151
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O’Shea W, Serrano-Davies E, Quinn JL. Do personality and innovativeness influence competitive ability? An experimental test in the great tit. Behav Ecol 2017. [DOI: 10.1093/beheco/arx104] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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152
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O'Mara MT, Wikelski M, Voigt CC, Ter Maat A, Pollock HS, Burness G, Desantis LM, Dechmann DK. Cyclic bouts of extreme bradycardia counteract the high metabolism of frugivorous bats. eLife 2017; 6. [PMID: 28923167 PMCID: PMC5605195 DOI: 10.7554/elife.26686] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Accepted: 08/13/2017] [Indexed: 12/04/2022] Open
Abstract
Active flight requires the ability to efficiently fuel bursts of costly locomotion while maximizing energy conservation during non-flying times. We took a multi-faceted approach to estimate how fruit-eating bats (Uroderma bilobatum) manage a high-energy lifestyle fueled primarily by fig juice. Miniaturized heart rate telemetry shows that they use a novel, cyclic, bradycardic state that reduces daily energetic expenditure by 10% and counteracts heart rates as high as 900 bpm during flight. Uroderma bilobatum support flight with some of the fastest metabolic incorporation rates and dynamic circulating cortisol in vertebrates. These bats will exchange fat reserves within 24 hr, meaning that they must survive on the food of the day and are at daily risk of starvation. Energetic flexibly in U. bilobatum highlights the fundamental role of ecological pressures on integrative energetic networks and the still poorly understood energetic strategies of animals in the tropics. To survive, all animals have to balance how much energy they take in and how much they use. They must find enough food to fuel the chemical processes that keep them alive – known as their metabolism – and store leftover fuel to use when food is not available. Bats, for example, have a fast metabolism and powerful flight muscles, which require a lot of energy. Some bat species, such as the tent-making bats, survive on fruit juice, and their food sources are often far apart and difficult to find. These bats are likely to starve if they go without food for more than 24 hours, and therefore need to conserve energy while they are resting. To deal with potential food shortages, bats and other animals can enter a low-energy resting state called torpor. In this state, animals lower their body temperature and slow down their heart rate and metabolism so that they need less energy to stay alive. However, many animals that live in tropical regions, including tent-making bats, cannot enter a state of torpor, as it is too hot to sufficiently lower their body temperature. Until now, scientists did not fully understand how these bats control how much energy they use. Now, O’Mara et al. studied tent-making bats in the wild by attaching small heart rate transmitters to four wild bats, and measured their heartbeats over several days. Since each heartbeat delivers oxygen and fuel to the rest of the body, measuring the bats’ heart rate indicates how much energy they are using. The experiments revealed for the first time that tent-making bats periodically lower their heart rates while resting (to around 200 beats per minute). This reduces the amount of energy they use each day by up to 10%, and helps counteract heart rates that can reach 900 beats per minute when the bats are flying. Overall, these findings show that animals have evolved in various ways to control their use of energy. Future research should use similar technology to continue uncovering how wild animals have adapted to survive in different conditions. This knowledge will help us to understand how life has become so diverse in the tropics and the strategies that animals may use as climates change.
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Affiliation(s)
- M Teague O'Mara
- Department of Migration and Immuno-ecology, Max Planck Institute for Ornithology, Radolfzell, Germany.,Department of Biology, University of Konstanz, Konstanz, Germany.,Smithsonian Tropical Research Institute, Panama City, Panama.,Zukunftskolleg, University of Konstanz, Konstanz, Germany
| | - Martin Wikelski
- Department of Migration and Immuno-ecology, Max Planck Institute for Ornithology, Radolfzell, Germany.,Department of Biology, University of Konstanz, Konstanz, Germany
| | | | - Andries Ter Maat
- Department of Behavioural Neurobiology, Max Planck Institute for Ornithology, Starnberg, Germany
| | - Henry S Pollock
- Program in Ecology, Evolution and Conservation Biology, University of Illinois at Urbana-Champaign, Urbana, United States
| | - Gary Burness
- Department of Biology, Trent University, Peterborough, Canada
| | - Lanna M Desantis
- Environmental and Life Sciences Graduate Program, Trent University, Peterborough, Canada
| | - Dina Kn Dechmann
- Department of Migration and Immuno-ecology, Max Planck Institute for Ornithology, Radolfzell, Germany.,Department of Biology, University of Konstanz, Konstanz, Germany.,Smithsonian Tropical Research Institute, Panama City, Panama
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153
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Baugh AT, Davidson SC, Hau M, van Oers K. Temporal dynamics of the HPA axis linked to exploratory behavior in a wild European songbird (Parus major). Gen Comp Endocrinol 2017. [PMID: 28636887 DOI: 10.1016/j.ygcen.2017.06.011] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Variation in the reactivity of the endocrine stress axis is thought to underlie aspects of persistent individual differences in behavior (i.e. animal personality). Previous studies, however, have focused largely on estimating baseline or peak levels of glucocorticoids (CORT), often in captive animals. In contrast, the temporal dynamics of the HPA axis-how quickly it turns on and off, for example-may better indicate how an individual copes with stressors. Moreover, these HPA components might be correlated, thereby representing endocrine suites. Using wild-caught great tits (Parus major) we tested birds for exploratory behavior using a standardized novel environment assay that serves as a validated proxy for personality. We then re-captured a subset of these birds (n=85) and characterized four components of HPA physiology: baseline, endogenous stress response, a dexamethasone (DEX) challenge to estimate the strength of negative feedback, and an adrenocorticotropic hormone (ACTH) challenge to estimate adrenal capacity. We predicted that these four HPA responses would be positively correlated and that less exploratory birds would have a more rapid onset of the stress response (a CORT elevation during the baseline bleed) and weaker negative feedback (higher CORT after DEX). We found support for the first two predictions but not the third. All four components were positively correlated with each other and less exploratory birds exhibited an elevation in CORT during the baseline bleed (<3min from capture). Less exploratory birds, however, did not exhibit weaker negative feedback following the DEX challenge, but did exhibit weaker adrenal capacity. Together, our findings provide partial support for the hypothesis that the temporal reactivity of the HPA axis is linked with consistent individual differences in behavior, with more cautious (slower exploring) individuals exhibiting a faster CORT response.
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Affiliation(s)
- Alexander T Baugh
- Department of Biology, 500 College Avenue, Swarthmore College, Swarthmore, PA 19081, USA.
| | - Sarah C Davidson
- Department of Migration and Immuno-ecology, Max Planck Institute for Ornithology, Radolfzell, Germany; Department of Civil, Environmental and Geodetic Engineering, The Ohio State University, USA
| | - Michaela Hau
- Evolutionary Physiology Group, Max Planck Institute for Ornithology, Eberhard-Gwinner-Str., 82319 Seewiesen, Germany; Department of Biology, Universitätsstrasse 10, University of Konstanz, Konstanz, Germany
| | - Kees van Oers
- Department of Animal Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Droevendaalsesteeg 10, 6708 PB Wageningen, The Netherlands
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154
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Fritzsche P, Chunkov MM, Ushakova MV, Omarov KZ, Weinert D, Surov AV. Diurnal surface activity of the Ciscaucasian hamster (Mesocricetus raddei) in the field. Mamm Biol 2017. [DOI: 10.1016/j.mambio.2017.02.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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155
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Fanjul MS, Zenuto RR. Female choice, male dominance and condition-related traits in the polygynous subterranean rodent Ctenomys talarum. Behav Processes 2017; 142:46-55. [PMID: 28591643 DOI: 10.1016/j.beproc.2017.05.019] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Revised: 03/31/2017] [Accepted: 05/27/2017] [Indexed: 12/27/2022]
Abstract
Ctenomys talarum is a solitary and highly territorial species in which dominant males aggressively deter other males and monopolize reproductive activity. Female preference for dominant males is not easy to assess due to coercive mating by males. Hence, we aimed to answer if behavioural dominance and several condition-related traits like testosterone and cortisol levels, endoparasite load, and hematocrit volume may affect female preference when they have the opportunity to exert it. We designed a laboratory experiment using wild-caught C. talarum and employed a combined approach involving behavioural observations and the measurements of parameters of physical condition. We staged dyadic encounters between males to determine dominance index and then analyzed female preference towards tethered males (n=15) or their odours (n=18). Male dominance did not affect female preferences when odours were presented. When two tethered males were offered, females preferred those with higher dominance index. Preference of females for dominant males would mainly represent indirect benefits. Females did not show preference for males in relation to any physiological trait evaluated. Dominance was found negatively related to cortisol levels, probably avoiding the glucocorticoids-related costs, and positively related to parasite diversity, since they could tolerate it without impairing their health.
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Affiliation(s)
- M S Fanjul
- Grupo 'Ecología Fisiológica y del Comportamiento', Instituto de Investigaciones Marinas y Costeras (IIMyC), Universidad Nacional de Mar del Plata, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Box 1260, CP 7600, Mar del Plata, Argentina.
| | - R R Zenuto
- Grupo 'Ecología Fisiológica y del Comportamiento', Instituto de Investigaciones Marinas y Costeras (IIMyC), Universidad Nacional de Mar del Plata, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Box 1260, CP 7600, Mar del Plata, Argentina
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156
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Stone RA, Cohen Y, McGlinn AM, Davison S, Casavant S, Shaffer J, Khurana TS, Pardue MT, Iuvone PM. Development of Experimental Myopia in Chicks in a Natural Environment. Invest Ophthalmol Vis Sci 2017; 57:4779-89. [PMID: 27618415 PMCID: PMC5024671 DOI: 10.1167/iovs.16-19310] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Purpose The hypothesis that outdoor exposure might protect against myopia has generated much interest, although available data find only modest clinical efficacy. We tested the effect of outdoor rearing on form-deprivation myopia in chicks, a myopia model markedly inhibited by high-intensity indoor laboratory lighting. Methods Unilaterally goggled cohorts of White Leghorn chicks were maintained in a species-appropriate, outdoor rural setting during daylight hours to the extent permitted by weather. Control chicks were reared indoors with incandescent lighting. Besides ocular refraction and ultrasound, we determined dopamine and 3,4-dihydroxyphenylacetic acid (DOPAC) content in retina and vitreous and measured mRNA expression levels of selected clock and circadian rhythm-related genes in the retina/RPE. Results Myopia developed in the goggled eyes of all cohorts. Whereas outdoor rearing lessened myopia by 44% at 4 days, a protective effect was no longer evident at 11 days. Outdoor rearing had no consistent effect on retinal or vitreous content of dopamine or DOPAC. Conforming to prior data on form-deprivation myopia, retina and vitreous levels of DOPAC were reduced in goggled eyes. Compared with contralateral eyes, the retinal expression of clock and circadian rhythm-related genes was modestly altered in myopic eyes of chicks reared indoors or outdoors. Conclusions Outdoor rearing of chicks induces only a partial decrease of goggle-induced myopia that is not maintained, without evidence that retinal dopamine metabolism accounts for the partial myopia inhibition under these outdoor conditions. Although modest, alterations in retinal gene expression suggest that studying circadian signals might be informative for understanding refractive mechanisms.
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Affiliation(s)
- Richard A Stone
- Department of Ophthalmology University of Pennsylvania School of Medicine, Scheie Eye Institute, Philadelphia, Pennsylvania, United States
| | - Yuval Cohen
- Department of Ophthalmology University of Pennsylvania School of Medicine, Scheie Eye Institute, Philadelphia, Pennsylvania, United States
| | - Alice M McGlinn
- Department of Ophthalmology University of Pennsylvania School of Medicine, Scheie Eye Institute, Philadelphia, Pennsylvania, United States
| | - Sherrill Davison
- Laboratory of Avian Medicine and Pathology, University of Pennsylvania School of Veterinary Medicine, New Bolton Center, Kennett Square, Pennsylvania, United States
| | - Susan Casavant
- Laboratory of Avian Medicine and Pathology, University of Pennsylvania School of Veterinary Medicine, New Bolton Center, Kennett Square, Pennsylvania, United States
| | - James Shaffer
- Department of Ophthalmology University of Pennsylvania School of Medicine, Scheie Eye Institute, Philadelphia, Pennsylvania, United States
| | - Tejvir S Khurana
- Department of Physiology and Pennsylvania Muscle Institute, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, United States
| | - Machelle T Pardue
- Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, Georgia, United States 5Center for Visual and Neurocognitive Rehabilitation, Atlanta VA Medical Center, Decatur, Georgia, United States
| | - P Michael Iuvone
- Department of Ophthalmology, Emory University School of Medicine, Atlanta, Georgia, United States 7Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia, United States
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157
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Needham KB, Dochtermann NA, Greives TJ. Consistent individual variation in day, night, and GnRH-induced testosterone concentrations in house sparrows (Passer domesticus). Gen Comp Endocrinol 2017; 246:211-217. [PMID: 28017731 DOI: 10.1016/j.ygcen.2016.12.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/09/2016] [Revised: 12/13/2016] [Accepted: 12/19/2016] [Indexed: 11/25/2022]
Abstract
The hypothalamic-pituitary-gonadal (HPG) axis, with gonadotropin-releasing hormone (GnRH) initiating the endocrine cascade, regulates testosterone secretion. Testosterone, through its pleiotropic effects, plays a crucial role in coordinating morphology, physiology and behavior in a reproductive context. The concentration of circulating testosterone, however, varies over the course of the day and in response to other internal or external stimuli, potentially making it difficult to relate testosterone sampled at one time point with traits of interest. Many researchers now utilize the administration of exogenous GnRH to elicit a standardized stimulation of testosterone secretion. However, it has remained unclear if and how this exogenously stimulated activation of the HPG axis is related with endogenously regulated testosterone that is capable of influencing testosterone related traits. Repeated measures of a hormone can uncover consistent individual variation in hormonal differences at the HPG axis level, variation that potentially stems from underlying genetic variation in a population experiencing identical environmental cues. Thus, we asked, using the house sparrow (Passer domesticus), how daily endogenous variation in testosterone profiles relates to GnRH-induced testosterone secretion. Further, we explore the relationship between endogenous daily testosterone peaks and GnRH-induced testosterone with badge size, a morphological trait related with status within a social group. We found that GnRH-induced testosterone levels reflect a highly repeatable hormonal phenotype that is strongly correlated with nighttime testosterone levels. The results demonstrate the usefulness of GnRH-induced testosterone in studies aimed at understanding individual variation and selection on endogenously regulated testosterone levels and the potential importance of nighttime testosterone levels to physiology and behavior.
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Affiliation(s)
- Katie B Needham
- Department of Biological Sciences, North Dakota State University, Fargo, ND 58102, USA.
| | - Ned A Dochtermann
- Department of Biological Sciences, North Dakota State University, Fargo, ND 58102, USA
| | - Timothy J Greives
- Department of Biological Sciences, North Dakota State University, Fargo, ND 58102, USA
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158
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Prior NH, Yap KN, Mainwaring MC, Adomat HH, Crino OL, Ma C, Guns ES, Griffith SC, Buchanan KL, Soma KK. Sex steroid profiles in zebra finches: Effects of reproductive state and domestication. Gen Comp Endocrinol 2017; 244:108-117. [PMID: 26899721 DOI: 10.1016/j.ygcen.2016.02.018] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Revised: 02/15/2016] [Accepted: 02/16/2016] [Indexed: 01/13/2023]
Abstract
The zebra finch is a common model organism in neuroscience, endocrinology, and ethology. Zebra finches are generally considered opportunistic breeders, but the extent of their opportunism depends on the predictability of their habitat. This plasticity in the timing of breeding raises the question of how domestication, a process that increases environmental predictability, has affected their reproductive physiology. Here, we compared circulating steroid levels in various "strains" of zebra finches. In Study 1, using radioimmunoassay, we examined circulating testosterone levels in several strains of zebra finches (males and females). Subjects were wild or captive (Captive Wild-Caught, Wild-Derived, or Domesticated). In Study 2, using liquid chromatography-tandem mass spectrometry (LC-MS/MS), we examined circulating sex steroid profiles in wild and domesticated zebra finches (males and females). In Study 1, circulating testosterone levels in males differed across strains. In Study 2, six steroids were detectable in plasma from wild zebra finches (pregnenolone, progesterone, dehydroepiandrosterone (DHEA), testosterone, androsterone, and 5α-dihydrotestosterone (5α-DHT)). Only pregnenolone and progesterone levels changed across reproductive states in wild finches. Compared to wild zebra finches, domesticated zebra finches had elevated levels of circulating pregnenolone, progesterone, DHEA, testosterone, androstenedione, and androsterone. These data suggest that domestication has profoundly altered the endocrinology of this common model organism. These results have implications for interpreting studies of domesticated zebra finches, as well as studies of other domesticated species.
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Affiliation(s)
- Nora H Prior
- Zoology Department, University of British Columbia, Vancouver, BC, Canada.
| | - Kang Nian Yap
- Psychology Department, University of British Columbia, Vancouver, BC, Canada
| | - Mark C Mainwaring
- Department of Biological Sciences, Macquarie University, North Ryde, New South Wales, Australia
| | - Hans H Adomat
- The Prostate Centre at Vancouver General Hospital, Vancouver, BC, Canada
| | - Ondi L Crino
- Department of Biological Sciences, Macquarie University, North Ryde, New South Wales, Australia; School of Life and Environmental Sciences, Deakin University, Geelong, Victoria, Australia
| | - Chunqi Ma
- Psychology Department, University of British Columbia, Vancouver, BC, Canada
| | - Emma S Guns
- The Prostate Centre at Vancouver General Hospital, Vancouver, BC, Canada
| | - Simon C Griffith
- Department of Biological Sciences, Macquarie University, North Ryde, New South Wales, Australia
| | - Katherine L Buchanan
- School of Life and Environmental Sciences, Deakin University, Geelong, Victoria, Australia
| | - Kiran K Soma
- Zoology Department, University of British Columbia, Vancouver, BC, Canada; Psychology Department, University of British Columbia, Vancouver, BC, Canada; Graduate Program in Neuroscience, University of British Columbia, Vancouver, BC, Canada; Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada
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159
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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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160
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Lattin CR, Pechenenko AV, Carson RE. Experimentally reducing corticosterone mitigates rapid captivity effects on behavior, but not body composition, in a wild bird. Horm Behav 2017; 89:121-129. [PMID: 28065712 PMCID: PMC5359069 DOI: 10.1016/j.yhbeh.2016.12.016] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Revised: 12/23/2016] [Accepted: 12/29/2016] [Indexed: 01/02/2023]
Abstract
Wild animals and captives display physiological and behavioral differences, and it has been hypothesized, but rarely tested, that these differences are caused by sustained elevation of the hormone corticosterone. We used repeated computed tomography (CT) imaging to examine body composition changes in breeding male and female wild house sparrows (Passer domesticus; n=20) in response to two weeks of captivity, and assessed behavioral changes using video recordings. Half of the birds received the drug mitotane, which significantly decreased stress-induced corticosterone titers compared to controls. Based on the CT images, fat volumes increased, and pectoralis muscle density and heart and testes volumes decreased, over the two weeks of captivity in both groups of birds. However, beak-wiping, a behavior that can indicate anxiety and aggression, showed increased occurrence in controls compared to mitotane-treated birds. While our results do not support the hypothesis that these body composition changes were primarily driven by stress-induced corticosterone, our data suggest that experimentally reducing stress-induced corticosterone may mitigate some captivity-induced behavioral changes. Broadly, our results emphasize that researchers should take behavioral and physiological differences between free-living animals and captives into consideration when designing studies and interpreting results. Further, time in captivity should be minimized when birds will be reintroduced back to the wild.
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Affiliation(s)
- Christine R Lattin
- Department of Radiology and Biomedical Imaging, Yale University, 801 Howard Avenue, PO Box 208048, New Haven, CT 06520-8048, United States.
| | - Anita V Pechenenko
- Department of Radiology and Biomedical Imaging, Yale University, 801 Howard Avenue, PO Box 208048, New Haven, CT 06520-8048, United States
| | - Richard E Carson
- Department of Radiology and Biomedical Imaging, Yale University, 801 Howard Avenue, PO Box 208048, New Haven, CT 06520-8048, United States
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161
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GaitKeeper: A System for Measuring Canine Gait. SENSORS 2017; 17:s17020309. [PMID: 28208707 PMCID: PMC5335924 DOI: 10.3390/s17020309] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Revised: 01/25/2017] [Accepted: 01/31/2017] [Indexed: 11/17/2022]
Abstract
It is understood gait has the potential to be used as a window into neurodegenerative disorders, identify markers of subclinical pathology, inform diagnostic algorithms of disease progression and measure the efficacy of interventions. Dogs’ gaits are frequently assessed in a veterinary setting to detect signs of lameness. Despite this, a reliable, affordable and objective method to assess lameness in dogs is lacking. Most described canine lameness assessments are subjective, unvalidated and at high risk of bias. This means reliable, early detection of canine gait abnormalities is challenging, which may have detrimental implications for dogs’ welfare. In this paper, we draw from approaches and technologies used in human movement science and describe a system for objectively measuring temporal gait characteristics in dogs (step-time, swing-time, stance-time). Asymmetries and variabilities in these characteristics are of known clinical significance when assessing lameness but presently may only be assessed on coarse scales or under highly instrumented environments. The system consists an inertial measurement unit, containing a 3-axis accelerometer and gyroscope coupled with a standardized walking course. The measurement unit is attached to each leg of the dog under assessment before it is walked around the course. The data by the measurement unit is then processed to identify steps and subsequently, micro-gait characteristics. This method has been tested on a cohort of 19 healthy dogs of various breeds ranging in height from 34.2 cm to 84.9 cm. We report the system as capable of making precise step delineations with detections of initial and final contact times of foot-to-floor to a mean precision of 0.011 s and 0.048 s, respectively. Results are based on analysis of 12,678 foot falls and we report a sensitivity, positive predictive value and F-score of 0.81, 0.83 and 0.82 respectively. To investigate the effect of gait on system performance, the approach was tested in both walking and trotting with no significant performance deviation with 7249 steps reported for a walking gait and 4977 for a trotting gait. The number of steps reported for each leg were approximately equal and this consistency was true in both walking and trotting gaits. In the walking gait 1965, 1790, 1726 and 1768 steps were reported for the front left, front right, hind left and hind right legs respectively. 1361, 1250, 1176 and 1190 steps were reported for each of the four legs in the trotting gait. The proposed system is a pragmatic and precise solution for obtaining objective measurements of canine gait. With further development, it promises potential for a wide range of applications in both research and clinical practice.
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162
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The glucocorticoid response in a free-living bird predicts whether long-lasting memories fade or strengthen with time. Anim Behav 2016. [DOI: 10.1016/j.anbehav.2016.10.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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163
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Magel JMT, Pleizier N, Wilson ADM, Shultz AD, Vera Chang MN, Moon TW, Cooke SJ. Do physical habitat complexity and predator cues influence the baseline and stress-induced glucocorticoid levels of a mangrove-associated fish? Comp Biochem Physiol A Mol Integr Physiol 2016; 203:281-287. [PMID: 27746133 DOI: 10.1016/j.cbpa.2016.10.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Revised: 09/07/2016] [Accepted: 10/09/2016] [Indexed: 10/20/2022]
Abstract
As human populations continue to expand, increases in coastal development have led to the alteration of much of the world's mangrove habitat, creating problems for the multitude of species that inhabit these unique ecosystems. Habitat alteration often leads to changes in habitat complexity and predation risk, which may serve as additional stressors for those species that rely on mangroves for protection from predators. However, few studies have been conducted to date to assess the effects of these specific stressors on glucocorticoid (GC) stress hormone levels in wild fish populations. Using the checkered puffer as a model, our study sought to examine the effects of physical habitat complexity and predator environment on baseline and acute stress-induced GC levels. This was accomplished by examining changes in glucose and cortisol concentrations of fish placed in artificial environments for short periods (several hours) where substrate type and the presence of mangrove roots and predator cues were manipulated. Our results suggest that baseline and stress-induced GC levels are not significantly influenced by changes in physical habitat complexity or the predator environment using the experimental protocol that we applied. Although more research is required, the current study suggests that checkered puffers may be capable of withstanding changes in habitat complexity and increases in predation risk without experiencing adverse GC-mediated physiological effects, possibly as a result of the puffers' unique morphological and chemical defenses that help them to avoid predation in the wild.
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Affiliation(s)
- Jennifer M T Magel
- Fish Ecology and Conservation Physiology Laboratory, Department of Biology and Institute of Environmental Science, Carleton University, Ottawa, ON K1S 5B6, Canada.
| | - Naomi Pleizier
- Fish Ecology and Conservation Physiology Laboratory, Department of Biology and Institute of Environmental Science, Carleton University, Ottawa, ON K1S 5B6, Canada
| | - Alexander D M Wilson
- Fish Ecology and Conservation Physiology Laboratory, Department of Biology and Institute of Environmental Science, Carleton University, Ottawa, ON K1S 5B6, Canada
| | - Aaron D Shultz
- Cape Eleuthera Institute, Rock Sound, Eleuthera, The Bahamas
| | - Marilyn N Vera Chang
- Department of Biology and Centre for Advanced Research in Environmental Genomics, University of Ottawa, Ottawa, ON K1N 6N5, Canada
| | - Thomas W Moon
- Department of Biology and Centre for Advanced Research in Environmental Genomics, University of Ottawa, Ottawa, ON K1N 6N5, Canada
| | - Steven J Cooke
- Fish Ecology and Conservation Physiology Laboratory, Department of Biology and Institute of Environmental Science, Carleton University, Ottawa, ON K1S 5B6, Canada
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164
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Calisi RM, Geraghty AC, Avila A, Kaufer D, Bentley GE, Wingfield JC. Patterns of hypothalamic GnIH change over the reproductive period in starlings and rats. Gen Comp Endocrinol 2016; 237:140-146. [PMID: 27591072 DOI: 10.1016/j.ygcen.2016.08.015] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Revised: 08/05/2016] [Accepted: 08/24/2016] [Indexed: 11/30/2022]
Abstract
Gonadotropin inhibitory hormone (GnIH) exerts powerful inhibitory effects on various levels of the vertebrate hypothalamic-pituitary-gonadal (reproductive) axis, yet little is known of how it might change naturally over the course of reproduction. We characterized patterns of hypothalamic GnIH cell abundance over the reproductive period in two popular models used for the study of reproductive endocrinology: European starlings (Sturnus vulgaris) and Sprague-Dawley rats (Rattus norvegicus). We also examined the effects on an unpredictable change in the environment on GnIH cell abundance during the reproductive period, specifically during the period of parental care, by simulating a nest predation event and removing eggs/pups. In both species, we report changes in GnIH cell abundance are occurring at similar reproductive time points but are not always directionally parallel; this may be due to a difference in life histories and physiology mediating parental care. We discovered that cells immunoreactive for the GnIH peptide in male and female starlings are most highly abundant on the first day of incubation and the first day after the first chick hatches. Conversely in rats, GnIH cell abundance decreases in dams on the first day after pups are born. In both male and female starlings and female rats, GnIH cell abundance increases in response to egg/pup loss, indicating that GnIH responds to an unpredictable change in the environment in a potentially conserved fashion. These changes in GnIH cell abundance during the reproductive period inspire further investigation of its adaptive role in reproductive physiological events and behaviors, especially parental care.
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Affiliation(s)
- R M Calisi
- Department of Neurobiology, Physiology, and Behavior, University of California, Davis, CA, USA; Department of Integrative Biology, University of California, Berkeley, CA, USA.
| | - A C Geraghty
- Department of Integrative Biology, University of California, Berkeley, CA, USA
| | - A Avila
- Department of Integrative Biology, University of California, Berkeley, CA, USA
| | - D Kaufer
- Department of Integrative Biology, University of California, Berkeley, CA, USA; Helen Wills Neuroscience Institute, University of California, Berkeley, CA, USA
| | - G E Bentley
- Department of Integrative Biology, University of California, Berkeley, CA, USA; Helen Wills Neuroscience Institute, University of California, Berkeley, CA, USA
| | - J C Wingfield
- Department of Neurobiology, Physiology, and Behavior, University of California, Davis, CA, USA
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165
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Stewart EC, Greives TJ. Short-term immune challenge does not influence social dominance behaviour in top-ranked black-capped chickadees. Anim Behav 2016. [DOI: 10.1016/j.anbehav.2016.07.023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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166
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LaDage LD. Factors That Modulate Neurogenesis: A Top-Down Approach. BRAIN, BEHAVIOR AND EVOLUTION 2016; 87:184-190. [PMID: 27560485 DOI: 10.1159/000446906] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Although hippocampal neurogenesis in the adult brain has been conserved across the vertebrate lineage, laboratory studies have primarily examined this phenomenon in rodent models. This approach has been successful in elucidating important factors and mechanisms that can modulate rates of hippocampal neurogenesis, including hormones, environmental complexity, learning and memory, motor stimulation, and stress. However, recent studies have found that neurobiological research on neurogenesis in rodents may not easily translate to, or explain, neurogenesis patterns in nonrodent systems, particularly in species examined in the field. This review examines some of the evolutionary and ecological variables that may also modulate neurogenesis patterns. This 'top-down' and more naturalistic approach, which incorporates ecology and natural history, particularly of nonmodel species, may allow for a more comprehensive understanding of the functional significance of neurogenesis.
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Affiliation(s)
- Lara D LaDage
- Division of Mathematics and Natural Sciences, Penn State University Altoona, Altoona, Pa., USA
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167
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Rosvall KA, Bergeon Burns CM, Jayaratna SP, Ketterson ED. Divergence along the gonadal steroidogenic pathway: Implications for hormone-mediated phenotypic evolution. Horm Behav 2016; 84:1-8. [PMID: 27206546 PMCID: PMC4996689 DOI: 10.1016/j.yhbeh.2016.05.015] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Revised: 04/18/2016] [Accepted: 05/16/2016] [Indexed: 11/19/2022]
Abstract
Across a range of taxa, hormones regulate suites of traits that influence survival and reproductive success; however, the mechanisms by which hormone-mediated traits evolve are still unclear. We hypothesized that phenotypic divergence might follow from differential regulation of genes encoding key steps in hormone biosynthesis and thus the rate of hormone production. We tested this hypothesis in relation to the steroid hormone testosterone by comparing two subspecies of junco (Junco hyemalis) in the wild and in captivity. These subspecies have diverged over the last 10-15kyears in multiple testosterone-mediated traits, including aggression, ornamentation, and body size. We show that variation in gonadal gene expression along the steroid biosynthetic pathway predicts phenotypic divergence within and among subspecies, and that the more androgenized subspecies exhibits a more prolonged time-course of elevated testosterone following exogenous stimulation. Our results point to specific genes that fulfill key conditions for phenotypic evolution because they vary functionally in their expression among individuals and between populations, and they map onto population variation in phenotype in a common garden. Our findings therefore build an important bridge between hormones, genes, and phenotypic evolution.
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Affiliation(s)
- Kimberly A Rosvall
- Department of Biology, Indiana University, 1001 E. Third Street, Bloomington, IN 47405, USA; Center for the Integrative Study of Animal Behavior, Indiana University, 1001 E. Third Street, Bloomington, IN 47405, USA.
| | - Christine M Bergeon Burns
- Center for the Integrative Study of Animal Behavior, Indiana University, 1001 E. Third Street, Bloomington, IN 47405, USA
| | - Sonya P Jayaratna
- Department of Biology, Indiana University, 1001 E. Third Street, Bloomington, IN 47405, USA
| | - Ellen D Ketterson
- Department of Biology, Indiana University, 1001 E. Third Street, Bloomington, IN 47405, USA; Center for the Integrative Study of Animal Behavior, Indiana University, 1001 E. Third Street, Bloomington, IN 47405, USA
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168
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Seelke A, Yuan SM, Perkeybile A, Krubitzer L, Bales K. Early experiences can alter the size of cortical fields in prairie voles ( Microtus ochrogaster). ENVIRONMENTAL EPIGENETICS 2016; 2:dvw019. [PMID: 27818789 PMCID: PMC5094187 DOI: 10.1093/eep/dvw019] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Revised: 07/29/2016] [Accepted: 08/05/2016] [Indexed: 06/06/2023]
Abstract
The neocortex of the prairie vole is composed of three well-defined sensory areas and one motor area: primary somatosensory, visual, auditory areas and the primary motor area respectively. The boundaries of these cortical areas are identifiable very early in development, and have been thought to resist alteration by all but the most extreme physical or genetic manipulations. Here we assessed the extent to which the boundaries of sensory/motor cortical areas can be altered by exposing young prairie voles (Microtus ochrogaster) to a chronic stimulus, high or low levels of parental contact, or an acute stimulus, a single dose of saline, oxytocin (OT), or oxytocin antagonist on the day of birth. When animals reached adulthood, their brains were removed, the cortex was flattened, cut parallel to the pial surface, and stained for myelin to identify the architectonic boundaries of sensory and motor areas. We measured the overall proportion of cortex that was myelinated, as well as the proportion of cortex devoted to the sensory and motor areas. Both the chronic and acute manipulations were linked to significant alterations in areal boundaries of cortical fields, but the areas affected differed with different conditions. Thus, differences in parental care and early exposure to OT can both change cortical organization, but their effects are not identical. Furthermore, the effects of both manipulations were sexually dimorphic, with a greater number of statistically significant differences in females than in males. These results indicate that early environmental experience, both through exposure to exogenous neuropeptides and parental contact, can alter the size of cortical fields.
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Affiliation(s)
- A.M.H. Seelke
- Psychology Department, University of California - Davis, Davis, CA, USA
| | - S.-M. Yuan
- Psychology Department, University of California - Davis, Davis, CA, USA
| | | | - L.A. Krubitzer
- Psychology Department, University of California - Davis, Davis, CA, USA
- Center for Neuroscience, University of California - Davis, Davis, CA, USA
| | - K.L. Bales
- Psychology Department, University of California - Davis, Davis, CA, USA
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169
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Sleep Ecophysiology: Integrating Neuroscience and Ecology. Trends Ecol Evol 2016; 31:590-599. [DOI: 10.1016/j.tree.2016.05.004] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2016] [Revised: 05/09/2016] [Accepted: 05/10/2016] [Indexed: 10/21/2022]
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170
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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: 2] [Impact Index Per Article: 0.3] [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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171
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Neo YY, Hubert J, Bolle L, Winter HV, Ten Cate C, Slabbekoorn H. Sound exposure changes European seabass behaviour in a large outdoor floating pen: Effects of temporal structure and a ramp-up procedure. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2016; 214:26-34. [PMID: 27061472 DOI: 10.1016/j.envpol.2016.03.075] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 03/31/2016] [Accepted: 03/31/2016] [Indexed: 06/05/2023]
Abstract
Underwater sound from human activities may affect fish behaviour negatively and threaten the stability of fish stocks. However, some fundamental understanding is still lacking for adequate impact assessments and potential mitigation strategies. For example, little is known about the potential contribution of the temporal features of sound, the efficacy of ramp-up procedures, and the generalisability of results from indoor studies to the outdoors. Using a semi-natural set-up, we exposed European seabass in an outdoor pen to four treatments: 1) continuous sound, 2) intermittent sound with a regular repetition interval, 3) irregular repetition intervals and 4) a regular repetition interval with amplitude 'ramp-up'. Upon sound exposure, the fish increased swimming speed and depth, and swam away from the sound source. The behavioural readouts were generally consistent with earlier indoor experiments, but the changes and recovery were more variable and were not significantly influenced by sound intermittency and interval regularity. In addition, the 'ramp-up' procedure elicited immediate diving response, similar to the onset of treatment without a 'ramp-up', but the fish did not swim away from the sound source as expected. Our findings suggest that while sound impact studies outdoors increase ecological and behavioural validity, the inherently higher variability also reduces resolution that may be counteracted by increasing sample size or looking into different individual coping styles. Our results also question the efficacy of 'ramp-up' in deterring marine animals, which warrants more investigation.
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Affiliation(s)
- Y Y Neo
- Behavioural Biology, Institute of Biology Leiden (IBL), Leiden University, The Netherlands.
| | - J Hubert
- Behavioural Biology, Institute of Biology Leiden (IBL), Leiden University, The Netherlands
| | - L Bolle
- Institute for Marine Resources & Ecosystem Studies (IMARES) IJmuiden, Wageningen UR, The Netherlands
| | - H V Winter
- Institute for Marine Resources & Ecosystem Studies (IMARES) IJmuiden, Wageningen UR, The Netherlands
| | - C Ten Cate
- Behavioural Biology, Institute of Biology Leiden (IBL), Leiden University, The Netherlands
| | - H Slabbekoorn
- Behavioural Biology, Institute of Biology Leiden (IBL), Leiden University, The Netherlands
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172
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Food Neophobia in Wild Rats (Rattus norvegicus) Inhabiting a Changeable Environment-A Field Study. PLoS One 2016; 11:e0156741. [PMID: 27254150 PMCID: PMC4890768 DOI: 10.1371/journal.pone.0156741] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 05/18/2016] [Indexed: 11/28/2022] Open
Abstract
Food neophobia is a reaction to novel food observed in many animal species, particularly omnivores, including Rattus norvegicus. A neophobic reaction is typically characterised by avoidance of novel food and the necessity to assess both its potential value and toxicity by the animal. It has been hypothesised that this reaction is not observed in rats inhabiting a changeable environment with a high level of variability with regard to food and food sources. This study was conducted in such changeable conditions and it aims to demonstrate the behaviour of wild rats R. norvegicus in their natural habitat. The rats were studied in a farm setting, and the experimental arena was demarcated by a specially constructed pen which was freely accessible to the rats. At regular intervals, the rats were given new flavour- and smell-altered foods, while their behaviour was video-recorded. The results obtained in the study seem to confirm the hypothesis that rats inhabiting a highly changeable environment do not exhibit food neophobia. The observed reaction to novel food may be connected with a reaction to a novel object to a larger extent than to food neophobia. The value of the results obtained lies primarily in the fact that the study was conducted in the animals’ natural habitat, and that it investigated their spontaneous behaviours.
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173
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Gaukler SM, Ruff JS, Galland T, Underwood TK, Kandaris KA, Liu NM, Morrison LC, Veranth JM, Potts WK. Quantification of cerivastatin toxicity supports organismal performance assays as an effective tool during pharmaceutical safety assessment. Evol Appl 2016; 9:685-96. [PMID: 27247619 PMCID: PMC4869410 DOI: 10.1111/eva.12365] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Accepted: 01/19/2016] [Indexed: 11/29/2022] Open
Abstract
A major problem in pharmaceutical development is that adverse effects remain undetected during preclinical and clinical trials, but are later revealed after market release when prescribed to many patients. We have developed a fitness assay known as the organismal performance assay (OPA), which evaluates individual performance by utilizing outbred wild mice (Mus musculus) that are assigned to an exposed or control group, which compete against each other for resources within semi-natural enclosures. Performance measurements included reproductive success, survival, and male competitive ability. Our aim was to utilize cerivastatin (Baycol(®), Bayer), a pharmaceutical with known adverse effects, as a positive control to assess OPAs as a potential tool for evaluating the safety of compounds during preclinical trials. Mice were exposed to cerivastatin (~4.5 mg/kg/day) into early adulthood. Exposure ceased and animals were released into semi-natural enclosures. Within enclosures, cerivastatin-exposed females had 25% fewer offspring and cerivastatin-exposed males had 10% less body mass, occupied 63% fewer territories, sired 41% fewer offspring, and experienced a threefold increase in mortality when compared to controls. OPAs detected several cerivastatin-induced adverse effects indicating that fitness assays, commonly used in ecology and evolutionary biology, could be useful as an additional tool in safety testing during pharmaceutical development.
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Affiliation(s)
- Shannon M Gaukler
- Department of Biology University of Utah Salt Lake City UT USA; Los Alamos National Laboratory Environmental Stewardship Group Los Alamos NM USA
| | - James S Ruff
- Department of Biology University of Utah Salt Lake City UT USA
| | - Tessa Galland
- Department of Biology University of Utah Salt Lake City UT USA
| | | | | | - Nicole M Liu
- Department of Biology University of Utah Salt Lake City UT USA
| | | | - John M Veranth
- Department of Pharmacology and Toxicology University of Utah Salt Lake City UT USA
| | - Wayne K Potts
- Department of Biology University of Utah Salt Lake City UT USA
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174
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On cognitive ecology and the environmental factors that promote Alzheimer disease: lessons from Octodon degus (Rodentia: Octodontidae). Biol Res 2016; 49:10. [PMID: 26897365 PMCID: PMC4761148 DOI: 10.1186/s40659-016-0074-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Accepted: 02/12/2016] [Indexed: 12/15/2022] Open
Abstract
Cognitive ecologist posits that the more efficiently an animal uses information from the biotic and abiotic environment, the more adaptive are its cognitive abilities. Nevertheless, this approach does not test for natural neurodegenerative processes under field or experimental conditions, which may recover animals information processing and decision making and may explain, mechanistically, maladaptive behaviors. Here, we call for integrative approaches to explain the relationship between ultimate and proximate mechanisms behind social behavior. We highlight the importance of using the endemic caviomorph rodent Octodon degus as a valuable natural model for mechanistic studies of social behavior and to explain how physical environments can shape social experiences that might influence impaired cognitive abilities and the onset and progression of neurodegenerative disorders such as Alzheimer disease. We consequently suggest neuroecological approaches to examine how key elements of the environment may affect neural and cognitive mechanisms associated with learning, memory processes and brain structures involved in social behavior. We propose the following three core objectives of a program comprising interdisciplinary research in O. degus, namely: (1) to determine whether diet types provided after weaning can lead to cognitive impairment associated with spatial memory, learning and predisposing to develop Alzheimer disease in younger ages; (2) to examine if early life social experience has long term effects on behavior and cognitive responses and risk for development Alzheimer disease in later life and (3) To determine if an increase of social interactions in adult degu reared in different degree of social stressful conditions alter their behavior and cognitive responses.
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175
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St Juliana JR, Mitchell WA. Optimal foraging behavior and the thermal neutral zone of Peromyscus leucopus during winter: A test using natural and controlled ambient temperatures. J Therm Biol 2016; 56:109-12. [PMID: 26857984 DOI: 10.1016/j.jtherbio.2016.01.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Revised: 12/24/2015] [Accepted: 01/12/2016] [Indexed: 11/29/2022]
Abstract
Endotherms foraging at temperatures outside of their thermal neutral zone (TNZ) pay an increased energetic cost. We asked if thermally-induced changes in foraging costs influence quitting harvest rate (QHR) of mice. We predicted that mice foraging during the winter would have a higher QHR in more costly colder conditions. We conducted our study with wild caught Peromyscus leucopus in an enclosure located in West Terre Haute, Indiana. We assayed changes in QHR using the forager's giving up density (GUD), which is the amount of uneaten seeds reaming in a tray after foraging activity. Each night from January 12th to March 13th, we assigned 4 trays as "cold trays" (at ambient temperature), and 4 trays as "hot trays" (trays with a ceramic heat element that increased the temperatures of feeding trays ca. 10-15°C). GUDs (and therfore QHRs) increased as a function of decreasing ambient temperature. Furthermore there was an interaction between tray temperature and ambient temperature; namely, on cool nights mice had lower GUDs in the "hot trays", but on warm nights mice had lower GUDs in the "cold trays". The TNZ for P. leucopus actively foraging during winter may be closer to the environmental average temperature than typically measured in the laboratory. Overall, these results support the idea that QHR is related to an animal's foraging in thermally challenged conditions. We present a unique way of measuring an animal's TNZ in the field using behavioral indicators.
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Affiliation(s)
- Justin R St Juliana
- Indiana State University, Department of Biology, 200 North Seventh Street, Terre Haute, IN, 47809, USA.
| | - William A Mitchell
- Indiana State University, Department of Biology, 200 North Seventh Street, Terre Haute, IN, 47809, USA
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176
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Rubenstein DR, Skolnik H, Berrio A, Champagne FA, Phelps S, Solomon J. Sex-specific fitness effects of unpredictable early life conditions are associated with DNA methylation in the avian glucocorticoid receptor. Mol Ecol 2016; 25:1714-28. [PMID: 26588348 DOI: 10.1111/mec.13483] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2015] [Revised: 10/25/2015] [Accepted: 11/05/2015] [Indexed: 01/09/2023]
Abstract
Organisms can adapt to variable environments by using environmental cues to modulate developmental gene expression. In principle, maternal influences can adaptively adjust offspring phenotype when early life and adult environments match, but they may be maladaptive when future environments are not predictable. One of the best-studied 'maternal effects' is through modification of the offspring's hypothalamic-pituitary-adrenal (HPA) axis, the neuroendocrine system that controls responses to stress. In addition to the direct transfer of glucocorticoids from mother to offspring, offspring HPA function and other phenotypes can also be affected by epigenetic modifications like DNA methylation of the glucocorticoid receptor promoter. Here we examine how among-year variation in rainfall is related to DNA methylation during development and fitness in adulthood in the superb starling (Lamprotornis superbus), which lives in a climatically unpredictable environment where early life and adult environments are unlikely to match. We found that DNA methylation in the putative promoter of the glucocorticoid receptor gene is reduced in chicks - particularly in males - born following drier prebreeding periods. Additionally, DNA methylation is lower in males that become breeders than those that never breed. However, there is no relationship in females between DNA methylation and the likelihood of dispersing from the natal group to breed elsewhere. These results suggest that early life conditions may positively affect fitness in a sex-specific manner through chemical modification of an HPA-associated gene. This study is the first to show that epigenetic modifications during early life may influence the fitness of free-living organisms adapted to unpredictable environments.
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Affiliation(s)
- Dustin R Rubenstein
- Department of Ecology, Evolution and Environmental Biology, Columbia University, 1200 Amsterdam Avenue, New York, NY, 10027, USA.,Center for Integrative Animal Behavior, Columbia University, 1200 Amsterdam Avenue, New York, NY, 10027, USA
| | - Hannah Skolnik
- Department of Ecology, Evolution and Environmental Biology, Columbia University, 1200 Amsterdam Avenue, New York, NY, 10027, USA
| | - Alejandro Berrio
- Department of Integrative Biology, University of Texas, Austin, TX, 78712, USA
| | - Frances A Champagne
- Center for Integrative Animal Behavior, Columbia University, 1200 Amsterdam Avenue, New York, NY, 10027, USA.,Department of Psychology, Columbia University, 1190 Amsterdam Avenue, New York, NY, 10027, USA
| | - Steven Phelps
- Department of Integrative Biology, University of Texas, Austin, TX, 78712, USA
| | - Joseph Solomon
- Department of Ecology, Evolution and Environmental Biology, Columbia University, 1200 Amsterdam Avenue, New York, NY, 10027, USA
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177
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Spoelstra K, Wikelski M, Daan S, Loudon ASI, Hau M. Natural selection against a circadian clock gene mutation in mice. Proc Natl Acad Sci U S A 2016; 113:686-91. [PMID: 26715747 PMCID: PMC4725470 DOI: 10.1073/pnas.1516442113] [Citation(s) in RCA: 99] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Circadian rhythms with an endogenous period close to or equal to the natural light-dark cycle are considered evolutionarily adaptive ("circadian resonance hypothesis"). Despite remarkable insight into the molecular mechanisms driving circadian cycles, this hypothesis has not been tested under natural conditions for any eukaryotic organism. We tested this hypothesis in mice bearing a short-period mutation in the enzyme casein kinase 1ε (tau mutation), which accelerates free-running circadian cycles. We compared daily activity (feeding) rhythms, survivorship, and reproduction in six replicate populations in outdoor experimental enclosures, established with wild-type, heterozygous, and homozygous mice in a Mendelian ratio. In the release cohort, survival was reduced in the homozygote mutant mice, revealing strong selection against short-period genotypes. Over the course of 14 mo, the relative frequency of the tau allele dropped from initial parity to 20%. Adult survival and recruitment of juveniles into the population contributed approximately equally to the selection for wild-type alleles. The expression of activity during daytime varied throughout the experiment and was significantly increased by the tau mutation. The strong selection against the short-period tau allele observed here contrasts with earlier studies showing absence of selection against a Period 2 (Per2) mutation, which disrupts internal clock function, but does not change period length. These findings are consistent with, and predicted by the theory that resonance of the circadian system plays an important role in individual fitness.
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Affiliation(s)
- Kamiel Spoelstra
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ 08544; Department of Migration and Immuno-Ecology, Max Planck Institute for Ornithology, D-78315 Radolfzell, Germany;
| | - Martin Wikelski
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ 08544; Department of Migration and Immuno-Ecology, Max Planck Institute for Ornithology, D-78315 Radolfzell, Germany; Department of Biology, University of Konstanz, D-78457 Konstanz, Germany
| | - Serge Daan
- Unit of Chronobiology, Institute of Evolutionary Life Sciences, University of Groningen, 9747 AG Groningen, The Netherlands
| | - Andrew S I Loudon
- Faculty of Life Sciences, University of Manchester, Manchester M13 9PL, United Kingdom
| | - Michaela Hau
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ 08544; Department of Biology, University of Konstanz, D-78457 Konstanz, Germany; Evolutionary Physiology Group, Max Planck Institute for Ornithology, D-82319 Seewiesen, Germany
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178
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Abstract
Biodiversity often serves to reduce zoonotic pathogens, such that prevalence is lower in communities of greater diversity. This phenomenon is termed the dilution effect, and although it has been reported for several pathogens (e.g. Sin Nombre virus, SNV), the mechanism is largely unknown. We investigated a putative mechanism, by testing the hypothesis that higher biodiversity alters behaviours important in pathogen transmission. Using deer mice (Peromyscus maniculatus) and SNV as our host-pathogen system, and a novel surveillance system, we compared host behaviours between high- and low-diversity communities. Behaviours were observed on foraging trays equipped with infrared cameras and passive integrated transponder (PIT) tag readers. Deer mice inhabiting the more diverse site spent less time in behaviours related to SNV transmission compared to deer mice from the less diverse site. The differences were attributed to the composition of behavioural phenotypes ('bold' versus 'shy') on the sites. Bold deer mice were 4.6 times more numerous on the less diverse site and three times more likely to be infected with SNV than shy deer mice. Our findings suggest that biodiversity affects pathogen transmission by altering the presence of different behavioural phenotypes. These findings have implications for human health and conservation.
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179
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Aiming for Progress in Understanding Underwater Noise Impact on Fish: Complementary Need for Indoor and Outdoor Studies. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 875:1057-65. [DOI: 10.1007/978-1-4939-2981-8_131] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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180
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Hau M, Casagrande S, Ouyang J, Baugh A. Glucocorticoid-Mediated Phenotypes in Vertebrates. ADVANCES IN THE STUDY OF BEHAVIOR 2016. [DOI: 10.1016/bs.asb.2016.01.002] [Citation(s) in RCA: 107] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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181
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Russ A, Reitemeier S, Weissmann A, Gottschalk J, Einspanier A, Klenke R. Seasonal and urban effects on the endocrinology of a wild passerine. Ecol Evol 2015; 5:5698-710. [PMID: 27069618 PMCID: PMC4813110 DOI: 10.1002/ece3.1820] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Revised: 10/14/2015] [Accepted: 10/15/2015] [Indexed: 11/27/2022] Open
Abstract
In order to maximize their fitness, organisms in seasonal environments rely on external cues to optimally time their life-history stages. One of the most important zeitgeber to time reproduction is the photoperiod, but further environmental cues are assessed to fine-tune reproduction due to year-to-year variation in environmental conditions. However, in urbanized environments, the pervasive artificial light at night has altered the natural signal of light and darkness. Accordingly, artificial light at night was repeatedly shown to affect avian reproductive physiology and to advance seasonal reproduction in birds. However, these experiments were mainly conducted in the absence of further environmental cues to facilitate the investigation of the mechanisms which are still poorly understood. Here, we investigate whether the endocrine system of free-ranging European blackbirds (Turdus merula) correlates with the amount of artificial light at night along a rural to urban gradient while the birds still encounter complementary environmental cues including seasonal variation in day length and temperature. Testosterone and estrone were assessed as metabolites in fecal samples and corticosterone in blood from mist-netted blackbirds. We demonstrate that seasonal fluctuations in abiotic factors, individual conditions, but also light at night affect the reproductive and stress physiology of wild European blackbirds. Elevated artificial night light intensities were significantly positively correlated with corticosterone and negatively with female estrone levels. No effects of artificial light were found for testosterone levels. Our results suggest that female blackbirds in particular perceive even low levels of artificial light at night as a weak but chronic stressor that interacts with the hypothalamic-pituitary-gonadal axis and leads to a reduced secretion of reproductive hormones. These findings point out that the impacts of light pollution are diverse and we only slowly disentangle its multiple effects on physiology, ecology, and biodiversity.
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Affiliation(s)
- Anja Russ
- Department of Conservation BiologyHelmholtz‐Centre for Environmental Research ‐ UFZPermoserstraße 1504318LeipzigGermany
| | - Susanne Reitemeier
- Institute of Physiological ChemistryUniversity of LeipzigAn den Tierkliniken 104103LeipzigGermany
| | - Anne Weissmann
- Institute of Physiological ChemistryUniversity of LeipzigAn den Tierkliniken 104103LeipzigGermany
| | - Jutta Gottschalk
- Institute of Physiological ChemistryUniversity of LeipzigAn den Tierkliniken 104103LeipzigGermany
| | - Almuth Einspanier
- Institute of Physiological ChemistryUniversity of LeipzigAn den Tierkliniken 104103LeipzigGermany
| | - Reinhard Klenke
- Department of Conservation BiologyHelmholtz‐Centre for Environmental Research ‐ UFZPermoserstraße 1504318LeipzigGermany
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182
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Sex steroid profiles and pair-maintenance behavior of captive wild-caught zebra finches (Taeniopygia guttata). J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2015; 202:35-44. [PMID: 26610331 DOI: 10.1007/s00359-015-1050-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Revised: 10/12/2015] [Accepted: 10/29/2015] [Indexed: 12/19/2022]
Abstract
Here, we studied the life-long monogamous zebra finch, to examine the relationship between circulating sex steroid profiles and pair-maintenance behavior in pairs of wild-caught zebra finches (paired in the laboratory for >1 month). We used liquid chromatography-tandem mass spectrometry to examine a total of eight androgens and progestins [pregnenolone, progesterone, dehydroepiandrosterone (DHEA), androstenediol, pregnan-3,17-diol-20-one, androsterone, androstanediol, and testosterone]. In the plasma, only pregnenolone, progesterone, DHEA, and testosterone were above the limit of quantification. Sex steroid profiles were similar between males and females, with only circulating progesterone levels significantly different between the sexes (female > male). Circulating pregnenolone levels were high in both sexes, suggesting that pregnenolone might serve as a circulating prohormone for local steroid synthesis in zebra finches. Furthermore, circulating testosterone levels were extremely low in both sexes. Additionally, we found no correlations between circulating steroid levels and pair-maintenance behavior. Taken together, our data raise several interesting questions about the neuroendocrinology of zebra finches.
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183
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Vocal production and playback of altered song do not affect ZENK expression in black-capped chickadees (Poecile atricapillus). Behav Brain Res 2015; 298:91-9. [PMID: 26523856 DOI: 10.1016/j.bbr.2015.10.047] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Revised: 10/17/2015] [Accepted: 10/24/2015] [Indexed: 11/23/2022]
Abstract
The two-note fee bee song of the black-capped chickadee (Poecile atricapillus) is sung at many different absolute frequencies, but the relative frequencies between the start and end of the fee note (the glissando) and between the fee and the bee notes (the inter-note ratio) are preserved regardless of absolute frequency. If these relative frequencies are experimentally manipulated, birds exhibit reduced behavioural responses to playback of altered songs both in field studies and laboratory studies. Interestingly, males appear to be sensitive to alterations in the glissando, while females appear to be sensitive to alterations in both the glissando and the inter-note ratio. In this study, we sought to determine whether the behaviour of male and female chickadees corresponds to differences in zenk protein immunoreactivity (ZENK-ir) in auditory perceptual regions following playback of fee bee songs with typical and altered pitch ratios. Overall, there was a small but significant sex difference in ZENK-ir (females>males), but altering relative frequencies did not reduce ZENK-ir compared to typical song. Birds did vocalize less in response to playback of songs that lacked an inter-note interval, but amount of singing fee bee song, chick-a-dee calls, or gargles was not correlated with ZENK-ir in perceptual regions (caudomedial nidopallium, NCM and caudomedial mesopallium, CMM) or in HVC, which is part of the song system. Our results confirm that ZENK-ir in NCM and CMM is not involved in fine-grain perceptual discrimination, however it did not support the idea that increased vocalizing increases ZENK-ir in HVC.
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184
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Perfito N, Zann RA, Hau M, Bentley GE. Seasonal-like variation in song control system volume of wild zebra finches. ACTA ACUST UNITED AC 2015; 323:586-91. [DOI: 10.1002/jez.1956] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Revised: 07/06/2015] [Accepted: 07/07/2015] [Indexed: 02/02/2023]
Affiliation(s)
- Nicole Perfito
- Max-Planck Institute for Ornithology; Radolfzell Germany
- Department of Integrative Biology and Helen Wills Neuroscience Institute; University of California at Berkeley; Berkeley California
| | - Richard A. Zann
- Department of Zoology; La Trobe University; Melbourne Australia
| | - Michaela Hau
- Max-Planck Institute for Ornithology; Radolfzell Germany
| | - George E. Bentley
- Department of Integrative Biology and Helen Wills Neuroscience Institute; University of California at Berkeley; Berkeley California
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185
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Pavitt AT, Walling CA, Pemberton JM, Kruuk LEB. Heritability and cross-sex genetic correlations of early-life circulating testosterone levels in a wild mammal. Biol Lett 2015; 10:20140685. [PMID: 25428929 DOI: 10.1098/rsbl.2014.0685] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Testosterone is an important hormone that has been shown to have sex-specific links to fitness in numerous species. Although testosterone concentrations vary substantially between individuals in a population, little is known about its heritable genetic basis or between-sex genetic correlations that determine its evolutionary potential. We found circulating neonatal testosterone levels to be both heritable (0.160 ± 0.064 s.e.) and correlated between the sexes (0.942 ± 0.648 s.e.) in wild red deer calves (Cervus elaphus). This may have important evolutionary implications if, as in adults, the sexes have divergent optima for circulating testosterone levels.
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Affiliation(s)
- Alyson T Pavitt
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, UK
| | - Craig A Walling
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, UK
| | - Josephine M Pemberton
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, UK
| | - Loeske E B Kruuk
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, UK Division of Evolution, Ecology and Genetics Research School of Biology, The Australian National University, Canberra, Australian Capital Territory 0200, Australia
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186
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Jandt JM, Thomson JL, Geffre AC, Toth AL. Lab rearing environment perturbs social traits: a case study withPolisteswasps. Behav Ecol 2015. [DOI: 10.1093/beheco/arv082] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
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187
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Amorin N, Calisi RM. Measurements of Neuronal Soma Size and Estimated Peptide Concentrations in Addition to Cell Abundance Offer a Higher Resolution of Seasonal and Reproductive Influences of GnRH-I and GnIH in European Starlings. Integr Comp Biol 2015; 55:332-42. [DOI: 10.1093/icb/icv063] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
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188
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Greives TJ, Kingma SA, Kranstauber B, Mortega K, Wikelski M, Oers K, Mateman AC, Ferguson GA, Beltrami G, Hau M. Costs of sleeping in: circadian rhythms influence cuckoldry risk in a songbird. Funct Ecol 2015. [DOI: 10.1111/1365-2435.12440] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Timothy J. Greives
- Department of Biological Sciences North Dakota State University 1340 Bolley Drive Fargo ND 58102 USA
| | - Sjouke A. Kingma
- School of Biological Sciences University of East Anglia Norwich Research Park Norwich NR4 7TJ UK
- Behavioural Ecology and Self‐organization group Center for Ecological and Evolutionary Studies University of Groningen Nijenborgh 7 9747 AG Groningen The Netherlands
| | - Bart Kranstauber
- Department of Migration and Immunoecology Max Planck Institute for Ornithology Am Obstberg 1 78315 Radolfzell Germany
| | - Kim Mortega
- Department of Migration and Immunoecology Max Planck Institute for Ornithology Am Obstberg 1 78315 Radolfzell Germany
- Department of Biology University of Konstanz Universitätstraße 10 78457 Konstanz Germany
| | - Martin Wikelski
- Department of Migration and Immunoecology Max Planck Institute for Ornithology Am Obstberg 1 78315 Radolfzell Germany
- Department of Biology University of Konstanz Universitätstraße 10 78457 Konstanz Germany
| | - Kees Oers
- Department of Animal Ecology Netherlands Institute for Ecology (NIOO‐KNAW) PO Box 50 6700 AB Wageningen The Nethesrlands
| | - A. Christa Mateman
- Department of Animal Ecology Netherlands Institute for Ecology (NIOO‐KNAW) PO Box 50 6700 AB Wageningen The Nethesrlands
| | - Glen A. Ferguson
- National Bioenergy Center National Renewable Energy Laboratory 15013 Denver West Parkway Golden CO 80401 USA
| | - Giulia Beltrami
- Dipartimento di Biologia ed Evoluzione Università di Ferrara Corso Ercole I d'Este, 32 44100 Ferrara Italy
| | - Michaela Hau
- Department of Biology University of Konstanz Universitätstraße 10 78457 Konstanz Germany
- Evolutionary Physiology Group Max Planck Institute for Ornithology Eberhard‐Gwinner‐Strasse 82319 Seewiesen Germany
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189
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van Breukelen NA, Snekser JL, Itzkowitz M. Male convict cichlid 11-ketotestosterone levels throughout the reproductive cycle: an exploratory profile study in laboratory and field populations. PeerJ 2015; 3:e949. [PMID: 26020006 PMCID: PMC4435447 DOI: 10.7717/peerj.949] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Accepted: 04/20/2015] [Indexed: 11/29/2022] Open
Abstract
The convict cichlid (Amatitlania nigrofasciata) has been extensively examined in relation to many behavioral topics, such as courtship, pair-bonding, bi-parental care, and territoriality. Recently, this model species has been utilized in studies on genetics, endocrinology, and neuroanatomy, with an ultimate goal of connecting behavior with its underlying mechanisms. The goal of this study was two-fold: (1) profile the circulating levels of plasma 11KT in the male convict cichlid at multiple points during the reproductive cycle and (2) generally compare the hormonal profiles of the widely used laboratory populations and those of a free-living population in the streams of Costa Rica. The results of the field experiment showed that male convict cichlids had higher levels of circulating 11KT during courtship and lower during the parental care and non-breeding phases. The profile of the laboratory population was similar to the profile of the free-living individuals, with significantly higher levels of 11KT occurring during courtship than during parental care, though the level of 11KT during non-breeding phase was elevated in the laboratory. The high levels of 11KT during courtship and low levels of 11KT during parental care found in both the field and the laboratory is similar to what has been reported in other species of teleosts, and may suggest an important function of 11KT in the expression of courtship behavior and the subsequent onset of parental behaviors in this model species.
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Affiliation(s)
| | | | - Murray Itzkowitz
- Lehigh University, Department of Biological Sciences , Bethlehem, PA , USA
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190
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Thomas JR, Woodley SK. Treatment with corticosterone delays cutaneous wound healing in male and female salamanders. Gen Comp Endocrinol 2015; 216:33-8. [PMID: 25913258 DOI: 10.1016/j.ygcen.2015.04.013] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Revised: 02/12/2015] [Accepted: 04/19/2015] [Indexed: 11/24/2022]
Abstract
In vertebrates, exposure to stressors and stress hormones has a number of physiological effects including modulation of immune function. These effects on immune function have been well studied in mammals, but less is known in other groups, in particular amphibians. To analyze the effects of exposure to stressors and the stress hormone corticosterone, we monitored cutaneous wound healing as a measure of integrated immunity in male and female semi-terrestrial salamanders (Desmognathus ochrophaeus) that were chased to induce endogenous release of corticosterone or were treated with physiologically relevant doses of corticosterone. As predicted, subjects treated daily with corticosterone healed more slowly than did controls. In contrast, subjects that had been chased daily healed at the same rate as controls. Surprisingly, repeated chasing did not elevate plasma corticosterone despite causing drops in body mass and survival. Additionally, females healed more slowly than males, possibly due to energetic constraints.
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Affiliation(s)
- Jessica R Thomas
- Department of Biological Sciences, Duquesne University, 600 Forbes Avenue, Pittsburgh, PA 15282, USA.
| | - Sarah K Woodley
- Department of Biological Sciences, Duquesne University, 600 Forbes Avenue, Pittsburgh, PA 15282, USA
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191
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Neo YY, Parie L, Bakker F, Snelderwaard P, Tudorache C, Schaaf M, Slabbekoorn H. Behavioral changes in response to sound exposure and no spatial avoidance of noisy conditions in captive zebrafish. Front Behav Neurosci 2015; 9:28. [PMID: 25741256 PMCID: PMC4330796 DOI: 10.3389/fnbeh.2015.00028] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2014] [Accepted: 01/28/2015] [Indexed: 11/13/2022] Open
Abstract
Auditory sensitivity in fish serves various important functions, but also makes fish susceptible to noise pollution. Human-generated sounds may affect behavioral patterns of fish, both in natural conditions and in captivity. Fish are often kept for consumption in aquaculture, on display in zoos and hobby aquaria, and for medical sciences in research facilities, but little is known about the impact of ambient sounds in fish tanks. In this study, we conducted two indoor exposure experiments with zebrafish (Danio rerio). The first experiment demonstrated that exposure to moderate sound levels (112 dB re 1 μPa) can affect the swimming behavior of fish by changing group cohesion, swimming speed and swimming height. Effects were brief for both continuous and intermittent noise treatments. In the second experiment, fish could influence exposure to higher sound levels by swimming freely between an artificially noisy fish tank (120-140 dB re 1 μPa) and another with ambient noise levels (89 dB re 1 μPa). Despite initial startle responses, and a brief period in which many individuals in the noisy tank dived down to the bottom, there was no spatial avoidance or noise-dependent tank preference at all. The frequent exchange rate of about 60 fish passages per hour between tanks was not affected by continuous or intermittent exposures. In conclusion, small groups of captive zebrafish were able to detect sounds already at relatively low sound levels and adjust their behavior to it. Relatively high sound levels were at least at the on-set disturbing, but did not lead to spatial avoidance. Further research is needed to show whether zebrafish are not able to avoid noisy areas or just not bothered. Quantitatively, these data are not directly applicable to other fish species or other fish tanks, but they do indicate that sound exposure may affect fish behavior in any captive condition.
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Affiliation(s)
- Yik Yaw Neo
- Behavioral Biology, Institute of Biology (IBL), Leiden University Leiden, Netherlands
| | - Lisa Parie
- Behavioral Biology, Institute of Biology (IBL), Leiden University Leiden, Netherlands
| | - Frederique Bakker
- Behavioral Biology, Institute of Biology (IBL), Leiden University Leiden, Netherlands ; Naturalis Biodiversity Center Leiden, Netherlands
| | - Peter Snelderwaard
- Behavioral Biology, Institute of Biology (IBL), Leiden University Leiden, Netherlands
| | - Christian Tudorache
- Behavioral Biology, Institute of Biology (IBL), Leiden University Leiden, Netherlands
| | - Marcel Schaaf
- Behavioral Biology, Institute of Biology (IBL), Leiden University Leiden, Netherlands
| | - Hans Slabbekoorn
- Behavioral Biology, Institute of Biology (IBL), Leiden University Leiden, Netherlands
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192
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Tian J, Courtiol A, Schneeberger K, Greenwood AD, Czirják GÁ. Circulating white blood cell counts in captive and wild rodents are influenced by body mass rather than testes mass, a correlate of mating promiscuity. Funct Ecol 2015. [DOI: 10.1111/1365-2435.12394] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jundong Tian
- Department of Wildlife Diseases Leibniz Institute for Zoo and Wildlife Research 10315 Berlin Germany
- Department of Veterinary Medicine Freie Universität Berlin 14163 Berlin Germany
| | - Alexandre Courtiol
- Department of Evolutionary Genetics Leibniz Institute for Zoo and Wildlife Research 10315 Berlin Germany
| | - Karin Schneeberger
- Department of Evolutionary Ecology Leibniz Institute for Zoo and Wildlife Research 10315 Berlin Germany
| | - Alex D. Greenwood
- Department of Wildlife Diseases Leibniz Institute for Zoo and Wildlife Research 10315 Berlin Germany
- Department of Veterinary Medicine Freie Universität Berlin 14163 Berlin Germany
| | - Gábor Á. Czirják
- Department of Wildlife Diseases Leibniz Institute for Zoo and Wildlife Research 10315 Berlin Germany
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193
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Kaiser K, Devito J, Jones CG, Marentes A, Perez R, Umeh L, Weickum RM, McGovern KE, Wilson EH, Saltzman W. Effects of anthropogenic noise on endocrine and reproductive function in White's treefrog, Litoria caerulea. CONSERVATION PHYSIOLOGY 2015; 3:cou061. [PMID: 27293682 PMCID: PMC4778486 DOI: 10.1093/conphys/cou061] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Revised: 12/05/2014] [Accepted: 12/08/2014] [Indexed: 05/23/2023]
Abstract
Urbanization is a major driver of ecological change and comes with a suite of habitat modifications, including alterations to the local temperature, precipitation, light and noise regimes. Although many recent studies have investigated the behavioural and ecological ramifications of urbanization, physiological work in this area has lagged. We tested the hypothesis that anthropogenic noise is a stressor for amphibians and that chronic exposure to such noise leads to reproductive suppression. In the laboratory, we exposed male White's treefrogs, Litoria caerulea, to conspecific chorus noise either alone or coupled with pre-recorded traffic noise nightly for 1 week. Frogs presented with anthropogenic noise had significantly higher circulating concentrations of corticosterone and significantly decreased sperm count and sperm viability than did control frogs. These results suggest that in addition to having behavioural and ecological effects, anthropogenic change might alter physiology and Darwinian fitness. Future work should integrate disparate fields such as behaviour, ecology and physiology to elucidate fully organisms' responses to habitat change.
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Affiliation(s)
- Kristine Kaiser
- Department of Biology, University of California, Riverside, CA 92521, USA
| | - Julia Devito
- Department of Biology, University of California, Riverside, CA 92521, USA
| | - Caitlin G. Jones
- Department of Biology, University of California, Riverside, CA 92521, USA
| | - Adam Marentes
- Department of Biology, University of California, Riverside, CA 92521, USA
| | - Rachel Perez
- Department of Biology, University of California, Riverside, CA 92521, USA
| | - Lisa Umeh
- Department of Biology, University of California, Riverside, CA 92521, USA
| | - Regina M. Weickum
- Department of Biology, University of California, Riverside, CA 92521, USA
| | - Kathryn E. McGovern
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, CA 92521, USA
| | - Emma H. Wilson
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, CA 92521, USA
| | - Wendy Saltzman
- Department of Biology, University of California, Riverside, CA 92521, USA
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194
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Newman AEM, Edmunds NB, Ferraro S, Heffell Q, Merritt GM, Pakkala JJ, Schilling CR, Schorno S. Using ecology to inform physiology studies: implications of high population density in the laboratory. Am J Physiol Regul Integr Comp Physiol 2015; 308:R449-54. [PMID: 25589015 DOI: 10.1152/ajpregu.00328.2014] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Conspecific density is widely recognized as an important ecological factor across the animal kingdom; however, the physiological impacts are less thoroughly described. In fact, population density is rarely mentioned as a factor in physiological studies on captive animals and, when it is infrequently addressed, the animals used are reared and housed at densities far above those in nature, making the translation of results from the laboratory to natural systems difficult. We survey the literature to highlight this important ecophysiological gap and bring attention to the possibility that conspecific density prior to experimentation may be a critical factor influencing results. Across three taxa: mammals, birds, and fish, we present evidence from ecology that density influences glucocorticoid levels, immune function, and body condition with the intention of stimulating discussion and increasing consideration of population density in physiology studies. We conclude with several directives to improve the applicability of insights gained in the laboratory to organisms in the natural environment.
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Affiliation(s)
- Amy E M Newman
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, Canada
| | - Nicholas B Edmunds
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, Canada
| | - Shannon Ferraro
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, Canada
| | - Quentin Heffell
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, Canada
| | - Gillian M Merritt
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, Canada
| | - Jesse J Pakkala
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, Canada
| | - Cory R Schilling
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, Canada
| | - Sarah Schorno
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, Canada
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195
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Lukas M, de Jong TR. Conspecific Interactions in Adult Laboratory Rodents: Friends or Foes? Curr Top Behav Neurosci 2015; 30:3-24. [PMID: 27240675 DOI: 10.1007/7854_2015_428] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Interactions between adult conspecifics, including sexual behaviors, affiliation, and aggression are crucial for the well-being, survival, and reproduction of mammals. This holds true for any mammalian species, but certainly for humans: An inability to optimally navigate the social system can have a strong negative impact on physical and mental health. Translational rodent models have been used for decades to unravel the neural pathways and substrates involved in normal and abnormal conspecific interactions. Researchers in the field of translational social neuroscience face a double challenge: Not only do they need to pay considerable attention to the behavioral ecology of their model species or their ancestors, they also have to expect a relatively large variability in behavior and adjust their experimental design accordingly. In this chapter, we will lay out traditional and novel rodent models and paradigms to study sexual, affiliative, and aggressive interactions among adult conspecifics. We will discuss the merits and main findings and briefly consider the most promising novel directions. Finally, we review the modulatory involvement of two major players in mammal social interaction: the central oxytocin and vasopressin system.
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Affiliation(s)
- Michael Lukas
- Molecular and Behavioral Neurobiology, University of Regensburg, Regensburg, Germany.
| | - Trynke R de Jong
- Molecular and Behavioral Neurobiology, University of Regensburg, Regensburg, Germany
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196
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Kaiser K, Devito J, Jones CG, Marentes A, Perez R, Umeh L, Weickum RM, McGovern KE, Wilson EH, Saltzman W. Reproductive and immune effects of chronic corticosterone treatment in male White's treefrogs, Litoria caerulea. CONSERVATION PHYSIOLOGY 2015; 3:cov022. [PMID: 27293707 PMCID: PMC4778456 DOI: 10.1093/conphys/cov022] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2015] [Revised: 04/17/2015] [Accepted: 04/25/2015] [Indexed: 05/08/2023]
Abstract
Amphibian populations are declining globally. The potential contribution of glucocorticoid hormones to these declines has received little attention, but chronic elevation of glucocorticoids has been linked to a suite of negative outcomes across vertebrate taxa. Recently, chronic environmental stress has been associated with precipitous declines in sperm count and sperm viability in White's treefrogs (Litoria caerulea), but the mechanism remains unknown. In order to determine whether corticosterone is responsible for suppressing reproductive and immune function in this species, we elevated circulating concentrations of corticosterone in 10 male captive-bred frogs via transdermal application for 7 days. We compared sperm count, sperm viability, splenic cell count and circulating leucocyte counts in corticosterone-treated frogs with those in untreated control frogs. Chronic application of exogenous corticosterone led to supraphysiological circulating concentrations of corticosterone, but had no effect on sperm count or viability. However, corticosterone-treated frogs demonstrated a significant decrease in circulating eosinophils, which are immune cells implicated in fighting a variety of pathogens, including extracellular parasites. These findings suggest that although chronic elevation of circulating corticosterone is not necessarily associated with reproductive suppression in this species, it may cause immunosuppression. Thus, chronic glucocorticoid elevations in amphibians might enhance susceptibility to infection with pathogens and parasites, and their potential contributions to global population declines warrant further study.
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Affiliation(s)
- Kristine Kaiser
- Department of Biology, University of California, Riverside, CA 92521, USA
- Corresponding author: Department of Biology, Pomona College, Claremont, CA 91711, USA. Tel: +1 909 607 0880.
| | - Julia Devito
- Department of Biology, University of California, Riverside, CA 92521, USA
| | - Caitlin G. Jones
- Department of Biology, University of California, Riverside, CA 92521, USA
| | - Adam Marentes
- Department of Biology, University of California, Riverside, CA 92521, USA
| | - Rachel Perez
- Department of Biology, University of California, Riverside, CA 92521, USA
| | - Lisa Umeh
- Department of Biology, University of California, Riverside, CA 92521, USA
| | - Regina M. Weickum
- Department of Biology, University of California, Riverside, CA 92521, USA
| | - Kathryn E. McGovern
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, CA 92521, USA
| | - Emma H. Wilson
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, CA 92521, USA
| | - Wendy Saltzman
- Department of Biology, University of California, Riverside, CA 92521, USA
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197
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Atwell JW, Cardoso GC, Whittaker DJ, Price TD, Ketterson ED. Hormonal, Behavioral, and Life-History Traits Exhibit Correlated Shifts in Relation to Population Establishment in a Novel Environment. Am Nat 2014; 184:E147-60. [DOI: 10.1086/678398] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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198
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Schumann K, Guenther A, Jewgenow K, Trillmich F. Animal housing and welfare: effects of housing conditions on body weight and cortisol in a medium-sized rodent (Cavia aperea). J APPL ANIM WELF SCI 2014; 17:111-24. [PMID: 24665951 DOI: 10.1080/10888705.2014.884407] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Rodents are the most abundant experimental nonhuman animals and are commonly studied under standard laboratory housing conditions. As housing conditions affect animals' physiology and behavior, this study investigated the effects of indoor and outdoor housing conditions on body weight and cortisol level of wild cavies, Cavia aperea. The changing housing condition strongly influenced both parameters, which are commonly used as indicators for animal welfare. The transfer from outdoor to indoor enclosures resulted in a body-weight loss of about 8%. In contrast, animals kept indoors showed a substantial weight gain of about 12% when they were transferred outdoors. These effects were reversible. To substantiate a connection between body-weight changes and the health states of the animals, blood basal cortisol concentrations were measured. Animals kept outdoors had significantly lower cortisol levels than did animals kept indoors. These results imply that indoor conditions have a direct effect on the animals' states. The physiological and metabolic consequences as well as potential welfare aspects should be taken into account when planning experimental work, especially on nondomestic animals.
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Affiliation(s)
- Kathrin Schumann
- a Leibniz Institute for Zoo and Wildlife Research , Berlin , Germany
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199
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Temporal behaviour profiles of Mus musculus in nature are affected by population activity. Physiol Behav 2014; 139:351-60. [PMID: 25446229 DOI: 10.1016/j.physbeh.2014.11.020] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Revised: 11/04/2014] [Accepted: 11/05/2014] [Indexed: 01/28/2023]
Abstract
Animals have circadian clocks that govern their activity pattern, resulting in 24h rhythms in physiology and behaviour. Under laboratory conditions, light is the major external signal that affects temporal patterns in behaviour, and Mus musculus is strictly nocturnal in its behaviour. In the present study we questioned whether under natural conditions, environmental factors other than light affect the temporal profile of mice. In order to test this, we investigated the activity patterns of free-ranging M. musculus in a natural habitat, using sensors and a camera integrated into a recording unit that the mice could freely enter and leave. Our data show that mice have seasonal fluctuations in activity duration (6.7±0.82 h in summer, 11.3±1.80 h in winter). Furthermore, although primarily nocturnal, wild mice also exhibit daytime activity from spring until late autumn. A multivariate analysis revealed that the major factor correlating with increased daytime activity was population activity, defined as the number of visits to the recording site. Day length had a small but significant effect. Further analysis revealed that the relative population activity (compared to the past couple of days) is a better predictor of daytime activity than absolute population activity. Light intensity and temperature did not have a significant effect on daytime activity. The amount of variance explained by external factors is 51.9%, leaving surprisingly little unexplained variance that might be attributed to the internal clock. Our data further indicate that mice determine population activity by comparing a given night with the preceding 2-7 nights, a time frame suggesting a role for olfactory cues. We conclude that relative population activity is a major factor controlling the temporal activity patterns of M. musculus in an unrestricted natural population.
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200
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Baugh AT, van Oers K, Dingemanse NJ, Hau M. Baseline and stress-induced glucocorticoid concentrations are not repeatable but covary within individual great tits (Parus major). Gen Comp Endocrinol 2014; 208:154-63. [PMID: 25218170 DOI: 10.1016/j.ygcen.2014.08.014] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Revised: 08/19/2014] [Accepted: 08/22/2014] [Indexed: 11/17/2022]
Abstract
In evolutionary endocrinology, there is a growing interest in the extent and basis of individual variation in endocrine traits, especially circulating concentrations of hormones. This is important because if targeted by selection, such individual differences present the opportunity for an evolutionary response to selection. It is therefore necessary to examine whether hormone traits are repeatable in natural populations. However, research in this area is complicated by the fact that different hormone traits can be correlated. The nature of these trait correlations (i.e., phenotypic, within-, or among-individual) is critically relevant in terms of the evolutionary implications, and these in turn, depend on the repeatability of each hormone trait. By decomposing phenotypic correlations between hormone traits into their within- and among-individual components it is possible to describe the multivariate nature of endocrine traits and generate inferences about their evolution. In the present study, we repeatedly captured individual great tits (Parus major) from a wild population and measured plasma concentrations of corticosterone. Using a mixed-modeling approach, we estimated repeatabilities in both initial (cf. baseline; CORT0) and stress-induced concentrations (CORT30) and the correlations between those traits among- and within-individuals. We found a lack of repeatability in both CORT0 and CORT30. Moreover, we found a strong phenotypic correlation between CORT0 and CORT30, and due to the lack of repeatability for both traits, there was no among-individual correlation between these two traits-i.e., an individual's average concentration of CORT0 was not correlated with its average concentration of CORT30. Instead, the phenotypic correlation was the result of a strong within-individual correlation, which implies that an underlying environmental factor co-modulates changes in initial and stress-induced concentrations within the same individual over time. These results demonstrate that (i) a phenotypic correlation between two hormone traits does not imply that the traits are correlated among individuals; (ii) the importance of repeated sampling to partition within- and among-individual variances and correlations among labile physiological traits; and (iii) that environmental factors explain a considerable fraction of the variation and co-variation in hormone concentrations.
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Affiliation(s)
- Alexander T Baugh
- Department of Biology, Swarthmore College, 500 College Avenue, Swarthmore, PA 19081, USA; Evolutionary Physiology Group, Max Planck Institute for Ornithology, Am Obstberg 1, 78315 Radolfzell, Germany.
| | - Kees van Oers
- Department of Animal Ecology, Netherlands Institute of Ecology (NIOO-KNAW), P.O. Box 50, 6708 PB Wageningen, The Netherlands.
| | - Niels J Dingemanse
- Evolutionary Ecology of Variation Research Group, Max Planck Institute for Ornithology, Eberhard-Gwinner-Str., 82319 Seewiesen, Germany; Behavioural Ecology, Department of Biology, Ludwig-Maximilians University of Munich, Planegg-Martinsried, Germany.
| | - Michaela Hau
- Evolutionary Physiology Group, Max Planck Institute for Ornithology, Am Obstberg 1, 78315 Radolfzell, Germany; Evolutionary Physiology Group, Max Planck Institute for Ornithology, Eberhard-Gwinner-Str., 82319 Seewiesen, Germany; Department of Biology, University of Konstanz, Universitätsstrasse 10, Konstanz, Germany.
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