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Albery GF, Sweeny AR, Webber Q. How behavioural ageing affects infectious disease. Neurosci Biobehav Rev 2023; 155:105426. [PMID: 37839673 PMCID: PMC10842249 DOI: 10.1016/j.neubiorev.2023.105426] [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: 12/31/2022] [Revised: 10/10/2023] [Accepted: 10/12/2023] [Indexed: 10/17/2023]
Abstract
Ageing is associated with profound changes in behaviour that could influence exposure and susceptibility to infectious disease. As well as determining emergent patterns of infection across individuals of different ages, behavioural ageing could interact with, confound, or counteract age-related changes in other traits. Here, we examine how behavioural ageing can manifest and influence patterns of infection in wild animals. We discuss a range of age-related changes that involve interactions between behaviour and components of exposure and susceptibility to infection, including social ageing and immunosenescence, acquisition of novel parasites and pathogens with age, changes in spatial behaviours, and age-related hygiene and sickness behaviours. Overall, most behavioural changes are expected to result in a reduced exposure rate, but there is relatively little evidence for this phenomenon, emerging largely from a rarity of explicit tests of exposure changes over the lifespan. This review offers a framework for understanding how ageing, behaviour, immunity, and infection interact, providing a series of hypotheses and testable predictions to improve our understanding of health in ageing societies.
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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, Scotland, UK; Leibniz Institute of Freshwater Ecology and Inland Fisheries, Berlin, Germany.
| | - Amy R Sweeny
- School of Biosciences, University of Sheffield, Sheffield, England, UK
| | - Quinn Webber
- Department of Integrative Biology, University of Guelph, Guelph, ON, Canada
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2
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McKee JL, Tompkins EM, Estela FA, Anderson DJ. Age effects on Nazca booby foraging performance are largely constant across variation in the marine environment: Results from a 5-year study in Galápagos. Ecol Evol 2023; 13:e10138. [PMID: 37304365 PMCID: PMC10253949 DOI: 10.1002/ece3.10138] [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: 02/21/2023] [Revised: 05/06/2023] [Accepted: 05/12/2023] [Indexed: 06/13/2023] Open
Abstract
Foraging outcomes dictate the nutritional resources available to an organism and may vary with intrinsic factors, like age. Thus, understanding how age affects foraging performance, alone or in interaction with extrinsic factors (like environmental quality), improves our understanding of aging processes in the wild. We examined how foraging traits, measured across five breeding seasons, change with age, environmental variation, and their interaction in Nazca boobies (Sula granti), a pelagic seabird in Galápagos. We evaluated the hypotheses that (1) foraging performance is better in middle-aged birds than in young ones, and that (2) foraging performance is better in middle-aged birds than in old ones. Furthermore, favorable environmental conditions will either (3) attenuate age differences in foraging performance (by relieving constraints on young, inexperienced and old, senescent age classes), or (4) accentuate age differences (if middle-aged birds can exploit abundant resources better than other age classes can). Incubating birds tagged with GPS loggers (N = 815) provided data on foraging performance (e.g., total distance traveled, mass gained) to evaluate interactions between age and environmental variation (e.g., sea surface temperature). Poor environmental conditions associated with the cool phase of the El Niño-Southern Oscillation increased foraging effort, including foraging distance and duration, for example. Across age classes, foraging boobies responded similarly to environmental variation except for female mass gain rate: age-related declines in mass gain rate were reduced under favorable environmental conditions. Birds of different ages also searched in somewhat distinct areas in the poor conditions of 2016, but not in other years. In several foraging traits, including foraging duration and distance, female boobies showed predicted early-life improvement and late-life decline, following the established pattern for reproductive traits in this species. Thus, deficits in resource acquisition (this study) may contribute to the poor survival and reproductive outcomes previously observed in old Nazca boobies, particularly in females.
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Affiliation(s)
- Jennifer L. McKee
- Department of BiologyWake Forest UniversityWinston‐SalemNorth CarolinaUSA
| | - Emily M. Tompkins
- Department of BiologyWake Forest UniversityWinston‐SalemNorth CarolinaUSA
| | - Felipe A. Estela
- Department of BiologyWake Forest UniversityWinston‐SalemNorth CarolinaUSA
- Departamento de Ciencias Naturales y MatemáticasPontificia Universidad Javeriana – CaliValle del CaucaColombia
| | - David J. Anderson
- Department of BiologyWake Forest UniversityWinston‐SalemNorth CarolinaUSA
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3
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Lescroël A, Schmidt A, Ainley DG, Dugger KM, Elrod M, Jongsomjit D, Morandini V, Winquist S, Ballard G. High-resolution recording of foraging behaviour over multiple annual cycles shows decline in old Adélie penguins' performance. Proc Biol Sci 2023; 290:20222480. [PMID: 37015277 PMCID: PMC10072935 DOI: 10.1098/rspb.2022.2480] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Accepted: 03/06/2023] [Indexed: 04/06/2023] Open
Abstract
Age-related variation in foraging performance can result from both within-individual change and selection processes. These mechanisms can only be disentangled by using logistically challenging long-term, longitudinal studies. Coupling a long-term demographic data set with high-temporal-resolution tracking of 18 Adélie penguins (Pygoscelis adeliae, age 4-15 yrs old) over three consecutive annual cycles, we examined how foraging behaviour changed within individuals of different age classes. Evidence indicated within-individual improvement in young and middle-age classes, but a significant decrease in foraging dive frequency within old individuals, associated with a decrease in the dive descent rate. Decreases in foraging performance occurred at a later age (from 12-15 yrs old to 15-18 yrs old) than the onset of senescence predicted for this species (9-11 yrs old). Foraging dive frequency was most affected by the interaction between breeding status and annual life-cycle periods, with frequency being highest during returning migration and breeding season and was highest overall for successful breeders during the chick-rearing period. Females performed more foraging dives per hour than males. This longitudinal, full annual cycle study allowed us to shed light on the changes in foraging performance occurring among individuals of different age classes and highlighted the complex interactions among drivers of individual foraging behaviour.
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Affiliation(s)
| | - Annie Schmidt
- Point Blue Conservation Science, Petaluma, CA 94954, USA
| | - David G. Ainley
- H. T. Harvey & Associates Ecological Consultants, Los Gatos, CA 95032, USA
| | - Katie M. Dugger
- US Geological Survey, Oregon Cooperative Fish and Wildlife Research Unit, Department of Fisheries, Wildlife, and Conservation Sciences, Oregon State University, Corvallis, OR 97333, USA
| | - Megan Elrod
- Point Blue Conservation Science, Petaluma, CA 94954, USA
| | | | - Virginia Morandini
- Oregon Cooperative Fish and Wildlife Research Unit, Department of Fisheries, Wildlife and Conservation Sciences, Oregon State University, 104 Nash Hall, Corvallis, OR 97331, USA
- Fundación Migres, CIMA, N-340km 85, E-11380 Tarifa, Spain
- Museo Nacional de Ciencias Naturales, CSIC, C/Jose Gutierrez Abascal, 2, 28006 Madrid, Spain
| | - Suzanne Winquist
- Oregon Cooperative Fish and Wildlife Research Unit, Department of Fisheries, Wildlife and Conservation Sciences, Oregon State University, Hatfield Marine Science Center, Newport, OR 97365, USA
| | - Grant Ballard
- Point Blue Conservation Science, Petaluma, CA 94954, USA
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4
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Environmental assessment of proposed areas for offshore wind farms areas off southern Brazil based on ecological niche modeling and a species richness index for albatrosses and petrels. Glob Ecol Conserv 2022. [DOI: 10.1016/j.gecco.2022.e02360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
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5
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Carneiro APB, Dias MP, Oppel S, Pearmain EJ, Clark BL, Wood AG, Clavelle T, Phillips RA. Integrating immersion with
GPS
data improves behavioural classification for wandering albatrosses and shows scavenging behind fishing vessels mirrors natural foraging. Anim Conserv 2022. [DOI: 10.1111/acv.12768] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
| | - M P Dias
- BirdLife International Cambridge UK
- Centre for Ecology, Evolution and Environmental Changes, cE3c & Department of Animal Biology, Faculdade de Ciências Universidade de Lisboa Lisbon Portugal
| | - S Oppel
- Royal Society for the Protection of Birds The David Attenborough Building Cambridge UK
| | | | | | - A G Wood
- British Antarctic Survey Natural Environment Research Council Cambridge UK
| | - T Clavelle
- Global Fishing Watch Washington District of Columbia USA
| | - R A Phillips
- British Antarctic Survey Natural Environment Research Council Cambridge UK
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6
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Orgeret F, Reisinger RR, Carpenter-Kling T, Keys DZ, Corbeau A, Bost CA, Weimerskirch H, Pistorius PA. Spatial segregation in a sexually dimorphic central place forager: Competitive exclusion or niche divergence? J Anim Ecol 2021; 90:2404-2420. [PMID: 34091891 DOI: 10.1111/1365-2656.13552] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 05/29/2021] [Indexed: 12/11/2022]
Abstract
Sexual competition is increasingly recognized as an important selective pressure driving species distributions. However, few studies have investigated the relative importance of interpopulation versus intrapopulation competition in relation to habitat availability and selection. To explain spatial segregation between sexes that often occurs in non-territorial and central place foragers, such as seabirds, two hypotheses are commonly used. The 'competitive exclusion' hypothesis states that dominant individuals should exclude subordinate individuals through direct competition, whereas the 'niche divergence' hypothesis states that segregation occurs due to past competition and habitat specialization. We tested these hypotheses in two populations of an extreme wide-ranging and sexually dimorphic seabird, investigating the relative role of intrapopulation and interpopulation competition in influencing sex-specific distribution and habitat preferences. Using GPS loggers, we tracked 192 wandering albatrosses Diomedea exulans during four consecutive years (2016-2019), from two neighbouring populations in the Southern Ocean (Prince Edward and Crozet archipelagos). We simulated pseudo-tracks to create a null spatial distribution and used Kernel Density Estimates (KDE) and Resource Selection Functions (RSF) to distinguish the relative importance of within- versus between-population competition. Kernel Density Estimates showed that only intrapopulation sexual segregation was significant for each monitoring year, and that tracks between the two colonies resulted in greater overlap than expected from the null distribution, especially for the females. RSF confirmed these results and highlighted key at-sea foraging areas, even if the estimated of at-sea densities were extremely low. These differences in selected areas between sites and sexes were, however, associated with high interannual variability in habitat preferences, with no clear specific preferences per site and sex. Our results suggest that even with low at-sea population densities, historic intrapopulation competition in wide-ranging seabirds may have led to sexual dimorphism and niche specialization, favouring the 'niche divergence' hypothesis. In this study, we provide a protocol to study competition within as well as between populations of central place foragers. This is relevant for understanding their distribution patterns and population regulation, which could potentially improve management of threatened populations.
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Affiliation(s)
- Florian Orgeret
- Marine Apex Predator Research Unit (MAPRU), Department of Zoology, Institute for Coastal and Marine Research, Nelson Mandela University, Port Elizabeth, South Africa
| | - Ryan R Reisinger
- Institute of Marine Sciences, University of California Santa Cruz, Santa Cruz, CA, USA
| | - Tegan Carpenter-Kling
- Marine Apex Predator Research Unit (MAPRU), Department of Zoology, Institute for Coastal and Marine Research, Nelson Mandela University, Port Elizabeth, South Africa.,DST-NRF Centre of Excellence at the FitzPatrick, Institute of African Ornithology, Nelson Mandela University, Port Elizabeth, South Africa
| | - Danielle Z Keys
- Marine Apex Predator Research Unit (MAPRU), Department of Zoology, Institute for Coastal and Marine Research, Nelson Mandela University, Port Elizabeth, South Africa
| | - Alexandre Corbeau
- Centre d'Etudes Biologiques de Chizé, UMR 7372 du CNRS-Université de La Rochelle, Villiers-en-Bois, France
| | - Charles-André Bost
- Centre d'Etudes Biologiques de Chizé, UMR 7372 du CNRS-Université de La Rochelle, Villiers-en-Bois, France
| | - Henri Weimerskirch
- Centre d'Etudes Biologiques de Chizé, UMR 7372 du CNRS-Université de La Rochelle, Villiers-en-Bois, France
| | - Pierre A Pistorius
- Marine Apex Predator Research Unit (MAPRU), Department of Zoology, Institute for Coastal and Marine Research, Nelson Mandela University, Port Elizabeth, South Africa.,DST-NRF Centre of Excellence at the FitzPatrick, Institute of African Ornithology, Nelson Mandela University, Port Elizabeth, South Africa
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7
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Howard JL, Tompkins EM, Anderson DJ. Effects of age, sex, and ENSO phase on foraging and flight performance in Nazca boobies. Ecol Evol 2021; 11:4084-4100. [PMID: 33976796 PMCID: PMC8093656 DOI: 10.1002/ece3.7308] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2020] [Revised: 01/15/2021] [Accepted: 01/28/2021] [Indexed: 12/02/2022] Open
Abstract
Age-related changes in survival and reproduction are common in seabirds; however, the underlying causes remain elusive. A lack of experience for young individuals, and a decline in foraging performance for old birds, could underlie age-related variation in reproduction because reproductive success is connected closely to provisioning offspring. For seabirds, flapping flight during foraging trips is physiologically costly; inexperience or senescent decline in performance of this demanding activity might cap delivery of food to the nest, providing a proximate explanation for poor breeding success in young and old age, respectively. We evaluated the hypothesis that young and old Nazca boobies (Sula granti), a Galápagos seabird, demonstrate deficits in foraging outcomes and flight performance. We tagged incubating male and female adults across the life span with both accelerometer and GPS loggers during the incubation periods of two breeding seasons (years), during the 2015 El Niño and the following weak La Niña. We tested the ability of age, sex, and environment to explain variation in foraging outcomes (e.g., mass gained) and flight variables (e.g., wingbeat frequency). Consistent with senescence, old birds gained less mass while foraging than middle-aged individuals, a marginal effect, and achieved a slower airspeed late in a foraging trip. Contrary to expectations, young birds showed no deficit in foraging outcomes or flight performance, except for airspeed (contingent on environment). Young birds flew slower than middle-aged birds in 2015, but faster than middle-aged birds in 2016. Wingbeat frequency, flap-glide ratio, and body displacement (approximating wingbeat strength) failed to predict airspeed and were unaffected by age. Sex influenced nearly all aspects of performance. Environment affected flight performance and foraging outcomes. Boobies' foraging outcomes were better during the extreme 2015 El Niño than during the 2016 weak La Niña, a surprising result given the negative effects tropical seabirds often experience during extreme El Niños.
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8
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Long-term changes in habitat and trophic level of Southern Ocean squid in relation to environmental conditions. Sci Rep 2020; 10:15215. [PMID: 32939006 PMCID: PMC7494860 DOI: 10.1038/s41598-020-72103-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Accepted: 08/10/2020] [Indexed: 11/22/2022] Open
Abstract
Long-term studies of pelagic nekton in the Southern Ocean and their responses to ongoing environmental change are rare. Using stable isotope ratios measured in squid beaks recovered from diet samples of wandering albatrosses Diomedea exulans, we assessed decadal variation (from 1976 to 2016) in the habitat (δ13C) and trophic level (δ15N) of five important Southern Ocean squid species in relation to indices of environmental conditions—Southern Oscillation Index (SOI) and Southern Annular Mode (SAM). Based on δ13C values, corrected for the Suess effect, habitat had changed over the last 50 years for Taonius sp. B (Voss), Gonatus antarcticus, Galiteuthis glacialis and Histioteuthis atlantica but not Moroteuthopsis longimana. By comparison, mean δ15N values were similar across decades for all five species, suggesting minimal changes in trophic levels. Both SAM and SOI have increased in strength and frequency over the study period but, of the five species, only in Taonius sp. B (Voss) did these indices correlate with, δ13C and δ15N values, indicating direct relationships between environmental conditions, habitat and trophic level. The five cephalopod species therefore changed their habitats with changing environmental conditions over the last 50 years but maintained similar trophic levels. Hence, cephalopods are likely to remain important prey for top predators in Southern Ocean food webs, despite ongoing climate change.
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9
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Clay TA, Joo R, Weimerskirch H, Phillips RA, den Ouden O, Basille M, Clusella-Trullas S, Assink JD, Patrick SC. Sex-specific effects of wind on the flight decisions of a sexually dimorphic soaring bird. J Anim Ecol 2020; 89:1811-1823. [PMID: 32557603 DOI: 10.1111/1365-2656.13267] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2019] [Accepted: 04/07/2020] [Indexed: 11/30/2022]
Abstract
In a highly dynamic airspace, flying animals are predicted to adjust foraging behaviour to variable wind conditions to minimize movement costs. Sexual size dimorphism is widespread in wild animal populations, and for large soaring birds which rely on favourable winds for energy-efficient flight, differences in morphology, wing loading and associated flight capabilities may lead males and females to respond differently to wind. However, the interaction between wind and sex has not been comprehensively tested. We investigated, in a large sexually dimorphic seabird which predominantly uses dynamic soaring flight, whether flight decisions are modulated to variation in winds over extended foraging trips, and whether males and females differ. Using GPS loggers we tracked 385 incubation foraging trips of wandering albatrosses Diomedea exulans, for which males are c. 20% larger than females, from two major populations (Crozet and South Georgia). Hidden Markov models were used to characterize behavioural states-directed flight, area-restricted search (ARS) and resting-and model the probability of transitioning between states in response to wind speed and relative direction, and sex. Wind speed and relative direction were important predictors of state transitioning. Birds were much more likely to take off (i.e. switch from rest to flight) in stronger headwinds, and as wind speeds increased, to be in directed flight rather than ARS. Males from Crozet but not South Georgia experienced stronger winds than females, and males from both populations were more likely to take-off in windier conditions. Albatrosses appear to deploy an energy-saving strategy by modulating taking-off, their most energetically expensive behaviour, to favourable wind conditions. The behaviour of males, which have higher wing loading requiring faster speeds for gliding flight, was influenced to a greater degree by wind than females. As such, our results indicate that variation in flight performance drives sex differences in time-activity budgets and may lead the sexes to exploit regions with different wind regimes.
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Affiliation(s)
- Thomas A Clay
- School of Environmental Sciences, University of Liverpool, Liverpool, UK
| | - Rocío Joo
- Department of Wildlife Ecology and Conservation, Fort Lauderdale Research and Education Center, University of Florida, Davie, FL, USA
| | - Henri Weimerskirch
- Centre d'Étude Biologique de Chizé, CNRS UMR 7273, Villiers-en-Bois, France
| | - Richard A Phillips
- British Antarctic Survey, Natural Environment Research Council, Cambridge, UK
| | - Olivier den Ouden
- R&D Seismology and Acoustics, Royal Netherlands Meteorological Institute, De Bilt, The Netherlands.,Faculty of Civil Engineering and Geosciences, Department of Geoscience and Engineering, Delft University of Technology, Delft, The Netherlands
| | - Mathieu Basille
- Department of Wildlife Ecology and Conservation, Fort Lauderdale Research and Education Center, University of Florida, Davie, FL, USA
| | - Susana Clusella-Trullas
- Department of Botany and Zoology and Centre for Invasion Biology, Stellenbosch University, Stellenbosch, South Africa
| | - Jelle D Assink
- R&D Seismology and Acoustics, Royal Netherlands Meteorological Institute, De Bilt, The Netherlands
| | - Samantha C Patrick
- School of Environmental Sciences, University of Liverpool, Liverpool, UK
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10
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Phillips RA, Waluda CM. Albatrosses and petrels at South Georgia as sentinels of marine debris input from vessels in the southwest Atlantic Ocean. ENVIRONMENT INTERNATIONAL 2020; 136:105443. [PMID: 31927465 DOI: 10.1016/j.envint.2019.105443] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Revised: 12/12/2019] [Accepted: 12/23/2019] [Indexed: 06/10/2023]
Abstract
Increasing amounts of anthropogenic debris enter the ocean because of mismanagement in coastal communities and, despite a global ban on deliberate dumping, also from vessels, endangering wildlife. Assessing marine plastic pollution directly is challenging, and an alternative is to use seabirds as bioindicators. Our analyses of long time-series (26-years) revealed substantial variation in the amount, characteristics and origin of marine debris (mainly macroplastics and mesoplastics, and excluding fishing gear) associated with seabirds at South Georgia, and, for two species, long-term increases in incidence since 1994. Annual debris recovery rates (items per capita) were 14 × higher in wandering albatrosses Diomedea exulans, and 6 × higher in grey-headed albatrosses Thalassarche chrysostoma and giant petrels Macronectes spp., than in black-browed albatrosses T. melanophris, partly related to differences in egestion (regurgitation), which clears items from the proventriculus. Although some debris types were common in all species, wandering albatrosses and giant petrels ingested higher proportions that were food-related or generic wrapping, gloves, clear or mixed colour, and packaged in South America. This was highly likely to originate from vessels, including the large South American fishing fleets with which they overlap. Debris associated with the two smaller albatrosses was more commonly shorter, rigid (miscellaneous plastic and bottle/tube caps), and packaged in East Asia. Grey-headed albatrosses are exposed to large and increasing amounts of user plastics transported from coastal South America in the Subantarctic Current, or discarded from vessels and circulating in the South Atlantic Gyre, whereas the lower debris ingestion by black-browed albatrosses suggests that plastic pollution in Antarctic waters remains relatively low. Current plastic loads in our study species seem unlikely to have an impact at the population level, but the results nevertheless affirm that marine plastics are a major, trans-boundary animal-welfare and environmental issue that needs to be addressed by much-improved waste-management practices and compliance-monitoring both on land and on vessels in the south Atlantic.
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Affiliation(s)
- Richard A Phillips
- British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Road, Cambridge CB3 0ET, United Kingdom.
| | - Claire M Waluda
- British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Road, Cambridge CB3 0ET, United Kingdom
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11
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Frankish CK, Manica A, Phillips RA. Effects of age on foraging behavior in two closely related albatross species. MOVEMENT ECOLOGY 2020; 8:7. [PMID: 32047635 PMCID: PMC7006180 DOI: 10.1186/s40462-020-0194-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Accepted: 01/23/2020] [Indexed: 06/10/2023]
Abstract
BACKGROUND Foraging performance is widely hypothesized to play a key role in shaping age-specific demographic rates in wild populations, yet the underlying behavioral changes are poorly understood. Seabirds are among the longest-lived vertebrates, and demonstrate extensive age-related variation in survival, breeding frequency and success. The breeding season is a particularly critical phase during the annual cycle, but it remains unclear whether differences in experience or physiological condition related to age interact with the changing degree of the central-place constraint in shaping foraging patterns in time and space. METHODS Here we analyze tracking data collected over two decades from congeneric black-browed (BBA) and grey-headed (GHA) albatrosses, Thalassarche melanophris and T. chrysostoma, breeding at South Georgia. We compare the foraging trip parameters, at-sea activity (flights and landings) and habitat preferences of individuals aged 10-45 years and contrast these patterns between the incubation and early chick-rearing stages. RESULTS Young breeders of both species showed improvements in foraging competency with age, reducing foraging trip duration until age 26. Thereafter, there were signs of foraging senescence; older adults took gradually longer trips, narrowed their habitat preference (foraging within a smaller range of sea surface temperatures) (GHA), made fewer landings and rested on the water for longer (BBA). Some age-specific effects were apparent for each species only in certain breeding stages, highlighting the complex interaction between intrinsic drivers in determining individual foraging strategies. CONCLUSIONS Using cross-sectional data, this study highlighted clear age-related patterns in foraging behavior at the population-level for two species of albatrosses. These trends are likely to have important consequences for the population dynamics of these threatened seabirds, as young or old individuals may be more vulnerable to worsening environmental conditions.
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Affiliation(s)
- Caitlin K. Frankish
- British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Road, Cambridge, CB3 0ET UK
- Department of Zoology, University of Cambridge, Downing Street, Cambridge, CB2 3EJ UK
| | - Andrea Manica
- Department of Zoology, University of Cambridge, Downing Street, Cambridge, CB2 3EJ UK
| | - Richard A. Phillips
- British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Road, Cambridge, CB3 0ET UK
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12
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Lescroël A, Ballard G, Massaro M, Dugger K, Jennings S, Pollard A, Porzig E, Schmidt A, Varsani A, Grémillet D, Ainley D. Evidence of age-related improvement in the foraging efficiency of Adélie penguins. Sci Rep 2019; 9:3375. [PMID: 30833598 PMCID: PMC6399253 DOI: 10.1038/s41598-019-39814-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Accepted: 01/30/2019] [Indexed: 11/21/2022] Open
Abstract
Age variation in reproductive performance is well-documented but the mechanisms underlying this variation remain unclear. Foraging efficiency is likely to be a key source of demographic variation as it determines the amount of energy that can be invested in fitness-related activities. Evidence of age-related changes in the foraging efficiency of adult seabirds is scarce and inconsistent. We investigated the effects of age on the foraging efficiency of breeding Adélie penguins, a relatively short-lived seabird species, in order to gain a broader perspective on the processes driving variation in ageing rates. We found support for a positive effect of age, either linear or levelling off at old ages, on both our proxies for daily catch rate and catch per unit effort. Across all age classes, males were more performant foragers than females. We found no strong evidence for differing ageing patterns between sexes or individual quality levels, and no evidence for senescence. We infer that continuous individual improvement could be responsible for a larger amount of the variation in foraging efficiency with age at our study site, compared with selective disappearance of underperforming phenotypes. The different results reported by other studies highlight the need to conduct longitudinal studies across a range of species in different environments.
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Affiliation(s)
- Amélie Lescroël
- Point Blue Conservation Science, Petaluma, CA, 94954, USA. .,Centre d'Ecologie Fonctionnelle et Evolutive, UMR 5175, CNRS - Université de Montpellier - Université Paul-Valéry Montpellier - EPHE, Montpellier, France.
| | - Grant Ballard
- Point Blue Conservation Science, Petaluma, CA, 94954, USA
| | - Melanie Massaro
- School of Environmental Sciences, Institute for Land, Water and Society, Charles Sturt University, Albury, NSW, 2640, Australia
| | - Katie Dugger
- U.S. Geological Survey, Oregon Cooperative Fish and Wildlife Research Unit, Department of Fisheries and Wildlife, Oregon State University, Corvallis, Oregon, USA
| | - Scott Jennings
- Point Blue Conservation Science, Petaluma, CA, 94954, USA.,U.S. Geological Survey, Oregon Cooperative Fish and Wildlife Research Unit, Department of Fisheries and Wildlife, Oregon State University, Corvallis, Oregon, USA
| | - Annie Pollard
- Point Blue Conservation Science, Petaluma, CA, 94954, USA
| | | | - Annie Schmidt
- Point Blue Conservation Science, Petaluma, CA, 94954, USA
| | - Arvind Varsani
- The Biodesign Center for Fundamental and Applied Microbiomics, Center for Evolution and Medicine, School of Life sciences, Arizona State University, Tempe, Arizona, USA.,Structural Biology Research Unit, Department of Clinical Laboratory Sciences, University of Cape Town, Observatory, Cape Town, South Africa
| | - David Grémillet
- Centre d'Ecologie Fonctionnelle et Evolutive, UMR 5175, CNRS - Université de Montpellier - Université Paul-Valéry Montpellier - EPHE, Montpellier, France.,FitzPatrick Institute, DST/NRF centre of excellence at the University of Cape Town, Rondebosch, 7701, South Africa
| | - David Ainley
- H.T. Harvey & Associates, Los Gatos, California, USA
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Seeker LA, Ilska JJ, Psifidi A, Wilbourn RV, Underwood SL, Fairlie J, Holland R, Froy H, Salvo-Chirnside E, Bagnall A, Whitelaw B, Coffey MP, Nussey DH, Banos G. Bovine telomere dynamics and the association between telomere length and productive lifespan. Sci Rep 2018; 8:12748. [PMID: 30143784 PMCID: PMC6109064 DOI: 10.1038/s41598-018-31185-z] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Accepted: 08/03/2018] [Indexed: 12/17/2022] Open
Abstract
Average telomere length (TL) in blood cells has been shown to decline with age in a range of vertebrate species, and there is evidence that TL is a heritable trait associated with late-life health and mortality in humans. In non-human mammals, few studies to date have examined lifelong telomere dynamics and no study has estimated the heritability of TL, despite these being important steps towards assessing the potential of TL as a biomarker of productive lifespan and health in livestock species. Here we measured relative leukocyte TL (RLTL) in 1,328 samples from 308 Holstein Friesian dairy cows and in 284 samples from 38 female calves. We found that RLTL declines after birth but remains relatively stable in adult life. We also calculated the first heritability estimates of RLTL in a livestock species which were 0.38 (SE = 0.03) and 0.32 (SE = 0.08) for the cow and the calf dataset, respectively. RLTL measured at the ages of one and five years were positively correlated with productive lifespan (p < 0.05). We conclude that bovine RLTL is a heritable trait, and its association with productive lifespan may be used in breeding programmes aiming to enhance cow longevity.
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Affiliation(s)
- Luise A Seeker
- Animal & Veterinary Sciences Group, SRUC, Roslin Institute Building, Easter Bush, Midlothian, UK.
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, UK.
| | - Joanna J Ilska
- Animal & Veterinary Sciences Group, SRUC, Roslin Institute Building, Easter Bush, Midlothian, UK
| | - Androniki Psifidi
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, UK
- Queen Mother Hospital for Animals, Royal Veterinary College, University of London, Hatfield, UK
| | - Rachael V Wilbourn
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, Midlothian, UK
| | - Sarah L Underwood
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, Midlothian, UK
| | - Jennifer Fairlie
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, Midlothian, UK
| | - Rebecca Holland
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, Midlothian, UK
| | - Hannah Froy
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, Midlothian, UK
| | | | | | - Bruce Whitelaw
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, UK
| | - Mike P Coffey
- Animal & Veterinary Sciences Group, SRUC, Roslin Institute Building, Easter Bush, Midlothian, UK
| | - Daniel H Nussey
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, Midlothian, UK
| | - Georgios Banos
- Animal & Veterinary Sciences Group, SRUC, Roslin Institute Building, Easter Bush, Midlothian, UK
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, UK
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14
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Clay TA, Pearmain EJ, McGill RAR, Manica A, Phillips RA. Age‐related variation in non‐breeding foraging behaviour and carry‐over effects on fitness in an extremely long‐lived bird. Funct Ecol 2018. [DOI: 10.1111/1365-2435.13120] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Thomas A. Clay
- British Antarctic SurveyNatural Environment Research Council Cambridge UK
- Department of ZoologyUniversity of Cambridge Cambridge UK
| | | | - Rona A. R. McGill
- NERC Life Sciences Mass Spectrometry FacilityScottish Universities Environmental Research Centre East Kilbride UK
| | - Andrea Manica
- Department of ZoologyUniversity of Cambridge Cambridge UK
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15
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Richardson PL, Wakefield ED, Phillips RA. Flight speed and performance of the wandering albatross with respect to wind. MOVEMENT ECOLOGY 2018; 6:3. [PMID: 29556395 PMCID: PMC5840797 DOI: 10.1186/s40462-018-0121-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Accepted: 02/26/2018] [Indexed: 06/08/2023]
Abstract
BACKGROUND Albatrosses and other large seabirds use dynamic soaring to gain sufficient energy from the wind to travel large distances rapidly and with little apparent effort. The recent development of miniature bird-borne tracking devices now makes it possible to explore the physical and biological implications of this means of locomotion in detail. Here we use GPS tracking and concurrent reanalyzed wind speed data to model the flight performance of wandering albatrosses Diomedea exulans soaring over the Southern Ocean. We investigate the extent to which flight speed and performance of albatrosses is facilitated or constrained by wind conditions encountered during foraging trips. RESULTS We derived simple equations to model observed albatross ground speed as a function of wind speed and relative wind direction. Ground speeds of the tracked birds in the along-wind direction varied primarily by wind-induced leeway, which averaged 0.51 (± 0.02) times the wind speed at a reference height of 5 m. By subtracting leeway velocity from ground velocity, we were able to estimate airspeed (the magnitude of the bird's velocity through the air). As wind speeds increased from 3 to 18 m/s, the airspeed of wandering albatrosses flying in an across-wind direction increased by 0.42 (± 0.04) times the wind speed (i.e. ~ 6 m/s). At low wind speeds, tracked birds increased their airspeed in upwind flight relative to that in downwind flight. At higher wind speeds they apparently limited their airspeeds to a maximum of around 20 m/s, probably to keep the forces on their wings in dynamic soaring well within tolerable limits. Upwind airspeeds were nearly constant and downwind leeway increased with wind speed. Birds therefore achieved their fastest upwind ground speeds (~ 9 m/s) at low wind speeds (~ 3 m/s). CONCLUSIONS This study provides insights into which flight strategies are optimal for dynamic soaring. Our results are consistent with the prediction that the optimal range speed of albatrosses is higher in headwind than tailwind flight but only in wind speeds of up to ~ 7 m/s. Our models predict that wandering albatrosses have oval-shaped airspeed polars, with the fastest airspeeds ~ 20 m/s centered in the across-wind direction. This suggests that in upwind flight in high winds, albatrosses can increase their ground speed by tacking like sailboats.
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Affiliation(s)
- Philip L. Richardson
- Department of Physical Oceanography, MS#21, Woods Hole Oceanographic Institution, 360 Woods Hole Road, Woods Hole, MA 02543 USA
| | - Ewan D. Wakefield
- Animal Health and Comparative Medicine, University of Glasgow, Institute of Biodiversity, Graham Kerr Building, Glasgow, G12 8QQ UK
| | - Richard A. Phillips
- British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Road, Cambridge, CB3 0ET UK
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16
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Seeker LA, Ilska JJ, Psifidi A, Wilbourn RV, Underwood SL, Fairlie J, Holland R, Froy H, Bagnall A, Whitelaw B, Coffey M, Nussey DH, Banos G. Longitudinal changes in telomere length and associated genetic parameters in dairy cattle analysed using random regression models. PLoS One 2018; 13:e0192864. [PMID: 29438415 PMCID: PMC5811042 DOI: 10.1371/journal.pone.0192864] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2017] [Accepted: 01/31/2018] [Indexed: 11/18/2022] Open
Abstract
Telomeres cap the ends of linear chromosomes and shorten with age in many organisms. In humans short telomeres have been linked to morbidity and mortality. With the accumulation of longitudinal datasets the focus shifts from investigating telomere length (TL) to exploring TL change within individuals over time. Some studies indicate that the speed of telomere attrition is predictive of future disease. The objectives of the present study were to 1) characterize the change in bovine relative leukocyte TL (RLTL) across the lifetime in Holstein Friesian dairy cattle, 2) estimate genetic parameters of RLTL over time and 3) investigate the association of differences in individual RLTL profiles with productive lifespan. RLTL measurements were analysed using Legendre polynomials in a random regression model to describe TL profiles and genetic variance over age. The analyses were based on 1,328 repeated RLTL measurements of 308 female Holstein Friesian dairy cattle. A quadratic Legendre polynomial was fitted to the fixed effect of age in months and to the random effect of the animal identity. Changes in RLTL, heritability and within-trait genetic correlation along the age trajectory were calculated and illustrated. At a population level, the relationship between RLTL and age was described by a positive quadratic function. Individuals varied significantly regarding the direction and amount of RLTL change over life. The heritability of RLTL ranged from 0.36 to 0.47 (SE = 0.05-0.08) and remained statistically unchanged over time. The genetic correlation of RLTL at birth with measurements later in life decreased with the time interval between samplings from near unity to 0.69, indicating that TL later in life might be regulated by different genes than TL early in life. Even though animals differed in their RLTL profiles significantly, those differences were not correlated with productive lifespan (p = 0.954).
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Affiliation(s)
- Luise A. Seeker
- Animal & Veterinary Sciences, SRUC, Easter Bush, Midlothian, United Kingdom
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, United Kingdom
- * E-mail:
| | - Joanna J. Ilska
- Animal & Veterinary Sciences, SRUC, Easter Bush, Midlothian, United Kingdom
| | - Androniki Psifidi
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, United Kingdom
- Royal Veterinary College, University of London, Hatfield, United Kingdom
| | - Rachael V. Wilbourn
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, Midlothian, United Kingdom
| | - Sarah L. Underwood
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, Midlothian, United Kingdom
| | - Jennifer Fairlie
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, Midlothian, United Kingdom
| | - Rebecca Holland
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, Midlothian, United Kingdom
| | - Hannah Froy
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, Midlothian, United Kingdom
| | | | - Bruce Whitelaw
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, United Kingdom
| | - Mike Coffey
- Animal & Veterinary Sciences, SRUC, Easter Bush, Midlothian, United Kingdom
| | - Daniel H. Nussey
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, Midlothian, United Kingdom
| | - Georgios Banos
- Animal & Veterinary Sciences, SRUC, Easter Bush, Midlothian, United Kingdom
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, United Kingdom
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17
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Johnson LR, Boersch-Supan PH, Phillips RA, Ryan SJ. Changing measurements or changing movements? Sampling scale and movement model identifiability across generations of biologging technology. Ecol Evol 2017; 7:9257-9266. [PMID: 29187966 PMCID: PMC5696428 DOI: 10.1002/ece3.3461] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Revised: 08/01/2017] [Accepted: 08/03/2017] [Indexed: 11/18/2022] Open
Abstract
Animal movement patterns contribute to our understanding of variation in breeding success and survival of individuals, and the implications for population dynamics. Over time, sensor technology for measuring movement patterns has improved. Although older technologies may be rendered obsolete, the existing data are still valuable, especially if new and old data can be compared to test whether a behavior has changed over time. We used simulated data to assess the ability to quantify and correctly identify patterns of seabird flight lengths under observational regimes used in successive generations of wet/dry logging technology. Care must be taken when comparing data collected at differing timescales, even when using inference procedures that incorporate the observational process, as model selection and parameter estimation may be biased. In practice, comparisons may only be valid when degrading all data to match the lowest resolution in a set. Changes in tracking technology, such as the wet/dry loggers explored here, that lead to aggregation of measurements at different temporal scales make comparisons challenging. We therefore urge ecologists to use synthetic data to assess whether accurate parameter estimation is possible for models comparing disparate data sets before planning experiments and conducting analyses such as responses to environmental changes or the assessment of management actions.
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Affiliation(s)
- Leah R Johnson
- Department of Statistics Virginia Tech Blacksburg VA USA.,Department of Integrative Biology University of South Florida Tampa FL USA
| | - Philipp H Boersch-Supan
- Department of Integrative Biology University of South Florida Tampa FL USA.,Department of Geography University of Florida Gainesville FL USA.,Emerging Pathogens Institute University of Florida Gainesville FL USA
| | - Richard A Phillips
- British Antarctic Survey Natural Environment Research Council Cambridge UK
| | - Sadie J Ryan
- Department of Geography University of Florida Gainesville FL USA.,Emerging Pathogens Institute University of Florida Gainesville FL USA
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18
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Reduced activity in middle-aged thick-billed murres: evidence for age related trends in fine-scale foraging behaviour. Anim Behav 2017. [DOI: 10.1016/j.anbehav.2017.02.010] [Citation(s) in RCA: 5] [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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19
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Jiménez S, Domingo A, Brazeiro A, Defeo O, Wood AG, Froy H, Xavier JC, Phillips RA. Sex-related variation in the vulnerability of wandering albatrosses to pelagic longline fleets. Anim Conserv 2015. [DOI: 10.1111/acv.12245] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- S. Jiménez
- Laboratorio de Recursos Pelágicos; Dirección Nacional de Recursos Acuáticos; Montevideo Uruguay
- British Antarctic Survey; Natural Environment Research Council, High Cross; Cambridge UK
| | - A. Domingo
- Laboratorio de Recursos Pelágicos; Dirección Nacional de Recursos Acuáticos; Montevideo Uruguay
| | - A. Brazeiro
- Instituto de Ecología y Ciencias Ambientales; Facultad de Ciencias, Universidad de la República; Montevideo Uruguay
| | - O. Defeo
- UNDECIMAR, Departamento de Ecología & Evolución; Facultad de Ciencias, Universidad de la República; Montevideo Uruguay
| | - A. G. Wood
- British Antarctic Survey; Natural Environment Research Council, High Cross; Cambridge UK
| | - H. Froy
- Institute of Evolutionary Biology; University of Edinburgh; Edinburgh UK
| | - J. C. Xavier
- British Antarctic Survey; Natural Environment Research Council, High Cross; Cambridge UK
- Department of Life Sciences, Faculty of Sciences and Technology; IMAR-CMA-Institute of Marine Research, University of Coimbra; Coimbra Portugal
- MARE - Marine and Environmental Sciences Centre; Faculty of Sciences and Technology; IMAR-CMA-Institute of Marine Research, University of Coimbra; Coimbra Portugal
| | - R. A. Phillips
- British Antarctic Survey; Natural Environment Research Council, High Cross; Cambridge UK
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20
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Hayward AD, Moorad J, Regan CE, Berenos C, Pilkington JG, Pemberton JM, Nussey DH. Asynchrony of senescence among phenotypic traits in a wild mammal population. Exp Gerontol 2015; 71:56-68. [PMID: 26277618 PMCID: PMC4661475 DOI: 10.1016/j.exger.2015.08.003] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Revised: 07/14/2015] [Accepted: 08/04/2015] [Indexed: 01/10/2023]
Abstract
The degree to which changes in lifespan are coupled to changes in senescence in different physiological systems and phenotypic traits is a central question in biogerontology. It is underpinned by deeper biological questions about whether or not senescence is a synchronised process, or whether levels of synchrony depend on species or environmental context. Understanding how natural selection shapes patterns of synchrony in senescence across physiological systems and phenotypic traits demands the longitudinal study of many phenotypes under natural conditions. Here, we examine the patterns of age-related variation in late adulthood in a wild population of Soay sheep (Ovis aries) that have been the subject of individual-based monitoring for thirty years. We examined twenty different phenotypic traits in both males and females, encompassing vital rates (survival and fecundity), maternal reproductive performance (offspring birth weight, birth date and survival), male rutting behaviour, home range measures, parasite burdens, and body mass. We initially quantified age-related variation in each trait having controlled for annual variation in the environment, among-individual variation and selective disappearance effects. We then standardised our age-specific trait means and tested whether age trajectories could be meaningfully grouped according to sex or the type of trait. Whilst most traits showed age-related declines in later life, we found striking levels of asynchrony both within and between the sexes. Of particular note, female fecundity and reproductive performance declined with age, but male annual reproductive success did not. We also discovered that whilst home range size and quality decline with age in females, home range size increases with age in males. Our findings highlight the complexity of phenotypic ageing under natural conditions and, along with emerging data from other wild populations and laboratory models, suggest that the long-standing hypothesis within evolutionary biology that fitness-related traits should senesce in a synchronous manner is seriously flawed.
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Affiliation(s)
- Adam D Hayward
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, United Kingdom
| | - Jacob Moorad
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, United Kingdom
| | - Charlotte E Regan
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, United Kingdom
| | - Camillo Berenos
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, United Kingdom
| | - Jill G Pilkington
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, United Kingdom
| | - Josephine M Pemberton
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, United Kingdom
| | - Daniel H Nussey
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, United Kingdom.
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