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Freiler MK, Deckard ML, Proffitt MR, Troy Smith G. Differential expression of steroid-related genes across electrosensory brain regions in two sexually dimorphic species of electric knifefish. Gen Comp Endocrinol 2024; 355:114549. [PMID: 38797340 PMCID: PMC11265523 DOI: 10.1016/j.ygcen.2024.114549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2023] [Revised: 05/14/2024] [Accepted: 05/15/2024] [Indexed: 05/29/2024]
Abstract
The production of communication signals can be modulated by hormones acting on the brain regions that regulate these signals. However, less is known about how signal perception is regulated by hormones. The electrocommunication signals of weakly electric fishes are sexually dimorphic, sensitive to hormones, and vary across species. The neural circuits that regulate the production and perception of these signals are also well-characterized, and electric fishes are thus an excellent model to examine the neuroendocrine regulation of sensorimotor mechanisms of communication. We investigated (1) whether steroid-related genes are expressed in sensory brain regions that process communication signals; and (2) whether this expression differs across sexes and species that have different patterns of sexual dimorphism in their signals. Apteronotus leptorhynchus and Apteronotus albifrons produce continuous electric organ discharges (EODs) that are used for communication. Two brain regions, the electrosensory lateral line lobe (ELL) and the dorsal torus semicircularis (TSd), process inputs from electroreceptors to allow fish to detect and discriminate electrocommunication signals. We used qPCR to quantify the expression of genes for two androgen receptors (ar1, ar2), two estrogen receptors (esr1, esr2b), and aromatase (cyp19a1b). Four out of five steroid-related genes were expressed in both sensory brain regions, and their expression often varied between sexes and species. These results suggest that expression of steroid-related genes in the brain may differentially influence how EOD signals are encoded across species and sexes, and that gonadal steroids may coordinately regulate central circuits that control both the production and perception of EODs.
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Affiliation(s)
- Megan K Freiler
- Department of Biology, Indiana University, 1001 E 3(rd) St., Bloomington, IN 47405, United States; Center for the Integrative Study of Animal Behavior, Indiana University, 409 N. Park Ave, Bloomington, IN 47405, United States.
| | - Mikayla L Deckard
- Department of Biology, Indiana University, 1001 E 3(rd) St., Bloomington, IN 47405, United States
| | - Melissa R Proffitt
- Department of Biology, Indiana University, 1001 E 3(rd) St., Bloomington, IN 47405, United States; Center for the Integrative Study of Animal Behavior, Indiana University, 409 N. Park Ave, Bloomington, IN 47405, United States
| | - G Troy Smith
- Department of Biology, Indiana University, 1001 E 3(rd) St., Bloomington, IN 47405, United States; Center for the Integrative Study of Animal Behavior, Indiana University, 409 N. Park Ave, Bloomington, IN 47405, United States
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2
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Proffitt MR, Smith GT. Species variation in steroid hormone-related gene expression contributes to species diversity in sexually dimorphic communication in electric fishes. Horm Behav 2024; 164:105576. [PMID: 38852479 PMCID: PMC11330740 DOI: 10.1016/j.yhbeh.2024.105576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Revised: 05/08/2024] [Accepted: 05/31/2024] [Indexed: 06/11/2024]
Abstract
Sexually dimorphic behaviors are often regulated by gonadal steroid hormones. Species diversity in behavioral sex differences may arise as expression of genes mediating steroid action in brain regions controlling these behaviors evolves. The electric communication signals of apteronotid knifefishes are an excellent model for comparatively studying neuroendocrine regulation of sexually dimorphic behavior. These fish produce and detect weak electric organ discharges (EODs) for electrolocation and communication. EOD frequency (EODf), controlled by the medullary pacemaker nucleus (Pn), is sexually dimorphic and regulated by androgens and estrogens in some species, but is sexually monomorphic and unaffected by hormones in other species. We quantified expression of genes for steroid receptors, metabolizing enzymes, and cofactors in the Pn of two species with sexually dimorphic EODf (Apteronotus albifrons and Apteronotus leptorhynchus) and two species with sexually monomorphic EODf ("Apteronotus" bonapartii and Parapteronotus hasemani). The "A." bonapartii Pn expressed lower levels of androgen receptor (AR) genes than the Pn of species with sexually dimorphic EODf. In contrast, the P. hasemani Pn robustly expressed AR genes, but expressed lower levels of genes for 5α-reductases, which convert androgens to more potent metabolites, and higher levels of genes for 17β-hydroxysteroid dehydrogenases that oxidize androgens and estrogens to less potent forms. These findings suggest that sexual monomorphism of EODf arose convergently via two different mechanisms. In "A." bonapartii, reduced Pn expression of ARs likely results in insensitivity of EODf to androgens, whereas in P. hasemani, gonadal steroids may be metabolically inactivated in the Pn, reducing their potential to influence EODf.
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Affiliation(s)
- Melissa R Proffitt
- Department of Biology, Indiana University, 1001 E. 3(rd) St., Bloomington, IN 47405, USA; Center for the Integrative Study of Animal Behavior, Indiana University, 409 N. Park Ave., Bloomington, IN 47505, USA
| | - G Troy Smith
- Department of Biology, Indiana University, 1001 E. 3(rd) St., Bloomington, IN 47405, USA; Center for the Integrative Study of Animal Behavior, Indiana University, 409 N. Park Ave., Bloomington, IN 47505, USA.
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3
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Bolton PE, Ryder TB, Dakin R, Houtz JL, Moore IT, Balakrishnan CN, Horton BM. Neurogenomic landscape associated with status-dependent cooperative behaviour. Mol Ecol 2024:e17327. [PMID: 38511765 DOI: 10.1111/mec.17327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Revised: 01/04/2024] [Accepted: 03/07/2024] [Indexed: 03/22/2024]
Abstract
The neurogenomic mechanisms mediating male-male reproductive cooperative behaviours remain unknown. We leveraged extensive transcriptomic and behavioural data on a neotropical bird species (Pipra filicauda) that performs cooperative courtship displays to understand these mechanisms. In this species, the cooperative display is modulated by testosterone, which promotes cooperation in non-territorial birds, but suppresses cooperation in territory holders. We sought to understand the neurogenomic underpinnings of three related traits: social status, cooperative display behaviour and testosterone phenotype. To do this, we profiled gene expression in 10 brain nuclei spanning the social decision-making network (SDMN), and two key endocrine tissues that regulate social behaviour. We associated gene expression with each bird's behavioural and endocrine profile derived from 3 years of repeated measures taken from free-living birds in the Ecuadorian Amazon. We found distinct landscapes of constitutive gene expression were associated with social status, testosterone phenotype and cooperation, reflecting the modular organization and engagement of neuroendocrine tissues. Sex-steroid and neuropeptide signalling appeared to be important in mediating status-specific relationships between testosterone and cooperation, suggesting shared regulatory mechanisms with male aggressive and sexual behaviours. We also identified differentially regulated genes involved in cellular activity and synaptic potentiation, suggesting multiple mechanisms underpin these genomic states. Finally, we identified SDMN-wide gene expression differences between territorial and floater males that could form the basis of 'status-specific' neurophysiological phenotypes, potentially mediated by testosterone and growth hormone. Overall, our findings provide new, systems-level insights into the mechanisms of cooperative behaviour and suggest that differences in neurogenomic state are the basis for individual differences in social behaviour.
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Affiliation(s)
- Peri E Bolton
- Department of Biology, East Carolina University, Greenville, North Carolina, USA
- Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, District of Columbia, USA
| | - T Brandt Ryder
- Migratory Bird Center, Smithsonian National Zoological Park, Washington, District of Columbia, USA
- Bird Conservancy of the Rockies, Fort Collins, Colorado, USA
| | - Roslyn Dakin
- Migratory Bird Center, Smithsonian National Zoological Park, Washington, District of Columbia, USA
- Department of Biology, Carleton University, Ottawa, Ontario, Canada
| | - Jennifer L Houtz
- Department of Biology, Millersville University, Millersville, Pennsylvania, USA
- Department of Biology, Allegheny College, Meadville, Pennsylvania, USA
| | - Ignacio T Moore
- Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia, USA
| | | | - Brent M Horton
- Department of Biology, Millersville University, Millersville, Pennsylvania, USA
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4
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Smiley KO, Munley KM, Aghi K, Lipshutz SE, Patton TM, Pradhan DS, Solomon-Lane TK, Sun SED. Sex diversity in the 21st century: Concepts, frameworks, and approaches for the future of neuroendocrinology. Horm Behav 2024; 157:105445. [PMID: 37979209 PMCID: PMC10842816 DOI: 10.1016/j.yhbeh.2023.105445] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Revised: 10/11/2023] [Accepted: 10/18/2023] [Indexed: 11/20/2023]
Abstract
Sex is ubiquitous and variable throughout the animal kingdom. Historically, scientists have used reductionist methodologies that rely on a priori sex categorizations, in which two discrete sexes are inextricably linked with gamete type. However, this binarized operationalization does not adequately reflect the diversity of sex observed in nature. This is due, in part, to the fact that sex exists across many levels of biological analysis, including genetic, molecular, cellular, morphological, behavioral, and population levels. Furthermore, the biological mechanisms governing sex are embedded in complex networks that dynamically interact with other systems. To produce the most accurate and scientifically rigorous work examining sex in neuroendocrinology and to capture the full range of sex variability and diversity present in animal systems, we must critically assess the frameworks, experimental designs, and analytical methods used in our research. In this perspective piece, we first propose a new conceptual framework to guide the integrative study of sex. Then, we provide practical guidance on research approaches for studying sex-associated variables, including factors to consider in study design, selection of model organisms, experimental methodologies, and statistical analyses. We invite fellow scientists to conscientiously apply these modernized approaches to advance our biological understanding of sex and to encourage academically and socially responsible outcomes of our work. By expanding our conceptual frameworks and methodological approaches to the study of sex, we will gain insight into the unique ways that sex exists across levels of biological organization to produce the vast array of variability and diversity observed in nature.
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Affiliation(s)
- Kristina O Smiley
- Department of Psychological and Brain Sciences, University of Massachusetts Amherst, 639 North Pleasant Street, Morrill IVN Neuroscience, Amherst, MA 01003, USA.
| | - Kathleen M Munley
- Department of Psychology, University of Houston, 3695 Cullen Boulevard, Houston, TX 77204, USA.
| | - Krisha Aghi
- Department of Integrative Biology and Physiology, University of California Los Angeles, 405 Hilgard Ave, Los Angeles, CA 90095, USA.
| | - Sara E Lipshutz
- Department of Biology, Duke University, 130 Science Drive, Durham, NC 27708, USA.
| | - Tessa M Patton
- Bioinformatics Program, Loyola University Chicago, 1032 West Sheridan Road, LSB 317, Chicago, IL 60660, USA.
| | - Devaleena S Pradhan
- Department of Biological Sciences, Idaho State University, 921 South 8th Avenue, Mail Stop 8007, Pocatello, ID 83209, USA.
| | - Tessa K Solomon-Lane
- Scripps, Pitzer, Claremont McKenna Colleges, 925 North Mills Avenue, Claremont, CA 91711, USA.
| | - Simón E D Sun
- Cold Spring Harbor Laboratory, 1 Bungtown Road, Cold Spring Harbor, NY 11724, USA.
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5
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Freiler MK, Smith GT. Neuroendocrine mechanisms contributing to the coevolution of sociality and communication. Front Neuroendocrinol 2023; 70:101077. [PMID: 37217079 PMCID: PMC10527162 DOI: 10.1016/j.yfrne.2023.101077] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 04/19/2023] [Accepted: 05/15/2023] [Indexed: 05/24/2023]
Abstract
Communication is inherently social, so signaling systems should evolve with social systems. The 'social complexity hypothesis' posits that social complexity necessitates communicative complexity and is generally supported in vocalizing mammals. This hypothesis, however, has seldom been tested outside the acoustic modality, and comparisons across studies are confounded by varying definitions of complexity. Moreover, proximate mechanisms underlying coevolution of sociality and communication remain largely unexamined. In this review, we argue that to uncover how sociality and communication coevolve, we need to examine variation in the neuroendocrine mechanisms that coregulate social behavior and signal production and perception. Specifically, we focus on steroid hormones, monoamines, and nonapeptides, which modulate both social behavior and sensorimotor circuits and are likely targets of selection during social evolution. Lastly, we highlight weakly electric fishes as an ideal system in which to comparatively address the proximate mechanisms underlying relationships between social and signal diversity in a novel modality.
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Affiliation(s)
- Megan K Freiler
- Department of Biology, Indiana University, Bloomington, IN, United States; Center for the Integrative Study of Animal Behavior, Indiana University, Bloomington, IN, United States.
| | - G Troy Smith
- Department of Biology, Indiana University, Bloomington, IN, United States; Center for the Integrative Study of Animal Behavior, Indiana University, Bloomington, IN, United States
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Fuxjager MJ, Ryder TB, Moody NM, Alfonso C, Balakrishnan CN, Barske J, Bosholn M, Boyle WA, Braun EL, Chiver I, Dakin R, Day LB, Driver R, Fusani L, Horton BM, Kimball RT, Lipshutz S, Mello CV, Miller ET, Webster MS, Wirthlin M, Wollman R, Moore IT, Schlinger BA. Systems biology as a framework to understand the physiological and endocrine bases of behavior and its evolution-From concepts to a case study in birds. Horm Behav 2023; 151:105340. [PMID: 36933440 DOI: 10.1016/j.yhbeh.2023.105340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 02/10/2023] [Accepted: 02/21/2023] [Indexed: 03/18/2023]
Abstract
Organismal behavior, with its tremendous complexity and diversity, is generated by numerous physiological systems acting in coordination. Understanding how these systems evolve to support differences in behavior within and among species is a longstanding goal in biology that has captured the imagination of researchers who work on a multitude of taxa, including humans. Of particular importance are the physiological determinants of behavioral evolution, which are sometimes overlooked because we lack a robust conceptual framework to study mechanisms underlying adaptation and diversification of behavior. Here, we discuss a framework for such an analysis that applies a "systems view" to our understanding of behavioral control. This approach involves linking separate models that consider behavior and physiology as their own networks into a singular vertically integrated behavioral control system. In doing so, hormones commonly stand out as the links, or edges, among nodes within this system. To ground our discussion, we focus on studies of manakins (Pipridae), a family of Neotropical birds. These species have numerous physiological and endocrine specializations that support their elaborate reproductive displays. As a result, manakins provide a useful example to help imagine and visualize the way systems concepts can inform our appreciation of behavioral evolution. In particular, manakins help clarify how connectedness among physiological systems-which is maintained through endocrine signaling-potentiate and/or constrain the evolution of complex behavior to yield behavioral differences across taxa. Ultimately, we hope this review will continue to stimulate thought, discussion, and the emergence of research focused on integrated phenotypes in behavioral ecology and endocrinology.
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Affiliation(s)
- Matthew J Fuxjager
- Department of Ecology, Evolution, and Organismal Biology, Brown University, Providence, RI 02906, USA.
| | - T Brandt Ryder
- Migratory Bird Center, Smithsonian Conservation Biology Institute, National Zoological Park, Washington, DC 20013, USA
| | - Nicole M Moody
- Department of Ecology, Evolution, and Organismal Biology, Brown University, Providence, RI 02906, USA
| | - Camilo Alfonso
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA 24060, USA
| | | | - Julia Barske
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA 90095, USA
| | - Mariane Bosholn
- Animal Behavior Lab, Ecology Department, National Institute for Amazon Research, Manaus, Amazonas, Brazil
| | - W Alice Boyle
- Division of Biology, Kansas State University, Manhattan, KS 66506, USA
| | - Edward L Braun
- Department of Biology, University of Florida, Gainesville, FL 32611, USA
| | - Ioana Chiver
- GIGA Neurosciences, University of Liège, Liege, Belgium
| | - Roslyn Dakin
- Migratory Bird Center, Smithsonian Conservation Biology Institute, National Zoological Park, Washington, DC 20013, USA
| | - Lainy B Day
- Department of Biology, University of Mississippi, University, MS 38677, USA
| | - Robert Driver
- Department of Biology, East Carolina University, Greenville, NC 27858, USA
| | - Leonida Fusani
- Department of Behavioral and Cognitive Biology, University of Vienna, and Konrad Lorenz Institute of Ethology, University of Veterinary Medicine, Vienna
| | - Brent M Horton
- Department of Biology, Millersville University, Millersville, PA 17551, USA
| | - Rebecca T Kimball
- Department of Biology, University of Florida, Gainesville, FL 32611, USA
| | - Sara Lipshutz
- Department of Biology, Loyola University Chicago, Chicago, IL 60660, USA
| | - Claudio V Mello
- Department of Behavioral Neuroscience, Oregon Health and Science University, Portland, OR 97239, USA
| | | | - Michael S Webster
- Cornell Lab of Ornithology, Ithaca, NY 14853, USA; Department of Neurobiology and Behavior, Cornell University, Ithaca, NY 14853, USA
| | - Morgan Wirthlin
- Computational Biology Department, Carnegie Melon University, Pittsburgh, PA 15213, USA
| | - Roy Wollman
- Department of Physiology and Integrative Biology, University of California, Los Angeles, CA 90095, USA
| | - Ignacio T Moore
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA 24060, USA
| | - Barney A Schlinger
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA 90095, USA; Department of Physiology and Integrative Biology, University of California, Los Angeles, CA 90095, USA; Smithsonian Tropical Research Institute, Panama City, Panama.
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7
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Rosvall KA. Evolutionary endocrinology and the problem of Darwin's tangled bank. Horm Behav 2022; 146:105246. [PMID: 36029721 DOI: 10.1016/j.yhbeh.2022.105246] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 06/20/2022] [Accepted: 08/10/2022] [Indexed: 11/04/2022]
Abstract
Like Darwin's tangled bank of biodiversity, the endocrine mechanisms that give rise to phenotypic diversity also exhibit nearly endless forms. This tangled bank of mechanistic diversity can prove problematic as we seek general principles on the role of endocrine mechanisms in phenotypic evolution. A key unresolved question is therefore: to what degree are specific endocrine mechanisms re-used to bring about replicated phenotypic evolution? Related areas of inquiry are booming in molecular ecology, but behavioral traits are underrepresented in this literature. Here, I leverage the rich comparative tradition in evolutionary endocrinology to evaluate whether and how certain mechanisms may be repeated hotspots of behavioral evolutionary change. At one extreme, mechanisms may be parallel, such that evolution repeatedly uses the same gene or pathway to arrive at multiple independent (or, convergent) origins of a particular behavioral trait. At the other extreme, the building blocks of behavior may be unique, such that outwardly similar phenotypes are generated via lineage-specific mechanisms. This review synthesizes existing case studies, phylogenetic analyses, and experimental evolutionary research on mechanistic parallelism in animal behavior. These examples show that the endocrine building blocks of behavior have some elements of parallelism across replicated evolutionary events. However, support for parallelism is variable among studies, at least some of which relates to the level of complexity at which we consider sameness (i.e. pathway vs. gene level). Moving forward, we need continued experimentation and better testing of neutral models to understand whether, how - and critically, why - mechanism A is used in one lineage and mechanism B is used in another. We also need continued growth of large-scale comparative analyses, especially those that can evaluate which endocrine parameters are more or less likely to undergo parallel evolution alongside specific behavioral traits. These efforts will ultimately deepen understanding of how and why hormone-mediated behaviors are constructed the way that they are.
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Affiliation(s)
- Kimberly A Rosvall
- Indiana University, Bloomington, USA; Department of Biology, USA; Center for the Integrative Study of Animal Behavior, USA.
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8
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Schwark RW, Fuxjager MJ, Schmidt MF. Proposing a neural framework for the evolution of elaborate courtship displays. eLife 2022; 11:e74860. [PMID: 35639093 PMCID: PMC9154748 DOI: 10.7554/elife.74860] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Accepted: 05/06/2022] [Indexed: 11/15/2022] Open
Abstract
In many vertebrates, courtship occurs through the performance of elaborate behavioral displays that are as spectacular as they are complex. The question of how sexual selection acts upon these animals' neuromuscular systems to transform a repertoire of pre-existing movements into such remarkable (if not unusual) display routines has received relatively little research attention. This is a surprising gap in knowledge, given that unraveling this extraordinary process is central to understanding the evolution of behavioral diversity and its neural control. In many vertebrates, courtship displays often push the limits of neuromuscular performance, and often in a ritualized manner. These displays can range from songs that require rapid switching between two independently controlled 'voice boxes' to precisely choreographed acrobatics. Here, we propose a framework for thinking about how the brain might not only control these displays, but also shape their evolution. Our framework focuses specifically on a major midbrain area, which we view as a likely important node in the orchestration of the complex neural control of behavior used in the courtship process. This area is the periaqueductal grey (PAG), as studies suggest that it is both necessary and sufficient for the production of many instinctive survival behaviors, including courtship vocalizations. Thus, we speculate about why the PAG, as well as its key inputs, might serve as targets of sexual selection for display behavior. In doing so, we attempt to combine core ideas about the neural control of behavior with principles of display evolution. Our intent is to spur research in this area and bring together neurobiologists and behavioral ecologists to more fully understand the role that the brain might play in behavioral innovation and diversification.
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Affiliation(s)
- Ryan W Schwark
- Department of Biology, University of PennsylvaniaPhiladelphiaUnited States
- Neuroscience Graduate Group, University of PennsylvaniaPhiladelphiaUnited States
| | - Matthew J Fuxjager
- Department of Ecology, Evolution, and Organismal Biology, Brown UniversityProvidenceUnited States
| | - Marc F Schmidt
- Department of Biology, University of PennsylvaniaPhiladelphiaUnited States
- Neuroscience Graduate Group, University of PennsylvaniaPhiladelphiaUnited States
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9
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Fuxjager MJ, Fusani L, Schlinger BA. Physiological innovation and the evolutionary elaboration of courtship behaviour. Anim Behav 2022. [DOI: 10.1016/j.anbehav.2021.03.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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10
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Alfonso C, Jones BC, Vernasco BJ, Moore IT. Integrative Studies of Sexual Selection in Manakins, a Clade of Charismatic Tropical Birds. Integr Comp Biol 2021; 61:1267-1280. [PMID: 34251421 DOI: 10.1093/icb/icab158] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 05/07/2021] [Accepted: 07/07/2021] [Indexed: 11/14/2022] Open
Abstract
The neotropical manakins (family Pipridae) provide a great opportunity for integrative studies of sexual selection as nearly all of the 51 species are lek-breeding, an extreme form of polygyny, and highly sexually dimorphic both in appearance and behavior. Male courtship displays are often elaborate and include auditory cues, both vocal and mechanical, as well as visual elements. In addition, the displays are often extremely rapid, highly acrobatic, and, in some species, multiple males perform coordinated displays that form the basis of long-term coalitions. Male manakins also exhibit unique neuroendocrine, physiological, and anatomical adaptations to support the performance of these complex displays and the maintenance of their intricate social systems. The Manakin Genomics Research Coordination Network (Manakin RCN, https://www.manakinsrcn.org) has brought together researchers (many in this symposium and this issue) from across disciplines to address the implications of sexual selection on evolution, ecology, behavior, and physiology in manakins. The objective of this paper is to present some of the most pertinent and integrative manakin research as well as introducing the papers presented in this issue. The results discussed at the manakin symposium, part of the 2021 Society for Integrative and Comparative Biology Conference, highlight the remarkable genomic, behavioral, and physiological adaptations as well as the evolutionary causes and consequences of strong sexual selection pressures that are evident in manakins.
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Affiliation(s)
- Camilo Alfonso
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA 24061, USA
| | - Blake C Jones
- Science and Mathematics, Bennington College, 1 College Dr., Bennington, VT 05201, USA
| | - Ben J Vernasco
- School of Biological Sciences, Washington State University, Pullman, WA, USA
| | - Ignacio T Moore
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA 24061, USA
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11
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Zheng DJ, Singh A, Phelps SM. Conservation and dimorphism in androgen receptor distribution in Alston's singing mouse (Scotinomys teguina). J Comp Neurol 2021; 529:2539-2557. [PMID: 33576501 DOI: 10.1002/cne.25108] [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: 04/27/2020] [Revised: 12/25/2020] [Accepted: 12/28/2020] [Indexed: 12/19/2022]
Abstract
Because of their roles in courtship and intrasexual competition, sexual displays are often sexually dimorphic, but we know little about the mechanisms that produce such dimorphism. Among mammals, one example is the vocalization of Alston's singing mouse (Scotinomys teguina), which consists of a series of rapidly repeated, frequency-modulated notes. The rate and duration of songs is sexually dimorphic and androgen responsive. To understand the neuronal mechanisms underlying this sexual dimorphism, we map the sites of androgen sensitivity throughout the brain, focusing analysis along a pathway that spans from limbic structures to vocal motor regions. We find widespread expression of AR immunoreactivity (AR-ir) throughout limbic structures important for social behavior and vocalization, including the lateral septum, extended amygdala, preoptic area and hypothalamus. We also find extensive AR staining along previously documented vocal motor pathways, including the periaqueductal gray, parabrachial nucleus, and nucleus ambiguus, the last of which innervates intrinsic laryngeal muscles. Lastly, AR-ir is also evident in sensory areas such as the medial geniculate, inferior, and superior colliculi. A quantitative analysis revealed that males exhibited more AR-ir than females, a pattern that was most pronounced in the hypothalamus. Despite the elaboration of vocalization in singing mice, comparison with prior literature suggests that the broad pattern of AR-ir may be conserved across a wide range of rodents. Together these data identify brain nuclei well positioned to shape the sexually dimorphic vocalization of S. teguina and suggest that such androgen modulation of vocalization is evolutionary conserved among rodents.
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Affiliation(s)
- Da-Jiang Zheng
- Department of Integrative Biology, The University of Texas at Austin, Austin, Texas, USA
| | - Aditi Singh
- Department of Integrative Biology, The University of Texas at Austin, Austin, Texas, USA
| | - Steven M Phelps
- Department of Integrative Biology, The University of Texas at Austin, Austin, Texas, USA
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12
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Bennett KFP, Lim HC, Braun MJ. Sexual selection and introgression in avian hybrid zones: Spotlight on Manacus. Integr Comp Biol 2021; 61:1291-1309. [PMID: 34128981 DOI: 10.1093/icb/icab135] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Hybrid zones offer a window into the processes and outcomes of evolution, from species formation or fusion to genomic underpinnings of specific traits and isolating mechanisms. Sexual selection is believed to be an important factor in speciation processes, and hybrid zones present special opportunities to probe its impact. The manakins (Aves, Pipridae) are a promising group in which to study the interplay of sexual selection and natural hybridization: they show substantial variation across the family in the strength of sexual selection they experience, they readily hybridize within and between genera, and they appear to have formed hybrid species, a rare event in birds. A hybrid zone between two manakins in the genus Manacus is unusual in that plumage and behavioral traits of one species have introgressed asymmetrically into populations of the second species through positive sexual selection, then apparently stalled at a river barrier. This is one of a handful of documented examples of asymmetric sexual trait introgression with a known selective mechanism. It offers opportunities to examine reproductive isolation, introgression, plumage color evolution, and natural factors enhancing or constraining the effects of sexual selection in real time. Here, we review previous work in this system, propose new hypotheses for observed patterns, and recommend approaches to test them.
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Affiliation(s)
- Kevin F P Bennett
- Behavior, Ecology, Evolution, and Systematics Program, University of Maryland, College Park, MD, USA.,Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, DC, USA
| | - Haw Chuan Lim
- Department of Biology, George Mason University, Manassas, VA, USA.,Center for Conservation Genomics, Smithsonian Conservation Biology Institute, Washington, DC, USA
| | - Michael J Braun
- Behavior, Ecology, Evolution, and Systematics Program, University of Maryland, College Park, MD, USA.,Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, DC, USA
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13
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Schaedler LM, Taylor LU, Prum RO, Anciães M. CONSTRAINT AND FUNCTION IN THE PREDEFINITIVE PLUMAGES OF MANAKINS (AVES: PIPRIDAE). Integr Comp Biol 2021; 61:1363-1377. [PMID: 33956153 DOI: 10.1093/icb/icab063] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Birds with delayed plumage maturation exhibit a drab predefinitive plumage, often despite gonad maturation, before developing the definitive plumage associated with increased reproductive success. Manakins are a diverse clade of neotropical lekking birds with extreme sexual dichromatism, radical sexual displays, and a unique diversity in the predefinitive plumages of males across species. Here, we provide the first full review of the natural history of manakin predefinitive plumages as the basis for qualitatively addressing the six major hypotheses about the production and function of predefinitive plumages. We find little evidence to support the possibilities that manakin predefinitive plumages are directly constrained by inflexible molt schedules, resource limitations to definitive coloration, or hormonal ties to reproductive behaviors. There is little evidence that could support a crypsis function, although direct experimentation is needed, and mimicry is refuted except for one unusual species in which predefinitive males sire young. Instead, evidence from a handful of well-studied species suggests that predefinitive plumages help young males explicitly signal their social status, and thereby gain entry to the social hierarchies which dictate future reproductive success. Our conclusions are especially influenced by the unique fact that males of at least 11 species throughout the family exhibit multiple predefinitive plumage stages with distinctively male patches. For each hypothesis, we highlight ways in which a better knowledge of female and young male birds offers critical opportunities for the use of manakins as a model clade.
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Affiliation(s)
- Laura M Schaedler
- Programa de Pós-Graduação em Ecologia, Instituto Nacional de Pesquisas da Amazônia, Manaus, AM 69067-375, Brazil
| | - Liam U Taylor
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT 06511, USA
| | - Richard O Prum
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT 06511, USA
| | - Marina Anciães
- Programa de Pós-Graduação em Ecologia, Instituto Nacional de Pesquisas da Amazônia, Manaus, AM 69067-375, Brazil
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14
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Schlinger BA, Chiver I. Behavioral Sex Differences and Hormonal Control in a Bird with an Elaborate Courtship Display. Integr Comp Biol 2021; 61:1319-1328. [PMID: 33885763 DOI: 10.1093/icb/icab033] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Gonadal hormones can activate performance of reproductive behavior in adult animals, but also organize sex-specific neural circuits developmentally. Few studies have examined the hormonal basis of sex differences in the performance of elaborate, physically complex and energetic male courtship displays. Here we describe our studies over more than 20 years examining sex difference and hormonal control of courtship in Golden-collared manakins (Manacus vitellinus) of Panamaian rainforests. Our recent studies of birds studied in an artificial "lek" in a rainforest aviary provide many new insights. Wild and captive males and females differ markedly in their performance of male-typical behaviors. Testosterone (T) treatment augments performance of virtually all of these behaviors in juvenile males with low levels of circulating T. By contrast, T-treatment of females (with low circulating T) either failed to activate some behaviors or activated male behaviors weakly or strongly. These results are discussed within a framework of our appreciation for hormonal vs genetic basis for sex differences in behavior with speculation about the neural mechanisms producing these patterns of hormonal activation.
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Affiliation(s)
- Barney A Schlinger
- Department of Integrative Biology and Physiology, University of California, Los Angeles, CA 90095.,Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA 90095.,Smithsonian Tropical Research Institute, Panama City, Panama
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15
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Newhouse DJ, Vernasco BJ. Developing a transcriptomic framework for testing testosterone-mediated handicap hypotheses. Gen Comp Endocrinol 2020; 298:113577. [PMID: 32739436 DOI: 10.1016/j.ygcen.2020.113577] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Revised: 07/21/2020] [Accepted: 07/25/2020] [Indexed: 12/17/2022]
Abstract
Sexually selected traits are hypothesized to be honest signals of individual quality due to the costs associated with their maintenance, development, and/or production. Testosterone, a sex steroid associated with the development and/or production of sexually selected traits, has been proposed to enforce the honesty of sexually selected traits via its immunosuppressive effects (i.e., the Immunocompetence Handicap Hypothesis) and/or by influencing an individual's exposure/susceptibility to oxidative stress (i.e., the Oxidation Handicap Hypothesis). Previous work testing these hypotheses has primarily focused on physiological measurements of immunity or oxidative stress, but little is known about the molecular pathways by which testosterone could influence immunity and/or oxidative stress pathways. To further understand the transcriptomic consequences of experimentally elevated testosterone in the context of handicap hypotheses, we used previously published RNA-seq data from studies that measured the transcriptome of individuals treated with either a testosterone-filled or an empty (i.e., control) implant. Two studies encompassing three species of bird and three tissue types fit our selection criteria and we reanalyzed the data using weighted gene co-expression network analysis. Testosterone-treated individuals exhibited signatures of immunosuppression and our results describe the molecular pathways underlying this effect. We also provide some evidence to suggest that the transcriptomic signature of immunosuppression is evolutionarily conserved between the three species. While our results provide no evidence to suggest testosterone mediates handicaps via pathways associated with oxidative stress, they do support the hypothesis that testosterone enforces the honesty of sexually-selected traits by influencing an individual's immunocompetence. Overall, this study develops a framework for testing testosterone-mediated handicap hypotheses and provides guidelines for future integrative and comparative studies focused on the proximate mechanisms mediating sexually selected traits.
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Affiliation(s)
- Daniel J Newhouse
- Department of Biology, East Carolina University, Greenville, NC, USA.
| | - Ben J Vernasco
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, USA
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16
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Vernasco BJ, Moore IT. Testosterone as a mediator of the tradeoff between cooperation and competition in the context of cooperative reproductive behaviors. Gen Comp Endocrinol 2020; 288:113369. [PMID: 31857075 DOI: 10.1016/j.ygcen.2019.113369] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Revised: 11/18/2019] [Accepted: 12/13/2019] [Indexed: 11/20/2022]
Abstract
Behavioral tradeoffs occur when the expression of one behavior detracts from the expression of another. Understanding the proximate mediators of behavioral tradeoffs is important as these tradeoffs can act as potential constraints on evolutionary responses to selection. Here, we describe the tradeoff between cooperation and competition faced by species that exhibit cooperative reproductive behaviors and propose that testosterone is a key hormonal mediator of the tradeoff. Cooperative reproductive behaviors occur when multiple individuals coordinate their efforts to gain a reproductive advantage over other individuals and/or those individuals attempting to reproduce in absence of cooperation. We propose that testosterone, a sex steroid known to mediate a number of physiological and behavioral actions associated with reproductive competition, is involved in mediating the tradeoff between cooperation and competition. To support this proposition, we first describe the importance of individual variation in behavior to the evolution of cooperative behaviors. We then describe how proximate mechanisms represent a prominent source of individual variation in social behaviors and highlight evidence suggesting testosterone mediates variation in cooperative behaviors. Two case studies in which the relationship between testosterone and cooperative behaviors have been investigated in detail are then summarized. Throughout we highlight the importance of studying individual variation to understand the mechanistic basis of behaviors, behavioral tradeoffs, and the evolution of cooperative reproductive behaviors more broadly.
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Affiliation(s)
- Ben J Vernasco
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, USA; School of Biological Sciences, Washington State University, Pullman, WA, USA.
| | - Ignacio T Moore
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, USA
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17
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Schlinger BA. Multidisciplinary science and the growth and future of behavioral neuroendocrinology: A perspective. Horm Behav 2020; 118:104618. [PMID: 31783027 DOI: 10.1016/j.yhbeh.2019.104618] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 10/30/2019] [Accepted: 10/31/2019] [Indexed: 01/24/2023]
Affiliation(s)
- Barney A Schlinger
- Department of Integrative Biology and Physiology, University of California, Los Angeles, CA 90095, USA; Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA 90095, USA; Smithsonian Tropical Research Institute, Panama City, Panama.
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18
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Vernasco BJ, Horton BM, Moore IT, Ryder TB. Reduced cooperative behavior as a cost of high testosterone in a lekking passerine bird. Behav Ecol 2019. [DOI: 10.1093/beheco/arz201] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Abstract
Many studies have identified the reproductive benefits of cooperative behaviors, yet few have identified the mechanisms that underlie these behaviors. Mechanistic studies can inform our understanding of why some individuals are more or less cooperative, as well as identify the physiological constraints imposed upon the evolution of reproductive traits. Male wire-tailed manakins (Pipra filicauda) exhibit cooperative courtship behaviors and more cooperative territory holders have been shown to exhibit higher reproductive success. To begin to understand the proximate basis of cooperative display behaviors, we conducted both an observational study and an experimental study. Because coordinated courtship displays underlie this form of cooperation, our study also examined both the hormonal and social drivers of individual variation in courtship behavior more broadly (e.g., courtship display rates). Our observational study revealed that males with higher testosterone levels performed fewer cooperative display bouts. In addition, our experimental study demonstrated that the proportion of a male’s courtship displays that were cooperative decreased after being administered a testosterone-filled hormone implant. We found no relationship between an individual’s courtship display effort (i.e., display rate and time spent performing courtship displays) and circulating testosterone in either study. However, more cooperative males spent a greater proportion of time performing courtship displays than did less cooperative males, suggesting that testosterone may indirectly mediate courtship display behaviors by influencing a territory holder’s cooperative behavior. Overall, both our observational and experimental results suggest that reduced cooperative behavior is a cost of maintaining high levels of testosterone for territory-holding males.
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Affiliation(s)
- Ben J Vernasco
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, USA
| | - Brent M Horton
- Department of Biology, Millersville University, Millersville, PA, USA
| | - Ignacio T Moore
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, USA
| | - T Brandt Ryder
- Migratory Bird Center, Smithsonian Conservation Biology Institute,, Washington DC, USA
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19
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Hoke KL, Adkins-Regan E, Bass AH, McCune AR, Wolfner MF. Co-opting evo-devo concepts for new insights into mechanisms of behavioural diversity. ACTA ACUST UNITED AC 2019; 222:222/8/jeb190058. [PMID: 30988051 DOI: 10.1242/jeb.190058] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
We propose that insights from the field of evolutionary developmental biology (or 'evo-devo') provide a framework for an integrated understanding of the origins of behavioural diversity and its underlying mechanisms. Towards that goal, in this Commentary, we frame key questions in behavioural evolution in terms of molecular, cellular and network-level properties with a focus on the nervous system. In this way, we highlight how mechanistic properties central to evo-devo analyses - such as weak linkage, versatility, exploratory mechanisms, criticality, degeneracy, redundancy and modularity - affect neural circuit function and hence the range of behavioural variation that can be filtered by selection. We outline why comparative studies of molecular and neural systems throughout ontogeny will provide novel insights into diversity in neural circuits and behaviour.
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Affiliation(s)
- Kim L Hoke
- Department of Biology, Colorado State University, Fort Collins, CO 80523, USA
| | - Elizabeth Adkins-Regan
- Department of Psychology, Cornell University, Ithaca, NY 14853, USA.,Department of Neurobiology and Behavior, Cornell University, Ithaca, NY 14853, USA
| | - Andrew H Bass
- Department of Neurobiology and Behavior, Cornell University, Ithaca, NY 14853, USA
| | - Amy R McCune
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY 14853, USA
| | - Mariana F Wolfner
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
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20
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21
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Fuxjager MJ, Schuppe ER. Androgenic signaling systems and their role in behavioral evolution. J Steroid Biochem Mol Biol 2018; 184:47-56. [PMID: 29883693 DOI: 10.1016/j.jsbmb.2018.06.004] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Revised: 05/25/2018] [Accepted: 06/04/2018] [Indexed: 12/13/2022]
Abstract
Sex steroids mediate the organization and activation of masculine reproductive phenotypes in diverse vertebrate taxa. However, the effects of sex steroid action in this context vary tremendously, in that steroid action influences reproductive physiology and behavior in markedly different ways (even among closely related species). This leads to the idea that the mechanisms underlying sex steroid action similarly differ across vertebrates in a manner that supports diversification of important sexual traits. Here, we highlight the Evolutionary Potential Hypothesis as a framework for understanding how androgen-dependent reproductive behavior evolves. This idea posits that the cellular mechanisms underlying androgenic action can independently evolve within a given target tissue to adjust the hormone's functional effects. The result is a seemingly endless number of permutations in androgenic signaling pathways that can be mapped onto the incredible diversity of reproductive phenotypes. One reason this hypothesis is important is because it shifts current thinking about the evolution of steroid-dependent traits away from an emphasis on circulating steroid levels and toward a focus on molecular mechanisms of hormone action. To this end, we also provide new empirical data suggesting that certain cellular modulators of androgen action-namely, the co-factors that dynamically adjust transcritpional effects of steroid action either up or down-are also substrates on which evolution can act. We then close the review with a detailed look at a case study in the golden-collared manakin (Manacus vitellinus). Work in this tropical bird shows how androgenic signaling systems are modified in specific parts of the skeletal muscle system to enhance motor performance necessary to produce acrobatic courtship displays. Altogether, this paper seeks to develop a platform to better understand how steroid action influences the evolution of complex animal behavior.
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Affiliation(s)
- Matthew J Fuxjager
- Department of Biology, Wake Forest University, 455 Vine Street, Winston-Salem, NC 27101, United States.
| | - Eric R Schuppe
- Department of Biology, Wake Forest University, 455 Vine Street, Winston-Salem, NC 27101, United States
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22
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Barske J, Eghbali M, Kosarussavadi S, Choi E, Schlinger BA. The heart of an acrobatic bird. Comp Biochem Physiol A Mol Integr Physiol 2018; 228:9-17. [PMID: 30367962 DOI: 10.1016/j.cbpa.2018.10.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Accepted: 10/11/2018] [Indexed: 10/28/2022]
Abstract
The courtship behavior of some species of birds can be energetically demanding, but it is unknown if cardiovascular specializations enable such behaviors. While performing a highly acrobatic courtship dance, heart rate in male golden-collared manakins increases briefly to 1300 beats per minute, among the highest heart rates recorded in any bird or mammal. We hypothesize that male manakins have enhanced cardiovascular capabilities to meet these demands on the heart. Using histological and molecular techniques, we examined manakin heart structure as well as expression of genes involved in Ca2+ handling, action potential duration, steroidal signaling and cardiac growth. These measures were also made on the hearts of zebra finches, a similar-sized bird with limited cardiovascular demands. Compared to the zebra finch, the manakin had a significantly thicker left ventricular (LV) muscle (cross-sectional thickness of the free LV wall and septum) with a smaller LV chamber. In addition, compared to zebra finches, manakin hearts had significantly greater gene expression of ryanodine receptors as well as androgen receptors. Testosterone (T) treatment of non-breeding manakins (with low T) increased gene expression of the Ca2+ pump SERCA. These observations suggest that hearts of breeding male manakins require specialized Ca2+ handling and androgens may facilitate manakin cardiovascular function.
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Affiliation(s)
- J Barske
- Departments of Ecology and Evolutionary Biology, Integrative Biology and Physiology, Laboratory of Neuroendocrinology, Brain Research Institute, University of California, Los Angeles, USA.
| | - M Eghbali
- Department of Anaesthesiology, Laboratory of Neuroendocrinology, University of California, Los Angeles, USA
| | - S Kosarussavadi
- Departments of Ecology and Evolutionary Biology, Integrative Biology and Physiology, Laboratory of Neuroendocrinology, Brain Research Institute, University of California, Los Angeles, USA
| | - E Choi
- Departments of Ecology and Evolutionary Biology, Integrative Biology and Physiology, Laboratory of Neuroendocrinology, Brain Research Institute, University of California, Los Angeles, USA
| | - B A Schlinger
- Departments of Ecology and Evolutionary Biology, Integrative Biology and Physiology, Laboratory of Neuroendocrinology, Brain Research Institute, University of California, Los Angeles, USA
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23
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Schlinger BA, Paul K, Monks DA. Muscle, a conduit to brain for hormonal control of behavior. Horm Behav 2018; 105:58-65. [PMID: 30040953 DOI: 10.1016/j.yhbeh.2018.07.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Revised: 07/03/2018] [Accepted: 07/12/2018] [Indexed: 12/13/2022]
Abstract
SBN Elsevier Lecture Investigation into mechanisms whereby hormones control behavior often starts with actions on central nervous system (CNS) motivation and motor systems and is followed by assessment of CNS drive of coordinated striated muscle contractions. Here we turn this perspective on its head by discussing ways in which hormones might first act on muscle that then secondarily drive upstream the evolution and function of the CNS. While there is a lengthy history for consideration of this perspective, newly discovered properties of muscle signaling reveal novel mechanisms that may well be captured by endocrine systems and thus of interest to behavioral endocrinologists.
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Affiliation(s)
- Barney A Schlinger
- Department of Integrative Biology and Physiology, University of California, Los Angeles, United States of America; Department of Ecology and Evolutionary Biology, University of California, Los Angeles, United States of America; Laboratory of Neuroendocrinology, Brain Research Institute, University of California, Los Angeles, United States of America; Smithsonian Tropical Research Institute, Panama City, Panama.
| | - Ketema Paul
- Department of Integrative Biology and Physiology, University of California, Los Angeles, United States of America; Laboratory of Neuroendocrinology, Brain Research Institute, University of California, Los Angeles, United States of America
| | - D Ashley Monks
- Department of Psychology, University of Toronto Mississauga, Canada; Cell and Systems Biology, University of Toronto, Canada
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24
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Eaton J, Pradhan DS, Barske J, Fusani L, Canoine V, Schlinger BA. 3β-HSD expression in the CNS of a manakin and finch. Gen Comp Endocrinol 2018; 256:43-49. [PMID: 28935582 PMCID: PMC5742301 DOI: 10.1016/j.ygcen.2017.09.016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Revised: 09/01/2017] [Accepted: 09/16/2017] [Indexed: 12/26/2022]
Abstract
The prohormone, dehydroepiandrosterone (DHEA) circulates in vertebrate blood with the potential for actions on target tissues including the central nervous system (CNS). Many actions of DHEA require its conversion into more active products, some of which are catalyzed by the enzyme 3β-hydroxysteroid-dehydrogenase/isomerase (3β-HSD). Studies of birds show both expression and activity of 3β-HSD in brain and its importance in regulating social behavior. In oscine songbirds, 3β-HSD is expressed at reasonably high levels in brain, possibly linked to their complex neural circuitry controlling song. Studies also indicate that circulating DHEA may serve as the substrate for neural 3β-HSD to produce active steroids that activate behavior during non-breeding seasons. In the golden-collared manakin (Manacus vitellinus), a sub-oscine bird, low levels of courtship behavior are displayed by males when circulating testosterone levels are basal. Therefore, we asked whether DHEA circulates in blood of manakins and whether the brain expresses 3β-HSD mRNA. Given that the spinal cord is a target of androgens and likely important in regulating acrobatic movements, we also examined expression of this enzyme in the manakin spinal cord. For comparison, we examined expression levels with those of an oscine songbird, the zebra finch (Taeniopygia guttata), a species in which brain, but not spinal cord, 3β-HSD has been well studied. DHEA was detected in manakin blood at levels similar to that seen in other species. As described previously, 3β-HSD was expressed in all zebra finch brain regions examined. By contrast, expression of 3β-HSD was only detected in the manakin hypothalamus where levels were greater than zebra finches. In spinal cord, 3β-HSD was detected in some but not all regions in both species. These data point to species differences and indicate that manakins have the substrate and neural machinery to convert circulating DHEA into potentially active androgens and/or estrogens.
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Affiliation(s)
- Joy Eaton
- Department of Integrative Biology and Physiology, University of California, Los Angeles, United States
| | - Devaleena S Pradhan
- Department of Integrative Biology and Physiology, University of California, Los Angeles, United States; Laboratory for Neuroendocrinology, University of California, Los Angeles, United States.
| | - Julia Barske
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, United States
| | - Leonida Fusani
- Department of Cognitive Biology, University of Vienna, Austria; Konrad Lorenz Institute of Ethology, University of Veterinary Medicine, Vienna, Austria
| | - Virginie Canoine
- Department of Behavioural Biology, University of Vienna, Austria
| | - Barney A Schlinger
- Department of Integrative Biology and Physiology, University of California, Los Angeles, United States; Laboratory for Neuroendocrinology, University of California, Los Angeles, United States; Department of Ecology and Evolutionary Biology, University of California, Los Angeles, United States
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25
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Fuxjager MJ, Fusani L, Goller F, Trost L, Maat AT, Gahr M, Chiver I, Ligon RM, Chew J, Schlinger BA. Neuromuscular mechanisms of an elaborate wing display in the golden-collared manakin ( Manacus vitellinus). ACTA ACUST UNITED AC 2017; 220:4681-4688. [PMID: 29061685 DOI: 10.1242/jeb.167270] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 10/18/2017] [Indexed: 01/26/2023]
Abstract
Many species perform elaborate physical displays to court mates and compete with rivals, but the biomechanical mechanisms underlying such behavior are poorly understood. We address this issue by studying the neuromuscular origins of display behavior in a small tropical passerine bird, the golden-collared manakin (Manacus vitellinus). Males of this species court females by dancing around the forest floor and rapidly snapping their wings together above their back. Using radio-telemetry, we collected electromyographic (EMG) recordings from the three main muscles that control avian forelimb movement, and found how these different muscles are activated to generate various aspects of display behavior. The muscle that raises the wing (supracoracoideus, SC) and the primary muscle that retracts the wing (scapulohumeralis caudalis, SH) were activated during the wing-snap, whereas the pectoralis (PEC), the main wing depressor, was not. SC activation began before wing elevation commenced, with further activation occurring gradually. By contrast, SH activation was swift, starting soon after wing elevation and peaking shortly after the snap. The intensity of this SH activation was comparable to that which occurs during flapping, whereas the SC activation was much lower. Thus, light activation of the SC likely helps position the wings above the back, so that quick, robust SH activation can drive these appendages together to generate the firecracker-like snap sonation. This is one of the first looks at the neuromuscular mechanisms that underlie the actuation of a dynamic courtship display, and it demonstrates that even complex, whole-body display movements can be studied with transmitter-aided EMG techniques.
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Affiliation(s)
- Matthew J Fuxjager
- Department of Biology, Wake Forest University, Winston-Salem, NC 27109, USA
| | - Leonida Fusani
- Konrad Lorenz Institute of Ethology, University of Veterinary Medicine, Vienna, Austria.,Department of Cognitive Biology, University of Vienna, 1160 Vienna, Austria
| | - Franz Goller
- Department of Biology, University of Utah, Salt Lake City, UT 84112, USA
| | - Lisa Trost
- Department of Behavioral Neurobiology, Max Planck Institute for Ornithology, Seewiesen, 82319, Germany
| | - Andries Ter Maat
- Department of Behavioral Neurobiology, Max Planck Institute for Ornithology, Seewiesen, 82319, Germany
| | - Manfred Gahr
- Department of Behavioral Neurobiology, Max Planck Institute for Ornithology, Seewiesen, 82319, Germany
| | - Ioana Chiver
- Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - R Miller Ligon
- Department of Biology, Wake Forest University, Winston-Salem, NC 27109, USA
| | - Jennifer Chew
- Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Barney A Schlinger
- Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, CA 90095, USA.,Department of Ecology and Evolution, University of California, Los Angeles, Los Angeles, CA 90095, USA.,Smithsonian Tropical Research Institute, Balboa, Ancón, Panama
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26
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Evolution of the androgen-induced male phenotype. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2017; 204:81-92. [DOI: 10.1007/s00359-017-1215-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Revised: 09/11/2017] [Accepted: 09/14/2017] [Indexed: 12/20/2022]
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27
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Insight into the neuroendocrine basis of signal evolution: a case study in foot-flagging frogs. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2017; 204:61-70. [DOI: 10.1007/s00359-017-1218-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 09/25/2017] [Accepted: 09/26/2017] [Indexed: 01/15/2023]
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28
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Chiver I, Schlinger BA. Clearing up the court: sex and the endocrine basis of display-court manipulation. Anim Behav 2017. [DOI: 10.1016/j.anbehav.2017.07.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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29
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Schuppe ER, Pradhan DS, Thonkulpitak K, Drilling C, Black M, Grober MS. Sex differences in neuromuscular androgen receptor expression and sociosexual behavior in a sex changing fish. PLoS One 2017; 12:e0177711. [PMID: 28520775 PMCID: PMC5433761 DOI: 10.1371/journal.pone.0177711] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Accepted: 05/02/2017] [Indexed: 12/16/2022] Open
Abstract
Androgen signaling, via receptor binding, is critical for regulating the physiological and morphological foundations of male-typical reproductive behavior in vertebrates. Muscles essential for male courtship behavior and copulation are highly sensitive to androgens. Differences in the distribution and density of the androgen receptor (AR) are important for maintaining dimorphic musculature and thus may provide for anatomical identification of sexually selected traits. In Lythrypnus dalli, a bi-directional hermaphroditic teleost fish, both sexes produce agonistic approach displays, but reproductive behavior is sexually dimorphic. The male-specific courtship behavior is characterized by rapid jerky movements (involving dorsal fin erection) towards a female or around their nest. Activation of the supracarinalis muscle is involved in dorsal fin contributions to both agonistic and sociosexual behavior in other fishes, suggesting that differences in goby sexual behavior may be reflected in sexual dimorphism in AR signaling in this muscle. We examined sex differences in the local distribution of AR in supracarinalis muscle and spinal cord. Our results demonstrate that males do express more AR in the supracarinalis muscle relative to females, but there was no sex difference in the number of spinal motoneurons expressing AR. Interestingly, AR expression in the supracarinalis muscle was also related to rates of sociosexual behavior in males, providing evidence that sexual selection may influence muscle androgenic sensitivity to enhance display vigor. Sex differences in the distribution and number of cells expressing AR in the supracarinalis muscle may underlie the expression of dimorphic behaviors in L. dalli.
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Affiliation(s)
- Eric R. Schuppe
- Department of Biology, Georgia State University, Atlanta, Georgia, United States of America
- * E-mail:
| | - Devaleena S. Pradhan
- Department of Biology, Georgia State University, Atlanta, Georgia, United States of America
| | - Kevin Thonkulpitak
- Department of Biology, Georgia State University, Atlanta, Georgia, United States of America
| | - Cathleen Drilling
- Department of Biology, Georgia State University, Atlanta, Georgia, United States of America
| | - Michael Black
- Department of Biology, Georgia State University, Atlanta, Georgia, United States of America
- Neuroscience Institute, Georgia State University, Atlanta, Georgia
| | - Matthew S. Grober
- Department of Biology, Georgia State University, Atlanta, Georgia, United States of America
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Day LB, Lindsay WR. Associations between Manakin Display Complexity and Both Body and Brain Size Challenge Assumptions of Allometric Correction: A Response to Gutierrez-Ibanez et al. (2016). BRAIN, BEHAVIOR AND EVOLUTION 2016; 87:227-31. [DOI: 10.1159/000446341] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Fuxjager MJ, Schuppe ER, Hoang J, Chew J, Shah M, Schlinger BA. Expression of 5α- and 5β-reductase in spinal cord and muscle of birds with different courtship repertoires. Front Zool 2016; 13:25. [PMID: 27293470 PMCID: PMC4901407 DOI: 10.1186/s12983-016-0156-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Accepted: 05/30/2016] [Indexed: 12/19/2022] Open
Abstract
Background Through the actions of one or more isoforms of the enzyme 5α-reductase in many male reproductive tissues, circulating testosterone (T) undergoes metabolic conversion into 5α-dihydrotestosterone (DHT), which binds to and activates androgen receptors (AR) with greater potency than T. In birds, T is also subject to local inactivation into 5β-DHT by the enzyme 5β-reductase. Male golden-collared manakins perform an androgen-dependent and physically elaborate courtship display, and these birds express androgen receptors in skeletal muscles and spinal cord at levels far greater than those expressed in species with more limited courtship routines, including male zebra finches. To determine if local T metabolism facilitates or impedes activation of male manakin courtship, we examined expression of two isoforms of 5α-reductase, as well as 5β-reductase, in forelimb muscles and spinal cords of males and females of the two aforementioned species. Results We found that all enzymes were expressed in all tissues, with patterns that partially predict a functional role for 5α-reductase in these birds, especially in both muscle and spinal cord of male manakins. Moreover, we found that 5β-reductase was markedly different between species, with far lower levels in golden-collared manakins, compared to zebra finches. Thus, modification to neuromuscular deactivation of T may also play a functional role in adaptive behavioral modulation. Conclusions Given that such a role for 5α-reductase in androgen-sensitive mammalian skeletal muscle is in dispute, our data suggest that, in birds, local metabolism may play a key role in providing active androgenic substrates to peripheral neuromuscular systems. Similarly, we provide the first evidence that 5β-reductase is expressed broadly through an organism and may be an important factor that regulates androgenic modulation of neuromuscular functioning.
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Affiliation(s)
- Matthew J Fuxjager
- Department of Biology, Wake Forest University, 228 Winston Hall, Winston-Salem, NC 27109 USA ; Center for Molecular Communication and Signaling, Wake Forest University, Winston-Salem, USA
| | - Eric R Schuppe
- Department of Biology, Wake Forest University, 228 Winston Hall, Winston-Salem, NC 27109 USA
| | - John Hoang
- Department of Integrative Biology and Physiology, University of California, Los Angeles, USA
| | - Jennifer Chew
- Department of Integrative Biology and Physiology, University of California, Los Angeles, USA
| | - Mital Shah
- Department of Integrative Biology and Physiology, University of California, Los Angeles, USA
| | - Barney A Schlinger
- Department of Integrative Biology and Physiology, University of California, Los Angeles, USA ; Laboratory of Neuroendocrinology, Brain Research Institute, University of California, Los Angeles, USA ; Department of Ecology and Evolutionary Biology, University of California, Los Angeles, USA ; Smithsonian Tropical Research Institute, Balboa, Ancon, Republic of Panama
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Fuxjager MJ, Goller F, Dirkse A, Sanin GD, Garcia S. Select forelimb muscles have evolved superfast contractile speed to support acrobatic social displays. eLife 2016; 5:e13544. [PMID: 27067379 PMCID: PMC4829423 DOI: 10.7554/elife.13544] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2015] [Accepted: 01/31/2016] [Indexed: 12/02/2022] Open
Abstract
Many species perform rapid limb movements as part of their elaborate courtship displays. However, because muscle performance is constrained by trade-offs between contraction speed and force, it is unclear how animals evolve the ability to produce both unusually fast appendage movement and limb force needed for locomotion. To address this issue, we compare the twitch speeds of forelimb muscles in a group of volant passerine birds, which produce different courtship displays. Our results show that the two taxa that perform exceptionally fast wing displays have evolved 'superfast' contractile kinetics in their main humeral retractor muscle. By contrast, the two muscles that generate the majority of aerodynamic force for flight show unmodified contractile kinetics. Altogether, these results suggest that muscle-specific adaptations in contractile speed allow certain birds to circumvent the intrinsic trade-off between muscular speed and force, and thereby use their forelimbs for both rapid gestural displays and powered locomotion. DOI:http://dx.doi.org/10.7554/eLife.13544.001 Many animals court mates and fight with rivals by performing physically elaborate and showy displays. From male fiddler crabs waving their claws to attract females, to the leaping dances of whooping cranes, these displays often involve remarkably fast limb movements. However, in many cases it is puzzling how animals can perform these behaviors, because the muscles that move the limbs are often geared to produce strength for walking, running or flying, and not speed. Indeed, decades of research in animal physiology has confirmed that limb-moving muscles can contract with either great strength or great speed, but never both. A small group of tropical birds called manakins produce different types of courtship displays, including some in which the wings are moved extremely rapidly. To date, nobody has examined if or how the limb muscles can generate such superfast movements. Fuxjager et al. now show that, in two species of manakins that produce rapid wing movements as part of their courtship displays, one of the main wing muscles has evolved to move the wings at superfast speeds. In fact, this muscle can move the wing at speeds that are more than twice as fast as those required for these birds to fly, and appears to be the fastest limb muscle on record for any animal with a backbone. Fuxjager et al. also show that the manakins’ other wing muscles are no different from other birds, and suggest that these muscles are preserved to produce the strength needed for flying. Further studies could now explore how this one muscle can create such superfast wing movements and whether male hormones, like testosterone, play a role in regulating the muscle’s speed. DOI:http://dx.doi.org/10.7554/eLife.13544.002
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Affiliation(s)
- Matthew J Fuxjager
- Department of Biology, Wake Forest University, Winston-Salem, United States
| | - Franz Goller
- Department of Biology, University of Utah, Salt Lake City, United States
| | - Annika Dirkse
- Department of Biology, Wake Forest University, Winston-Salem, United States
| | - Gloria D Sanin
- Department of Biology, Wake Forest University, Winston-Salem, United States
| | - Sarah Garcia
- Department of Biology, University of Utah, Salt Lake City, United States
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Friscia A, Sanin GD, Lindsay WR, Day LB, Schlinger BA, Tan J, Fuxjager MJ. Adaptive evolution of a derived radius morphology in manakins (Aves, Pipridae) to support acrobatic display behavior. J Morphol 2016; 277:766-75. [PMID: 27027525 DOI: 10.1002/jmor.20534] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2016] [Revised: 02/18/2016] [Accepted: 02/27/2016] [Indexed: 01/07/2023]
Abstract
The morphology of the avian skeleton is often studied in the context of adaptations for powered flight. The effects of other evolutionary forces, such as sexual selection, on avian skeletal design are unclear, even though birds produce diverse behaviors that undoubtedly require a variety of osteological modifications. Here, we investigate this issue in a family of passerine birds called manakins (Pipridae), which have evolved physically unusual and elaborate courtship displays. We report that, in species within the genus Manacus, the shaft of the radius is heavily flattened and shows substantial solidification. Past work anecdotally notes this morphology and attributes it to the species' ability to hit their wings together above their heads to produce loud mechanical sonations. Our results show that this feature is unique to Manacus compared to the other species in our study, including a variety of taxa that produce other sonations through alternate wing mechanisms. At the same time, our data reveal striking similarities across species in total radius volume and solidification. Together, this suggests that supposedly adaptive alterations in radial morphology occur within a conserved framework of a set radius volume and solidness, which in turn is likely determined by natural selection. Further allometric analyses imply that the radius is less constrained by body size and the structural demands that underlie powered flight, compared to other forelimb bones that are mostly unmodified across taxa. These results are consistent with the idea that the radius is more susceptible to selective modification by sexual selection. Overall, this study provides some of the first insight into the osteological evolution of passerine birds, as well as the way in which opposing selective forces can shape skeletal design in these species. J. Morphol. 277:766-775, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Anthony Friscia
- Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, California, 90095
| | - Gloria D Sanin
- Department of Biology, Wake Forest University, Winston-Salem, North Carolina, 27109
| | - Willow R Lindsay
- Department of Biological and Environmental Sciences, Gothenburg University, Gothenburg, Sweden.,Department of Biology, University of Mississippi, University, Mississippi, 38677
| | - Lainy B Day
- Department of Biology, University of Mississippi, University, Mississippi, 38677
| | - Barney A Schlinger
- Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, California, 90095.,Laboratory of Neuroendocrinology, University of California, Los Angeles, California, 90095.,Department of Ecology and Evolutionary Biology, University of California, Los Angeles, California, 90095.,Smithsonian Tropical Research Institute, Balboa, Ancon, Panama
| | - Josh Tan
- Department of Radiology, Wake Forest University School of Medicine, Winston-Salem, North Carolina, 27157
| | - Matthew J Fuxjager
- Department of Biology, Wake Forest University, Winston-Salem, North Carolina, 27109
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Waltzing Taeniopygia: integration of courtship song and dance in the domesticated Australian zebra finch. Anim Behav 2016. [DOI: 10.1016/j.anbehav.2015.11.012] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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Fuxjager MJ, Lee JH, Chan TM, Bahn JH, Chew JG, Xiao X, Schlinger BA. Research Resource: Hormones, Genes, and Athleticism: Effect of Androgens on the Avian Muscular Transcriptome. Mol Endocrinol 2016; 30:254-71. [PMID: 26745669 DOI: 10.1210/me.2015-1270] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Male vertebrate social displays vary from physically simple to complex, with the latter involving exquisite motor command of the body and appendages. Studies of these displays have, in turn, provided substantial insight into neuromotor mechanisms. The neotropical golden-collared manakin (Manacus vitellinus) has been used previously as a model to investigate intricate motor skills because adult males of this species perform an acrobatic and androgen-dependent courtship display. To support this behavior, these birds express elevated levels of androgen receptors (AR) in their skeletal muscles. Here we use RNA sequencing to explore how testosterone (T) modulates the muscular transcriptome to support male manakin courtship displays. In addition, we explore how androgens influence gene expression in the muscles of the zebra finch (Taenopygia guttata), a model passerine bird with a limited courtship display and minimal muscle AR. We identify androgen-dependent, muscle-specific gene regulation in both species. In addition, we identify manakin-specific effects that are linked to muscle use during the manakin display, including androgenic regulation of genes associated with muscle fiber contractility, cellular homeostasis, and energetic efficiency. Overall, our results point to numerous genes and gene networks impacted by androgens in male birds, including some that underlie optimal muscle function necessary for performing acrobatic display routines. Manakins are excellent models to explore gene regulation promoting athletic ability.
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Affiliation(s)
- Matthew J Fuxjager
- Department of Biology (M.J.F.), Wake Forest University, Winston-Salem, North Carolina 27109; Department of Life and Nanopharmaceutical Sciences (J.-H.L.), and Department of Maxillofacial Biomedical Engineering (J.-H.L.), School of Dentistry, Kyung Hee University, Dongdaemun-gu, Seoul 130-701, Republic of Korea; Department of Integrative Biology and Physiology (M.J.F., J.-H.L., T.-M.C., J.H.B., J.G.C., X.X., B.A.S.) and Laboratory of Neuroendocrinology (M.J.F., B.A.S.), Brain Research Institute, University of California, Los Angeles, Los Angeles, California 90095; and Smithsonian Tropical Research Institute (B.A.S.), 0843-03092 Balboa, Ancón, Panama
| | - Jae-Hyung Lee
- Department of Biology (M.J.F.), Wake Forest University, Winston-Salem, North Carolina 27109; Department of Life and Nanopharmaceutical Sciences (J.-H.L.), and Department of Maxillofacial Biomedical Engineering (J.-H.L.), School of Dentistry, Kyung Hee University, Dongdaemun-gu, Seoul 130-701, Republic of Korea; Department of Integrative Biology and Physiology (M.J.F., J.-H.L., T.-M.C., J.H.B., J.G.C., X.X., B.A.S.) and Laboratory of Neuroendocrinology (M.J.F., B.A.S.), Brain Research Institute, University of California, Los Angeles, Los Angeles, California 90095; and Smithsonian Tropical Research Institute (B.A.S.), 0843-03092 Balboa, Ancón, Panama
| | - Tak-Ming Chan
- Department of Biology (M.J.F.), Wake Forest University, Winston-Salem, North Carolina 27109; Department of Life and Nanopharmaceutical Sciences (J.-H.L.), and Department of Maxillofacial Biomedical Engineering (J.-H.L.), School of Dentistry, Kyung Hee University, Dongdaemun-gu, Seoul 130-701, Republic of Korea; Department of Integrative Biology and Physiology (M.J.F., J.-H.L., T.-M.C., J.H.B., J.G.C., X.X., B.A.S.) and Laboratory of Neuroendocrinology (M.J.F., B.A.S.), Brain Research Institute, University of California, Los Angeles, Los Angeles, California 90095; and Smithsonian Tropical Research Institute (B.A.S.), 0843-03092 Balboa, Ancón, Panama
| | - Jae Hoon Bahn
- Department of Biology (M.J.F.), Wake Forest University, Winston-Salem, North Carolina 27109; Department of Life and Nanopharmaceutical Sciences (J.-H.L.), and Department of Maxillofacial Biomedical Engineering (J.-H.L.), School of Dentistry, Kyung Hee University, Dongdaemun-gu, Seoul 130-701, Republic of Korea; Department of Integrative Biology and Physiology (M.J.F., J.-H.L., T.-M.C., J.H.B., J.G.C., X.X., B.A.S.) and Laboratory of Neuroendocrinology (M.J.F., B.A.S.), Brain Research Institute, University of California, Los Angeles, Los Angeles, California 90095; and Smithsonian Tropical Research Institute (B.A.S.), 0843-03092 Balboa, Ancón, Panama
| | - Jenifer G Chew
- Department of Biology (M.J.F.), Wake Forest University, Winston-Salem, North Carolina 27109; Department of Life and Nanopharmaceutical Sciences (J.-H.L.), and Department of Maxillofacial Biomedical Engineering (J.-H.L.), School of Dentistry, Kyung Hee University, Dongdaemun-gu, Seoul 130-701, Republic of Korea; Department of Integrative Biology and Physiology (M.J.F., J.-H.L., T.-M.C., J.H.B., J.G.C., X.X., B.A.S.) and Laboratory of Neuroendocrinology (M.J.F., B.A.S.), Brain Research Institute, University of California, Los Angeles, Los Angeles, California 90095; and Smithsonian Tropical Research Institute (B.A.S.), 0843-03092 Balboa, Ancón, Panama
| | - Xinshu Xiao
- Department of Biology (M.J.F.), Wake Forest University, Winston-Salem, North Carolina 27109; Department of Life and Nanopharmaceutical Sciences (J.-H.L.), and Department of Maxillofacial Biomedical Engineering (J.-H.L.), School of Dentistry, Kyung Hee University, Dongdaemun-gu, Seoul 130-701, Republic of Korea; Department of Integrative Biology and Physiology (M.J.F., J.-H.L., T.-M.C., J.H.B., J.G.C., X.X., B.A.S.) and Laboratory of Neuroendocrinology (M.J.F., B.A.S.), Brain Research Institute, University of California, Los Angeles, Los Angeles, California 90095; and Smithsonian Tropical Research Institute (B.A.S.), 0843-03092 Balboa, Ancón, Panama
| | - Barney A Schlinger
- Department of Biology (M.J.F.), Wake Forest University, Winston-Salem, North Carolina 27109; Department of Life and Nanopharmaceutical Sciences (J.-H.L.), and Department of Maxillofacial Biomedical Engineering (J.-H.L.), School of Dentistry, Kyung Hee University, Dongdaemun-gu, Seoul 130-701, Republic of Korea; Department of Integrative Biology and Physiology (M.J.F., J.-H.L., T.-M.C., J.H.B., J.G.C., X.X., B.A.S.) and Laboratory of Neuroendocrinology (M.J.F., B.A.S.), Brain Research Institute, University of California, Los Angeles, Los Angeles, California 90095; and Smithsonian Tropical Research Institute (B.A.S.), 0843-03092 Balboa, Ancón, Panama
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Bodony DJ, Day L, Friscia AR, Fusani L, Kharon A, Swenson GW, Wikelski M, Schlinger BA. Determination of the wingsnap sonation mechanism of the Golden-collared manakin (Manacus vitellinus). J Exp Biol 2016; 219:1524-34. [DOI: 10.1242/jeb.128231] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 02/25/2016] [Indexed: 11/20/2022]
Abstract
Male Golden-collared manakins (Manacus vitellinus), small suboscine passeriform birds of Panamanian forests, communicate acoustically using a variety of nonvocal sonations. The most prominent sonations are single or multiple intense ‘wingsnaps’ with a dominant acoustic frequency around 5 kHz. Several hypotheses have been proposed addressing the source of the sound, ranging from purely aerodynamic origins (due to a rapid jet of air formed by the wings or by a ‘whiplike’ motion) to purely structural origins (such as physical contact of the wings), but without definitive assessment. Using anatomical analysis as well as high-speed video and synchronized audio recordings, we show that compared to related species, Manacus radii are morphologically unique and confirm that they collide over the back of the bird at the moment (± 1 ms) the wingsnap is produced. Using aeroacoustic theory, we quantitatively estimate the acoustic signatures from three previously proposed sonation mechanisms. We conclude that only the physical contact hypothesis, wherein the wing collisions create the sound, is consistent with the measured sonation.
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Affiliation(s)
- Daniel J. Bodony
- Department of Aerospace Engineering, University of Illinois at Urbana-Champaign, IL, USA
| | - Lainy Day
- Department of Biology, The University of Mississippi, MS, USA
| | - Anthony R. Friscia
- Department of Integrative Biology and Physiology, University of California, Los Angeles, USA
| | - Leonida Fusani
- Department of Cognitive Biology, University of Vienna, and Konrad Lorenz Institute for Ethology, University of Veterinary Medicine, Vienna, Austria
| | - Aharon Kharon
- Department of Aerospace Engineering, Georgia Institute of Technology, USA
| | - George W. Swenson
- Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, IL, USA
| | - Martin Wikelski
- Max Planck Institute for Ornithology, Radolfzell, Germany and Dept. of Biology, University of Konstanz, Konstanz, Germany
| | - Barney A. Schlinger
- Departments of Integrative Biology and Physiology & Ecology and Evolutionary Biology, University of California at Los Angeles and Smithsonian Tropical Research Institute, Panama City, Panama
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Fuxjager MJ, Schlinger BA. Perspectives on the evolution of animal dancing: a case study of manakins. Curr Opin Behav Sci 2015. [DOI: 10.1016/j.cobeha.2015.06.007] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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Cayetano L, Bonduriansky R. Condition dependence of male and female genital structures in the seed beetle Callosobruchus maculatus (Coleoptera: Bruchidae). J Evol Biol 2015; 28:1364-72. [PMID: 26077617 DOI: 10.1111/jeb.12659] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Accepted: 05/13/2015] [Indexed: 01/16/2023]
Abstract
Theory predicts that costly secondary sexual traits will evolve heightened condition dependence, and many studies have reported strong condition dependence of signal and weapon traits in a variety of species. However, although genital structures often play key roles in intersexual interactions and appear to be subject to sexual or sexually antagonistic selection, few studies have examined the condition dependence of genital structures, especially in both sexes simultaneously. We investigated the responses of male and female genital structures to manipulation of larval diet quality (new versus once-used mung beans) in the bruchid seed beetle Callosobruchus maculatus. We quantified effects on mean relative size and static allometry of the male aedeagus, aedeagal spines, flap and paramere and the female reproductive tract and bursal spines. None of the male traits showed a significant effect of diet quality. In females, we found that longer bursal spines (relative to body size) were expressed on low-quality diet. Although the function of bursal spines is poorly understood, we suggest that greater bursal spine length in low-condition females may represent a sexually antagonistic adaptation. Overall, we found no evidence that genital traits in C. maculatus are expressed to a greater extent when nutrients are more abundant. This suggests that, even though some genital traits appear to function as secondary sexual traits, genital traits do not exhibit heightened condition dependence in this species. We discuss possible reasons for this finding.
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Affiliation(s)
- L Cayetano
- EvoLab, Department of Environmental Science, Policy and Management, University of California, Berkeley, Berkeley, CA, USA
| | - R Bonduriansky
- Evolution and Ecology Research Centre, School of Biological, Earth and Environmental Sciences, The University of New South Wales, Sydney, NSW, Australia
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Krilow JM, Iwaniuk AN. Seasonal Variation in Forebrain Region Sizes in Male Ruffed Grouse (Bonasa umbellus). BRAIN, BEHAVIOR AND EVOLUTION 2015; 85:189-202. [PMID: 25997574 DOI: 10.1159/000381277] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Accepted: 02/26/2015] [Indexed: 11/19/2022]
Abstract
The song system of songbirds has provided significant insight into the underlying mechanisms and behavioural consequences of seasonal neuroplasticity. The extent to which seasonal changes in brain region volumes occur in non-songbird species has, however, remained largely untested. Here, we tested whether brain region volumes varied with season in the ruffed grouse (Bonasa umbellus), a gallinaceous bird that produces a unique wing-beating display known as 'drumming' as its primary form of courtship behaviour. Using unbiased stereology, we measured the sizes of the cerebellum, nucleus rotundus, telencephalon, mesopallium, hippocampal formation, striatopallidal complex and arcopallium across spring males, fall males and fall females. The majority of these brain regions did not vary significantly across these three groups. The two exceptions were the striatopallidal complex and arcopallium, both of which were significantly larger in spring males that are actively drumming. These seasonal changes in volume strongly implicate the striatopallidal complex and arcopallium as key structures in the production and/or modulation of the ruffed grouse drumming display and represent the first evidence of seasonal plasticity in the telencephalon underlying a non-vocal courtship behaviour. Our findings also suggest that seasonal plasticity in the striatopallidal complex and arcopallium might be a trait that is shared across many bird species and that both structures are related to the production of multiple forms of courtship and not just learned song.
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Affiliation(s)
- Justin M Krilow
- Department of Neuroscience, University of Lethbridge, Lethbridge, Alta., Canada
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Fuxjager MJ, Eaton J, Lindsay WR, Salwiczek LH, Rensel MA, Barske J, Sorenson L, Day LB, Schlinger BA. Evolutionary patterns of adaptive acrobatics and physical performance predict expression profiles of androgen receptor - but not oestrogen receptor - in the forelimb musculature. Funct Ecol 2015; 29:1197-1208. [PMID: 26538789 DOI: 10.1111/1365-2435.12438] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
1. Superior physical competence is vital to the adaptive behavioral routines of many animals, particularly those that engage in elaborate socio-sexual displays. How such traits evolve across species remains unclear. 2. Recent work suggests that activation of sex steroid receptors in neuromuscular systems is necessary for the fine motor skills needed to execute physically elaborate displays. Thus, using passerine birds as models, we test whether interspecific variation in display complexity predicts species differences in the abundance of androgen and estrogen receptors (AR and ERα) expressed in the forelimb musculature and spinal cord. 3. We find that small-scale evolutionary patterns in physical display complexity positively predict expression of the AR in the main muscles that lift and retract the wings. No such relationship is detected in the spinal cord, and we do not find a correlation between display behavior and neuromuscular expression of ERα. Also, we find that AR expression levels in different androgen targets throughout the body - namely the wing muscles, spinal cord, and testes - are not necessarily correlated, providing evidence that evolutionary forces may drive AR expression in a tissue-specific manner. 4. These results suggest co-evolution between the physical prowess necessary for display performance and levels of AR expression in avian forelimb muscles. Moreover, this relationship appears to be specific to muscle and AR-mediated, but not ERα-mediated, signaling. 5. Given that prior work suggests that activation of muscular AR is a necessary component of physical display performance, our current data support the hypothesis that sexual selection shapes levels of AR expressed in the forelimb skeletal muscles to help drive the evolution of adaptive motor abilities.
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Affiliation(s)
- Matthew J Fuxjager
- Department of Biology, Wake Forest University, 228 Winston Hall, Winston-Salem, NC 27109, USA ; Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, CA 90095, USA ; Laboratory of Neuroendocrinology, Brain Research Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Joy Eaton
- Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Willow R Lindsay
- Department of Biology, University of Mississippi, University, MS 38677, USA
| | - Lucie H Salwiczek
- Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, CA 90095, USA ; Department of Behavioral Neurobiology, Max Planck Institute for Ornithology, Seewiesen, Germany
| | - Michelle A Rensel
- Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Julia Barske
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Laurie Sorenson
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Lainy B Day
- Department of Biology, University of Mississippi, University, MS 38677, USA
| | - Barney A Schlinger
- Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, CA 90095, USA ; Laboratory of Neuroendocrinology, Brain Research Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA ; Department of Ecology and Evolutionary Biology, University of California, Los Angeles, Los Angeles, CA 90095, USA ; Smithsonian Tropical Research Institute, Apartado Postal 0843-03092, Balboa, Ancón, Panama
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42
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Pradhan DS, Solomon-Lane TK, Grober MS. Contextual modulation of social and endocrine correlates of fitness: insights from the life history of a sex changing fish. Front Neurosci 2015; 9:8. [PMID: 25691855 PMCID: PMC4315020 DOI: 10.3389/fnins.2015.00008] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Accepted: 01/09/2015] [Indexed: 12/18/2022] Open
Abstract
Steroid hormones are critical regulators of reproductive life history, and the steroid sensitive traits (morphology, behavior, physiology) associated with particular life history stages can have substantial fitness consequences for an organism. Hormones, behavior and fitness are reciprocally associated and can be used in an integrative fashion to understand how the environment impacts organismal function. To address the fitness component, we highlight the importance of using reliable proxies of reproductive success when studying proximate regulation of reproductive phenotypes. To understand the mechanisms by which the endocrine system regulates phenotype, we discuss the use of particular endocrine proxies and the need for appropriate functional interpretation of each. Lastly, in any experimental paradigm, the responses of animals vary based on the subtle differences in environmental and social context and this must also be considered. We explore these different levels of analyses by focusing on the fascinating life history transitions exhibited by the bi-directionally hermaphroditic fish, Lythrypnus dalli. Sex changing fish are excellent models for providing a deeper understanding of the fitness consequences associated with behavioral and endocrine variation. We close by proposing that local regulation of steroids is one potential mechanism that allows for the expression of novel phenotypes that can be characteristic of specific life history stages. A comparative species approach will facilitate progress in understanding the diversity of mechanisms underlying the contextual regulation of phenotypes and their associated fitness correlates.
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Affiliation(s)
| | | | - Matthew S Grober
- Department of Biology, Georgia State University Atlanta, GA, USA ; Neuroscience Institute, Georgia State University Atlanta, GA, USA
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43
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Lindsay WR, Houck JT, Giuliano CE, Day LB. Acrobatic Courtship Display Coevolves with Brain Size in Manakins (Pipridae). BRAIN, BEHAVIOR AND EVOLUTION 2015; 85:29-36. [DOI: 10.1159/000369244] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2014] [Accepted: 10/10/2014] [Indexed: 11/19/2022]
Abstract
Acrobatic display behaviour is sexually selected in manakins (Pipridae) and can place high demands on many neural systems. Manakin displays vary across species in terms of behavioural complexity, differing in number of unique motor elements, production of mechanical sounds, cooperation between displaying males, and construction of the display site. Historically, research emphasis has been placed on neurological specializations for vocal aspects of courtship, and less is known about the control of physical, non-vocal displays. By examining brain evolution in relation to extreme acrobatic feats such as manakin displays, we can vastly expand our knowledge of how sexual selection acts on motor behaviour. We tested the hypothesis that sexual selection for complex motor displays has selected for larger brains across the Pipridae. We found that display complexity positively predicts relative brain weight (adjusted for body size) after controlling for phylogeny in 12 manakin species and a closely related flycatcher. This evidence suggests that brain size has evolved in response to sexual selection to facilitate aspects of display such as motor, sensorimotor, perceptual, and cognitive abilities. We show, for the first time, that sexual selection for acrobatic motor behaviour can drive brain size evolution in avian species and, in particular, a family of suboscine birds.
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Fusani L, Donaldson Z, London SE, Fuxjager MJ, Schlinger BA. Expression of androgen receptor in the brain of a sub-oscine bird with an elaborate courtship display. Neurosci Lett 2014; 578:61-5. [PMID: 24954076 PMCID: PMC4359618 DOI: 10.1016/j.neulet.2014.06.028] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Revised: 06/04/2014] [Accepted: 06/11/2014] [Indexed: 01/12/2023]
Abstract
Sex steroids control vertebrate behavior by modulating neural circuits specialized for sex steroid sensitivity. In birds, receptors for androgens (AR) and estrogens (ERα) show conserved expression in neural circuits controlling copulatory and vocal behaviors. Male golden-collared manakins have become a model for evaluating hormonal control of complex physical courtship displays. These birds perform visually and acoustically elaborate displays involving considerable neuromuscular coordination. Androgens activate manakin courtship and AR are expressed widely in spinal circuits and peripheral muscles utilized in courtship. Using in situ hybridization, we report here the distributions of AR and ERα mRNA in the brains of golden-collared manakins. Overall patterns of AR and ERα mRNA expression resemble what has been observed in non-vocal learning species. Notably, however, we detected a large area of AR expression in the arcopallium, a forebrain region that contains a crucial premotor song nucleus in vocal learning species. These results support the idea that AR signaling both centrally and peripherally is responsible for the activation of male manakin courtship, and the arcopallium is likely a premotor site for AR-mediated displays.
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Affiliation(s)
- Leonida Fusani
- Department of Life Science and Biotechnology, University of Ferrara, 44121 Ferrara, Italy.
| | - Zoe Donaldson
- Division of Integrative Neuroscience, Department of Psychiatry, Columbia University, New York, NY 10023, USA
| | - Sarah E London
- Department of Psychology, Institute for Mind and Biology, University of Chicago, Chicago, IL, USA
| | - Matthew J Fuxjager
- Departments of Integrative Biology and Physiology, Ecology and Evolutionary Biology and the Laboratory of Neuroendocrinology, Brain Research Institute, University of California, Los Angeles, CA 90095, USA
| | - Barney A Schlinger
- Departments of Integrative Biology and Physiology, Ecology and Evolutionary Biology and the Laboratory of Neuroendocrinology, Brain Research Institute, University of California, Los Angeles, CA 90095, USA.
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45
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Fusani L, Barske J, Day LD, Fuxjager MJ, Schlinger BA. Physiological control of elaborate male courtship: female choice for neuromuscular systems. Neurosci Biobehav Rev 2014; 46 Pt 4:534-46. [PMID: 25086380 DOI: 10.1016/j.neubiorev.2014.07.017] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Revised: 07/14/2014] [Accepted: 07/22/2014] [Indexed: 12/19/2022]
Abstract
Males of many animal species perform specialized courtship behaviours to gain copulations with females. Identifying physiological and anatomical specializations underlying performance of these behaviours helps clarify mechanisms through which sexual selection promotes the evolution of elaborate courtship. Our knowledge about neuromuscular specializations that support elaborate displays is limited to a few model species. In this review, we focus on the physiological control of the courtship of a tropical bird, the golden-collared manakin, which has been the focus of our research for nearly 20 years. Male manakins perform physically elaborate courtship displays that are quick, accurate and powerful. Females seem to choose males based on their motor skills suggesting that neuromuscular specializations possessed by these males are driven by female choice. Male courtship is activated by androgens and androgen receptors are expressed in qualitatively and quantitatively unconventional ways in manakin brain, spinal cord and skeletal muscles. We propose that in some species, females select males based on their neuromuscular capabilities and acquired skills and that elaborate steroid-dependent courtship displays evolve to signal these traits.
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Affiliation(s)
- Leonida Fusani
- Department of Life Sciences and Biotechnology, University of Ferrara, 44121 Ferrara, Italy.
| | - Julia Barske
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, Los Angeles, CA 90095, USA.
| | - Lainy D Day
- Department of Biology, University of Mississippi, University, MS 38677, USA.
| | - Matthew J Fuxjager
- Department of Integrative Biology and Physiology, Laboratory of Neuroendocrinology, Brain Research Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA.
| | - Barney A Schlinger
- Department of Integrative Biology and Physiology, Laboratory of Neuroendocrinology, Brain Research Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA; Department of Ecology and Evolutionary Biology, University of California, Los Angeles, Los Angeles, CA 90095, USA.
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46
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Fuxjager MJ, Heston JB, Schlinger BA. Peripheral androgen action helps modulate vocal production in a suboscine passerine. THE AUK 2014; 131:327-334. [PMID: 25780269 PMCID: PMC4359617 DOI: 10.1642/auk-13-252.1] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Androgenic activation of intracellular androgen receptors (AR) influences avian vocal production, though this has largely been investigated at the level of the brain. We investigated the influence of predominantly peripheral AR on vocal output in wild Golden-collared Manakins (Manacus vitellinus). In this suboscine species, males court females by performing acrobatic displays and by producing relatively simple chee-poo vocalizations. To assess whether peripheral AR influences the acoustic structure of these vocal signals, we treated reproductively active adult males with the peripherally selective antiandrogen bicalutamide and then measured phonation performance. Inhibiting AR outside of the central nervous system increased the duration of the chee note and decreased the fundamental frequency of the poo note. This treatment caused no discernable change to chee-poo frequency modulation or entropy. Our results show that activation of peripheral AR mediates note-specific changes to temporal and pitch characteristics of the Golden-collared Manakin's main sexual call. Thus, our study provides one of the first demonstrations that androgenic action originating outside of the brain and likely on musculoskeletal targets can modulate avian vocal production.
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Affiliation(s)
- Matthew J. Fuxjager
- Department of Integrative Biology and Physiology, University of California, Los Angeles, California, USA
- Laboratory of Neuroendocrinology, Brain Research Institute, University of California, Los Angeles, California, USA
| | - Jonathan B. Heston
- Department of Integrative Biology and Physiology, University of California, Los Angeles, California, USA
- Interdepartmental Program in Neuroscience, University of California, Los Angeles, California, USA
| | - Barney A. Schlinger
- Department of Integrative Biology and Physiology, University of California, Los Angeles, California, USA
- Laboratory of Neuroendocrinology, Brain Research Institute, University of California, Los Angeles, California, USA
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, California, USA
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