1
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Bialas JT, Dylewski Ł, Tobolka M. Brain size mediates the choice of breeding strategy in the red-backed shrike Lanius collurio. Integr Zool 2024; 19:683-693. [PMID: 38196090 DOI: 10.1111/1749-4877.12803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2024]
Abstract
The brain size of vertebrates represents a trade-off between natural selection for enhanced cognitive abilities and the energetic constraints of brain tissue production. Processing information efficiently can confer benefits, but it also entails time costs. Breeding strategies, encompassing timing of breeding onset and nest-site selection, may be related to brain size. In this study, we aim to elucidate the relationship between brain size, breeding timing, nest-site choice, and breeding success in the red-backed shrike Lanius collurio. Our findings revealed that the timing of the first egg-laying date was associated with female head size, with larger-headed females tending to lay eggs later in the breeding season. Additionally, we observed that breeding success was positively correlated with increased nest concealment. However, this relationship was stronger in males with smaller heads. In turn, nest concealment was not related to head size but primarily influenced breeding onset. These results suggest that the choice of breeding strategy may be moderated by brain size, with differences between sexes. Larger-headed females may invest more time in selecting nesting sites, leading to delayed breeding onset, while larger-headed males may compensate for suboptimal nest concealment. Our study sheds light on the intricate interplay between brain size, breeding timing, nest-site preferences, and breeding success in passerine birds, underscoring the potential role of cognitive capacity in shaping individual decision-making processes.
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Affiliation(s)
- Joanna T Bialas
- Department of Zoology, Poznań University of Life Sciences, Poznań, Poland
| | - Łukasz Dylewski
- Department of Zoology, Poznań University of Life Sciences, Poznań, Poland
| | - Marcin Tobolka
- Department of Zoology, Poznań University of Life Sciences, Poznań, Poland
- Konrad Lorenz Institute of Ethology, University of Veterinary Medicine Vienna, Wien, Austria
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2
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Yang Y, Axelrod CJ, Grant E, Earl SR, Urquhart EM, Talbert K, Johnson LE, Walker Z, Hsiao K, Stone I, Carlson BA, López-Sepulcre A, Gordon SP. Evolutionary divergence of developmental plasticity and learning of mating tactics in Trinidadian guppies. J Anim Ecol 2023. [PMID: 38156548 DOI: 10.1111/1365-2656.14043] [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: 08/30/2023] [Accepted: 11/30/2023] [Indexed: 12/30/2023]
Abstract
Behavioural plasticity is a major driver in the early stages of adaptation, but its effects in mediating evolution remain elusive because behavioural plasticity itself can evolve. In this study, we investigated how male Trinidadian guppies (Poecilia reticulata) adapted to different predation regimes diverged in behavioural plasticity of their mating tactic. We reared F2 juveniles of high- or low-predation population origins with different combinations of social and predator cues and assayed their mating behaviour upon sexual maturity. High-predation males learned their mating tactic from conspecific adults as juveniles, while low-predation males did not. High-predation males increased courtship when exposed to chemical predator cues during development; low-predation males decreased courtship in response to immediate chemical predator cues, but only when they were not exposed to such cues during development. Behavioural changes induced by predator cues were associated with developmental plasticity in brain morphology, but changes acquired through social learning were not. We thus show that guppy populations diverged in their response to social and ecological cues during development, and correlational evidence suggests that different cues can shape the same behaviour via different neural mechanisms. Our study demonstrates that behavioural plasticity, both environmentally induced and socially learnt, evolves rapidly and shapes adaptation when organisms colonize ecologically divergent habitats.
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Affiliation(s)
- Yusan Yang
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, USA
- Department of Integrative Biology, University of South Florida, Tampa, Florida, USA
| | - Caleb J Axelrod
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, USA
- Department of Ecology and Evolution, Cornell University, Ithaca, New York, USA
| | - Elly Grant
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Shayna R Earl
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, USA
- Department of Biology, University of Louisville, Louisville, Kentucky, USA
| | - Ellen M Urquhart
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Katie Talbert
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, USA
- Department of Ecology and Evolution, Cornell University, Ithaca, New York, USA
| | - Lauren E Johnson
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Zakiya Walker
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Kyle Hsiao
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Isabel Stone
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Bruce A Carlson
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Andrés López-Sepulcre
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, USA
- Department of Ecology and Evolution, Cornell University, Ithaca, New York, USA
| | - Swanne P Gordon
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, USA
- Department of Ecology and Evolution, Cornell University, Ithaca, New York, USA
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3
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Dunbar RIM, Shultz S. Four errors and a fallacy: pitfalls for the unwary in comparative brain analyses. Biol Rev Camb Philos Soc 2023; 98:1278-1309. [PMID: 37001905 DOI: 10.1111/brv.12953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Revised: 03/17/2023] [Accepted: 03/17/2023] [Indexed: 04/03/2023]
Abstract
Comparative analyses are the backbone of evolutionary analysis. However, their record in producing a consensus has not always been good. This is especially true of attempts to understand the factors responsible for the evolution of large brains, which have been embroiled in an increasingly polarised debate over the past three decades. We argue that most of these disputes arise from a number of conceptual errors and associated logical fallacies that are the result of a failure to adopt a biological systems-based approach to hypothesis-testing. We identify four principal classes of error: a failure to heed Tinbergen's Four Questions when testing biological hypotheses, misapplying Dobzhansky's Dictum when testing hypotheses of evolutionary adaptation, poorly chosen behavioural proxies for underlying hypotheses, and the use of inappropriate statistical methods. In the interests of progress, we urge a more careful and considered approach to comparative analyses, and the adoption of a broader, rather than a narrower, taxonomic perspective.
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Affiliation(s)
- Robin I M Dunbar
- Department of Experimental Psychology, Anna Watts Building, University of Oxford, Oxford, OX2 6GG, UK
| | - Susanne Shultz
- Department of Earth and Environmental Sciences, Michael Smith Building, University of Manchester, Manchester, M13 9PT, UK
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4
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Knoll F, Lautenschlager S, Kawabe S, Martínez G, Espílez E, Mampel L, Alcalá L. Palaeoneurology of the early cretaceous iguanodont Proa valdearinnoensis and its bearing on the parallel developments of cognitive abilities in theropod and ornithopod dinosaurs. J Comp Neurol 2021; 529:3922-3945. [PMID: 34333763 DOI: 10.1002/cne.25224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 07/21/2021] [Accepted: 07/22/2021] [Indexed: 11/10/2022]
Abstract
Proa valdearinnoensis is a relatively large-headed and stocky iguanodontian dinosaur from the latest Early Cretaceous of Spain. Its braincase is known from three specimens. Similar to that of other dinosaurs, it shows a mosaic ossification pattern in which most of the bones seem to have fused together indistinguishably while a few (frontoparietal, basioccipital) might have remained loosely attached. The endocasts of the three specimens are described based on CT data and digital reconstructions. They show unmistakable morphological similarities with the endocast of closely related taxa, such as Sirindhorna khoratensis (which is close in age but from Thailand). This supports a high conservatism of the endocranial cavity. The issue of volumetric correspondence between endocranial cavity and brain in dinosaurs is analyzed. Although a brain-to-endocranial cavity (BEC) index of 0.50 has been traditionally used, we employ instead 0.73. This is indeed the mid-value between the situation in adults of Alligator mississippiensis and Gallus gallus, which are members of the extant bracketing taxa of dinosaurs (Crocodilia and Aves). We thence gauge the level of encephalization of P. valdearinnoensis through the calculation of the encephalization quotient (EQ), which remains valuable as a metric for assessing the degree of cognitive function in extinct taxa, especially those with fully ossified braincases like dinosaurs and other archosaurs. The EQ obtained for P. valdearinnoensis (3.611) suggests that this species was significantly more encephalized than most if not all extant nonavian, nonmammalian amniotes. Our work adds to the growing body of data concerning theoretical cognitive capabilities in dinosaurs and supports the idea that an increasing encephalization was fostered not only in theropods but also in parallel in the shorter-lived lineage of ornithopods. P. valdearinnoensis was ill-equipped to respond to theropod dinosaurs and possibly lived in groups as a strategy to mitigate the risk of being predated upon. We hypothesize that group-living and protracted caring of juveniles in this and possibly many other iguanodontian ornithopods favored a degree of encephalization that was outstanding by reptile standards.
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Affiliation(s)
- Fabien Knoll
- Fundación ARAID, Zaragoza, Spain.,Fundación Conjunto Paleontológico de Teruel-Dinópolis, Teruel, Spain.,Departamento de Paleobiología, Museo Nacional de Ciencias Naturales-CSIC, Madrid, Spain
| | - Stephan Lautenschlager
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, UK
| | - Soichiro Kawabe
- Institute of Dinosaur Research, Fukui Prefectural University, Fukui, Japan.,Fukui Prefectural Dinosaur Museum, Fukui, Japan
| | - Gloria Martínez
- Servicio de Radiodiagnóstico, Hospital General Obispo Polanco, Teruel, Spain
| | - Eduardo Espílez
- Fundación Conjunto Paleontológico de Teruel-Dinópolis, Teruel, Spain
| | - Luis Mampel
- Fundación Conjunto Paleontológico de Teruel-Dinópolis, Teruel, Spain
| | - Luis Alcalá
- Fundación Conjunto Paleontológico de Teruel-Dinópolis, Teruel, Spain
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Triki Z, Emery Y, Teles MC, Oliveira RF, Bshary R. Brain morphology predicts social intelligence in wild cleaner fish. Nat Commun 2020; 11:6423. [PMID: 33349638 PMCID: PMC7752907 DOI: 10.1038/s41467-020-20130-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Accepted: 11/12/2020] [Indexed: 11/08/2022] Open
Abstract
It is generally agreed that variation in social and/or environmental complexity yields variation in selective pressures on brain anatomy, where more complex brains should yield increased intelligence. While these insights are based on many evolutionary studies, it remains unclear how ecology impacts brain plasticity and subsequently cognitive performance within a species. Here, we show that in wild cleaner fish (Labroides dimidiatus), forebrain size of high-performing individuals tested in an ephemeral reward task covaried positively with cleaner density, while cerebellum size covaried negatively with cleaner density. This unexpected relationship may be explained if we consider that performance in this task reflects the decision rules that individuals use in nature rather than learning abilities: cleaners with relatively larger forebrains used decision-rules that appeared to be locally optimal. Thus, social competence seems to be a suitable proxy of intelligence to understand individual differences under natural conditions.
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Affiliation(s)
- Zegni Triki
- Institute of Biology, University of Neuchâtel, Emile-Argand 11, 2000, Neuchâtel, Switzerland.
- Department of Zoology, Stockholm University, Svante Arrheniusväg 18 B, Stockholm, Sweden.
| | - Yasmin Emery
- Institute of Biology, University of Neuchâtel, Emile-Argand 11, 2000, Neuchâtel, Switzerland
| | - Magda C Teles
- Instituto Gulbenkian de Ciência, Rua da Quinta Grande, 6, 2780-156, Oeiras, Portugal
| | - Rui F Oliveira
- Instituto Gulbenkian de Ciência, Rua da Quinta Grande, 6, 2780-156, Oeiras, Portugal
- ISPA - Instituto Universitário, Rua Jardim do Tabaco 34, 1149-041, Lisboa, Portugal
| | - Redouan Bshary
- Institute of Biology, University of Neuchâtel, Emile-Argand 11, 2000, Neuchâtel, Switzerland
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6
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Møller AP, Hongisto K, Korpimäki E. Predation risk in relation to brain size in alternative prey of pygmy owls varies depending on the abundance of main prey. PLoS One 2020; 15:e0236155. [PMID: 32915780 PMCID: PMC7485837 DOI: 10.1371/journal.pone.0236155] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Accepted: 06/30/2020] [Indexed: 11/23/2022] Open
Abstract
Large brains in prey may select for adoption of anti-predator behavior that facilitates escape. Prey species with relatively large brains have been shown to be less likely to fall prey to predators. This results in the prediction that individuals that have been captured by predators on average should have smaller brains than sympatric conspecifics. We exploited the fact that Eurasian pygmy owls Glaucidium passerinum hoard small mammals and birds in cavities and nest-boxes for over-winter survival, allowing for comparison of the phenotype of prey with that of live conspecifics. In Northern Europe, main prey of pygmy owls are voles of the genera Myodes and Microtus, while forest birds and shrews are the most important alternative prey. Large fluctuations (amplitude 100-200-fold) in vole populations induce rapid numerical responses of pygmy owls to main prey populations, which in turn results in varying predation pressure on small birds. We found, weighed and measured 153 birds in food-stores of pygmy owls and mist-netted, weighed and measured 333 live birds of 12 species in central-western Finland during two autumns with low (2017) and high (2018) pygmy owl predation risk. In two autumns, individuals with large brains were captured later compared to individuals with small brains, consistent with the hypothesis that such individuals survived for longer. Avian prey of pygmy owls had smaller heads than live birds in autumn 2018 when predation risk by pygmy owls was high. This difference in head size was not significant in 2017 when predation risk by pygmy owls was reduced. Finally, avian survivors were in better body condition than avian prey individuals. These findings are consistent with the hypothesis that pygmy owls differentially prey on birds in poor condition with small brains. These findings are consistent with the hypothesis that predation risk imposed by pygmy owls on small birds in boreal forests varies depending on the abundance of the main prey (voles).
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Affiliation(s)
- Anders Pape Møller
- Ecologie Systématique Evolution, Université Paris-Sud, CNRS, AgroParisTech, Université Paris-Saclay, France
- * E-mail:
| | | | - Erkki Korpimäki
- Section of Ecology, Department of Biology, University of Turku, Turku, Finland
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7
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Triki Z, Levorato E, McNeely W, Marshall J, Bshary R. Population densities predict forebrain size variation in the cleaner fish Labroides dimidiatus. Proc Biol Sci 2019; 286:20192108. [PMID: 31744435 DOI: 10.1098/rspb.2019.2108] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The 'social brain hypothesis' proposes a causal link between social complexity and either brain size or the size of key brain parts known to be involved in cognitive processing and decision-making. While previous work has focused on comparisons between species, how social complexity affects plasticity in brain morphology at the intraspecific level remains mostly unexplored. A suitable study model is the mutualist 'cleaner' fish Labroides dimidiatus, a species that removes ectoparasites from a variety of 'client' fishes in iterative social interactions. Here, we report a positive relationship between the local density of cleaners, as a proxy of both intra- and interspecific sociality, and the size of the cleaner's brain parts suggested to be associated with cognitive functions, such as the diencephalon and telencephalon (that together form the forebrain). In contrast, the size of the mesencephalon, rhombencephalon, and brain stem, assumed more basal in function, were independent of local fish densities. Selective enlargement of brain parts, that is mosaic brain adjustment, appears to be driven by population density in cleaner fish.
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Affiliation(s)
- Zegni Triki
- Institute of Biology, University of Neuchâtel, Emile-Argand 11, 2000 Neuchâtel, Switzerland
| | - Elena Levorato
- Institute of Biology, University of Neuchâtel, Emile-Argand 11, 2000 Neuchâtel, Switzerland
| | - William McNeely
- Institute of Biology, University of Neuchâtel, Emile-Argand 11, 2000 Neuchâtel, Switzerland
| | - Justin Marshall
- Queensland Brain Institute, University of Queensland, St Lucia, Queensland 4072, Australia
| | - Redouan Bshary
- Institute of Biology, University of Neuchâtel, Emile-Argand 11, 2000 Neuchâtel, Switzerland
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8
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Jaatinen K, Møller AP, Öst M. Annual variation in predation risk is related to the direction of selection for brain size in the wild. Sci Rep 2019; 9:11847. [PMID: 31413345 PMCID: PMC6694153 DOI: 10.1038/s41598-019-48153-w] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Accepted: 07/22/2019] [Indexed: 11/09/2022] Open
Abstract
The direction of predator-mediated selection on brain size is debated. However, the speed and the accuracy of performing a task cannot be simultaneously maximized. Large-brained individuals may be predisposed to accurate but slow decision-making, beneficial under high predation risk, but costly under low risk. This creates the possibility of temporally fluctuating selection on brain size depending on overall predation risk. We test this idea in nesting wild eider females (Somateria mollissima), in which head volume is tightly linked to brain mass (r2 = 0.73). We determined how female relative head volume relates to survival, and characterized the seasonal timing of predation. Previous work suggests that relatively large-brained and small-brained females make slow versus fast nest-site decisions, respectively, and that predation events occur seasonally earlier when predation is severe. Large-brained, late-breeding females may therefore have higher survival during high-predation years, but lower survival during safe years, assuming that predation disproportionately affects late breeders in such years. Relatively large-headed females outsurvived smaller-headed females during dangerous years, whereas the opposite was true in safer years. Predation events occurred relatively later during safe years. Fluctuations in the direction of survival selection on relative brain size may therefore arise due to brain-size dependent breeding phenology.
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Affiliation(s)
- Kim Jaatinen
- Nature and Game Management Trust Finland, Degerbyvägen 176, FI-10160, Degerby, Finland.
| | - Anders P Møller
- Ecologie Systématique Evolution, Université Paris-Sud, CNRS, AgroParisTech, Université Paris-Saclay, F-91405, Orsay Cedex, France
| | - Markus Öst
- Environmental and Marine Biology, Faculty of Science and Engineering, Åbo Akademi University, Artillerigatan 6, FI-20520, Turku, Finland
- Novia University of Applied Sciences, Raseborgsvägen 9, FI-10600, Ekenäs, Finland
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9
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Varela SAM, Teles MC, Oliveira RF. The correlated evolution of social competence and social cognition. Funct Ecol 2019. [DOI: 10.1111/1365-2435.13416] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Susana A. M. Varela
- Instituto Gulbenkian de Ciência Oeiras Portugal
- ISPA‐Instituto Universitário Lisboa Portugal
| | - Magda C. Teles
- Instituto Gulbenkian de Ciência Oeiras Portugal
- ISPA‐Instituto Universitário Lisboa Portugal
| | - Rui F. Oliveira
- Instituto Gulbenkian de Ciência Oeiras Portugal
- ISPA‐Instituto Universitário Lisboa Portugal
- Champalimaud Neuroscience Programme Lisboa Portugal
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10
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Simons M, Tibbetts E. Insects as models for studying the evolution of animal cognition. CURRENT OPINION IN INSECT SCIENCE 2019; 34:117-122. [PMID: 31271948 DOI: 10.1016/j.cois.2019.05.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 05/23/2019] [Accepted: 05/28/2019] [Indexed: 06/09/2023]
Abstract
Research on the evolution of cognition has long centered on vertebrates. Current research indicates that both complex social behavior and ecology influence the evolution of vertebrate cognition. Insects provide a powerful and underappreciated model system for research on cognitive evolution because they are a large group with multiple evolutionary transitions to complex social behavior as well as extensive ecological variation. Here, we integrate current research on cognitive evolution in vertebrates and insects. We specifically highlight recent advances in vertebrate research that are applicable to insects. We focus on two key topics: 1) The challenges of quantifying cognition 2) What factors contribute to the evolution of cognition? Applying methods like comparative analysis and behavioral cognition measurement to insects are likely to provide key insight into the evolution of animal minds.
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Affiliation(s)
- Meagan Simons
- University of Michigan, 1105 N. University Ave., Ann Arbor, MI 48104, United States
| | - Elizabeth Tibbetts
- University of Michigan, 1105 N. University Ave., Ann Arbor, MI 48104, United States.
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11
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De Meester G, Huyghe K, Van Damme R. Brain size, ecology and sociality: a reptilian perspective. Biol J Linn Soc Lond 2019. [DOI: 10.1093/biolinnean/bly206] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Gilles De Meester
- Functional Morphology Group, Department of Biology, University of Antwerp, Wilrijk, Belgium
| | - Katleen Huyghe
- Functional Morphology Group, Department of Biology, University of Antwerp, Wilrijk, Belgium
| | - Raoul Van Damme
- Functional Morphology Group, Department of Biology, University of Antwerp, Wilrijk, Belgium
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12
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Mattson MP. An Evolutionary Perspective on Why Food Overconsumption Impairs Cognition. Trends Cogn Sci 2019; 23:200-212. [PMID: 30670325 DOI: 10.1016/j.tics.2019.01.003] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Revised: 11/02/2018] [Accepted: 01/07/2019] [Indexed: 01/01/2023]
Abstract
Brain structures and neuronal networks that mediate spatial navigation, decision-making, sociality, and creativity evolved, in part, to enable success in food acquisition. Here, I discuss evidence suggesting that the reason that overconsumption of energy-rich foods negatively impacts cognition is that signaling pathways that evolved to respond adaptively to food scarcity are relatively disengaged in the setting of continuous food availability. Obesity impairs cognition and increases the risk for some psychiatric disorders and dementias. Moreover, maternal and paternal obesity predispose offspring to poor cognitive outcomes by epigenetic molecular mechanisms. Neural signaling pathways that evolved to bolster cognition in settings of food insecurity can be stimulated by intermittent fasting and exercise to support the cognitive health of current and future generations.
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Affiliation(s)
- Mark P Mattson
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Laboratory of Neurosciences, National Institute on Aging Intramural Research Program, Baltimore, MD 21224, USA.
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13
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Amodio P, Boeckle M, Schnell AK, Ostojíc L, Fiorito G, Clayton NS. Grow Smart and Die Young: Why Did Cephalopods Evolve Intelligence? Trends Ecol Evol 2018; 34:45-56. [PMID: 30446408 DOI: 10.1016/j.tree.2018.10.010] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 10/16/2018] [Accepted: 10/18/2018] [Indexed: 11/16/2022]
Abstract
Intelligence in large-brained vertebrates might have evolved through independent, yet similar processes based on comparable socioecological pressures and slow life histories. This convergent evolutionary route, however, cannot explain why cephalopods developed large brains and flexible behavioural repertoires: cephalopods have fast life histories and live in simple social environments. Here, we suggest that the loss of the external shell in cephalopods (i) caused a dramatic increase in predatory pressure, which in turn prevented the emergence of slow life histories, and (ii) allowed the exploitation of novel challenging niches, thus favouring the emergence of intelligence. By highlighting convergent and divergent aspects between cephalopods and large-brained vertebrates we illustrate how the evolution of intelligence might not be constrained to a single evolutionary route.
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Affiliation(s)
- Piero Amodio
- Department of Psychology, University of Cambridge, Cambridge, UK.
| | - Markus Boeckle
- Department of Psychology, University of Cambridge, Cambridge, UK
| | | | - Ljerka Ostojíc
- Department of Psychology, University of Cambridge, Cambridge, UK
| | - Graziano Fiorito
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Napoli, Italy
| | - Nicola S Clayton
- Department of Psychology, University of Cambridge, Cambridge, UK
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14
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Sociality does not drive the evolution of large brains in eusocial African mole-rats. Sci Rep 2018; 8:9203. [PMID: 29907782 PMCID: PMC6003933 DOI: 10.1038/s41598-018-26062-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Accepted: 05/02/2018] [Indexed: 11/15/2022] Open
Abstract
The social brain hypothesis (SBH) posits that the demands imposed on individuals by living in cohesive social groups exert a selection pressure favouring the evolution of large brains and complex cognitive abilities. Using volumetry and the isotropic fractionator to determine the size of and numbers of neurons in specific brain regions, here we test this hypothesis in African mole-rats (Bathyergidae). These subterranean rodents exhibit a broad spectrum of social complexity, ranging from strictly solitary through to eusocial cooperative breeders, but feature similar ecologies and life history traits. We found no positive association between sociality and neuroanatomical correlates of information-processing capacity. Solitary species are larger, tend to have greater absolute brain size and have more neurons in the forebrain than social species. The neocortex ratio and neuronal counts correlate negatively with social group size. These results are clearly inconsistent with the SBH and show that the challenges coupled with sociality in this group of rodents do not require brain enlargement or fundamental reorganization. These findings suggest that group living or pair bonding per se does not select strongly for brain enlargement unless coupled with Machiavellian interactions affecting individual fitness.
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15
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Reddon AR, Chouinard‐Thuly L, Leris I, Reader SM. Wild and laboratory exposure to cues of predation risk increases relative brain mass in male guppies. Funct Ecol 2018. [DOI: 10.1111/1365-2435.13128] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Adam R. Reddon
- Department of BiologyMcGill University Montreal Quebec Canada
| | | | - Ioannis Leris
- Department of BiologyMcGill University Montreal Quebec Canada
- Department of Biology and Helmholtz InstituteUtrecht University Utrecht The Netherlands
| | - Simon M. Reader
- Department of BiologyMcGill University Montreal Quebec Canada
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16
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Dunlap KD, Keane G, Ragazzi M, Lasky E, Salazar VL. Simulated predator stimuli reduce brain cell proliferation in two electric fish species, Brachyhypopomus gauderio and Apteronotus leptorhynchus. ACTA ACUST UNITED AC 2018; 220:2328-2334. [PMID: 28679791 DOI: 10.1242/jeb.158246] [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: 02/14/2017] [Accepted: 04/10/2017] [Indexed: 12/19/2022]
Abstract
The brain structure of many animals is influenced by their predators, but the cellular processes underlying this brain plasticity are not well understood. Previous studies showed that electric fish (Brachyhypopomus occidentalis) naturally exposed to high predator (Rhamdia quelen) density and tail injury had reduced brain cell proliferation compared with individuals facing few predators and those with intact tails. However, these field studies described only correlations between predator exposure and cell proliferation. Here, we used a congener Brachyhypopomus gauderio and another electric fish Apteronotus leptorhynchus to experimentally test the hypothesis that exposure to a predator stimulus and tail injury causes alterations in brain cell proliferation. To simulate predator exposure, we either amputated the tail followed by short-term (1 day) or long-term (17-18 days) recovery or repeatedly chased intact fish with a plastic rod over a 7 day period. We measured cell proliferation (PCNA+ cell density) in the telencephalon and diencephalon, and plasma cortisol, which commonly mediates stress-induced changes in brain cell proliferation. In both species, either tail amputation or simulated predator chase decreased cell proliferation in the telencephalon in a manner resembling the effect of predators in the field. In A. leptorhynchus, cell proliferation decreased drastically in the short term after tail amputation and partially rebounded after long-term recovery. In B. gauderio, tail amputation elevated cortisol levels, but repeated chasing had no effect. In A. leptorhynchus, tail amputation elevated cortisol levels in the short term but not in the long term. Thus, predator stimuli can cause reductions in brain cell proliferation, but the role of cortisol is not clear.
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Affiliation(s)
- Kent D Dunlap
- Department of Biology, Trinity College, Hartford, CT 06106, USA
| | - Geoffrey Keane
- Department of Biology, Trinity College, Hartford, CT 06106, USA
| | - Michael Ragazzi
- Department of Biology, Trinity College, Hartford, CT 06106, USA.,Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, CT 06030, USA
| | - Elise Lasky
- Department of Biology, Trinity College, Hartford, CT 06106, USA
| | - Vielka L Salazar
- Department of Biology, Cape Breton University, Sydney, NS, Canada B1P 6L2
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17
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Kotrschal A, Szorkovszky A, Romenskyy M, Perna A, Buechel SD, Zeng HL, Pelckmans K, Sumpter D, Kolm N. Brain size does not impact shoaling dynamics in unfamiliar groups of guppies (Poecilia reticulata). Behav Processes 2017; 147:13-20. [PMID: 29248747 DOI: 10.1016/j.beproc.2017.12.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Revised: 12/13/2017] [Accepted: 12/13/2017] [Indexed: 11/26/2022]
Abstract
Collective movement is achieved when individuals adopt local rules to interact with their neighbours. How the brain processes information about neighbours' positions and movements may affect how individuals interact in groups. As brain size can determine such information processing it should impact collective animal movement. Here we investigate whether brain size affects the structure and organisation of newly forming fish shoals by quantifying the collective movement of guppies (Poecilia reticulata) from large- and small-brained selection lines, with known differences in learning and memory. We used automated tracking software to determine shoaling behaviour of single-sex groups of eight or two fish and found no evidence that brain size affected the speed, group size, or spatial and directional organisation of fish shoals. Our results suggest that brain size does not play an important role in how fish interact with each other in these types of moving groups of unfamiliar individuals. Based on these results, we propose that shoal dynamics are likely to be governed by relatively basic cognitive processes that do not differ in these brain size selected lines of guppies.
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Affiliation(s)
| | | | - Maksym Romenskyy
- Department of Mathematics, Uppsala University, 75106, Uppsala, Sweden
| | - Andrea Perna
- Department of Life Sciences, University of Roehampton, London, United Kingdom
| | - Severine D Buechel
- Department of Zoology, Stockholm University, SE-10691, Stockholm, Sweden
| | - Hong-Li Zeng
- Department of Mathematics, Uppsala University, 75106, Uppsala, Sweden
| | | | - David Sumpter
- Department of Mathematics, Uppsala University, 75106, Uppsala, Sweden
| | - Niclas Kolm
- Department of Zoology, Stockholm University, SE-10691, Stockholm, Sweden
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18
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Kotrschal A, Deacon AE, Magurran AE, Kolm N. Predation pressure shapes brain anatomy in the wild. Evol Ecol 2017; 31:619-633. [PMID: 32009719 PMCID: PMC6961500 DOI: 10.1007/s10682-017-9901-8] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Accepted: 05/08/2017] [Indexed: 11/30/2022]
Abstract
There is remarkable diversity in brain anatomy among vertebrates and evidence is accumulating that predatory interactions are crucially important for this diversity. To test this hypothesis, we collected female guppies (Poecilia reticulata) from 16 wild populations and related their brain anatomy to several aspects of predation pressure in this ecosystem, such as the biomass of the four major predators of guppies (one prawn and three fish species), and predator diversity (number of predatory fish species in each site). We found that populations from localities with higher prawn biomass had relatively larger telencephalon size as well as larger brains. Optic tectum size was positively associated with one of the fish predator’s biomass and with overall predator diversity. However, both olfactory bulb and hypothalamus size were negatively associated with the biomass of another of the fish predators. Hence, while fish predator occurrence is associated with variation in brain anatomy, prawn occurrence is associated with variation in brain size. Our results suggest that cognitive challenges posed by local differences in predator communities may lead to changes in prey brain anatomy in the wild.
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Affiliation(s)
- Alexander Kotrschal
- 1Department of Ethology/Zoology, Stockholm University, Svante Arheniusväg 18B, 10691 Stockholm, Sweden
| | - Amy E Deacon
- 2Department of Life Sciences, The University of the West Indies, St Augustine, Trinidad and Tobago
| | - Anne E Magurran
- 3School of Biology, University of St Andrews, St Andrews, Scotland, UK
| | - Niclas Kolm
- 1Department of Ethology/Zoology, Stockholm University, Svante Arheniusväg 18B, 10691 Stockholm, Sweden
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19
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Williams AC, Hill LJ. Meat and Nicotinamide: A Causal Role in Human Evolution, History, and Demographics. Int J Tryptophan Res 2017; 10:1178646917704661. [PMID: 28579800 PMCID: PMC5417583 DOI: 10.1177/1178646917704661] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Accepted: 03/15/2017] [Indexed: 01/15/2023] Open
Abstract
Hunting for meat was a critical step in all animal and human evolution. A key brain-trophic element in meat is vitamin B3 / nicotinamide. The supply of meat and nicotinamide steadily increased from the Cambrian origin of animal predators ratcheting ever larger brains. This culminated in the 3-million-year evolution of Homo sapiens and our overall demographic success. We view human evolution, recent history, and agricultural and demographic transitions in the light of meat and nicotinamide intake. A biochemical and immunological switch is highlighted that affects fertility in the 'de novo' tryptophan-to-kynurenine-nicotinamide 'immune tolerance' pathway. Longevity relates to nicotinamide adenine dinucleotide consumer pathways. High meat intake correlates with moderate fertility, high intelligence, good health, and longevity with consequent population stability, whereas low meat/high cereal intake (short of starvation) correlates with high fertility, disease, and population booms and busts. Too high a meat intake and fertility falls below replacement levels. Reducing variances in meat consumption might help stabilise population growth and improve human capital.
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Affiliation(s)
- Adrian C Williams
- Department of Neurology, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK
| | - Lisa J Hill
- Neuroscience and Ophthalmology Research Group, Institute of Inflammation and Ageing, University of Birmingham, Birmingham, UK
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20
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Beston SM, Broyles W, Walsh MR. Increased juvenile predation is not associated with evolved differences in adult brain size in Trinidadian killifish ( Rivulus hartii). Ecol Evol 2017; 7:884-894. [PMID: 28168025 PMCID: PMC5288286 DOI: 10.1002/ece3.2668] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Revised: 11/02/2016] [Accepted: 11/05/2016] [Indexed: 11/12/2022] Open
Abstract
Vertebrates exhibit extensive variation in brain size. The long-standing assumption is that this variation is driven by ecologically mediated selection. Recent work has shown that an increase in predator-induced mortality is associated with evolved increases and decreases in brain size. Thus, the manner in which predators induce shifts in brain size remains unclear. Increased predation early in life is a key driver of many adult traits, including life-history and behavioral traits. Such results foreshadow a connection between age-specific mortality and selection on adult brain size. Trinidadian killifish, Rivulus hartii, are found in sites with and without guppies, Poecilia reticulata. The densities of Rivulus drop dramatically in sites with guppies because guppies prey upon juvenile Rivulus. Previous work has shown that guppy predation is associated with the evolution of adult life-history traits in Rivulus. In this study, we compared second-generation laboratory-born Rivulus from sites with and without guppies for differences in brain size and associated trade-offs between brain size and other components of fitness. Despite the large amount of existing research on the importance of early-life events on the evolution of adult traits, and the role of predation on both behavior and brain size, we did not find an association between the presence of guppies and evolutionary shifts in Rivulus brain size. Such results argue that increased rates of juvenile mortality may not alter selection on adult brain size.
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Affiliation(s)
| | - Whitnee Broyles
- Department of BiologyUniversity of Texas at ArlingtonArlingtonTXUSA
| | - Matthew R. Walsh
- Department of BiologyUniversity of Texas at ArlingtonArlingtonTXUSA
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21
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Walsh MR, Broyles W, Beston SM, Munch SB. Predator-driven brain size evolution in natural populations of Trinidadian killifish (Rivulus hartii). Proc Biol Sci 2016; 283:20161075. [PMID: 27412278 PMCID: PMC4947895 DOI: 10.1098/rspb.2016.1075] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Accepted: 06/17/2016] [Indexed: 11/12/2022] Open
Abstract
Vertebrates exhibit extensive variation in relative brain size. It has long been assumed that this variation is the product of ecologically driven natural selection. Yet, despite more than 100 years of research, the ecological conditions that select for changes in brain size are unclear. Recent laboratory selection experiments showed that selection for larger brains is associated with increased survival in risky environments. Such results lead to the prediction that increased predation should favour increased brain size. Work on natural populations, however, foreshadows the opposite trajectory of evolution; increased predation favours increased boldness, slower learning, and may thereby select for a smaller brain. We tested the influence of predator-induced mortality on brain size evolution by quantifying brain size variation in a Trinidadian killifish, Rivulus hartii, from communities that differ in predation intensity. We observed strong genetic differences in male (but not female) brain size between fish communities; second generation laboratory-reared males from sites with predators exhibited smaller brains than Rivulus from sites in which they are the only fish present. Such trends oppose the results of recent laboratory selection experiments and are not explained by trade-offs with other components of fitness. Our results suggest that increased male brain size is favoured in less risky environments because of the fitness benefits associated with faster rates of learning and problem-solving behaviour.
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Affiliation(s)
- Matthew R Walsh
- Department of Biology, University of Texas at Arlington, Arlington, TX 76019, USA
| | - Whitnee Broyles
- Department of Biology, University of Texas at Arlington, Arlington, TX 76019, USA
| | - Shannon M Beston
- Department of Biology, University of Texas at Arlington, Arlington, TX 76019, USA
| | - Stephan B Munch
- National Marine Fisheries Service, 110 Shaffer Road, Santa Cruz, CA 95060, USA
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