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Leimar O, Bshary R. Reproductive skew, fighting costs, and winner-loser effects in social-dominance evolution. J Anim Ecol 2022; 91:1036-1046. [PMID: 35304750 PMCID: PMC9315160 DOI: 10.1111/1365-2656.13691] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Accepted: 03/02/2022] [Indexed: 11/28/2022]
Abstract
1. Social hierarchies are often found in group-living animals and can be formed through pairwise aggressive interactions. The dominance rank can influence reproductive success (RS) with a skew towards high-ranking individuals. 2. Using game theory we investigate how the opportunity for differently ranked individuals to achieve RS influences the costs of hierarchy formation and the strength of winner and loser effects. 3. In our model, individuals adjust their aggressive and submissive behaviour towards others through reinforcement learning. The learning is based on rewards and penalties, which depend on relative fighting ability. From individual-based simulations we determine evolutionary equilibria of traits such as learning rates. We examine situations that differ in the extent of monopolisation of contested RS by dominants and in the proportion of total RS that is contested. 4. The model implements two kinds of fighting costs: a decrease in effective fighting ability from damage (loss of condition), and a risk of mortality that increases with the total accumulated damage. Either of these costs can limit the amount of fighting. 5. We find that stable dominance hierarchies form, with a positive correlation between dominance position and fighting ability. The accumulated costs differ between dominance positions, with the highest costs paid by low or intermediately ranked individuals. Costs tend to be higher in high-skew situations. 6. We identify a 'stay-in, opt-out' syndrome, comprising a range from weaker (stay-in) to stronger (opt-out) winner-loser effects. We interpret the opt-out phenotype to be favoured by selection on lower-ranked individuals to opt out of contests over social dominance, because it is more pronounced when more of the total RS is uncontested. 7. We discuss our results in relation to field and experimental observations and argue that there is a need for empirical investigation of the behaviour and reproductive success of lower-ranked individuals.
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Affiliation(s)
- Olof Leimar
- Department of Zoology, Stockholm University, Stockholm, Sweden
| | - Redouan Bshary
- Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
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2
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Williams JL, Harley D, Watchorn D, McBurney L, Lindenmayer DB. Relationship between body weight and elevation in Leadbeater’s possum (Gymnobelideus leadbeateri). AUST J ZOOL 2022. [DOI: 10.1071/zo21042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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3
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Gutiérrez J, Seguel M, Saenz‐Agudelo P, Acosta‐Jamett G, Verdugo C. Genetic diversity and kinship relationships in one of the largest South American fur seal (
Arctocephalus australis
) populations of the Pacific Ocean. Ecol Evol 2021. [DOI: 10.1002/ece3.7683] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Affiliation(s)
- Josefina Gutiérrez
- Instituto de Patología Animal Facultad de Ciencias Veterinarias Universidad Austral de Chile Valdivia Chile
- Programa de Investigación Aplicada a la Fauna Silvestre Facultad de Ciencias Veterinarias Universidad Austral de Chile Valdivia Chile
| | - Mauricio Seguel
- Department of Pathobiology Ontario Veterinary College University of Guelph ON Canada
| | - Pablo Saenz‐Agudelo
- Instituto de Ciencias Ambientales y Evolutivas Facultad de Ciencias Universidad Austral de Chile Valdivia Chile
| | - Gerardo Acosta‐Jamett
- Programa de Investigación Aplicada a la Fauna Silvestre Facultad de Ciencias Veterinarias Universidad Austral de Chile Valdivia Chile
- Instituto de Medicina Preventiva Veterinaria Facultad de Ciencias Veterinarias Universidad Austral de Chile Valdivia Chile
| | - Claudio Verdugo
- Instituto de Patología Animal Facultad de Ciencias Veterinarias Universidad Austral de Chile Valdivia Chile
- Programa de Investigación Aplicada a la Fauna Silvestre Facultad de Ciencias Veterinarias Universidad Austral de Chile Valdivia Chile
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4
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Brusa JL, Rotella JJ, Banner KM, Hutchins PR. Challenges and opportunities for comparative studies of survival rates: An example with male pinnipeds. Ecol Evol 2021; 11:7980-7999. [PMID: 34188866 PMCID: PMC8216918 DOI: 10.1002/ece3.7627] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 03/11/2021] [Accepted: 04/13/2021] [Indexed: 11/30/2022] Open
Abstract
Survival rates are a central component of life-history strategies of large vertebrate species. However, comparative studies seldom investigate interspecific variation in survival rates with respect to other life-history traits, especially for males. The lack of such studies could be due to the challenges associated with obtaining reliable datasets, incorporating information on the 0-1 probability scale, or dealing with several types of measurement error in life-history traits, which can be a computationally intensive process that is often absent in comparative studies. We present a quantitative approach using a Bayesian phylogenetically controlled regression with the flexibility to incorporate uncertainty in estimated survival rates and quantitative life-history traits while considering genetic similarity among species and uncertainty in relatedness. As with any comparative analysis, our approach makes several assumptions regarding the generalizability and comparability of empirical data from separate studies. Our model is versatile in that it can be applied to any species group of interest and include any life-history traits as covariates. We used an unbiased simulation framework to provide "proof of concept" for our model and applied a slightly richer model to a real data example for pinnipeds. Pinnipeds are an excellent taxonomic group for comparative analysis, but survival rate data are scarce. Our work elucidates the challenges associated with addressing important questions related to broader ecological life-history patterns and how survival-reproduction trade-offs might shape evolutionary histories of extant taxa. Specifically, we underscore the importance of having high-quality estimates of age-specific survival rates and information on other life-history traits that reasonably characterize a species for accurately comparing across species.
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Affiliation(s)
- Jamie L. Brusa
- Department of EcologyMontana State UniversityBozemanMTUSA
- School of Environmental and Forest SciencesUniversity of WashingtonSeattleWAUSA
| | - Jay J. Rotella
- Department of EcologyMontana State UniversityBozemanMTUSA
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5
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Davidian E, Wachter B, Heckmann I, Dehnhard M, Hofer H, Höner OP. The interplay between social rank, physiological constraints and investment in courtship in male spotted hyenas. Funct Ecol 2021. [DOI: 10.1111/1365-2435.13733] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- Eve Davidian
- Department of Evolutionary Ecology Leibniz Institute for Zoo and Wildlife Research Berlin Germany
| | - Bettina Wachter
- Department of Evolutionary Ecology Leibniz Institute for Zoo and Wildlife Research Berlin Germany
| | - Ilja Heckmann
- Department of Evolutionary Ecology Leibniz Institute for Zoo and Wildlife Research Berlin Germany
| | - Martin Dehnhard
- Department of Reproduction Biology Leibniz Institute for Zoo and Wildlife Research Berlin Germany
| | - Heribert Hofer
- Department of Evolutionary Ecology Leibniz Institute for Zoo and Wildlife Research Berlin Germany
- Department of Veterinary Medicine Freie Universität Berlin Berlin Germany
- Department of Biology, Chemistry, Pharmacy Freie Universität Berlin Berlin Germany
| | - Oliver P. Höner
- Department of Evolutionary Ecology Leibniz Institute for Zoo and Wildlife Research Berlin Germany
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6
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Shafer ABA, Peart CR, Tusso S, Maayan I, Brelsford A, Wheat CW, Wolf JBW. Bioinformatic processing of RAD‐seq data dramatically impacts downstream population genetic inference. Methods Ecol Evol 2016. [DOI: 10.1111/2041-210x.12700] [Citation(s) in RCA: 189] [Impact Index Per Article: 23.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Aaron B. A. Shafer
- Department of Evolutionary Biology Evolutionary Biology Centre Uppsala University Norbyvägen 18D SE‐752 36 Uppsala Sweden
- Forensic Science and Environmental & Life Sciences Trent University 2014 East Bank Dr K9J 7B8 Peterborough Canada
| | - Claire R. Peart
- Department of Evolutionary Biology Evolutionary Biology Centre Uppsala University Norbyvägen 18D SE‐752 36 Uppsala Sweden
| | - Sergio Tusso
- Department of Evolutionary Biology Evolutionary Biology Centre Uppsala University Norbyvägen 18D SE‐752 36 Uppsala Sweden
| | - Inbar Maayan
- Department of Evolutionary Biology Evolutionary Biology Centre Uppsala University Norbyvägen 18D SE‐752 36 Uppsala Sweden
| | - Alan Brelsford
- Department of Ecology and Evolution University of Lausanne CH‐1015 Lausanne Switzerland
| | | | - Jochen B. W. Wolf
- Department of Evolutionary Biology Evolutionary Biology Centre Uppsala University Norbyvägen 18D SE‐752 36 Uppsala Sweden
- Division of Evolutionary Biology Faculty of Biology Ludwig‐Maximilians University of Munich Grosshaderner Str. 2 82152 Planegg‐Martinsried Germany
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7
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Trillmich F, Meise K, Kalberer S, Mueller B, Piedrahita P, Pörschmann U, Wolf JBW, Krüger O. On the Challenge of Interpreting Census Data: Insights from a Study of an Endangered Pinniped. PLoS One 2016; 11:e0154588. [PMID: 27148735 PMCID: PMC4858284 DOI: 10.1371/journal.pone.0154588] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Accepted: 04/16/2016] [Indexed: 11/18/2022] Open
Abstract
Population monitoring is vital for conservation and management. However, simple counts of animals can be misleading and this problem is exacerbated in seals (pinnipeds) where individuals spend much time foraging away from colonies. We analyzed a 13-year-series of census data of Galapagos sea lions (Zalophus wollebaeki) from the colony of Caamaño, an islet in the center of the Galapagos archipelago where a large proportion of animals was individually marked. Based on regular resighting efforts during the cold, reproductive (cold-R; August to January) and the warm, non-reproductive (warm-nR; February to May) season, we document changes in numbers for different sex and age classes. During the cold-R season the number of adults increased as the number of newborn pups increased. Numbers were larger in the morning and evening than around mid-day and not significantly influenced by tide levels. More adults frequented the colony during the warm-nR season than the cold-R season. Raw counts suggested a decline in numbers over the 13 years, but Lincoln-Petersen (LP-) estimates (assuming a closed population) did not support that conclusion. Raw counts and LP estimates were not significantly correlated, demonstrating the overwhelming importance of variability in attendance patterns of individuals. The probability of observing a given adult in the colony varied between 16% (mean for cold-R season) and 23% (warm-nR season) and may be much less for independent 2 to 4 year olds. Dependent juveniles (up to the age of about 2 years) are observed much more frequently ashore (35% during the cold-R and 50% during the warm-nR seasons). Simple counts underestimate real population size by a factor of 4-6 and may lead to erroneous conclusions about trends in population size.
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Affiliation(s)
- Fritz Trillmich
- Animal Behaviour, University of Bielefeld, Bielefeld, Germany
| | - Kristine Meise
- Animal Behaviour, University of Bielefeld, Bielefeld, Germany
- Department of Evolution, Ecology and Behaviour, Institute of Integrative Biology, University of Liverpool, Biosciences Building, Liverpool, United Kingdom
| | | | - Birte Mueller
- Center for Biology Education, University of Münster, Münster, Germany
| | - Paolo Piedrahita
- Animal Behaviour, University of Bielefeld, Bielefeld, Germany
- Facultad de Ciencias de la Vida, Escuela Superior Politécnica del Litoral, ESPOL, Guayaquil, Ecuador
| | | | | | - Oliver Krüger
- Animal Behaviour, University of Bielefeld, Bielefeld, Germany
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8
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Drago M, Franco-Trecu V, Cardona L, Inchausti P, Tapia W, Páez-Rosas D. Stable Isotopes Reveal Long-Term Fidelity to Foraging Grounds in the Galapagos Sea Lion (Zalophus wollebaeki). PLoS One 2016; 11:e0147857. [PMID: 26808381 PMCID: PMC4725682 DOI: 10.1371/journal.pone.0147857] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Accepted: 01/08/2016] [Indexed: 11/30/2022] Open
Abstract
Most otariids have colony-specific foraging areas during the breeding season, when they behave as central place foragers. However, they may disperse over broad areas after the breeding season and individuals from different colonies may share foraging grounds at that time. Here, stable isotope ratios in the skull bone of adult Galapagos sea lions (Zalophus wollebaeki) were used to assess the long-term fidelity of both sexes to foraging grounds across the different regions of the Galapagos archipelago. Results indicated that the stable isotope ratios (δ13C and δ15N) of sea lion bone significantly differed among regions of the archipelago, without any significant difference between sexes and with a non significant interaction between sex and region. Moreover, standard ellipses, estimated by Bayesian inference and used as a measure of the isotopic resource use area at the population level, overlapped widely for the sea lions from the southern and central regions, whereas the overlap of the ellipses for sea lions from the central and western regions was small and non-existing for those from the western and southern regions. These results suggest that males and females from the same region within the archipelago use similar foraging grounds and have similar diets. Furthermore, they indicate that the exchange of adults between regions is limited, thus revealing a certain degree of foraging philopatry at a regional scale within the archipelago. The constraints imposed on males by an expanded reproductive season (~ 6 months), resulting from the weak reproductive synchrony among females, and those imposed on females by a very long lactation period (at least one year but up to three years), may explain the limited mobility of adult Galapagos sea lions of both sexes across the archipelago.
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Affiliation(s)
- Massimiliano Drago
- Programa PROMETEO-SENESCYT, Secretaría de Educación Superior, Ciencia, Tecnología e Innovación, Quito, Ecuador
- Department of Ecology & Evolution, Centro Universitario Regional Este (CURE), University of the Republic (UdeLaR), Maldonado, Uruguay
- * E-mail:
| | - Valentina Franco-Trecu
- Department of Ecology & Evolution, Faculty of Sciences, University of the Republic (UdeLaR), Montevideo, Uruguay
| | - Luis Cardona
- Department of Animal Biology, Faculty of Biology, University of Barcelona, Barcelona, Spain
| | - Pablo Inchausti
- Department of Ecology & Evolution, Centro Universitario Regional Este (CURE), University of the Republic (UdeLaR), Maldonado, Uruguay
| | - Washington Tapia
- Department of Applied Research, Galapagos National Park Service, Puerto Ayora, Galápagos, Ecuador
- Galapagos Conservancy, Santa Cruz, Galápagos, Ecuador
| | - Diego Páez-Rosas
- Universidad San Francisco de Quito (USFQ) and Galapagos Science Center, San Cristóbal, Galápagos, Ecuador
- Dirección Parque Nacional Galápagos, Unidad Técnica Operativa San Cristóbal, Galápagos, Ecuador
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9
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Brock PM, Goodman SJ, Hall AJ, Cruz M, Acevedo-Whitehouse K. Context-dependent associations between heterozygosity and immune variation in a wild carnivore. BMC Evol Biol 2015; 15:242. [PMID: 26537228 PMCID: PMC4634738 DOI: 10.1186/s12862-015-0519-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Accepted: 10/23/2015] [Indexed: 11/25/2022] Open
Abstract
Background A multitude of correlations between heterozygosity and fitness proxies associated with disease have been reported from wild populations, but the genetic basis of these associations is unresolved. We used a longitudinal dataset on wild Galapagos sea lions (Zalophus wollebaeki) to develop a relatively new perspective on this problem, by testing for associations between heterozygosity and immune variation across age classes and between ecological contexts. Results Homozygosity by locus was negatively correlated with serum immunoglobulin G production in pups (0–3 months of age), suggesting that reduced genetic diversity has a detrimental influence on the early development of immune defence in the Galapagos sea lion. In addition, homozygosity by locus was positively correlated with total circulating leukocyte concentration in juveniles (6–24 months of age), but only in a colony subject to the anthropogenic environmental impacts of development, pollution and introduced species, which suggests that reduced genetic diversity influences mature immune system activity in circumstances of high antigen exposure. Conclusions These findings demonstrate the environmental context-dependency of the phenotypic expression of immune variation, which is implicit in the theory of ecoimmunology, but which has been rarely demonstrated in the wild. They also indicate that heterozygosity may be linked to the maintenance of heterogeneity in mammalian immune system development and response to infection, adding to the body of evidence on the nature of the mechanistic link between heterozygosity and fitness. Electronic supplementary material The online version of this article (doi:10.1186/s12862-015-0519-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Patrick M Brock
- Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G61 1QH, UK. .,Zoological Society of London, Regent's Park, London, NW1 4RY, UK. .,School of Biology, University of Leeds, Leeds, LS2 9JT, UK.
| | | | - Ailsa J Hall
- Sea Mammal Research Unit, Scottish Ocean Institute, University of St. Andrews, Fife, KY16 8LB, UK.
| | - Marilyn Cruz
- Galapagos Genetics, Epidemiology and Pathology Laboratory, Galapagos National Park & University of Guayaquil, Puerto Ayora, Galapagos Islands, Ecuador.
| | - Karina Acevedo-Whitehouse
- Zoological Society of London, Regent's Park, London, NW1 4RY, UK. .,Unit for Basic and Applied Microbiology, School of Natural Sciences, Autonomous University of Queretaro, Queretaro, 76230, Mexico.
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10
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Differences in foraging ecology align with genetically divergent ecotypes of a highly mobile marine top predator. Oecologia 2015; 179:1041-52. [PMID: 26307593 DOI: 10.1007/s00442-015-3424-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Accepted: 08/07/2015] [Indexed: 10/23/2022]
Abstract
Foraging differentiation within a species can contribute to restricted gene flow between ecologically different groups, promoting ecological speciation. Galapagos sea lions (Zalophus wollebaeki) show genetic and morphological divergence between the western and central archipelago, possibly as a result of an ecologically mediated contrast in the marine habitat. We use global positioning system (GPS) data, time-depth recordings (TDR), stable isotope and scat data to compare foraging habitat characteristics, diving behaviour and diet composition of Galapagos sea lions from a western and a central colony. We consider both juvenile and adult life stages to assess the potential role of ontogenetic shifts that can be crucial in shaping foraging behaviour and habitat choice for life. We found differences in foraging habitat use, foraging style and diet composition that aligned with genetic differentiation. These differences were consistent between juvenile and adult sea lions from the same colony, overriding age-specific behavioural differences. Our study contributes to an understanding of the complex interaction of ecological condition, plastic behavioural response and genetic make-up of interconnected populations.
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11
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Rioux-Paquette E, Garant D, Martin AM, Coulson G, Festa-Bianchet M. Paternity in eastern grey kangaroos: moderate skew despite strong sexual dimorphism. Behav Ecol 2015. [DOI: 10.1093/beheco/arv052] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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12
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Meise K, Mueller B, Zein B, Trillmich F. Applicability of single-camera photogrammetry to determine body dimensions of pinnipeds: Galapagos sea lions as an example. PLoS One 2014; 9:e101197. [PMID: 24987983 PMCID: PMC4079256 DOI: 10.1371/journal.pone.0101197] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2013] [Accepted: 06/03/2014] [Indexed: 11/23/2022] Open
Abstract
Morphological features correlate with many life history traits and are therefore of high interest to behavioral and evolutionary biologists. Photogrammetry provides a useful tool to collect morphological data from species for which measurements are otherwise difficult to obtain. This method reduces disturbance and avoids capture stress. Using the Galapagos sea lion (Zalophus wollebaeki) as a model system, we tested the applicability of single-camera photogrammetry in combination with laser distance measurement to estimate morphological traits which may vary with an animal's body position. We assessed whether linear morphological traits estimated by photogrammetry can be used to estimate body length and mass. We show that accurate estimates of body length (males: ±2.0%, females: ±2.6%) and reliable estimates of body mass are possible (males: ±6.8%, females: 14.5%). Furthermore, we developed correction factors that allow the use of animal photos that diverge somewhat from a flat-out position. The product of estimated body length and girth produced sufficiently reliable estimates of mass to categorize individuals into 10 kg-classes of body mass. Data of individuals repeatedly photographed within one season suggested relatively low measurement errors (body length: 2.9%, body mass: 8.1%). In order to develop accurate sex- and age-specific correction factors, a sufficient number of individuals from both sexes and from all desired age classes have to be captured for baseline measurements. Given proper validation, this method provides an excellent opportunity to collect morphological data for large numbers of individuals with minimal disturbance.
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Affiliation(s)
- Kristine Meise
- Department of Animal Behaviour, University of Bielefeld, Bielefeld, Germany
| | - Birte Mueller
- Department of Animal Behaviour, University of Bielefeld, Bielefeld, Germany
| | - Beate Zein
- Department of Animal Behaviour, University of Bielefeld, Bielefeld, Germany
| | - Fritz Trillmich
- Department of Animal Behaviour, University of Bielefeld, Bielefeld, Germany
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13
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Parker P, Maniscalco JM. A long-term study reveals multiple reproductive behavior strategies among territorial adult male Steller sea lions (Eumetopias jubatus). CAN J ZOOL 2014. [DOI: 10.1139/cjz-2013-0099] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We conducted a long-term study to assess how tenure and territorial behaviors influence reproductive success among male Steller sea lions (Eumetopias jubatus (Schreber, 1776)). Copulations by males (n = 44) that maintained territories on a rookery in the Gulf of Alaska from 2001 to 2009 were observed using a remote video system. Approximately half of postpartum females copulated with a male in a different territory from where they gave birth. Nearly two-thirds of territorial males with known tenure were unsuccessful in copulating during their first year. Number of copulations for territorial males increased from acquisition year to year 2 with no change in subsequent years. Cluster analysis of tenure and territorial tactic variables for 15 males with observed lifetime reproductive success was used to describe multiple reproductive strategies. Characteristics of the two most successful strategies were the following: (i) males typically copulated in their first year, retained the same territories for 3–5 years, and occupied centrally located coastal territories where the highest percentage of females gave birth and (ii) males did not copulate until at least their third year and occupied peripheral territories with fewer births for a longer tenure of 7–8 years. Results indicated that lifetime reproductive success was not achieved solely by time on the breeding area; rather, it was achieved from a combination of tenure and territorial tactics.
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Affiliation(s)
- Pamela Parker
- Alaska SeaLife Center, P.O. Box 1329, Seward, AK 99664, USA
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14
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Lenz TL, Mueller B, Trillmich F, Wolf JBW. Divergent allele advantage at MHC-DRB through direct and maternal genotypic effects and its consequences for allele pool composition and mating. Proc Biol Sci 2013; 280:20130714. [PMID: 23677346 DOI: 10.1098/rspb.2013.0714] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
It is still debated whether main individual fitness differences in natural populations can be attributed to genome-wide effects or to particular loci of outstanding functional importance such as the major histocompatibility complex (MHC). In a long-term monitoring project on Galápagos sea lions (Zalophus wollebaeki), we collected comprehensive fitness and mating data for a total of 506 individuals. Controlling for genome-wide inbreeding, we find strong associations between the MHC locus and nearly all fitness traits. The effect was mainly attributable to MHC sequence divergence and could be decomposed into contributions of own and maternal genotypes. In consequence, the population seems to have evolved a pool of highly divergent alleles conveying near-optimal MHC divergence even by random mating. Our results demonstrate that a single locus can significantly contribute to fitness in the wild and provide conclusive evidence for the 'divergent allele advantage' hypothesis, a special form of balancing selection with interesting evolutionary implications.
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Affiliation(s)
- Tobias L Lenz
- Department of Evolutionary Ecology, Max Planck Institute for Evolutionary Biology, 24306 Plön, Germany
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15
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Activity predicts male reproductive success in a polygynous lizard. PLoS One 2012; 7:e38856. [PMID: 22808016 PMCID: PMC3394749 DOI: 10.1371/journal.pone.0038856] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2012] [Accepted: 05/11/2012] [Indexed: 11/19/2022] Open
Abstract
Activity patterns and social interactions play a key role in determining reproductive success, although this is poorly understood for species that lack overt social behaviour. We used genetic paternity analysis to quantify both multiple paternity and the relative roles of activity and social behaviour in determining reproductive success in a nondescript Australian lizard. During the breeding season we intensively followed and recorded the behaviour of a group of seven males and 13 females in a naturalistic outdoor enclosure to examine the relative roles of body size, activity and social interactions in determining male fertilization success. We found multiple paternity in 42% of clutches. No single behaviour was a significant predictor of male fertilization success in isolation, but male-female association, interactions and courtship explained 41% of the variation in male fertilization success. Males with the highest number of offspring sired invested heavily in interacting with females but spent very little time in interactions with males. These same males also sired offspring from more clutches. When taken collectively, an index of overall male activity, including locomotion and all social interactions, significantly explained 81% of the variation in the total number of offspring sired and 90% of the variation in the number of clutches in which males sired offspring. We suggest that the most successful male strategy is a form of endurance rivalry in which active mate searching and interactions with females have the greatest fitness benefits.
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16
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Flatz R, González-Suárez M, Young JK, Hernández-Camacho CJ, Immel AJ, Gerber LR. Weak polygyny in California sea lions and the potential for alternative mating tactics. PLoS One 2012; 7:e33654. [PMID: 22432039 PMCID: PMC3303858 DOI: 10.1371/journal.pone.0033654] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2011] [Accepted: 02/17/2012] [Indexed: 11/21/2022] Open
Abstract
Female aggregation and male territoriality are considered to be hallmarks of polygynous mating systems. The development of genetic parentage assignment has called into question the accuracy of behavioral traits in predicting true mating systems. In this study we use 14 microsatellite markers to explore the mating system of one of the most behaviorally polygynous species, the California sea lion (Zalophus californianus). We sampled a total of 158 female-pup pairs and 99 territorial males across two breeding rookeries (San Jorge and Los Islotes) in the Gulf of California, Mexico. Fathers could be identified for 30% of pups sampled at San Jorge across three breeding seasons and 15% of sampled pups at Los Islotes across two breeding seasons. Analysis of paternal relatedness between the pups for which no fathers were identified (sampled over four breeding seasons at San Jorge and two at Los Islotes) revealed that few pups were likely to share a father. Thirty-one percent of the sampled males on San Jorge and 15% of the sampled males on Los Islotes were assigned at least one paternity. With one exception, no male was identified as the father of more than two pups. Furthermore, at Los Islotes rookery there were significantly fewer pups assigned paternity than expected given the pool of sampled males (p<0.0001). Overall, we found considerably lower variation in male reproductive success than expected in a species that exhibits behavior associated with strongly polygynous mating. Low variation in male reproductive success may result from heightened mobility among receptive females in the Gulf of California, which reduces the ability of males to monopolize groups of females. Our results raise important questions regarding the adaptive role of territoriality and the potential for alternative mating tactics in this species.
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Affiliation(s)
- Ramona Flatz
- School of Life Sciences, Arizona State University, Tempe, Arizona, United States of America.
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Gerber LR, González-Suárez M, Hernández-Camacho CJ, Young JK, Sabo JL. The cost of male aggression and polygyny in California sea lions (Zalophus californianus). PLoS One 2010; 5:e12230. [PMID: 20808931 PMCID: PMC2923196 DOI: 10.1371/journal.pone.0012230] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2010] [Accepted: 07/22/2010] [Indexed: 11/18/2022] Open
Abstract
In polygynous mating systems, males often increase their fecundity via aggressive defense of mates and/or resources necessary for successful mating. Here we show that both male and female reproductive behavior during the breeding season (June-August) affect female fecundity, a vital rate that is an important determinant of population growth rate and viability. By using 4 years of data on behavior and demography of California sea lions (Zalophus californianus), we found that male behavior and spatial dynamics--aggression and territory size--are significantly related to female fecundity. Higher rates of male aggression and larger territory sizes were associated with lower estimates of female fecundity within the same year. Female aggression was significantly and positively related to fecundity both within the same year as the behavior was measured and in the following year. These results indicate that while male aggression and defense of territories may increase male fecundity, such interactions may cause a reduction in the overall population growth rate by lowering female fecundity. Females may attempt to offset male-related reductions in female fecundity by increasing their own aggression-perhaps to defend pups from incidental injury or mortality. Thus in polygynous mating systems, male aggression may increase male fitness at the cost of female fitness and overall population viability.
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Affiliation(s)
- Leah R Gerber
- School of Life Sciences, Arizona State University, Tempe, Arizona, United States of America.
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