1
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Dickinson ER, Nwafor-Okoli C, Checkley SL, Elkin B, Branigan M, Serrano E, Kutz SJ. Direct and indirect costs of parasitism preceding a population decline of an Arctic ungulate. Sci Rep 2024; 14:17133. [PMID: 39054352 PMCID: PMC11272786 DOI: 10.1038/s41598-024-67904-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Accepted: 07/17/2024] [Indexed: 07/27/2024] Open
Abstract
Parasites negatively affect the fitness of ungulate hosts directly, and in wild ungulates, these effects may be synzootic with other stressors, such as limited nutritional resources. In the Arctic, muskoxen (Ovibos moschatus) occur in a highly seasonal environment and must rely on finite energetic resources for survival and productivity. We investigated the costs of gastrointestinal nematodes on the body condition and reproductive status of 141 muskoxen, on Banks Island, Canada, when the population was at a peak in numbers and density. Using a Partial Least Squares Path Modelling approach, we found that high adult nematode abundance was associated with lower body condition, and high parasite abundance was associated with female reproduction including the indirect effect through on body condition (n = 87). These findings suggest that individuals prioritize energetic reserves for reproduction over parasite defence. In fall 2003, a severe icing event that restricted access to forage was associated with high overwinter mortality of muskoxen and a population crash. Through direct and indirect costs of parasite infection on body condition and reproduction, the high abundance of parasites may have contributed to the effects of this extreme weather event. Understanding the mechanisms in which parasites impact fitness can help explain the ecological drivers of ungulate populations and predict the interactions between the environment and populations.
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Affiliation(s)
- Eleanor R Dickinson
- Faculty of Veterinary Medicine, University of Calgary, 3280 University Drive, NW, Calgary, AB, T2N 1N4, Canada.
| | - Chinyere Nwafor-Okoli
- Faculty of Veterinary Medicine, University of Calgary, 3280 University Drive, NW, Calgary, AB, T2N 1N4, Canada
| | - Sylvia L Checkley
- Faculty of Veterinary Medicine, University of Calgary, 3280 University Drive, NW, Calgary, AB, T2N 1N4, Canada
| | - Brett Elkin
- Environment and Natural Resources, Government of the Northwest Territories, Yellowknife, NT, X1A 1Y3, Canada
| | - Marsha Branigan
- Environment and Natural Resources, Government of the Northwest Territories, Inuvik, NT, X0E 0T0, Canada
| | - Emmanuel Serrano
- Wildlife Ecology & Health Group (WE&H), Servei d'Ecopatologia de Fauna Salvatge (SEFaS), Departament de Medicina i Cirurgia Animals, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Susan J Kutz
- Faculty of Veterinary Medicine, University of Calgary, 3280 University Drive, NW, Calgary, AB, T2N 1N4, Canada
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2
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Martin RA, Riesch R, Plath M, Al Hanoosh NA, Wronski T. Reproductive biology of Gazella arabica: Predictors of offspring weight and short- and long-term offspring survival. Curr Zool 2023; 69:643-653. [PMID: 37876648 PMCID: PMC10591149 DOI: 10.1093/cz/zoac084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Accepted: 10/13/2022] [Indexed: 10/26/2023] Open
Abstract
Reproductive traits are central to organismal fitness, and so the factors influencing patterns of reproduction and offspring survival are at the heart of biology. Making use of breeding data collected over 16 years at the King Khalid Wildlife Research Centre in Saudi Arabia, we investigated the reproductive biology of Arabian gazelles Gazella arabica. Offspring survival was mainly a function of birth weight, with heavier offspring having higher survival rates than lighter offspring. However, while sons were heavier than daughters, daughters had higher survival rates. We could not find evidence that giving birth to sons negatively impacts offspring weight in the following year. We uncovered large narrow-sense heritability (h2) in offspring weight at birth, while maternal effects (m2) on birth weight were of lesser importance. However, maternal effects on offspring survival were strong until weaning age, while paternal effects dominated survival to sexual maturity and first reproduction. We propose that variation in maternal postnatal care might overshadow the effects of maternal inheritance of birth weights, while the overall strong heritability of weight at birth and the paternal effects on survival illustrates strong variance in sire fitness based on genetic quality, suggesting a role for sexual selection by female mate choice in wild populations.
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Affiliation(s)
- Ryan A Martin
- Department of Biology, DeGrace Hall, Case Western Reserve University, Cleveland, OH, USA
| | - Rüdiger Riesch
- Department of Biological Sciences, Centre for Ecology, Evolution and Behaviour, Royal Holloway University of London, Egham, Surrey, UK
- CEFE, CNRS, Univ Montpellier, EPHE, IRD, Montpellier, France
| | - Martin Plath
- College of Nursing of Ribeirão Preto, University of São Paulo, Avenida Bandeirantes 3900, 14040-902, Brazil
| | - Naif A Al Hanoosh
- National Center for Wildlife, King Khalid Wildlife Research Center, Thumamah, Kingdom of Saudi Arabia
| | - Torsten Wronski
- Faculty of Science, School of Biological and Environmental Sciences, Liverpool John Moores University, Liverpool, UK
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3
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Chapman EG, Pilkington JG, Pemberton JM. Correlates of early reproduction and apparent fitness consequences in male Soay sheep. Ecol Evol 2023; 13:e10058. [PMID: 37168987 PMCID: PMC10164647 DOI: 10.1002/ece3.10058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 04/05/2023] [Accepted: 04/17/2023] [Indexed: 05/13/2023] Open
Abstract
Life history trade-offs are ubiquitous across species and place constraints on the timing of life history events, including the optimal age at first reproduction. However, studies on lifetime breeding success of male mammals are rare due to sex-biased dispersal and the requirement for genetic paternity inferences. We studied the correlates and apparent fitness consequences of early life reproduction among males in a free-living population of Soay sheep (Ovis aries) on St Kilda, Scotland. We investigated the factors associated with early breeding success and the apparent consequences of early success for survival and future reproduction. We used genetic paternity inferences, population data, and individual morphology measurements collected over 30 years. We found that individuals born in years with low-density population size had the highest early life breeding success and singletons were more likely to be successful than twins. Individuals that bred successfully at 7 months were more likely to survive their first winter. For individuals that survived their first winter, early breeding success was not associated with later breeding success. As individual heterogeneity affects breeding success, we believe that variation in individual quality masks the costs of early reproduction in this population. Our findings provide no evidence for selection for delayed age at reproduction in male Soay sheep.
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Affiliation(s)
- Elisabeth G. Chapman
- School of Biological Sciences, Institute of Ecology and EvolutionUniversity of EdinburghEdinburghUK
| | - Jill G. Pilkington
- School of Biological Sciences, Institute of Ecology and EvolutionUniversity of EdinburghEdinburghUK
| | - Josephine M. Pemberton
- School of Biological Sciences, Institute of Ecology and EvolutionUniversity of EdinburghEdinburghUK
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4
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Ravindran S, Froy H, Underwood SL, Dorrens J, Seeker LA, Watt K, Wilbourn RV, Pilkington JG, Harrington L, Pemberton JM, Nussey DH. The association between female reproductive performance and leukocyte telomere length in wild Soay sheep. Mol Ecol 2022; 31:6184-6196. [PMID: 34514660 DOI: 10.1111/mec.16175] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2021] [Accepted: 08/03/2021] [Indexed: 01/31/2023]
Abstract
Telomere length (TL), typically measured across a sample of blood cells, has emerged as an exciting potential marker of physiological state and of the costs of investment in growth and reproduction within evolutionary ecology. While there is mounting evidence from studies of wild vertebrates that short TL predicts raised subsequent mortality risk, the relationship between reproductive investment and TL is less clear cut, and previous studies report both negative and positive associations. In this study, we examined the relationship between TL and different aspects of maternal reproductive performance in a free-living population of Soay sheep. We find evidence for shorter TL in females that bred, and thus paid any costs of gestation, compared to females that did not breed. However, we found no evidence for any association between TL and litter size. Furthermore, females that invested in gestation and lactation actually had longer TL than females who only invested in gestation because their offspring died shortly after birth. We used multivariate models to decompose these associations into among- and within-individual effects, and discovered that within-individual effects were driving both the negative association between TL and gestation, and the positive association between TL and lactation. This suggests that telomere dynamics may reflect recent physiologically costly investment or variation in physiological condition, depending on the aspect of reproduction being investigated. Our results highlight the physiological complexity of vertebrate reproduction, and the need to better understand how and why different aspects of physiological variation underpinning life histories impact blood cell TL.
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Affiliation(s)
- Sanjana Ravindran
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Hannah Froy
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, UK.,Centre for Biodiversity Dynamics, Institute for Biology, Norwegian University for Science and Technology (NTNU), Trondheim, Norway
| | - Sarah L Underwood
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Jennifer Dorrens
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Luise A Seeker
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Kathryn Watt
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Rachael V Wilbourn
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Jill G Pilkington
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Lea Harrington
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Canada
| | - Josephine M Pemberton
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Daniel H Nussey
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
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5
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Pemberton JM, Kruuk LE, Clutton-Brock T. The Unusual Value of Long-Term Studies of Individuals: The Example of the Isle of Rum Red Deer Project. ANNUAL REVIEW OF ECOLOGY, EVOLUTION, AND SYSTEMATICS 2022. [DOI: 10.1146/annurev-ecolsys-012722-024041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Long-term studies of individuals enable incisive investigations of questions across ecology and evolution. Here, we illustrate this claim by reference to our long-term study of red deer on the Isle of Rum, Scotland. This project has established many of the characteristics of social organization, selection, and population ecology typical of large, polygynous, seasonally breeding mammals, with wider implications for our understanding of sexual selection and the evolution of sex differences, as well as for their population dynamics and population management. As molecular genetic techniques have developed, the project has pivoted to investigate evolutionary genetic questions, also breaking new ground in this field. With ongoing advances in genomics and statistical approaches and the development of increasingly sophisticated ways to assay new phenotypic traits, the questions that long-term studies such as the red deer study can answer become both broader and ever more sophisticated. They also offer powerful means of understanding the effects of ongoing climate change on wild populations.
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Affiliation(s)
- Josephine M. Pemberton
- Institute of Ecology and Evolution, School of Biological Sciences, The University of Edinburgh, Edinburgh, United Kingdom
| | - Loeske E.B. Kruuk
- Institute of Ecology and Evolution, School of Biological Sciences, The University of Edinburgh, Edinburgh, United Kingdom
| | - Tim Clutton-Brock
- Department of Zoology, University of Cambridge, Cambridge, United Kingdom
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6
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Gauzere J, Pemberton JM, Kruuk LEB, Morris A, Morris S, Walling CA. Maternal effects do not resolve the paradox of stasis in birth weight in a wild red deer populaton. Evolution 2022; 76:2605-2617. [PMID: 36111977 PMCID: PMC9828841 DOI: 10.1111/evo.14622] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Accepted: 08/14/2022] [Indexed: 01/22/2023]
Abstract
In natural populations, quantitative traits seldom show short-term evolution at the rate predicted by evolutionary models. Resolving this "paradox of stasis" is a key goal in evolutionary biology, as it directly challenges our capacity to predict evolutionary change. One particularly promising hypothesis to explain the lack of evolutionary responses in a key offspring trait, body weight, is that positive selection on juveniles is counterbalanced by selection against maternal investment in offspring growth, given that reproduction is costly for the mothers. Here, we used data from one of the longest individual-based studies of a wild mammal population to test this hypothesis. We first showed that despite positive directional selection on birth weight, and heritable variation for this trait, no genetic change has been observed for birth weight over the past 47 years in the study population. Contrarily to our expectation, we found no evidence of selection against maternal investment in birth weight-if anything, selection favors mothers that produce large calves. Accordingly, we show that genetic change in birth weight over the study period is actually lower than that predicted from models including selection on maternal performance; ultimately our analysis here only deepens rather than resolves the paradox of stasis.
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Affiliation(s)
- Julie Gauzere
- Institute of Evolutionary Biology, School of Biological SciencesUniversity of EdinburghEdinburghEH9 3FLUK
| | - Josephine M. Pemberton
- Institute of Evolutionary Biology, School of Biological SciencesUniversity of EdinburghEdinburghEH9 3FLUK
| | - Loeske E. B. Kruuk
- Institute of Evolutionary Biology, School of Biological SciencesUniversity of EdinburghEdinburghEH9 3FLUK,Research School of BiologyThe Australian National UniversityCanberraACT 0200Australia
| | - Alison Morris
- Institute of Evolutionary Biology, School of Biological SciencesUniversity of EdinburghEdinburghEH9 3FLUK
| | - Sean Morris
- Institute of Evolutionary Biology, School of Biological SciencesUniversity of EdinburghEdinburghEH9 3FLUK
| | - Craig A. Walling
- Institute of Evolutionary Biology, School of Biological SciencesUniversity of EdinburghEdinburghEH9 3FLUK
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7
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Albery GF, Clutton-Brock TH, Morris A, Morris S, Pemberton JM, Nussey DH, Firth JA. Ageing red deer alter their spatial behaviour and become less social. Nat Ecol Evol 2022; 6:1231-1238. [PMID: 35864228 PMCID: PMC10859100 DOI: 10.1038/s41559-022-01817-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 05/27/2022] [Indexed: 01/19/2023]
Abstract
Social relationships are important to many aspects of animals' lives, and an individual's connections may change over the course of their lifespan. Currently, it is unclear whether social connectedness declines within individuals as they age, and what the underlying mechanisms might be, so the role of age in structuring animal social systems remains unresolved, particularly in non-primates. Here we describe senescent declines in social connectedness using 46 years of data in a wild, individually monitored population of a long-lived mammal (European red deer, Cervus elaphus). Applying a series of spatial and social network analyses, we demonstrate that these declines occur because of within-individual changes in social behaviour, with correlated changes in spatial behaviour (smaller home ranges and movements to lower-density, lower-quality areas). These findings demonstrate that within-individual socio-spatial behavioural changes can lead older animals in fission-fusion societies to become less socially connected, shedding light on the ecological and evolutionary processes structuring wild animal populations.
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Affiliation(s)
- Gregory F Albery
- Department of Biology, Georgetown University, Washington DC, USA.
- Institute of Evolutionary Biology, University of Edinburgh, Edinburgh, UK.
- Wissenschaftskolleg zu Berlin, Berlin, Germany.
| | | | - Alison Morris
- Institute of Evolutionary Biology, University of Edinburgh, Edinburgh, UK
| | - Sean Morris
- Institute of Evolutionary Biology, University of Edinburgh, Edinburgh, UK
| | | | - Daniel H Nussey
- Institute of Evolutionary Biology, University of Edinburgh, Edinburgh, UK
| | - Josh A Firth
- Department of Zoology, University of Oxford, Oxford, UK
- Merton College, University of Oxford, Oxford, UK
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8
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Holser RR, Crocker DE, Robinson PW, Condit R, Costa DP. Density-dependent effects on reproductive output in a capital breeding carnivore, the northern elephant seal ( Mirounga angustirostris). Proc Biol Sci 2021; 288:20211258. [PMID: 34641731 PMCID: PMC8511744 DOI: 10.1098/rspb.2021.1258] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 09/17/2021] [Indexed: 11/12/2022] Open
Abstract
All organisms face resource limitations that will ultimately restrict population growth, but the controlling mechanisms vary across ecosystems, taxa, and reproductive strategies. Using four decades of data, we examine how variation in the environment and population density affect reproductive outcomes in a capital-breeding carnivore, the northern elephant seal (Mirounga angustirostris). This species provides a unique opportunity to examine the relative importance of resource acquisition and density-dependence on breeding success. Capital breeders accrue resources over large temporal and spatial scales for use during an abbreviated reproductive period. This strategy may have evolved, in part, to confer resilience to short-term environmental variability. We observed density-dependent effects on weaning mass, and maternal age (experience) was more important than oceanographic conditions or maternal mass in determining offspring weaning mass. Together these findings show that the mechanisms controlling reproductive output are conserved across terrestrial and marine systems and vary with population dynamics, an important consideration when assessing the effect of extrinsic changes, such as climate change, on a population.
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Affiliation(s)
- Rachel R. Holser
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, 130 McAllister Way, Santa Cruz, CA 95060, USA
| | - Daniel E. Crocker
- Department of Biology, Sonoma State University, Rohnert Park, CA 94928, USA
| | - Patrick W. Robinson
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, 130 McAllister Way, Santa Cruz, CA 95060, USA
| | - Richard Condit
- Field Museum of Natural History, 1400 South Lake Shore Drive, Chicago, IL 60605, USA
- Morton Arboretum, 4100 Illinois Route 53, Lisle, IL 60532, USA
| | - Daniel P. Costa
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, 130 McAllister Way, Santa Cruz, CA 95060, USA
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9
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Abstract
[Figure: see text].
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10
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Gauzere J, Walling CA, Pick JL, Watt K, Jack P, Morris A, Morris S, Pemberton JM. The role of maternally transferred antibodies in maternal performance in red deer. Ecol Lett 2021; 24:2065-2076. [PMID: 34245475 DOI: 10.1111/ele.13834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Revised: 03/25/2021] [Accepted: 06/04/2021] [Indexed: 11/28/2022]
Abstract
Maternal effects are ubiquitous. Yet, the pathways through which maternal effects occur in wild mammals remain largely unknown. We hypothesise that maternal immune transfer is a key mechanism by which mothers can affect their offspring fitness, and that individual variation in maternally derived antibodies mainly depends on a mother's characteristics and the environmental conditions she experiences. To test this, we assayed six colostrum-derived antibodies in the plasma of 1447 neonates in a wild red deer population. Neonatal antibody levels were mainly affected by maternal genes, environmental variation and costs of prior reproductive investment. We found consistent heterogeneity in maternal performance across traits, with mothers producing the heaviest calves also having calves with more antibodies. Unexpectedly, antibody levels were not associated with calf survival. We provide a unique example of how evolutionary theory on maternal effects can be used to gain insight into the causes of maternal effects in wild populations.
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Affiliation(s)
- Julie Gauzere
- 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
| | - Joel L Pick
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3FL, UK
| | - Kathryn Watt
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3FL, UK
| | - Penny Jack
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3FL, UK
| | - Alison Morris
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3FL, UK
| | - Sean Morris
- 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
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11
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Tidière M, Douay G, Müller P, Siberchicot A, Sliwa A, Whipple M, Douhard M. Lifespan decreases with proportion of sons in males but not females of zoo-housed tigers and lemurs. J Evol Biol 2021; 34:1061-1070. [PMID: 33914999 DOI: 10.1111/jeb.13793] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 03/30/2021] [Accepted: 04/16/2021] [Indexed: 11/29/2022]
Abstract
Several studies have shown higher costs of rearing sons than daughters in mammals where males are larger than females. These studies typically focus on females by examining how the offspring sex ratio during a single reproductive event affected mothers' subsequent reproduction or survival probability. Here, we examine relationships between offspring sex ratio during single or multiple reproductive events and several survival metrics in mothers and fathers, using data from zoo-housed tigers (Panthera tigris) and ruffed lemurs (Varecia sp.). Our analyses failed to reveal an overall cost of reproduction or a higher cost of sons to mothers. In male ruffed lemurs, the proportion of sons produced during early life (before 10 years old) was negatively correlated with lifespan later in life. In tigers, males with a higher proportion of sons during their lifetime had shorter lifespans. One likely mechanism is the difference in testosterone levels between males: a high concentration of testosterone can increase the proportion of sons and compromise immune function. Our results suggest studies in wild populations should address the outstanding challenge of understanding consequences of sex allocation for males, and open an opportunity to predict lifespan in an applied conservation context.
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Affiliation(s)
- Morgane Tidière
- Université de Lyon, Laboratoire de Biométrie et Biologie Evolutive UMR5558 CNRS, Université Claude Bernard Lyon 1, Villeurbanne, France
| | - Guillaume Douay
- Wildlife Reserves Singapore, Conservation, Research and Veterinary Department, Singapore
| | | | - Aurélie Siberchicot
- Université de Lyon, Laboratoire de Biométrie et Biologie Evolutive UMR5558 CNRS, Université Claude Bernard Lyon 1, Villeurbanne, France
| | | | | | - Mathieu Douhard
- Université de Lyon, Laboratoire de Biométrie et Biologie Evolutive UMR5558 CNRS, Université Claude Bernard Lyon 1, Villeurbanne, France
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12
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Albery GF, Morris A, Morris S, Pemberton JM, Clutton-Brock TH, Nussey DH, Firth JA. Multiple spatial behaviours govern social network positions in a wild ungulate. Ecol Lett 2021; 24:676-686. [PMID: 33583128 DOI: 10.1111/ele.13684] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 12/22/2020] [Accepted: 12/23/2020] [Indexed: 01/19/2023]
Abstract
The structure of wild animal social systems depends on a complex combination of intrinsic and extrinsic drivers. Population structuring and spatial behaviour are key determinants of individuals' observed social behaviour, but quantifying these spatial components alongside multiple other drivers remains difficult due to data scarcity and analytical complexity. We used a 43-year dataset detailing a wild red deer population to investigate how individuals' spatial behaviours drive social network positioning, while simultaneously assessing other potential contributing factors. Using Integrated Nested Laplace Approximation (INLA) multi-matrix animal models, we demonstrate that social network positions are shaped by two-dimensional landscape locations, pairwise space sharing, individual range size, and spatial and temporal variation in population density, alongside smaller but detectable impacts of a selection of individual-level phenotypic traits. These results indicate strong, multifaceted spatiotemporal structuring in this society, emphasising the importance of considering multiple spatial components when investigating the causes and consequences of sociality.
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Affiliation(s)
- Gregory F Albery
- Department of Biology, Georgetown University, Washington, DC, USA.,Institute of Evolutionary Biology, University of Edinburgh, Edinburgh, UK
| | - Alison Morris
- Institute of Evolutionary Biology, University of Edinburgh, Edinburgh, UK
| | - Sean Morris
- Institute of Evolutionary Biology, University of Edinburgh, Edinburgh, UK
| | | | - Tim H Clutton-Brock
- Institute of Evolutionary Biology, University of Edinburgh, Edinburgh, UK.,Department of Zoology, University of Cambridge, Cambridge, UK
| | - Daniel H Nussey
- Institute of Evolutionary Biology, University of Edinburgh, Edinburgh, UK
| | - Josh A Firth
- Department of Zoology, University of Oxford, Oxford, UK.,Merton College, University of Oxford, Oxford, UK
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13
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Albery GF, Morris A, Morris S, Kenyon F, Nussey DH, Pemberton JM. Fitness Costs of Parasites Explain Multiple Life-History Trade-Offs in a Wild Mammal. Am Nat 2021; 197:324-335. [PMID: 33625970 DOI: 10.1086/712633] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
AbstractReproduction in wild animals can divert limited resources away from immune defense, resulting in increased parasite burdens. A long-standing prediction of life-history theory states that these parasites can harm the reproductive individual, reducing its subsequent survival and fecundity, producing reproduction-fitness trade-offs. Here, we examined associations among reproductive allocation, immunity, parasitism, and subsequent survival and fecundity in a wild population of individually identified red deer (Cervus elaphus). Using path analysis, we investigated whether costs of lactation in terms of downstream survival and fecundity were mediated by changes in strongyle nematode count and mucosal antibody levels. Lactating females exhibited increased parasite counts, which were in turn associated with substantially decreased fitness in the following year in terms of overwinter survival, fecundity, subsequent calf weight, and parturition date. This study offers observational evidence for parasite regulation of multiple life-history trade-offs, supporting the role of parasites as an important mediating factor in wild mammal populations.
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14
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Lv L, Liu Y, Osmond HL, Cockburn A, Kruuk LEB. When to start and when to stop: Effects of climate on breeding in a multi-brooded songbird. GLOBAL CHANGE BIOLOGY 2020; 26:443-457. [PMID: 31581368 DOI: 10.1111/gcb.14831] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2018] [Revised: 08/15/2019] [Accepted: 08/21/2019] [Indexed: 06/10/2023]
Abstract
Climate warming has been shown to affect the timing of the onset of breeding of many bird species across the world. However, for multi-brooded species, climate may also affect the timing of the end of the breeding season, and hence also its duration, and these effects may have consequences for fitness. We used 28 years of field data to investigate the links between climate, timing of breeding, and breeding success in a cooperatively breeding passerine, the superb fairy-wren (Malurus cyaneus). This multi-brooded species from southeastern Australia has a long breeding season and high variation in phenology between individuals. By applying a "sliding window" approach, we found that higher minimum temperatures in early spring resulted in an earlier start and a longer duration of breeding, whereas less rainfall and more heatwaves (days > 29°C) in late summer resulted in an earlier end and a shorter duration of breeding. Using a hurdle model analysis, we found that earlier start dates did not predict whether or not females produced any young in a season. However, for successful females who produced at least one young, earlier start dates were associated with higher numbers of young produced in a season. Earlier end dates were associated with a higher probability of producing at least one young, presumably because unsuccessful females kept trying when others had ceased. Despite larger scale trends in climate, climate variables in the windows relevant to this species' phenology did not change across years, and there were no temporal trends in phenology during our study period. Our results illustrate a scenario in which higher temperatures advanced both start and end dates of individuals' breeding seasons, but did not generate an overall temporal shift in breeding times. They also suggest that the complexity of selection pressures on breeding phenology in multi-brooded species may have been underestimated.
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Affiliation(s)
- Lei Lv
- Department of Ecology, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
- Division of Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, ACT, Australia
| | - Yang Liu
- Department of Ecology, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Helen L Osmond
- Division of Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, ACT, Australia
| | - Andrew Cockburn
- Division of Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, ACT, Australia
| | - Loeske E B Kruuk
- Division of Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, ACT, Australia
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15
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Albery GF, Watt KA, Keith R, Morris S, Morris A, Kenyon F, Nussey DH, Pemberton JM. Reproduction has different costs for immunity and parasitism in a wild mammal. Funct Ecol 2019. [DOI: 10.1111/1365-2435.13475] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- Gregory F. Albery
- Institute of Evolutionary Biology School of Biological Sciences University of Edinburgh Edinburgh UK
| | - Kathryn A. Watt
- Institute of Evolutionary Biology School of Biological Sciences University of Edinburgh Edinburgh UK
| | - Rosie Keith
- Institute of Evolutionary Biology School of Biological Sciences University of Edinburgh Edinburgh UK
| | - Sean Morris
- Institute of Evolutionary Biology School of Biological Sciences University of Edinburgh Edinburgh UK
| | - Alison Morris
- Institute of Evolutionary Biology School of Biological Sciences University of Edinburgh Edinburgh UK
| | - Fiona Kenyon
- Moredun Research Institute Pentlands Science Park Midlothian UK
| | - Daniel H. Nussey
- Institute of Evolutionary Biology School of Biological Sciences University of Edinburgh Edinburgh UK
| | - Josephine M. Pemberton
- Institute of Evolutionary Biology School of Biological Sciences University of Edinburgh Edinburgh UK
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16
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Festa‐Bianchet M, Côté SD, Hamel S, Pelletier F. Long‐term studies of bighorn sheep and mountain goats reveal fitness costs of reproduction. J Anim Ecol 2019; 88:1118-1133. [DOI: 10.1111/1365-2656.13002] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Accepted: 03/20/2019] [Indexed: 11/30/2022]
Affiliation(s)
- Marco Festa‐Bianchet
- Département de biologie Université de Sherbrooke Sherbrooke Québec Canada
- Centre d'études nordiques Québec City Québec Canada
| | - Steeve D. Côté
- Centre d'études nordiques Québec City Québec Canada
- Département de biologie Université Laval Sainte‐Foy Québec Canada
| | - Sandra Hamel
- Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries, and Economics UiT The Arctic University of Norway Tromsø Norway
| | - Fanie Pelletier
- Département de biologie Université de Sherbrooke Sherbrooke Québec Canada
- Centre d'études nordiques Québec City Québec Canada
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17
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Landes J, Henry P, Hardy I, Perret M, Pavard S. Female reproduction bears no survival cost in captivity for gray mouse lemurs. Ecol Evol 2019; 9:6189-6198. [PMID: 31236213 PMCID: PMC6580269 DOI: 10.1002/ece3.5124] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2018] [Revised: 02/19/2019] [Accepted: 02/22/2019] [Indexed: 12/24/2022] Open
Abstract
The survival cost of reproduction has been revealed in many free-ranging vertebrates. However, recent studies on captive populations failed to detect this cost. Theoretically, this lack of survival/reproduction trade-off is expected when resources are not limiting, but these studies may have failed to detect the cost, as they may not have fully accounted for potential confounding effects, in particular interindividual heterogeneity. Here, we investigated the effects of current and past reproductive effort on later survival in captive females of a small primate, the gray mouse lemur. Survival analyses showed no cost of reproduction in females; and the pattern was even in the opposite direction: the higher the reproductive effort, the higher the chances of survival until the next reproductive event. These conclusions hold even while accounting for interindividual heterogeneity. In agreement with aforementioned studies on captive vertebrates, these results remind us that reproduction is expected to be traded against body maintenance and the survival prospect only when resources are so limiting that they induce an allocation trade-off. Thus, the cost of reproduction has a major extrinsic component driven by environmental conditions.
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Affiliation(s)
- Julie Landes
- Eco‐Anthropologie, UMR 7206CNRS, MNHN, Univ. Paris DiderotParisFrance
- Mécanismes Adaptatifs et Evolution (MECADEV ‐ UMR 7179)CNRS, MNHNBrunoyFrance
- Département de Biologie, Faculté des SciencesUniversité de SherbrookeSherbrookeQuébecCanada
| | - Pierre‐Yves Henry
- Mécanismes Adaptatifs et Evolution (MECADEV ‐ UMR 7179)CNRS, MNHNBrunoyFrance
| | - Isabelle Hardy
- Mécanismes Adaptatifs et Evolution (MECADEV ‐ UMR 7179)CNRS, MNHNBrunoyFrance
| | - Martine Perret
- Mécanismes Adaptatifs et Evolution (MECADEV ‐ UMR 7179)CNRS, MNHNBrunoyFrance
| | - Samuel Pavard
- Eco‐Anthropologie, UMR 7206CNRS, MNHN, Univ. Paris DiderotParisFrance
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18
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Leivesley JA, Bussière LF, Pemberton JM, Pilkington JG, Wilson K, Hayward AD. Survival costs of reproduction are mediated by parasite infection in wild Soay sheep. Ecol Lett 2019; 22:1203-1213. [PMID: 31111651 DOI: 10.1111/ele.13275] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 04/08/2019] [Accepted: 04/10/2019] [Indexed: 01/03/2023]
Abstract
A trade-off between current and future fitness potentially explains variation in life-history strategies. A proposed mechanism behind this is parasite-mediated reproductive costs: individuals that allocate more resources to reproduction have fewer to allocate to defence against parasites, reducing future fitness. We examined how reproduction influenced faecal egg counts (FEC) of strongyle nematodes using data collected between 1989 and 2008 from a wild population of Soay sheep in the St. Kilda archipelago, Scotland (741 individuals). Increased reproduction was associated with increased FEC during the lambing season: females that gave birth, and particularly those that weaned a lamb, had higher FEC than females that failed to reproduce. Structural equation modelling revealed future reproductive costs: a positive effect of reproduction on spring FEC and a negative effect on summer body weight were negatively associated with overwinter survival. Overall, we provide evidence that parasite resistance and body weight are important mediators of survival costs of reproduction.
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Affiliation(s)
- Jessica A Leivesley
- Department of Biological and Environmental Sciences, University of Stirling, Stirling, FK9 4LA, UK
| | - Luc F Bussière
- Department of Biological and Environmental Sciences, University of Stirling, Stirling, FK9 4LA, UK
| | - Josephine M Pemberton
- Institute of Evolutionary Biology, University of Edinburgh, Ashworth Laboratories, Charlotte Auerbach Road, Edinburgh, EH9 3FL, UK
| | - Jill G Pilkington
- Institute of Evolutionary Biology, University of Edinburgh, Ashworth Laboratories, Charlotte Auerbach Road, Edinburgh, EH9 3FL, UK.,School of Biology, University of St Andrews, Sir Harold Mitchell Building, St Andrews, KY16 9TF, UK
| | - Kenneth Wilson
- Lancaster Environment Centre, Lancaster University, Lancaster, LA1 4YQ, UK
| | - Adam D Hayward
- Department of Biological and Environmental Sciences, University of Stirling, Stirling, FK9 4LA, UK
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19
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Edwards AM, Cameron EZ, Deakin JE, Ezaz T, Pereira JC, Ferguson‐Smith MA, Robert KA. Sexual conflict in action: An antagonistic relationship between maternal and paternal sex allocation in the tammar wallaby, Notamacropus eugenii. Ecol Evol 2019; 9:4340-4348. [PMID: 31031909 PMCID: PMC6476839 DOI: 10.1002/ece3.4813] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2018] [Accepted: 11/22/2018] [Indexed: 01/29/2023] Open
Abstract
Sex ratio biases are often inconsistent, both among and within species and populations. While some of these inconsistencies may be due to experimental design, much of the variation remains inexplicable. Recent research suggests that an exclusive focus on mothers may account for some of the inconsistency, with an increasing number of studies showing variation in sperm sex ratios and seminal fluids. Using fluorescent in-situ hybridization, we show a significant population-level Y-chromosome bias in the spermatozoa of wild tammar wallabies, but with significant intraindividual variation between males. We also show a population-level birth sex ratio trend in the same direction toward male offspring, but a weaning sex ratio that is significantly female-biased, indicating that males are disproportionately lost during lactation. We hypothesize that sexual conflict between parents may cause mothers to adjust offspring sex ratios after birth, through abandonment of male pouch young and reactivation of diapaused embryos. Further research is required in a captive, controlled setting to understand what is driving and mechanistically controlling sperm sex ratio and offspring sex ratio biases and to understand the sexually antagonistic relationship between mothers and fathers over offspring sex. These results extend beyond sex allocation, as they question studies of population processes that assume equal input of sex chromosomes from fathers, and will also assist with future reproduction studies for management and conservation of marsupials.
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Affiliation(s)
- Amy M. Edwards
- Department of Ecology, Environment and Evolution, School of Life SciencesLa Trobe UniversityMelbourneVictoriaAustralia
| | - Elissa Z. Cameron
- School of Biological SciencesUniversity of CanterburyChristchurchNew Zealand
| | - Janine E. Deakin
- Institute for Applied EcologyUniversity of CanberraCanberraAustralian Capital TerritoryAustralia
| | - Tariq Ezaz
- Institute for Applied EcologyUniversity of CanberraCanberraAustralian Capital TerritoryAustralia
| | - Jorge C. Pereira
- Department of Veterinary MedicineUniversity of CambridgeCambridgeUK
- Cytocell Ltd.CambridgeUK
| | | | - Kylie A. Robert
- Department of Ecology, Environment and Evolution, School of Life SciencesLa Trobe UniversityMelbourneVictoriaAustralia
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20
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Douhard M, Festa-Bianchet M, Hamel S, Nussey DH, Côté SD, Pemberton JM, Pelletier F. Maternal longevity and offspring sex in wild ungulates. Proc Biol Sci 2019; 286:20181968. [PMID: 30963926 PMCID: PMC6408606 DOI: 10.1098/rspb.2018.1968] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Accepted: 01/14/2019] [Indexed: 01/08/2023] Open
Abstract
In species with sexual size dimorphism, the offspring of the larger sex usually have greater energy requirements and may lead to greater fitness costs for parents. The effects of offspring sex on maternal longevity, however, have only been tested in humans. Human studies produced mixed results and considerable debate mainly owing to the difficulty of distinguishing the effects of sexual dimorphism from sociocultural factors. To advance this debate, we examined how the relative number of sons influenced maternal longevity in four species of free-living ungulates (Soay sheep Ovis aries; bighorn sheep, Ovis canadensis; red deer, Cervus elaphus; mountain goat, Oreamnos americanus), with high male-biased sexual size dimorphism but without complicating sociocultural variables. We found no evidence for a higher cumulative cost of sons than of daughters on maternal longevity. For a given number of offspring, most females with many sons in all four populations lived longer than females with few sons. The higher cost of sons over daughters on maternal lifespan reported by some human studies may be the exception rather than the rule in long-lived iteroparous species.
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Affiliation(s)
- Mathieu Douhard
- Département de Biologie, Université de Sherbrooke, Sherbrooke, Quebec, CanadaJ1K 2R1
| | - Marco Festa-Bianchet
- Département de Biologie, Université de Sherbrooke, Sherbrooke, Quebec, CanadaJ1K 2R1
| | - Sandra Hamel
- Department of Arctic and Marine Biology, UiT The Arctic University of Norway, 9037 Tromsø, Norway
| | - Daniel H. Nussey
- Institute of Evolutionary Biology, University of Edinburgh, Edinburgh EH9 3FL, UK
| | - Steeve D. Côté
- Département de Biologie et Centre d’études Nordiques, Université Laval, Québec, Quebec, CanadaG1V 0A6
| | | | - Fanie Pelletier
- Département de Biologie, Université de Sherbrooke, Sherbrooke, Quebec, CanadaJ1K 2R1
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21
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22
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Albery GF, Kenyon F, Morris A, Morris S, Nussey DH, Pemberton JM. Seasonality of helminth infection in wild red deer varies between individuals and between parasite taxa. Parasitology 2018; 145:1410-1420. [PMID: 29519265 PMCID: PMC6137381 DOI: 10.1017/s0031182018000185] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Revised: 01/19/2018] [Accepted: 01/20/2018] [Indexed: 12/03/2022]
Abstract
Parasitism in wild mammals can vary according to myriad intrinsic and extrinsic factors, many of which vary seasonally. However, seasonal variation in parasitism is rarely studied using repeated samples from known individuals. Here we used a wild population of individually recognized red deer (Cervus elaphus) on the Isle of Rum to quantify seasonality and intrinsic factors affecting gastrointestinal helminth parasitism over the course of a year. We collected 1020 non-invasive faecal samples from 328 known individuals which we then analysed for propagules of three helminth taxa: strongyle nematodes, the common liver fluke Fasciola hepatica and the tissue nematode Elaphostrongylus cervi. Zero-inflated Poisson models were used to investigate how season, age and sex were associated with parasite prevalence and count intensity, while Poisson models were used to quantify individual repeatability within and between sampling seasons. Parasite intensity and prevalence varied according to all investigated factors, with opposing seasonality, age profiles and sex biases between parasite taxa. Repeatability was moderate, decreased between seasons and varied between parasites; both F. hepatica and E. cervi showed significant between-season repeatability, while strongyle nematode counts were only repeatable within-season and showed no repeatability within individuals across the year.
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Affiliation(s)
- Gregory F. Albery
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3JT, UK
| | - Fiona Kenyon
- Moredun Research Institute, Pentlands Science Park, Bush Loan, Midlothian, EH26 0PZ, UK
| | - Alison Morris
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3JT, UK
| | - Sean Morris
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3JT, UK
| | - Daniel H. Nussey
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3JT, UK
| | - Josephine M. Pemberton
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3JT, UK
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23
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Sibling competition and not maternal allocation drives differential offspring feeding in a sexually size-dimorphic bird. Anim Behav 2018. [DOI: 10.1016/j.anbehav.2017.12.021] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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24
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Froy H, Walling CA, Pemberton JM, Clutton-Brock TH, Kruuk LEB. Relative costs of offspring sex and offspring survival in a polygynous mammal. Biol Lett 2017; 12:rsbl.2016.0417. [PMID: 27601725 PMCID: PMC5046923 DOI: 10.1098/rsbl.2016.0417] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2016] [Accepted: 08/15/2016] [Indexed: 11/12/2022] Open
Abstract
Costs of reproduction are expected to be ubiquitous in wild animal populations and understanding the drivers of variation in these costs is an important aspect of life-history evolution theory. We use a 43 year dataset from a wild population of red deer to examine the relative importance of two factors that influence the costs of reproduction to mothers, and to test whether these costs vary with changing ecological conditions. Like previous studies, our analyses indicate fitness costs of lactation: mothers whose calves survived the summer subsequently showed lower survival and fecundity than those whose calves died soon after birth, accounting for 5% and 14% of the variation in mothers' survival and fecundity, respectively. The production of a male calf depressed maternal survival and fecundity more than production of a female, but accounted for less than 1% of the variation in either fitness component. There was no evidence for any change in the effect of calf survival or sex with increasing population density.
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Affiliation(s)
- Hannah Froy
- Institute of Evolutionary Biology, University of Edinburgh, Edinburgh, UK
| | - Craig A Walling
- Institute of Evolutionary Biology, University of Edinburgh, Edinburgh, UK
| | | | | | - Loeske E B Kruuk
- Institute of Evolutionary Biology, University of Edinburgh, Edinburgh, UK Research School of Biology, Australian National University, Canberra, Australian Capital Territory, Australia
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25
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Fitness correlates of age at primiparity in a hunted moose population. Oecologia 2017; 186:447-458. [DOI: 10.1007/s00442-017-4021-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Accepted: 11/22/2017] [Indexed: 10/18/2022]
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26
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Clutton-Brock T. Reproductive competition and sexual selection. Philos Trans R Soc Lond B Biol Sci 2017; 372:20160310. [PMID: 28760754 PMCID: PMC5540853 DOI: 10.1098/rstb.2016.0310] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/29/2017] [Indexed: 12/18/2022] Open
Abstract
This paper traces the development of our understanding of the development of different approaches to estimating the strength of reproductive competition and sexual selection in the two sexes, based on measures of the operational sex ratio, the opportunity for sexual selection and contrasts in selection gradients between the sexes. It argues that different approaches provide complementary insights into the causes of sex differences in reproductive competition, the operation of sexual selection and the evolution of secondary sexual characters and that improvements in our understanding of the evolution of secondary sexual characters will require a more comprehensive understanding of the ways in which social and ecological conditions modify reproductive competition and development in females and males.This article is part of the themed issue 'Adult sex ratios and reproductive decisions: a critical re-examination of sex differences in human and animal societies'.
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Affiliation(s)
- Tim Clutton-Brock
- Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK
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27
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Douhard M. Offspring sex ratio in mammals and the Trivers-Willard hypothesis: In pursuit of unambiguous evidence. Bioessays 2017; 39. [DOI: 10.1002/bies.201700043] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Mathieu Douhard
- Département de Biologie; Université de Sherbrooke; Sherbrooke Québec Canada
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