Planck Research School (IMPRS) for Organismal Biology Max‐Planck‐Institut für Ornithologie Radolfzell Germany
| | - Paolo Franchini
- Lehrstuhl für Zoologie und Evolutionsbiologie Department of Biology University of Konstanz Konstanz Germany
| | - Andreas F. Kautt
- Lehrstuhl für Zoologie und Evolutionsbiologie Department of Biology University of Konstanz Konstanz Germany
| | - Axel Meyer
- Lehrstuhl für Zoologie und Evolutionsbiologie Department of Biology University of Konstanz Konstanz Germany
- International Max Planck Research School (IMPRS) for Organismal Biology Max‐Planck‐Institut für Ornithologie Radolfzell Germany
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20
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MARTIN CHRISTOPHERH, RICHARDS EMILIEJ. The paradox behind the pattern of rapid adaptive radiation: how can the speciation process sustain itself through an early burst? ANNUAL REVIEW OF ECOLOGY, EVOLUTION, AND SYSTEMATICS 2019; 50:569-593. [PMID: 36237480 PMCID: PMC9555815 DOI: 10.1146/annurev-ecolsys-110617-062443] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/27/2023]
Abstract
Rapid adaptive radiation poses a distinct question apart from speciation and adaptation: what happens after one speciation event? That is, how are some lineages able to continue speciating through a rapid burst? This question connects global macroevolutionary patterns to microevolutionary processes. Here we review major features of rapid radiations in nature and their mismatch with theoretical models and what is currently known about speciation mechanisms. Rapid radiations occur on three major diversification axes - species richness, phenotypic disparity, and ecological diversity - with exceptional outliers on each axis. The paradox is that the hallmark early stage of adaptive radiation, a rapid burst of speciation and niche diversification, is contradicted by most existing speciation models which instead predict continuously decelerating speciation rates and niche subdivision through time. Furthermore, while speciation mechanisms such as magic traits, phenotype matching, and physical linkage of co-adapted alleles promote speciation, it is often not discussed how these mechanisms could promote multiple speciation events in rapid succession. Additional mechanisms beyond ecological opportunity are needed to understand how rapid radiations occur. We review the evidence for five emerging theories: 1) the 'transporter' hypothesis: introgression and the ancient origins of adaptive alleles, 2) the 'signal complexity' hypothesis: the dimensionality of sexual traits, 3) the connectivity of fitness landscapes, 4) 'diversity begets diversity', and 5) flexible stem/'plasticity first'. We propose new questions and predictions to guide future work on the mechanisms underlying the rare origins of rapid radiation.
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Affiliation(s)
- CHRISTOPHER H. MARTIN
- Department of Biology, University of North Carolina at Chapel Hill, NC, USA
- Integrative Biology and Museum of Vertebrate Zoology, University of California, Berkeley, CA, USA
| | - EMILIE J. RICHARDS
- Department of Biology, University of North Carolina at Chapel Hill, NC, USA
- Integrative Biology and Museum of Vertebrate Zoology, University of California, Berkeley, CA, USA
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21
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Martin CH, McGirr JA, Richards EJ, St. John ME. How to Investigate the Origins of Novelty: Insights Gained from Genetic, Behavioral, and Fitness Perspectives. Integr Org Biol 2019; 1:obz018. [PMID: 33791533 PMCID: PMC7671130 DOI: 10.1093/iob/obz018] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Biologists are drawn to the most extraordinary adaptations in the natural world, often referred to as evolutionary novelties, yet rarely do we understand the microevolutionary context underlying the origins of novel traits, behaviors, or ecological niches. Here we discuss insights gained into the origins of novelty from a research program spanning biological levels of organization from genotype to fitness in Caribbean pupfishes. We focus on a case study of the origins of novel trophic specialists on San Salvador Island, Bahamas and place this radiation in the context of other rapid radiations. We highlight questions that can be addressed about the origins of novelty at different biological levels, such as measuring the isolation of novel phenotypes on the fitness landscape, locating the spatial and temporal origins of adaptive variation contributing to novelty, detecting dysfunctional gene regulation due to adaptive divergence, and connecting behaviors with novel traits. Evolutionary novelties are rare, almost by definition, and we conclude that integrative case studies can provide insights into this rarity relative to the dynamics of adaptation to more common ecological niches and repeated parallel speciation, such as the relative isolation of novel phenotypes on fitness landscapes and the transient availability of ecological, genetic, and behavioral opportunities.
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Affiliation(s)
- C H Martin
- Department of Integrative Biology and Museum of Vertebrate Zoology, University of California, Berkeley, CA 94720, USA
| | - J A McGirr
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27514, USA
| | - E J Richards
- Department of Integrative Biology and Museum of Vertebrate Zoology, University of California, Berkeley, CA 94720, USA
| | - M E St. John
- Department of Integrative Biology and Museum of Vertebrate Zoology, University of California, Berkeley, CA 94720, USA
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22
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Seamone S, McCaffrey T, Syme D. Disc starts: the pectoral disc of stingrays promotes omnidirectional fast starts across the substrate. CAN J ZOOL 2019. [DOI: 10.1139/cjz-2018-0054] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We explored how the flattened and rounded pectoral disc of the ocellate river stingray (Potamotrygon motoro (Müller and Henle, 1841)) enables them to use the benthic plane during fast-start escape. Escape responses were elicited via prodding different locations around the pectoral disc and were recorded using video. Modulation of pectoral-fin movements that power swimming enabled omnidirectional escape across the substrate, with similar performance in all directions of escape. Hence, translation of the body did not necessarily have to follow the orientation of the head, overcoming the constraint of a rigid body axis. An increase in prod speed was associated with an increase in initial translational speed and acceleration away from the prod. As prod location shifted towards the snout, yaw rotation increased, eventually reorienting the fish into a forward swimming position away from the prod. Furthermore, P. motoro yawed with essentially zero turning radius, allowing reorientation of the head with simultaneous rapid translation away from the prod, and yaw rate during escape was substantially greater than reported during routine swimming for stingrays. We conclude that stingrays employ a distinctive approach to escape along the substrate, which we have termed disc starts, that results in effective manoeuvrability across the benthic environment despite limited longitudinal flexibility of the body and that challenges the concept of manoeuvrability typically used for fishes.
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Affiliation(s)
- S.G. Seamone
- Department of Biological Sciences, University of Calgary, 2500 University Drive NW, Calgary, AB T2N 1N4, Canada
- Department of Biological Sciences, University of Calgary, 2500 University Drive NW, Calgary, AB T2N 1N4, Canada
| | - T.M. McCaffrey
- Department of Biological Sciences, University of Calgary, 2500 University Drive NW, Calgary, AB T2N 1N4, Canada
- Department of Biological Sciences, University of Calgary, 2500 University Drive NW, Calgary, AB T2N 1N4, Canada
| | - D.A. Syme
- Department of Biological Sciences, University of Calgary, 2500 University Drive NW, Calgary, AB T2N 1N4, Canada
- Department of Biological Sciences, University of Calgary, 2500 University Drive NW, Calgary, AB T2N 1N4, Canada
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23
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Martinez CM, Wainwright PC. Extending the Geometric Approach for Studying Biomechanical Motions. Integr Comp Biol 2019; 59:684-695. [DOI: 10.1093/icb/icz104] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Abstract
Whether it is swimming, walking, eating, or jumping, motions are a fundamental way in which organisms interact with their environment. Understanding how morphology contributes to motion is a primary focus of kinematic research and is necessary for gaining insights into the evolution of functional systems. However, an element that is largely missing from traditional analyses of motion is the spatial context in which they occur. We explore an application of geometric morphometrics (GM) for analyzing and comparing motions to evaluate the outputs of biomechanical linkage models. We focus on a common model for oral jaw mechanics of perciform fishes, the fourbar linkage, using GM to summarize motion as a trajectory of shape change. Two traits derived from trajectories capture the total kinesis generated by a linkage (trajectory length) and the kinematic asynchrony (KA) of its mobile components (trajectory nonlinearity). Oral jaw fourbar data from two subfamilies of Malagasy cichlids were used to generate form–function landscapes, describing broad features of kinematic diversity. Our results suggest that kinesis and KA have complex relationships with fourbar morphology, each displaying a pattern in which different shapes possess equivalent kinematic trait values, known as many-to-one mapping of form-to-function. Additionally, we highlight the observation that KA captures temporal differences in the activation of motion components, a feature of kinesis that has long been appreciated but was difficult to measure. The methods used here to study fourbar linkages can also be applied to more complex biomechanical models and broadly to motions of live organisms. We suggest that they provide a suitable alternative to traditional approaches for evaluating linkage function and kinematics.
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Affiliation(s)
- C M Martinez
- Department of Evolution and Ecology, University of California, Davis, CA 95616, USA
| | - P C Wainwright
- Department of Evolution and Ecology, University of California, Davis, CA 95616, USA
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24
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Population genetic structure and species delimitation of a widespread, Neotropical dwarf gecko. Mol Phylogenet Evol 2019; 133:54-66. [DOI: 10.1016/j.ympev.2018.12.029] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2018] [Revised: 12/19/2018] [Accepted: 12/21/2018] [Indexed: 12/24/2022]
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25
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Whitford MD, Freymiller GA, Higham TE, Clark RW. Determinants of predation success: How to survive an attack from a rattlesnake. Funct Ecol 2019. [DOI: 10.1111/1365-2435.13318] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Affiliation(s)
- Malachi D. Whitford
- Department of Biology San Diego State University San Diego California
- Ecology Graduate Group University of California Davis California
| | - Grace A. Freymiller
- Department of Biology San Diego State University San Diego California
- Department of Evolution, Ecology, and Organismal Biology University of California Riverside California
| | - Timothy E. Higham
- Department of Evolution, Ecology, and Organismal Biology University of California Riverside California
| | - Rulon W. Clark
- Department of Biology San Diego State University San Diego California
- Chiricahua Desert Museum Rodeo New Mexico
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26
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Gough WT, Segre PS, Bierlich KC, Cade DE, Potvin J, Fish FE, Dale J, di Clemente J, Friedlaender AS, Johnston DW, Kahane-Rapport SR, Kennedy J, Long JH, Oudejans M, Penry G, Savoca MS, Simon M, Videsen SKA, Visser F, Wiley DN, Goldbogen JA. Scaling of swimming performance in baleen whales. J Exp Biol 2019; 222:jeb.204172. [DOI: 10.1242/jeb.204172] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Accepted: 09/24/2019] [Indexed: 12/11/2022]
Abstract
The scale-dependence of locomotor factors have long been studied in comparative biomechanics, but remain poorly understood for animals at the upper extremes of body size. Rorqual baleen whales include the largest animals, but we lack basic kinematic data about their movements and behavior below the ocean surface. Here we combined morphometrics from aerial drone photogrammetry, whale-borne inertial sensing tag data, and hydrodynamic modeling to study the locomotion of five rorqual species. We quantified changes in tail oscillatory frequency and cruising speed for individual whales spanning a threefold variation in body length, corresponding to an order of magnitude variation in estimated body mass. Our results showed that oscillatory frequency decreases with body length (∝ length−0.53) while cruising speed remains roughly invariant (∝ length0.08) at 2 m s−1. We compared these measured results for oscillatory frequency against simplified models of an oscillating cantilever beam (∝ length−1) and an optimized oscillating Strouhal vortex generator (∝ length−1). The difference between our length-scaling exponent and the simplified models suggests that animals are often swimming non-optimally in order to feed or perform other routine behaviors. Cruising speed aligned more closely with an estimate of the optimal speed required to minimize the energetic cost of swimming (∝ length0.07). Our results are among the first to elucidate the relationships between both oscillatory frequency and cruising speed and body size for free-swimming animals at the largest scale.
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Affiliation(s)
- William T. Gough
- Hopkins Marine Station, Stanford University, Pacific Grove, CA 93950, USA
| | - Paolo S. Segre
- Hopkins Marine Station, Stanford University, Pacific Grove, CA 93950, USA
| | - K. C. Bierlich
- Nicholas School of the Environment, Duke University, Beaufort, NC 28516, USA
| | - David E. Cade
- Hopkins Marine Station, Stanford University, Pacific Grove, CA 93950, USA
| | - Jean Potvin
- Department of Physics, Saint Louis University, St. Louis, MO 633103, USA
| | - Frank E. Fish
- Department of Biology, West Chester University, West Chester, PA 19383, USA
| | - Julian Dale
- Nicholas School of the Environment, Duke University, Beaufort, NC 28516, USA
| | | | - Ari S. Friedlaender
- Institute of Marine Sciences, University of California Santa Cruz, Santa Cruz, CA 95064, USA
| | - David W. Johnston
- Nicholas School of the Environment, Duke University, Beaufort, NC 28516, USA
| | | | - John Kennedy
- Department of Physics, Saint Louis University, St. Louis, MO 633103, USA
| | - John H. Long
- Departments of Biology and Cognitive Science, Vassar College, Poughkeepsie, NY 12604, USA
| | | | - Gwenith Penry
- Department of Zoology, Institute for Coastal and Marine Research, Nelson Mandela University, Port Elizabeth, South Africa
| | - Matthew S. Savoca
- Hopkins Marine Station, Stanford University, Pacific Grove, CA 93950, USA
| | - Malene Simon
- Greenland Climate Research Centre, Greenland Institute of Natural Resources, Kivioq 2, 3900 Nuuk, Greenland
| | - Simone K. A. Videsen
- Zoophysiology, Department of Bioscience, Faculty of Science and Technology, Aarhus University, Aarhus 8000, Denmark
| | - Fleur Visser
- Kelp Marine Research, Hoorn, the Netherlands
- Institute for Biodiversity and Ecosystem Dynamics – Freshwater and Marine Ecology, University of Amsterdam, the Netherlands
- Royal Netherlands Institute for Sea Research, Texel, the Netherlands
| | - David N. Wiley
- US National Oceanic and Atmospheric Administration, Office of National Marine Sanctuaries, Stellwagen Bank National Marine Sanctuary, Scituate, MA 02066, USA
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Boerma DB, Barrantes JP, Chung C, Chaverri G, Swartz SM. Specialized landing maneuvers in Spix's disk-winged bats (Thyroptera tricolor) reveal linkage between roosting ecology and landing biomechanics. J Exp Biol 2019; 222:jeb.204024. [DOI: 10.1242/jeb.204024] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Accepted: 09/16/2019] [Indexed: 11/20/2022]
Abstract
Disk-winged bats (Thyroptera spp.) are the only mammals that use suction to cling to smooth surfaces, having evolved suction cups at the bases of the thumbs and feet that facilitate attachment to specialized roosts: the protective funnels of ephemeral furled leaves. We predicted that this combination of specialized morphology and roosting ecology is coupled with concomitantly specialized landing maneuvers. We tested this prediction by investigating landings in Thyroptera tricolor using high-speed videography and a force-measuring landing pad disguised within a furled leaf analogue. We found that their landing maneuvers are distinct among all bats observed to date. Landings comprised three phases: 1) approach, 2) ballistic descent, and 3) adhesion. During approach, bats adjusted trajectory until centered in front of and above the landing site, typically the leaf's protruding apex. Bats initiated ballistic descent by arresting the wingbeat cycle and tucking their wings to descend toward the leaf, simultaneously extending the thumb-disks cranially. Adhesion commenced when the thumb-disks contacted the landing site. Significant body reorientation occurred only during adhesion, and only after contact, when the thumb-disks acted as fulcra about which the bats pitched 75.02±26.17° (mean±s.d.) to swing the foot-disks into contact. Landings imposed 6.98±1.89 bodyweights of peak impact force. These landing mechanics are likely influenced by the orientation, spatial constraints, and compliance of furled leaf roosts. Roosting ecology influences critical aspects of bat biology, and taken as a case-study, this work suggests that roosting habits and landing mechanics could be functionally linked across bats.
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Affiliation(s)
- David B. Boerma
- Department of Ecology and Evolutionary Biology, Brown University, Providence, RI 02906, USA
| | - José P. Barrantes
- Escuela de Ciencias de la Computación e Informática, Universidad de Costa Rica, San José 11501, Costa Rica
| | - Charles Chung
- The Peddie School, Hightstown, New Jersey 08520, USA
| | - Gloriana Chaverri
- Recinto de Golfito, Universidad de Costa Rica, Golfito 60701, Costa Rica
- Smithsonian Tropical Research Institute, Apartado 0843-03092, Balboa, Ancón, República de Panamá
| | - Sharon M. Swartz
- Department of Ecology and Evolutionary Biology, Brown University, Providence, RI 02906, USA
- School of Engineering, Brown University, Providence, RI 02906, USA
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Salmon M, Mott CR, Bresette MJ. Biphasic allometric growth in juvenile green turtles Chelonia mydas. ENDANGER SPECIES RES 2018. [DOI: 10.3354/esr00930] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Jamniczky HA, Le A, Barry TN, Rogers SM. Freshwater influence is associated with differences in bone mineral density and armour configuration in threespine stickleback (Gasterosteus aculeatus). Facets (Ott) 2018. [DOI: 10.1139/facets-2017-0120] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Threespine stickleback ( Gasterosteus aculeatus Linnaeus, 1758) exhibit a well-documented reduction in plate number associated with adaptation to freshwater environments. We tested the hypothesis that changes in plate number are accompanied by changes in plate bone mineral density and plate shape, reflecting the presence of a complex plate “armour” phenotype and a complex adaptive response to different selective pressures in changing habitats. We used traditional and novel morphometric techniques to characterize armour traits from stickleback occupying three marine habitats and one tidally influenced freshwater stream in southwestern British Columbia. Stickleback inhabiting marine environments share a conserved plate phenotype that includes a full complement of highly mineralized plates that exhibit a characteristic density profile along the plate. Stickleback inhabiting tidally influenced fresh water display an average reduction in plate number along with increased variation in number and reduced total mineralization despite maintenance of a marine-like density profile. Further, we found that although mineralization and armour shape are correlated with size, after accounting for size variation in both traits remains attributable to habitat. Our results hint at an important role for development in structuring phenotypic variation during the process of adaptive change in stickleback.
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Affiliation(s)
- Heather A. Jamniczky
- Department of Cell Biology & Anatomy, Cumming School of Medicine, University of Calgary, 3330 Hospital Drive NW, Calgary, AB T2N 4Z6, Canada
| | - Amie Le
- Department of Cell Biology & Anatomy, Cumming School of Medicine, University of Calgary, 3330 Hospital Drive NW, Calgary, AB T2N 4Z6, Canada
| | - Tegan N. Barry
- Department of Biological Sciences, University of Calgary, 2500 University Drive NW, Calgary, AB T2N 1N4, Canada
| | - Sean M. Rogers
- Department of Biological Sciences, University of Calgary, 2500 University Drive NW, Calgary, AB T2N 1N4, Canada
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Schmitz O. Predator and prey functional traits: understanding the adaptive machinery driving predator-prey interactions. F1000Res 2017; 6:1767. [PMID: 29043073 PMCID: PMC5621104 DOI: 10.12688/f1000research.11813.1] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/28/2017] [Indexed: 12/16/2022] Open
Abstract
Predator–prey relationships are a central component of community dynamics. Classic approaches have tried to understand and predict these relationships in terms of consumptive interactions between predator and prey species, but characterizing the interaction this way is insufficient to predict the complexity and context dependency inherent in predator–prey relationships. Recent approaches have begun to explore predator–prey relationships in terms of an evolutionary-ecological game in which predator and prey adapt to each other through reciprocal interactions involving context-dependent expression of functional traits that influence their biomechanics. Functional traits are defined as any morphological, behavioral, or physiological trait of an organism associated with a biotic interaction. Such traits include predator and prey body size, predator and prey personality, predator hunting mode, prey mobility, prey anti-predator behavior, and prey physiological stress. Here, I discuss recent advances in this functional trait approach. Evidence shows that the nature and strength of many interactions are dependent upon the relative magnitude of predator and prey functional traits. Moreover, trait responses can be triggered by non-consumptive predator–prey interactions elicited by responses of prey to risk of predation. These interactions in turn can have dynamic feedbacks that can change the context of the predator–prey interaction, causing predator and prey to adapt their traits—through phenotypically plastic or rapid evolutionary responses—and the nature of their interaction. Research shows that examining predator–prey interactions through the lens of an adaptive evolutionary-ecological game offers a foundation to explain variety in the nature and strength of predator–prey interactions observed in different ecological contexts.
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Affiliation(s)
- Oswald Schmitz
- School of Forestry and Environmental Studies, Yale University, 370 Prospect Street, New Haven, CT, 06515, USA
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31
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Morris MRJ, Petrovitch E, Bowles E, Jamniczky HA, Rogers SM. Exploring Jordan's rule in Pacific three-spined stickleback Gasterosteus aculeatus. JOURNAL OF FISH BIOLOGY 2017; 91:645-663. [PMID: 28776706 DOI: 10.1111/jfb.13379] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2016] [Accepted: 06/05/2017] [Indexed: 06/07/2023]
Abstract
Coastal marine Gasterosteus aculeatus were captured from seven locations along the Pacific coast of North America, ranging across 21·8° latitude to test Jordan's rule, i.e. that vertebral number should increase with increasing latitude for related populations of fish. Vertebral number significantly increased with increasing latitude for both total and caudal vertebral number. Increasing length with latitude (sensu Bergmann's rule) was also supported, but the predictions for Jordan's rule held when controlling for standard length. Pleomerism was weakly evidenced. Gasterosteus aculeatus exhibited sexual dimorphism for Jordan's rule, with both sexes having more vertebrae at higher latitudes, but only males showing a positive association between latitude and the ratio of caudal to abdominal vertebrae. The number of dorsal- and anal-fin rays and basals increased with increasing latitude, while pectoral-fin ray number decreased. This study reinforces the association between phenotypic variation and environmental variation in marine populations of G. aculeatus.
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Affiliation(s)
- M R J Morris
- Department of Biological Sciences, University of Calgary, 2500 University Dr NW, Calgary, Alberta, T2N 1N4, Canada
| | - E Petrovitch
- Department of Biological Sciences, University of Calgary, 2500 University Dr NW, Calgary, Alberta, T2N 1N4, Canada
| | - E Bowles
- Department of Biological Sciences, University of Calgary, 2500 University Dr NW, Calgary, Alberta, T2N 1N4, Canada
| | - H A Jamniczky
- McCaig Institute for Bone and Joint Health, Department of Cell Biology & Anatomy, University of Calgary, 3330 Hospital Dr NW, Calgary, Alberta, T2N 4Z6, Canada
| | - S M Rogers
- Department of Biological Sciences, University of Calgary, 2500 University Dr NW, Calgary, Alberta, T2N 1N4, Canada
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Higham TE, Jamniczky HA, Jagnandan K, Smith SJ, Barry TN, Rogers SM. Comparative dynamics of suction feeding in marine and freshwater three-spined stickleback, Gasterosteus aculeatus: kinematics and geometric morphometrics. Biol J Linn Soc Lond 2017. [DOI: 10.1093/biolinnean/blx069] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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Higham TE, Clark RW, Collins CE, Whitford MD, Freymiller GA. Rattlesnakes are extremely fast and variable when striking at kangaroo rats in nature: Three-dimensional high-speed kinematics at night. Sci Rep 2017; 7:40412. [PMID: 28084400 PMCID: PMC5234031 DOI: 10.1038/srep40412] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Accepted: 12/06/2016] [Indexed: 11/09/2022] Open
Abstract
Predation plays a central role in the lives of most organisms. Predators must find and subdue prey to survive and reproduce, whereas prey must avoid predators to do the same. The resultant antagonistic coevolution often leads to extreme adaptations in both parties. Few examples capture the imagination like a rapid strike from a venomous snake. However, almost nothing is known about strike performance of viperid snakes under natural conditions. We obtained high-speed (500 fps) three-dimensional video in the field (at night using infrared lights) of Mohave rattlesnakes (Crotalus scutulatus) attempting to capture Merriam's kangaroo rats (Dipodomys merriami). Strikes occurred from a range of distances (4.6 to 20.6 cm), and rattlesnake performance was highly variable. Missed capture attempts resulted from both rapid escape maneuvers and poor strike accuracy. Maximum velocity and acceleration of some rattlesnake strikes fell within the range of reported laboratory values, but some far exceeded most observations. Thus, quantifying rapid predator-prey interactions in the wild will propel our understanding of animal performance.
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Affiliation(s)
- Timothy E Higham
- Department of Biology, University of California, Riverside, CA 92521, USA
| | - Rulon W Clark
- Department of Biology, San Diego State University, San Diego, CA 92182, USA
| | - Clint E Collins
- Department of Biology, University of California, Riverside, CA 92521, USA
| | - Malachi D Whitford
- Department of Biology, San Diego State University, San Diego, CA 92182, USA
| | - Grace A Freymiller
- Department of Biology, San Diego State University, San Diego, CA 92182, USA
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Haines GE, Sanderson SL. Integration of swimming kinematics and ram suspension feeding in a model American paddlefish, Polyodon spathula. J Exp Biol 2017; 220:4535-4547. [DOI: 10.1242/jeb.166835] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2017] [Accepted: 10/11/2017] [Indexed: 11/20/2022]
Abstract
Ram suspension-feeding fishes swim with an open mouth to force water through the oral cavity and extract prey items that are too small to be pursued individually. Recent research has indicated that, rather than using a dead-end mechanical sieve, American paddlefish (Polyodon spathula Walbaum) employ vortical cross-step filtration. In this filtration mechanism, vortical flow that is generated posterior to the branchial arches organizes crossflow filtration processes into a spatial structure across the gill rakers. Despite the known impact of locomotor kinematics on fluid flow around the bodies of swimming fish, the effects of locomotor kinematics on filtration mechanisms in ram suspension feeders are unknown. Potential temporal organization of filtration mechanisms in ram suspension-feeding fish has not been studied previously. We investigated the effects of locomotor kinematics associated with undulatory swimming on intra-oral flow patterns and food particle transport. A mechanized model of the oral cavity was used to simulate the swimming kinematics of suspension-feeding paddlefish. We recorded fluctuations of flow speed and pressure within the model, which occurred at a frequency that corresponded with the frequency of the model's strides. Using the mechanized model in a flow tank seeded with Artemia cysts, we also showed that swimming kinematics aided the transport of this simulated food to the posterior margins of the gill slots, although the time scale of this transport is expected to vary with prey parameters such as size and concentration. Dye stream experiments revealed that, while stable vortical flow formed due to flow separation downstream of backward-facing steps in control trials, vortical flow structures in mechanized trials repeatedly formed and shed. These findings suggest strong integration between locomotor and feeding systems in ram suspension-feeding fishes.
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Affiliation(s)
- Grant E. Haines
- Department of Biology, College of William & Mary, Williamsburg, VA 23187-8795, USA
| | - S. Laurie Sanderson
- Department of Biology, College of William & Mary, Williamsburg, VA 23187-8795, USA
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