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Nine Levels of Explanation : A Proposed Expansion of Tinbergen's Four-Level Framework for Understanding the Causes of Behavior. HUMAN NATURE-AN INTERDISCIPLINARY BIOSOCIAL PERSPECTIVE 2021; 32:748-793. [PMID: 34739657 DOI: 10.1007/s12110-021-09414-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 08/23/2021] [Indexed: 01/16/2023]
Abstract
Tinbergen's classic "On Aims and Methods of Ethology" (Zeitschrift für Tierpsychologie, 20, 1963) proposed four levels of explanation of behavior, which he thought would soon apply to humans. This paper discusses the need for multilevel explanation; Huxley and Mayr's prior models, and others that followed; Tinbergen's differences with Lorenz on "the innate"; and Mayr's ultimate/proximate distinction. It synthesizes these approaches with nine levels of explanation in three categories: phylogeny, natural selection, and genomics (ultimate causes); maturation, sensitive period effects, and routine environmental effects (intermediate causes); and hormonal/metabolic processes, neural circuitry, and eliciting stimuli (proximate causes), as a respectful extension of Tinbergen's levels. The proposed classification supports and builds on Tinbergen's multilevel model and Mayr's ultimate/proximate continuum, adding intermediate causes in accord with Tinbergen's emphasis on ontogeny. It requires no modification of Standard Evolutionary Theory or The Modern Synthesis, but shows that much that critics claim was missing was in fact part of Neo-Darwinian theory (so named by J. Mark Baldwin in The American Naturalist in 1896) all along, notably reciprocal causation in ontogeny, niche construction, cultural evolution, and multilevel selection. Updates of classical examples in ethology are offered at each of the nine levels, including the neuroethological and genomic findings Tinbergen foresaw. Finally, human examples are supplied at each level, fulfilling his hope of human applications as part of the biology of behavior. This broad ethological framework empowers us to explain human behavior-eventually completely-and vindicates the idea of human nature, and of humans as a part of nature.
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Lorena J, Olson CR, Fontana CS, Mello CV, Schneider MPC, Schneider PN. Seasonal changes in the song control nuclei of the Rufous-bellied Thrush, Turdus rufiventris (Oscine, Passeriformes, and Turdidae). JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2019; 332:92-98. [PMID: 31004403 DOI: 10.1002/jez.b.22853] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Revised: 02/25/2019] [Accepted: 03/20/2019] [Indexed: 11/11/2022]
Abstract
In vocal learning birds, memorization and song production rely on a set of telencephalic nuclei referred to as the song control system. Seasonal changes in song production are correlated with changes in the volume of the song control nuclei and are influenced by photoperiodic conditions and hormonal cues. The seasonal volume changes in the avian brain that controls singing are thought to involve regulation of neuronal replacement, which is a striking example of neuronal plasticity. The Rufous-bellied Thrush (Turdus rufiventris) is a seasonally breeding bird that actively sings during the spring and summer (breeding season) and is relatively silent in the fall, yet possible mechanisms behind the periodic changes in song production remain unknown. Here, we have examined two song control nuclei: High vocal center (HVC) and robust nucleus of arcopallium (RA) in fall males, spring males, and fall females of Rufous-bellied Thrush. The cytoarchitectonic organization was analyzed and quantified from Nissl-stained sections, and gene expression of song nuclei markers was examined by in situ hybridization during breeding and nonbreeding seasons. We observed a reduction in HVC volume and reductions in parvalbumin, and RGS4 expression in HVC and RA in males during the nonbreeding season. These findings provide evidence of seasonal changes in the song system of a representative tropical-breeding Turdidae species that does not maintain territories or mate bonding, setting the histological and molecular groundwork for future studies aimed at better understanding of song nuclei changes in seasonally breeding songbirds.
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Affiliation(s)
- Jamily Lorena
- Instituto de Ciências Biológicas, Centro de Genômica e Biologia de Sistemas, Universidade Federal do Pará, Belém, Brazil
| | | | - Carla S Fontana
- Museu de Ciência e Tecnologia, Laboratório de Ornitologia, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil
| | - Claudio V Mello
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, Oregon
| | - Maria Paula C Schneider
- Instituto de Ciências Biológicas, Centro de Genômica e Biologia de Sistemas, Universidade Federal do Pará, Belém, Brazil
| | - Patricia N Schneider
- Instituto de Ciências Biológicas, Centro de Genômica e Biologia de Sistemas, Universidade Federal do Pará, Belém, Brazil
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Hunt KE, Hahn TP, Buck CL, Wingfield JC. Effect of testosterone blockers on male aggression, song and parental care in an arctic passerine, the Lapland longspur (Calcarius lapponicus). Horm Behav 2019; 110:10-18. [PMID: 30735664 DOI: 10.1016/j.yhbeh.2019.02.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Revised: 01/16/2019] [Accepted: 02/04/2019] [Indexed: 01/19/2023]
Abstract
In many passerine birds, testosterone stimulates song and aggression but inhibits paternal care, but few studies have explored whether such effects can be reversed with testosterone blockers. We explored the effect of testosterone blockers on song, aggression and paternal care of Lapland longspurs (Calcarius lapponicus), an arctic passerine with a short breeding season. Twenty-one "blocker males" received implants containing an androgen receptor blocker and an aromatase inhibitor, compared to 27 control males with empty or no implants. Song, aggression and other behaviors were evaluated with simulated territorial intrusions (STI) during mate-guarding, and with focal observations (without STI) during mate-guarding and incubation. Nests were monitored and nestlings weighed as an indirect measure of paternal care. During STI, blocker males exhibited similar song rates, significantly lower aggression, and were significantly less likely to be found on territory than control males. Focal observations revealed no differences in spontaneous song, aggression, foraging, preening, or flight activity. Blocker males' nestlings had greater body mass on day 5 after hatching, but this difference disappeared by fledging, and both groups fledged similar numbers of young. Two blocker males exhibited unusual paternal care: incubation and brooding of young, or feeding of nestlings at another male's nest. In sum, testosterone blockers affected aggression but not song, contrasting with results from previously published testosterone implant studies. Effects on paternal care were concordant with testosterone implant studies. These patterns may be related to rapid behavioral changes characteristic of the short breeding season of the Arctic.
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Affiliation(s)
- Kathleen E Hunt
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ 86011, USA.
| | - Thomas P Hahn
- Department of Neurobiology, Physiology & Behavior, University of California, One Shields Ave., Davis, CA 95616, USA.
| | - C Loren Buck
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ 86011, USA.
| | - John C Wingfield
- Department of Neurobiology, Physiology & Behavior, University of California, One Shields Ave., Davis, CA 95616, USA.
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Moore IT, Vernasco BJ, Escallón C, Small TW, Ryder TB, Horton BM. Tales of testosterone: Advancing our understanding of environmental endocrinology through studies of neotropical birds. Gen Comp Endocrinol 2019; 273:184-191. [PMID: 29990493 DOI: 10.1016/j.ygcen.2018.07.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Revised: 06/21/2018] [Accepted: 07/06/2018] [Indexed: 01/29/2023]
Abstract
Studies of birds have greatly advanced our understanding of how testosterone modulates complex phenotypes, specifically its role in mediating male reproductive and associated behaviors. Yet most of the foundational studies have been limited to northern latitude breeding species despite the fact that they represent only a small fraction of worldwide avian diversity. In contrast, phylogenetic, life-history, and mating system diversity all reach their apex in neotropical avifauna and yet these birds, along with more southern latitude species, remain very poorly understood from an endocrine perspective. Despite the relatively limited previous work on taxa breeding in Central and South America, empirical findings have had a disproportionately large impact on our understanding of testosterone's role in everything from geographic variation to behavioral roles and neuroplasticity. Here, we synthesize how studies of neotropical breeding avifauna have advanced our understanding of how testosterone's actions can and are associated with the broad patterns of phenotypic diversity that we see in birds. In addition, we outline how these studies can be used individually or in a comparative context to address fundamental questions about the environmental endocrinology of testosterone and to understand the diversity of roles that testosterone plays in mediating behavioral variation, reproductive strategies, and associated life-history trade-offs.
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Affiliation(s)
- I T Moore
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA 24061, USA.
| | - B J Vernasco
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA 24061, USA
| | - C Escallón
- Departamento de Ciencias Básicas, Universidad de la Salle, Cra 2 No. 10-70, Bogotá, Colombia
| | - T W Small
- Department of Biology, University of Memphis, Memphis, TN 38152, USA
| | - T B Ryder
- Migratory Bird Center, Smithsonian Conservation Biology Institute, National Zoological Park, PO Box 37012, MRC 5503, Washington DC 20013, USA
| | - B M Horton
- Department of Biology, Millersville University of Pennsylvania, Millersville, PA 17551, USA
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Shevchouk OT, Ghorbanpoor S, Smith E, Liere P, Schumacher M, Ball GF, Cornil CA, Balthazart J. Behavioral evidence for sex steroids hypersensitivity in castrated male canaries. Horm Behav 2018; 103:80-96. [PMID: 29909262 DOI: 10.1016/j.yhbeh.2018.06.004] [Citation(s) in RCA: 9] [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: 11/07/2017] [Revised: 06/05/2018] [Accepted: 06/10/2018] [Indexed: 12/30/2022]
Abstract
In seasonally breeding songbirds such as canaries, singing behavior is predominantly under the control of testosterone and its metabolites. Short daylengths in the fall that break photorefractoriness are followed by increasing daylengths in spring that activate singing via both photoperiodic and hormonal mechanisms. However, we observed in a group of castrated male Fife fancy canaries maintained for a long duration under a short day photoperiod a large proportion of subjects that sang at high rates. This singing rate was not correlated with variation in the low circulating concentrations of testosterone. Treatment of these actively singing castrated male canaries with a combination of an aromatase inhibitor (ATD) and an androgen receptor blocker (flutamide) only marginally decreased this singing activity as compared to control untreated birds and did not affect various measures of song quality. The volumes of HVC and of the medial preoptic nucleus (POM) were also unaffected by these treatments but were relatively large and similar to volumes in testosterone-treated males. In contrast, peripheral androgen-sensitive structures such as the cloacal protuberance and syrinx mass were small, similar to what is observed in castrates. Together these data suggest that after a long-term steroid deprivation singing behavior can be activated by very low concentrations of testosterone. Singing normally depends on the activation by testosterone and its metabolites of multiple downstream neurochemical systems such as catecholamines, nonapeptides or opioids. These transmitter systems might become hypersensitive to steroid action after long term castration as they probably are at the end of winter during the annual cycle in seasonally breeding temperate zone species.
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Affiliation(s)
| | | | - Ed Smith
- Department of Psychology, University of Maryland, College Park, MD 20742, United States of America
| | - Philippe Liere
- INSERM UMR 1195 and Université Paris Sud and University Paris-Saclay, Le Kremlin-Bicêtre Cedex, France
| | - Michael Schumacher
- INSERM UMR 1195 and Université Paris Sud and University Paris-Saclay, Le Kremlin-Bicêtre Cedex, France
| | - Gregory F Ball
- Department of Psychology, University of Maryland, College Park, MD 20742, United States of America
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LaDage LD, Roth TC, Downs CJ, Sinervo B, Pravosudov VV. Increased Testosterone Decreases Medial Cortical Volume and Neurogenesis in Territorial Side-Blotched Lizards ( Uta stansburiana). Front Neurosci 2017; 11:97. [PMID: 28298883 PMCID: PMC5331184 DOI: 10.3389/fnins.2017.00097] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2017] [Accepted: 02/14/2017] [Indexed: 01/18/2023] Open
Abstract
Variation in an animal's spatial environment can induce variation in the hippocampus, an area of the brain involved in spatial cognitive processing. Specifically, increased spatial area use is correlated with increased hippocampal attributes, such as volume and neurogenesis. In the side-blotched lizard (Uta stansburiana), males demonstrate alternative reproductive tactics and are either territorial—defending large, clearly defined spatial boundaries—or non-territorial—traversing home ranges that are smaller than the territorial males' territories. Our previous work demonstrated cortical volume (reptilian hippocampal homolog) correlates with these spatial niches. We found that territorial holders have larger medial cortices than non-territory holders, yet these differences in the neural architecture demonstrated some degree of plasticity as well. Although we have demonstrated a link among territoriality, spatial use, and brain plasticity, the mechanisms that underlie this relationship are unclear. Previous studies found that higher testosterone levels can induce increased use of the spatial area and can cause an upregulation in hippocampal attributes. Thus, testosterone may be the mechanistic link between spatial area use and the brain. What remains unclear, however, is if testosterone can affect the cortices independent of spatial experiences and whether testosterone differentially interacts with territorial status to produce the resultant cortical phenotype. In this study, we compared neurogenesis as measured by the total number of doublecortin-positive cells and cortical volume between territorial and non-territorial males supplemented with testosterone. We found no significant differences in the number of doublecortin-positive cells or cortical volume among control territorial, control non-territorial, and testosterone-supplemented non-territorial males, while testosterone-supplemented territorial males had smaller medial cortices containing fewer doublecortin-positive cells. These results demonstrate that testosterone can modulate medial cortical attributes outside of differential spatial processing experiences but that territorial males appear to be more sensitive to alterations in testosterone levels compared with non-territorial males.
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Affiliation(s)
- Lara D LaDage
- Division of Mathematics and Natural Sciences, Penn State University Altoona Altoona, PA, USA
| | - Timothy C Roth
- Department of Psychology, Franklin and Marshall College Lancaster, PA, USA
| | | | - Barry Sinervo
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, CA, USA
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Longmoor GK, Lange CH, Darvell H, Walker L, Rytkönen S, Vatka E, Hohtola E, Orell M, Smulders TV. Different Seasonal Patterns in Song System Volume in Willow Tits and Great Tits. BRAIN, BEHAVIOR AND EVOLUTION 2016; 87:265-74. [PMID: 27442125 DOI: 10.1159/000447114] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Accepted: 05/25/2016] [Indexed: 11/19/2022]
Abstract
In most species of seasonally breeding songbirds studied to date, the brain areas that control singing (i.e. the song control system, SCS) are larger during the breeding season than at other times of the year. In the family of titmice and chickadees (Paridae), one species, the blue tit (Cyanistes caeruleus), shows the typical pattern of seasonal changes, while another species, the black-capped chickadee (Poecile atricapillus), shows, at best, very reduced seasonal changes in the SCS. To test whether this pattern holds up in the two Parid lineages to which these two species belong, and to rule out that the differences in seasonal patterns observed were due to differences in geography or laboratory, we compared the seasonal patterns in two song system nuclei volumes (HVC and Area X) in willow tits (Poecile montanus), closely related to black-capped chickadees, and in great tits (Parus major), more closely related to blue tits, from the same area around Oulu, Finland. Both species had larger gonads in spring than during the rest of the year. Great tit males had a larger HVC in spring than at other times of the year, but their Area X did not change in size. Willow tits showed no seasonal change in HVC or Area X size, despite having much larger gonads in spring than the great tits. Our findings suggest that the song system of willow tits and their relatives may be involved in learning and producing nonsong social vocalizations. Since these vocalizations are used year-round, there may be a year-round demand on the song system. The great tit and blue tit HVC may change seasonally because the demand is only placed on the song system during the breeding season, since they only produce learned vocalizations during this time. We suggest that changes were not observed in Area X because its main role is in song learning, and there is evidence that great tits do not learn new songs after their first year of life. Further study is required to determine whether our hypothesis about the role of the song system in the learned, nonsong vocalizations of the willow tit and chickadee is correct, and to test our hypothesis about the role of Area X in the great tit song system.
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Affiliation(s)
- Georgia K Longmoor
- Centre for Behaviour and Evolution, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, UK
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