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Álvarez-Quintero N, Kim SY. Effects of maternal age and environmental enrichment on learning ability and brain size. Behav Ecol 2024; 35:arae049. [PMID: 38952837 PMCID: PMC11215699 DOI: 10.1093/beheco/arae049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Revised: 05/27/2024] [Accepted: 06/10/2024] [Indexed: 07/03/2024] Open
Abstract
It is well known that maternal age at reproduction affects offspring lifespan and some other fitness-related traits, but it remains understudied whether maternal senescence affects how offspring respond to their environments. Early environment often plays a significant role in the development of an animal's behavioral phenotype. For example, complex environments can promote changes in cognitive ability and brain morphology in young animals. Here, we study whether and how maternal effect senescence influences offspring plasticity in cognition, group behavior, and brain morphology in response to environmental complexity. For this, juvenile 3-spined sticklebacks from young and old mothers (i.e. 1-yr and 2-yr-old) were exposed to different levels of environmental enrichment and complexity (i.e. none, simple, and complex), and their behavior, cognitive ability, and brain size were measured. Exposing fish to enriched conditions improved individual learning ability assessed by a repeated detour-reaching task, increased the size of the whole brain, and decreased aggressive interactions in the shoal. Maternal age did not influence the inhibitory control, learning ability, and group behavioral responses of offspring to the experimental environmental change. However, maternal age affected how some brain regions of offspring changed in response to environmental complexity. In offspring from old mothers, those exposed to the complex environment had larger telencephalons and cerebellums than those who experienced simpler environments. Our results suggest that maternal effect senescence may influence how offspring invest in brain functions related to cognition in response to environmental complexity.
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Affiliation(s)
- Náyade Álvarez-Quintero
- Grupo de Ecoloxía Animal, Centro de Investigación Mariña, Universidade de Vigo, Fonte das Abelleiras, s/n, Vigo, 36310 Pontevedra, Spain
- Dipartimento di Biologia, Complesso Interdepartamentale A. Vallisneri, Università di Padova, Via Ugo Bassi, 58b, 35121 Padova PD, Italy
| | - Sin-Yeon Kim
- Grupo de Ecoloxía Animal, Centro de Investigación Mariña, Universidade de Vigo, Fonte das Abelleiras, s/n, Vigo, 36310 Pontevedra, Spain
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2
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Gatto E, Lucon-Xiccato T, Bertolucci C. Environmental conditions shape learning in larval zebrafish. Behav Processes 2024; 218:105045. [PMID: 38692461 DOI: 10.1016/j.beproc.2024.105045] [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: 01/04/2024] [Revised: 04/26/2024] [Accepted: 04/27/2024] [Indexed: 05/03/2024]
Abstract
Growing evidence reveals notable phenotypic plasticity in cognition among teleost fishes. One compelling example is the positive impact of enriched environments on learning performance. Most studies on this effect have focused on juvenile or later life stages, potentially overlooking the importance of early life plasticity. To address this gap, we investigated whether cognitive plasticity in response to environmental factors emerges during the larval stage in zebrafish. Our findings indicate that larvae exposed to an enriched environment after hatching exhibited enhanced habituation learning performance compared to their counterparts raised in a barren environment. This work underscores the presence of developmental phenotypic plasticity in cognition among teleost fish, extending its influence to the very earliest stages of an individual's life.
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Affiliation(s)
- Elia Gatto
- Department of Chemical, Pharmaceutical and Agricultural Sciences, University of Ferrara, Ferrara, Italy; Department of Life Sciences and Biotechnology, University of Ferrara, Ferrara, Italy.
| | - Tyrone Lucon-Xiccato
- Department of Life Sciences and Biotechnology, University of Ferrara, Ferrara, Italy
| | - Cristiano Bertolucci
- Department of Life Sciences and Biotechnology, University of Ferrara, Ferrara, Italy
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3
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Joyce BJ, Brown GE. Olfaction and reaction: The role of olfactory and hypothalamic investment in the antipredator responses to chemical alarm cues by northern redbelly dace. Curr Zool 2023; 69:738-746. [PMID: 37876646 PMCID: PMC10591147 DOI: 10.1093/cz/zoac086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 10/22/2022] [Indexed: 10/26/2023] Open
Abstract
Neuroplasticity enables teleosts to promote or downregulate the growth of their brains regionally. To compensate for the effects of predation pressure, teleosts may alter their brain morphology and behavioral responses to mitigate its impact on individual fitness. High-predation environments often promote specific patterns of brain growth and produce bolder and more proactive populations. Owing to the expense of maintaining neural tissue, relative size indicates the regions most relied upon. In northern redbelly dace Chrosomus eos, as little as 2 weeks of elevated predation pressure, resulted in increased investment in their olfactory bulbs and optic tecta, while the imposition of captivity produced smaller, less symmetric hypothalami. Taken together, these results suggest that an individual could potentially become better able to detect a threat, and simultaneously less inclined to react to it, making the impact of either change in isolation is difficult to discern. Here, we compared interindividual variation in gross brain morphology, risk-taking tactics in a novel arena (shy-bold personality), and responding to olfactory cues (proactive/reactive stress-coping style). We hypothesized that olfactory investment would positively correlate with response intensity to predator cue concentration and respond across a wider range of cue concentrations, while hypothalamus size would correlate with shyness and reactivity. Exposure to heightened risk produced more bold/proactive individuals, with larger olfactory bulbs and smaller hypothalami. However, the direction of the correlation between hypothalamus size and behavior varied by treatment, and olfactory investment only corresponded with response intensity amongst proactive individuals. Our findings illustrate the potential pitfalls of relating gross brain morphology to complex behavior and suggest that stress-coping style is a relevant consideration in future studies.
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Affiliation(s)
- Brendan J Joyce
- Department of Biology, Concordia University, Montreal, Quebec, Canada
| | - Grant E Brown
- Department of Biology, Concordia University, Montreal, Quebec, Canada
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4
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Versteeg EJ, Fernandes T, Guzzo MM, Laberge F, Middel T, Ridgway M, McMeans BC. Seasonal variation of behavior and brain size in a freshwater fish. Ecol Evol 2021; 11:14950-14959. [PMID: 34765152 PMCID: PMC8571637 DOI: 10.1002/ece3.8179] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 08/25/2021] [Accepted: 09/03/2021] [Indexed: 01/17/2023] Open
Abstract
Teleost fishes occupy a range of ecosystem, and habitat types subject to large seasonal fluctuations. Temperate fishes, in particular, survive large seasonal shifts in temperature, light availability, and access to certain habitats. Mobile species such as lake trout (Salvelinus namaycush) can behaviorally respond to seasonal variation by shifting their habitat deeper and further offshore in response to warmer surface water temperatures during the summer. During cooler seasons, the use of more structurally complex nearshore zones by lake trout could increase cognitive demands and potentially result in a larger relative brain size during those periods. Yet, there is limited understanding of how such behavioral responses to a seasonally shifting environment might shape, or be shaped by, the nervous system.Here, we quantified variation in relative brain size and the size of five externally visible brain regions in lake trout, across six consecutive seasons in two different lakes. Acoustic telemetry data from one of our study lakes were collected during the study period from a different subset of individuals and used to infer relationships between brain size and seasonal behaviors (habitat use and movement rate).Our results indicated that lake trout relative brain size was larger in the fall and winter compared with the spring and summer in both lakes. Larger brains coincided with increased use of nearshore habitats and increased horizontal movement rates in the fall and winter based on acoustic telemetry. The telencephalon followed the same pattern as whole brain size, while the other brain regions (cerebellum, optic tectum, olfactory bulbs, and hypothalamus) were only smaller in the spring.These findings provide evidence that flexibility in brain size could underpin shifts in behavior, which could potentially subserve functions associated with differential habitat use during cold and warm seasons and allow fish to succeed in seasonally variable environments.
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Affiliation(s)
| | | | | | - Frédéric Laberge
- Department of Integrative BiologyUniversity of GuelphGuelphONCanada
| | - Trevor Middel
- Harkness Laboratory of Fisheries ResearchOntario Ministry of Natural ResourcesWhitneyONCanada
| | - Mark Ridgway
- Harkness Laboratory of Fisheries ResearchOntario Ministry of Natural ResourcesWhitneyONCanada
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5
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Mousavi SE, Purser GJ, Patil JG. Embryonic Onset of Sexually Dimorphic Heart Rates in the Viviparous Fish, Gambusia holbrooki. Biomedicines 2021; 9:165. [PMID: 33567532 PMCID: PMC7915484 DOI: 10.3390/biomedicines9020165] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 02/01/2021] [Accepted: 02/04/2021] [Indexed: 12/12/2022] Open
Abstract
In fish, little is known about sex-specific differences in physiology and performance of the heart and whether these differences manifest during development. Here for the first time, the sex-specific heart rates during embryogenesis of Gambusia holbrooki, from the onset of the heart rates (HRs) to just prior to parturition, was investigated using light cardiogram. The genetic sex of the embryos was post-verified using a sex-specific genetic marker. Results reveal that heart rates and resting time significantly increase (p < 0.05) with progressive embryonic development. Furthermore, both ventricular and atrial frequencies of female embryos were significantly higher (p < 0.05) than those of their male sibs at the corresponding developmental stages and remained so at all later developmental stages (p < 0.05). In concurrence, the heart rate and ventricular size of the adult females were also significantly (p < 0.05) higher and larger respectively than those of males. Collectively, the results suggest that the cardiac sex-dimorphism manifests as early as late-organogenesis and persists through adulthood in this species. These findings suggest that the cardiac measurements can be employed to non-invasively sex the developing embryos, well in advance of when their phenotypic sex is discernible. In addition, G. holbrooki could serve as a better model to study comparative vertebrate cardiovascular development as well as to investigate anthropogenic and climatic impacts on heart physiology of this species, that may be sex influenced.
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Affiliation(s)
- Seyed Ehsan Mousavi
- Fisheries and Aquaculture Centre, Institute for Marine and Antarctic Studies, University of Tasmania, Taroona, TAS 7053, Australia;
| | - G. John Purser
- Fisheries and Aquaculture Centre, Institute for Marine and Antarctic Studies, University of Tasmania, Taroona, TAS 7053, Australia;
| | - Jawahar G. Patil
- Fisheries and Aquaculture Centre, Institute for Marine and Antarctic Studies, University of Tasmania, Taroona, TAS 7053, Australia;
- Inland Fisheries Service, New Norfolk, TAS 7140, Australia
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6
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Höök TO, Svanbäck R, Eklöv P. Sex-specific plasticity in a trophic polymorphic aquatic predator: a modeling approach. Oecologia 2021; 195:341-354. [PMID: 33420521 DOI: 10.1007/s00442-020-04843-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Accepted: 12/23/2020] [Indexed: 11/30/2022]
Abstract
Phenotypic plasticity is common among animal taxa. While there are clearly limits and likely costs to plasticity, these costs are unknown for most organisms. Further, as plasticity is partially genetically determined, the potential magnitude of exhibited plasticity may vary among individuals. In addition to phenotypic plasticity, various animal taxa also display sexual size dimorphism, a feature ultimately thought to arise due to differential size-dependent fitness costs and benefits between sexes. We hypothesized that differential selection acting on males and females can indirectly select for unequal genetically defined plasticity potential between the sexes. We evaluate this possibility for Eurasian perch (Perca fluviatilis), a species that displays modest sexual size dimorphism and habitat-related morphological plasticity. Using 500-year simulations of an ecogenetic agent-based model, we demonstrate that genetically determined morphological plasticity potential may evolve differently for males and females, leading to greater realized morphological variation between habitats for one sex over the other. Genetically determined potential for plasticity evolved differently between sexes across (a) various sex-specific life-history differences and (b) a variety of assumed costs of plasticity acting on both growth and survival. Morphological analyses of Eurasian perch collected in situ were consistent with model predictions: realized morphological variation between habitats was greater for females than males. We suggest that due to sex-specific selective pressures, differences in male and female genetically defined potential for plasticity may be a common feature across organisms.
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Affiliation(s)
- Tomas O Höök
- Department of Forestry and Natural Resources and Illinois-Indiana Sea Grant Program, Purdue University, West Lafayette, IN, 47906, USA.
| | - Richard Svanbäck
- Department of Ecology and Genetics, Animal Ecology, Uppsala University, Norbyv. 18 D, 75236, Uppsala, Sweden
| | - Peter Eklöv
- Department of Ecology and Genetics, Limnology, Uppsala University, Norbyv. 18 D, 75236, Uppsala, Sweden
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7
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Álvarez-Quintero N, Velando A, Kim SY. Long-Lasting Negative Effects of Learning Tasks During Early Life in the Three-Spined Stickleback. Front Ecol Evol 2020. [DOI: 10.3389/fevo.2020.562404] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
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8
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Buechel SD, Noreikiene K, DeFaveri J, Toli E, Kolm N, Merilä J. Variation in sexual brain size dimorphism over the breeding cycle in the three-spined stickleback. ACTA ACUST UNITED AC 2019; 222:jeb.194464. [PMID: 30936267 DOI: 10.1242/jeb.194464] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Accepted: 03/22/2019] [Indexed: 01/25/2023]
Abstract
Snapshot analyses have demonstrated dramatic intraspecific variation in the degree of brain sexual size dimorphism (SSD). Although brain SSD is believed to be generated by the sex-specific cognitive demands of reproduction, the relative roles of developmental and population-specific contributions to variation in brain SSD remain little studied. Using a common garden experiment, we tested for sex-specific changes in brain anatomy over the breeding cycle in three-spined stickleback (Gasterosteus aculeatus) sampled from four locations in northern Europe. We found that the male brain increased in size (ca. 24%) significantly more than the female brain towards breeding, and that the resulting brain SSD was similar (ca. 20%) for all populations over the breeding cycle. Our findings support the notion that the stickleback brain is highly plastic and changes over the breeding cycle, especially in males, likely as an adaptive response to the cognitive demands of reproduction (e.g. nest construction and parental care). The results also provide evidence to suggest that breeding-related changes in brain size may be the reason for the widely varying estimates of brain SSD across studies of this species, cautioning against interpreting brain size measurements from a single time point as fixed/static.
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Affiliation(s)
- Séverine D Buechel
- Department of Zoology/Ethology, Stockholm University, Svante Arrhenius väg 18B, 10691 Stockholm, Sweden
| | - Kristina Noreikiene
- Ecological Genetics Research Unit, Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, PO Box 65, FI-00014 Helsinki, Finland.,Chair of Aquaculture, Institute of Veterinary Medicine and Animal Sciences, Estonian University of Life Sciences, Kreutzwaldi tn. 46, 51006 Tartu, Estonia
| | - Jacquelin DeFaveri
- Ecological Genetics Research Unit, Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, PO Box 65, FI-00014 Helsinki, Finland
| | - Elisavet Toli
- Ecological Genetics Research Unit, Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, PO Box 65, FI-00014 Helsinki, Finland.,Molecular Ecology & Conservation Genetics Lab, Department of Biological Applications & Technology, University of Ioannina, 45110 Ioannina, Greece
| | - Niclas Kolm
- Department of Zoology/Ethology, Stockholm University, Svante Arrhenius väg 18B, 10691 Stockholm, Sweden
| | - Juha Merilä
- Ecological Genetics Research Unit, Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, PO Box 65, FI-00014 Helsinki, Finland
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9
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Puga S, Cardoso V, Pinto-Ribeiro F, Pacheco M, Almeida A, Pereira P. Brain morphometric profiles and their seasonal modulation in fish (Liza aurata) inhabiting a mercury contaminated estuary. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2018; 237:318-328. [PMID: 29499575 DOI: 10.1016/j.envpol.2018.02.047] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Revised: 02/09/2018] [Accepted: 02/16/2018] [Indexed: 06/08/2023]
Abstract
Mercury (Hg) is a potent neurotoxicant known to induce important adverse effects on fish, but a deeper understanding is lacking regarding how environmental exposure affects the brain morphology and neural plasticity of specific brain regions in wild specimens. In this work, it was evaluated the relative volume and cell density of the lateral pallium, hypothalamus, optic tectum and molecular layer of the cerebellum on wild Liza aurata captured in Hg-contaminated (LAR) and non-contaminated (SJ) sites of a coastal system (Ria de Aveiro, Portugal). Given the season-related variations in the environment that fish are naturally exposed, this assessment was performed in the winter and summer. Hg triggered a deficit in cell density of hypothalamus during the winter that could lead to hormonal dysfunctions, while in the summer Hg promoted larger volumes of the optic tectum and cerebellum, indicating the warm period as the most critical for the manifestation of putative changes in visual acuity and motor-dependent tasks. Moreover, in fish from the SJ site, the lateral pallium relative volume and the cell density of the hypothalamus and optic tectum were higher in the winter than in summer. Thus, season-related stimuli strongly influence the size and/or cell density of specific brain regions in the non-contaminated area, pointing out the ability of fish to adapt to environmental and physiological demands. Conversely, fish from the Hg-contaminated site showed a distinct seasonal profile of brain morphology, presenting a larger optic tectum in the summer, as well as a larger molecular layer of the cerebellum with higher cell density. Moreover, Hg exposure impaired the winter-summer variation of the lateral pallium relative size (as observed at SJ). Altogether, seasonal variations in fish neural morphology and physiology should be considered when performing ecotoxicological studies in order to better discriminate the Hg neurotoxicity.
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Affiliation(s)
- Sónia Puga
- Life and Health Sciences Research Institute (ICVS), School of Medicine (EM), Campus of Gualtar, University of Minho, 4750-057 Braga, Portugal; ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal.
| | - Vera Cardoso
- Life and Health Sciences Research Institute (ICVS), School of Medicine (EM), Campus of Gualtar, University of Minho, 4750-057 Braga, Portugal; ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal.
| | - Filipa Pinto-Ribeiro
- Life and Health Sciences Research Institute (ICVS), School of Medicine (EM), Campus of Gualtar, University of Minho, 4750-057 Braga, Portugal; ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal.
| | - Mário Pacheco
- Department of Biology and CESAM, University of Aveiro, 3810-193 Aveiro, Portugal.
| | - Armando Almeida
- Life and Health Sciences Research Institute (ICVS), School of Medicine (EM), Campus of Gualtar, University of Minho, 4750-057 Braga, Portugal; ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal.
| | - Patrícia Pereira
- Department of Biology and CESAM, University of Aveiro, 3810-193 Aveiro, Portugal.
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10
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Angyal D, Balázs G, Krízsik V, Herczeg G, Fehér Z. Molecular and morphological divergence in a stygobiont gastropod lineage (Truncatelloidea, Moitessieriidae, Paladilhiopsis
) within an isolated karstic area in the Mecsek Mountains (Hungary). J ZOOL SYST EVOL RES 2018. [DOI: 10.1111/jzs.12220] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Dorottya Angyal
- Department of Zoology; Hungarian Natural History Museum; Budapest Hungary
| | - Gergely Balázs
- Department of Systematic Zoology and Ecology; Eötvös Loránd University; Budapest Hungary
| | - Virág Krízsik
- Laboratory of Molecular Taxonomy; Hungarian Natural History Museum; Budapest Hungary
| | - Gábor Herczeg
- Department of Systematic Zoology and Ecology; Eötvös Loránd University; Budapest Hungary
| | - Zoltán Fehér
- Department of Zoology; Hungarian Natural History Museum; Budapest Hungary
- Central Research Laboratories; Zoology Department; Natural History Museum; Vienna Austria
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11
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Noreikiene K, Kuparinen A, Merilä J. Age at maturation has sex- and temperature-specific effects on telomere length in a fish. Oecologia 2017; 184:767-777. [PMID: 28730343 DOI: 10.1007/s00442-017-3913-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Accepted: 07/03/2017] [Indexed: 01/01/2023]
Abstract
Telomeres are highly conserved nucleoprotein structures which protect genome integrity. The length of telomeres is influenced by both genetic and environmental factors, but relatively little is known about how different hereditary and environmental factors interact in determining telomere length. We manipulated growth rates and timing of maturation by exposing full-sib nine-spined sticklebacks (Pungitius pungitius) to two different temperature treatments and quantified the effects of temperature treatments, sex, timing of maturation, growth rate and family (genetic influences) on telomere length. We did not find the overall effect of temperature treatment on the relative telomere length. However, we found that variation in telomere length was related to timing of maturation in a sex- and temperature-dependent manner. Telomere length was negatively related to age at maturation in elevated temperature and early maturing males and females differed in telomere length. Variation in growth rate did not explain any variation in telomere length. The broad sense heritability (h 2) of telomere length was estimated at h 2 = 0.31 - 0.47, suggesting predominance of environmental over genetic determinants of telomere length variability. This study provides the first evidence that age at maturation together with factors associated with it are influencing telomere length in an ectotherm. Future studies are encouraged to identify the extent to which these results can be replicated in other ectotherms.
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Affiliation(s)
- Kristina Noreikiene
- Ecological Genetics Research Unit, Department of Biosciences, University of Helsinki, PO Box 65, 00014, Helsinki, Finland.
| | - Anna Kuparinen
- Department of Biological and Environmental Science, University of Jyväskylä, PO Box 35, 40014, Jyväskylä, Finland
| | - Juha Merilä
- Ecological Genetics Research Unit, Department of Biosciences, University of Helsinki, PO Box 65, 00014, Helsinki, Finland
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12
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Toli EA, Noreikiene K, DeFaveri J, Merilä J. Environmental enrichment, sexual dimorphism, and brain size in sticklebacks. Ecol Evol 2017; 7:1691-1698. [PMID: 28331580 PMCID: PMC5355184 DOI: 10.1002/ece3.2717] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Revised: 11/21/2016] [Accepted: 12/17/2016] [Indexed: 01/29/2023] Open
Abstract
Evidence for phenotypic plasticity in brain size and the size of different brain parts is widespread, but experimental investigations into this effect remain scarce and are usually conducted using individuals from a single population. As the costs and benefits of plasticity may differ among populations, the extent of brain plasticity may also differ from one population to another. In a common garden experiment conducted with three-spined sticklebacks (Gasterosteus aculeatus) originating from four different populations, we investigated whether environmental enrichment (aquaria provided with structural complexity) caused an increase in the brain size or size of different brain parts compared to controls (bare aquaria). We found no evidence for a positive effect of environmental enrichment on brain size or size of different brain parts in either of the sexes in any of the populations. However, in all populations, males had larger brains than females, and the degree of sexual size dimorphism (SSD) in relative brain size ranged from 5.1 to 11.6% across the populations. Evidence was also found for genetically based differences in relative brain size among populations, as well as for plasticity in the size of different brain parts, as evidenced by consistent size differences among replicate blocks that differed in their temperature.
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Affiliation(s)
- Elisavet A Toli
- Molecular Ecology & Conservation Genetics Lab Department of Biological Applications & Technology University of Ioannina Ioannina Greece; Ecological Genetics Research Unit Department of Biosciences University of Helsinki Helsinki Finland
| | - Kristina Noreikiene
- Ecological Genetics Research Unit Department of Biosciences University of Helsinki Helsinki Finland
| | - Jacquelin DeFaveri
- Ecological Genetics Research Unit Department of Biosciences University of Helsinki Helsinki Finland
| | - Juha Merilä
- Ecological Genetics Research Unit Department of Biosciences University of Helsinki Helsinki Finland
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13
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Li Z, Guo B, Yang J, Herczeg G, Gonda A, Balázs G, Shikano T, Calboli FCF, Merilä J. Deciphering the genomic architecture of the stickleback brain with a novel multilocus gene-mapping approach. Mol Ecol 2017; 26:1557-1575. [DOI: 10.1111/mec.14005] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Revised: 11/11/2016] [Accepted: 11/14/2016] [Indexed: 12/24/2022]
Affiliation(s)
- Zitong Li
- Ecological Genetics Research Unit; Department of Biosciences; University of Helsinki; P.O. Box 65 FI-00014 Helsinki Finland
| | - Baocheng Guo
- Ecological Genetics Research Unit; Department of Biosciences; University of Helsinki; P.O. Box 65 FI-00014 Helsinki Finland
| | - Jing Yang
- Ecological Genetics Research Unit; Department of Biosciences; University of Helsinki; P.O. Box 65 FI-00014 Helsinki Finland
| | - Gábor Herczeg
- Ecological Genetics Research Unit; Department of Biosciences; University of Helsinki; P.O. Box 65 FI-00014 Helsinki Finland
- Behavioural Ecology Group; Department of Systematic Zoology and Ecology; Eötvös Loránd University; Pázmány Péter sétány1/C 1117 Budapest Hungary
| | - Abigél Gonda
- Ecological Genetics Research Unit; Department of Biosciences; University of Helsinki; P.O. Box 65 FI-00014 Helsinki Finland
| | - Gergely Balázs
- Behavioural Ecology Group; Department of Systematic Zoology and Ecology; Eötvös Loránd University; Pázmány Péter sétány1/C 1117 Budapest Hungary
| | - Takahito Shikano
- Ecological Genetics Research Unit; Department of Biosciences; University of Helsinki; P.O. Box 65 FI-00014 Helsinki Finland
| | - Federico C. F. Calboli
- Ecological Genetics Research Unit; Department of Biosciences; University of Helsinki; P.O. Box 65 FI-00014 Helsinki Finland
| | - Juha Merilä
- Ecological Genetics Research Unit; Department of Biosciences; University of Helsinki; P.O. Box 65 FI-00014 Helsinki Finland
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14
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Metzger DCH, Schulte PM. Maternal stress has divergent effects on gene expression patterns in the brains of male and female threespine stickleback. Proc Biol Sci 2016; 283:rspb.2016.1734. [PMID: 27683372 DOI: 10.1098/rspb.2016.1734] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Accepted: 09/05/2016] [Indexed: 11/12/2022] Open
Abstract
Maternal stress can have long-term effects on neurodevelopment that can influence offspring performance and population evolutionary trajectories. To examine the mechanistic basis for these neurodevelopmental effects of maternal stress, we used RNA-seq to assess differential gene expression across the brain transcriptome of adult male and female threespine stickleback (Gasterosteus aculeatus) from stressed and unstressed mothers. We identified sexually divergent effects of maternal stress on the brain transcriptome. In males, genes that were upregulated by maternal stress were enriched for processes involved in synaptic function and organization and steroid hormone-mediated signalling pathways, whereas in females genes that were upregulated by maternal stress were enriched for processes involved in protein translation and metabolic functions. The expression of several genes involved in the hypothalamic-pituitary-interrenal response to stress and epigenetic processes such as the regulation of DNA methylation patterns and miRNAs increased in males and not in females. These data suggest that maternal stress has markedly different effects on cellular pathways in the brains of male and female offspring of mothers that are exposed to stress, which could have important implications when assessing the long-term ecological and evolutionary impacts of stress across generations.
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Affiliation(s)
- David C H Metzger
- Department of Zoology, 6270 University Boulevard, University of British Columbia, Vancouver, BC, Canada V6T 1Z4
| | - Patricia M Schulte
- Department of Zoology, 6270 University Boulevard, University of British Columbia, Vancouver, BC, Canada V6T 1Z4
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Øverli Ø, Sørensen C. On the Role of Neurogenesis and Neural Plasticity in the Evolution of Animal Personalities and Stress Coping Styles. BRAIN, BEHAVIOR AND EVOLUTION 2016; 87:167-174. [DOI: 10.1159/000447085] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Individual variation in how animals react to stress and environmental change has become a central topic in a wide range of biological disciplines, from evolutionary ecology to biomedicine. Such variation manifests phenotypically as correlated trait-clusters (referred to as coping styles, behavioral syndromes, shyness-boldness, or personality traits). Thresholds for switching from active coping (fight-flight) to inhibition and passive behavior when exposed to stress depend on experience and genetic factors. Comparative research has revealed a range of neuroendocrine-behavioral associations which are conserved throughout the vertebrate subphylum, including factors affecting perception, learning, and memory of stimuli and events. Here we review conserved aspects of the contribution of neurogenesis and other aspects of neural plasticity to stress coping. In teleost fish, brain cell proliferation and neurogenesis have received recent attention. This work reveals that brain cell proliferation and neurogenesis are associated with heritable variation in stress coping style, and they are also differentially affected by short- and long-term stress in a biphasic manner. Routine-dependent and inflexible behavior in proactive individuals is associated with limited neural plasticity. These evolutionarily conserved relationships hold the potential to illuminate the biological background for stress-related neurobiological disorders.
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16
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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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