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Mureb LS, Rocha-Santos L, Cassano CR, da Silva Lopes G, Rosa B, Miranda FR, Miranda CRR, Giné GAF. Tree diversity mediates individual diet specialization of the maned sloth (Bradypus torquatus). Mamm Biol 2023. [DOI: 10.1007/s42991-023-00348-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
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Hämäläinen A, Kiljunen M, Koskela E, Koteja P, Mappes T, Rajala M, Tiainen K. Artificial selection for predatory behaviour results in dietary niche differentiation in an omnivorous mammal. Proc Biol Sci 2022; 289:20212510. [PMID: 35259986 PMCID: PMC8905149 DOI: 10.1098/rspb.2021.2510] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The diet of an individual is a result of the availability of dietary items and the individual's foraging skills and preferences. Behavioural differences may thus influence diet variation, but the evolvability of diet choice through behavioural evolution has not been studied. We used experimental evolution combined with a field enclosure experiment to test whether behavioural selection leads to dietary divergence. We analysed the individual dietary niche via stable isotope ratios of nitrogen (δ15N) and carbon (δ13C) in the hair of an omnivorous mammal, the bank vole, from four lines selected for predatory behaviour and four unselected control lines. Predatory voles had higher hair δ15N values than control voles, supporting our hypothesis that predatory voles would consume a higher trophic level diet (more animal versus plant foods). This difference was significant in the early but not the late summer season. The δ13C values also indicated a seasonal change in the consumed plant matter and a difference in food sources among selection lines in the early summer. These results imply that environmental factors interact with evolved behavioural tendencies to determine dietary niche heterogeneity. Behavioural selection thus has potential to contribute to the evolution of diet choice and ultimately the species' ecological niche breadth.
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Affiliation(s)
- Anni Hämäläinen
- Institute of Environmental Sciences, Jagiellonian University, Cracow, Poland.,Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland
| | - Mikko Kiljunen
- Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland
| | - Esa Koskela
- Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland
| | - Pawel Koteja
- Institute of Environmental Sciences, Jagiellonian University, Cracow, Poland
| | - Tapio Mappes
- Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland
| | - Milla Rajala
- Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland
| | - Katariina Tiainen
- Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland
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Brewer CT, Rauch-Davis WA, Fraser EE. The Use of Intrinsic Markers for Studying the Migratory Movements of Bats. Animals (Basel) 2021; 11:3477. [PMID: 34944252 PMCID: PMC8698158 DOI: 10.3390/ani11123477] [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: 10/14/2021] [Revised: 11/26/2021] [Accepted: 12/01/2021] [Indexed: 11/30/2022] Open
Abstract
Mortality of migratory bat species at wind energy facilities is a well-documented phenomenon, and mitigation and management are partially constrained by the current limited knowledge of bat migratory movements. Analyses of biochemical signatures in bat tissues ("intrinsic markers") can provide information about the migratory origins of individual bats. Many tissue samples for intrinsic marker analysis may be collected from living and dead bats, including carcasses collected at wind energy facilities. In this paper, we review the full suite of available intrinsic marker analysis techniques that may be used to study bat migration, with the goal of summarizing the current literature and highlighting knowledge gaps and opportunities. We discuss applications of the stable isotopes of hydrogen, oxygen, nitrogen, carbon, sulfur; radiogenic strontium isotopes; trace elements and contaminants; and the combination of these markers with each other and with other extrinsic markers. We further discuss the tissue types that may be analyzed for each and provide a synthesis of the generalized workflow required to link bats to origins using intrinsic markers. While stable hydrogen isotope techniques have clearly been the leading approach to infer migratory bat movement patterns across the landscape, here we emphasize a variety of lesser used intrinsic markers (i.e., strontium, trace elements, contaminants) that may address new study areas or answer novel research questions.
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Affiliation(s)
| | | | - Erin E. Fraser
- School of Science and the Environment, Grenfell Campus, Memorial University of Newfoundland, 20 University Drive, Corner Brook, NL A2H 5G4, Canada; (C.T.B.); (W.A.R.-D.)
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Kerches-Rogeri P, Ramos DL, Siren J, de Oliveira Teles B, Alves RSC, Priante CF, Ribeiro MC, Araújo MS, Ovaskainen O. Movement syndromes of a Neotropical frugivorous bat inhabiting heterogeneous landscapes in Brazil. MOVEMENT ECOLOGY 2021; 9:35. [PMID: 34233767 PMCID: PMC8262009 DOI: 10.1186/s40462-021-00266-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Accepted: 05/28/2021] [Indexed: 06/13/2023]
Abstract
BACKGROUND There is growing evidence that individuals within populations can vary in both habitat use and movement behavior, but it is still not clear how these two relate to each other. The aim of this study was to test if and how individual bats in a Stunira lilium population differ in their movement activity and preferences for landscape features in a correlated manner. METHODS We collected data on movements of 27 individuals using radio telemetry. We fitted a heterogeneous-space diffusion model to the movement data in order to evaluate signals of movement variation among individuals. RESULTS S. lilium individuals generally preferred open habitat with Solanum fruits, regularly switched between forest and open areas, and showed high site fidelity. Movement variation among individuals could be summarized in four movement syndromes: (1) average individuals, (2) forest specialists, (3) explorers which prefer Piper, and (4) open area specialists which prefer Solanum and Cecropia. CONCLUSIONS Individual preferences for landscape features plus food resource and movement activity were correlated, resulting in different movement syndromes. Individual variation in preferences for landscape elements and food resources highlight the importance of incorporating explicitly the interaction between landscape structure and individual heterogeneity in descriptions of animal movement.
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Affiliation(s)
- Patricia Kerches-Rogeri
- Departamento de Biodiversidade, Universidade Estadual Paulista – UNESP, Avenida 24 A,1515, Rio Claro, São Paulo, Brazil
| | - Danielle Leal Ramos
- Departamento de Biodiversidade, Universidade Estadual Paulista – UNESP, Avenida 24 A,1515, Rio Claro, São Paulo, Brazil
| | - Jukka Siren
- Faculty of Biological and Environmental Sciences, University of Helsinki, P.O. Box 65, Viikinkaari 1, 00014 Helsinki, Finland
- Department of Computer Science, Aalto University, Espoo, Finland
| | - Beatriz de Oliveira Teles
- Departamento de Biodiversidade, Universidade Estadual Paulista – UNESP, Avenida 24 A,1515, Rio Claro, São Paulo, Brazil
| | - Rafael Souza Cruz Alves
- Departamento de Biodiversidade, Universidade Estadual Paulista – UNESP, Avenida 24 A,1515, Rio Claro, São Paulo, Brazil
| | - Camila Fátima Priante
- Departamento de Biodiversidade, Universidade Estadual Paulista – UNESP, Avenida 24 A,1515, Rio Claro, São Paulo, Brazil
| | - Milton Cezar Ribeiro
- Departamento de Biodiversidade, Universidade Estadual Paulista – UNESP, Avenida 24 A,1515, Rio Claro, São Paulo, Brazil
| | - Márcio Silva Araújo
- Departamento de Biodiversidade, Universidade Estadual Paulista – UNESP, Avenida 24 A,1515, Rio Claro, São Paulo, Brazil
| | - Otso Ovaskainen
- Faculty of Biological and Environmental Sciences, University of Helsinki, P.O. Box 65, Viikinkaari 1, 00014 Helsinki, Finland
- Centre for Biodiversity Dynamics, Department of Biology, Norwegian University of Science and Technology, N-7491 Trondheim, Norway
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Bachorec E, Horáček I, Hulva P, Konečný A, Lučan RK, Jedlička P, Shohdi WM, Řeřucha Š, Abi-Said M, Bartonička T. Spatial networks differ when food supply changes: Foraging strategy of Egyptian fruit bats. PLoS One 2020; 15:e0229110. [PMID: 32097434 PMCID: PMC7041839 DOI: 10.1371/journal.pone.0229110] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Accepted: 01/29/2020] [Indexed: 11/19/2022] Open
Abstract
Animals are faced with a range of ecological constraints that shape their behavioural decisions. Habitat features that affect resource abundance will also have an impact, especially as regards spatial distribution, which will in turn affect associations between the animals. Here we utilised a network approach, using spatial and genetic data, to describe patterns in use of space (foraging sites) by free-ranging Egyptian fruit bats (Rousettus aegyptiacus) at the Dakhla Oasis in Egypt. We observed a decrease in home range size during spring, when food availability was lowest, which was reflected by differences in space sharing networks. Our data showed that when food was abundant, space sharing networks were less connected and more related individuals shared more foraging sites. In comparison, when food was scarce the bats had few possibilities to decide where and with whom to forage. Overall, both networks had high mean degree, suggesting communal knowledge of predictable food distribution.
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Affiliation(s)
- Erik Bachorec
- Department of Botany and Zoology, Masaryk University, Kotlářská, Brno, Czech Republic
| | - Ivan Horáček
- Department of Zoology, Charles University in Prague, Viničná, Prague, Czech Republic
| | - Pavel Hulva
- Department of Zoology, Charles University in Prague, Viničná, Prague, Czech Republic
| | - Adam Konečný
- Department of Botany and Zoology, Masaryk University, Kotlářská, Brno, Czech Republic
| | - Radek K. Lučan
- Department of Zoology, Charles University in Prague, Viničná, Prague, Czech Republic
| | - Petr Jedlička
- Institute of Scientific Instruments of the Czech Academy of Sciences (ISI), Královopolská, Brno, Czech Republic
| | | | - Šimon Řeřucha
- Institute of Scientific Instruments of the Czech Academy of Sciences (ISI), Královopolská, Brno, Czech Republic
| | - Mounir Abi-Said
- Department of Earth and Life Sciences, Faculty of Sciences II, Lebanese University, Fanar, Lebanon
| | - Tomáš Bartonička
- Department of Botany and Zoology, Masaryk University, Kotlářská, Brno, Czech Republic
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Jacquier M, Simon L, Ruette S, Vandel JM, Hemery A, Devillard S. Isotopic evidence of individual specialization toward free-ranging chickens in a rural population of red foxes. EUR J WILDLIFE RES 2020. [DOI: 10.1007/s10344-019-1352-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Foraging strategies of individual silky pocket mice over a boom-bust cycle in a stochastic dryland ecosystem. Oecologia 2019; 190:569-578. [PMID: 31190119 DOI: 10.1007/s00442-019-04432-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2018] [Accepted: 06/07/2019] [Indexed: 01/19/2023]
Abstract
Small mammals use multiple foraging strategies to compensate for fluctuating resource quality in stochastic environments. These strategies may lead to increased dietary overlap when competition for resources is strong. To quantify temporal contributions of high (C3) versus low quality (C4) resources in diets of silky pocket mice (Perognathus flavus), we used stable carbon isotope (δ13C) analysis of 1391 plasma samples collected over 2 years. Of these, 695 samples were from 170 individuals sampled ≥ 3 times across seasons or years, allowing us to assess changes in dietary breadth at the population and individual levels across a boom-bust population cycle. In 2014, the P. flavus population increased to 412 captures compared to 8 captures in prior and subsequent years, while populations of co-occurring small mammals remained stable. As intraspecific competition increased, the population-wide dietary niche of P. flavus did not change, but individual specialization increased significantly. During this period, ~ 27% (41/151) of individuals sampled specialized on C3 resources, which were abundant during the spring and previous fall seasons. Most of the remaining individuals were C3-C4 generalists (64%) (96/151), and only 9% (14/151) specialized on C4 resources. In 2015, P. flavus population density and resource availability declined, individual dietary breadth expanded (84% generalists), no C3 specialists were found, and specialization on C4 resources increased (16%). Our results demonstrate a high degree of inter-individual plasticity in P. flavus foraging strategies, which has implications for how this species will respond to environmental change that is predicted to decrease C3 resources in the future.
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Zwolak R. How intraspecific variation in seed-dispersing animals matters for plants. Biol Rev Camb Philos Soc 2017; 93:897-913. [DOI: 10.1111/brv.12377] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Revised: 09/13/2017] [Accepted: 09/18/2017] [Indexed: 12/13/2022]
Affiliation(s)
- Rafał Zwolak
- Department of Systematic Zoology, Faculty of Biology; Adam Mickiewicz University, Umultowska 89; 61-614 Poznań Poland
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Marklund MHK, Svanbäck R, Zha Y, Scharnweber K, Eklöv P. The influence of habitat accessibility on the dietary and morphological specialisation of an aquatic predator. OIKOS 2017. [DOI: 10.1111/oik.04094] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Maria H. K. Marklund
- Dept of Ecology and Genetics; Evolutionary Biology Centre, Uppsala Univ., Norbyvägen 18d; SE-75236 Uppsala Sweden
- Water Research Centre and The Environment Institute, School of Biological Sciences, Univ. of Adelaide; North Terrace SA Australia
| | - Richard Svanbäck
- Dept of Ecology and Genetics; Evolutionary Biology Centre, Uppsala Univ., Norbyvägen 18d; SE-75236 Uppsala Sweden
| | - Yinghua Zha
- Dept of Ecology and Genetics; Evolutionary Biology Centre, Uppsala Univ., Norbyvägen 18d; SE-75236 Uppsala Sweden
| | - Kristin Scharnweber
- Dept of Ecology and Genetics; Evolutionary Biology Centre, Uppsala Univ., Norbyvägen 18d; SE-75236 Uppsala Sweden
| | - Peter Eklöv
- Dept of Ecology and Genetics; Evolutionary Biology Centre, Uppsala Univ., Norbyvägen 18d; SE-75236 Uppsala Sweden
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Dehnhard N, Eens M, Sturaro N, Lepoint G, Demongin L, Quillfeldt P, Poisbleau M. Is individual consistency in body mass and reproductive decisions linked to individual specialization in foraging behavior in a long-lived seabird? Ecol Evol 2016; 6:4488-501. [PMID: 27386091 PMCID: PMC4930996 DOI: 10.1002/ece3.2213] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Revised: 04/25/2016] [Accepted: 05/11/2016] [Indexed: 01/02/2023] Open
Abstract
Individual specialization in diet or foraging behavior within apparently generalist populations has been described for many species, especially in polar and temperate marine environments, where resource distribution is relatively predictable. It is unclear, however, whether and how increased environmental variability – and thus reduced predictability of resources – due to global climate change will affect individual specialization. We determined the within‐ and among‐individual components of the trophic niche and the within‐individual repeatability of δ13C and δ15N in feathers and red blood cells of individual female southern rockhopper penguins (Eudyptes chrysocome) across 7 years. We also investigated the effect of environmental variables (Southern Annular Mode, Southern Oscillation Index, and local sea surface temperature anomaly) on the isotopic values, as well as the link between stable isotopes and female body mass, clutch initiation dates, and total clutch mass. We observed consistent red blood cell δ13C and δ15N values within individuals among years, suggesting a moderate degree of within‐individual specialization in C and N during the prebreeding period. However, the total niche width was reduced and individual specialization not present during the premolt period. Despite significant interannual differences in isotope values of C and N and environmental conditions, none of the environmental variables were linked to stable isotope values and thus able to explain phenotypic plasticity. Furthermore, neither the within‐individual nor among‐individual effects of stable isotopes were found to be related to female body mass, clutch initiation date, or total clutch mass. In conclusion, our results emphasize that the degree of specialization within generalist populations can vary over the course of 1 year, even when being consistent within the same season across years. We were unable to confirm that environmental variability counteracts individual specialization in foraging behavior, as phenotypic plasticity in δ13C and δ15N was not linked to any of the environmental variables studied.
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Affiliation(s)
- Nina Dehnhard
- Department Biology - Behavioural Ecology & Ecophysiology Group University of Antwerp Campus Drie Eiken, Universiteitsplein 12610 Antwerp (Wilrijk) Belgium; Department of Migration and Immuno-Ecology Max Planck Institute for Ornithology Am Obstberg 178315 Radolfzell Germany; Department of Biology University of Konstanz 78457 Konstanz Germany
| | - Marcel Eens
- Department Biology - Behavioural Ecology & Ecophysiology Group University of Antwerp Campus Drie Eiken, Universiteitsplein 1 2610 Antwerp (Wilrijk) Belgium
| | - Nicolas Sturaro
- Laboratory of Oceanology MARE Centre University of Liège B6C, Sart Tilman 4000 Liège Belgium
| | - Gilles Lepoint
- Laboratory of Oceanology MARE Centre University of Liège B6C, Sart Tilman 4000 Liège Belgium
| | - Laurent Demongin
- Department Biology - Behavioural Ecology & Ecophysiology Group University of Antwerp Campus Drie Eiken, Universiteitsplein 12610 Antwerp (Wilrijk) Belgium; Department of Migration and Immuno-Ecology Max Planck Institute for Ornithology Am Obstberg 178315 Radolfzell Germany; Department of Biology University of Konstanz 78457 Konstanz Germany
| | - Petra Quillfeldt
- Department of Migration and Immuno-Ecology Max Planck Institute for Ornithology Am Obstberg 178315 Radolfzell Germany; Department of Biology University of Konstanz 78457 Konstanz Germany; Department of Animal Ecology & Systematics Justus-Liebig University Gießen Heinrich-Buff-Ring 38D-35392 Gießen Germany
| | - Maud Poisbleau
- Department Biology - Behavioural Ecology & Ecophysiology Group University of Antwerp Campus Drie Eiken, Universiteitsplein 12610 Antwerp (Wilrijk) Belgium; Department of Migration and Immuno-Ecology Max Planck Institute for Ornithology Am Obstberg 178315 Radolfzell Germany; Department of Biology University of Konstanz 78457 Konstanz Germany
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Reuter KE, Wills AR, Lee RW, Cordes EE, Sewall BJ. Using Stable Isotopes to Infer the Impacts of Habitat Change on the Diets and Vertical Stratification of Frugivorous Bats in Madagascar. PLoS One 2016; 11:e0153192. [PMID: 27097316 PMCID: PMC4838311 DOI: 10.1371/journal.pone.0153192] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Accepted: 03/24/2016] [Indexed: 11/18/2022] Open
Abstract
Human-modified habitats are expanding rapidly; many tropical countries have highly fragmented and degraded forests. Preserving biodiversity in these areas involves protecting species–like frugivorous bats–that are important to forest regeneration. Fruit bats provide critical ecosystem services including seed dispersal, but studies of how their diets are affected by habitat change have often been rather localized. This study used stable isotope analyses (δ15N and δ13C measurement) to examine how two fruit bat species in Madagascar, Pteropus rufus (n = 138) and Eidolon dupreanum (n = 52) are impacted by habitat change across a large spatial scale. Limited data for Rousettus madagascariensis are also presented. Our results indicated that the three species had broadly overlapping diets. Differences in diet were nonetheless detectable between P. rufus and E. dupreanum, and these diets shifted when they co-occurred, suggesting resource partitioning across habitats and vertical strata within the canopy to avoid competition. Changes in diet were correlated with a decrease in forest cover, though at a larger spatial scale in P. rufus than in E. dupreanum. These results suggest fruit bat species exhibit differing responses to habitat change, highlight the threats fruit bats face from habitat change, and clarify the spatial scales at which conservation efforts could be implemented.
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Affiliation(s)
- Kim E. Reuter
- Temple University, Department of Biology, Philadelphia, Pennsylvania, United States of America
- * E-mail:
| | - Abigail R. Wills
- Mpingo Conservation & Development Initiative, Kilwa Masoko, Tanzania
| | - Raymond W. Lee
- Washington State University, School of Biological Sciences, Pullman, Washington, United States of America
| | - Erik E. Cordes
- Temple University, Department of Biology, Philadelphia, Pennsylvania, United States of America
| | - Brent J. Sewall
- Temple University, Department of Biology, Philadelphia, Pennsylvania, United States of America
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12
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Lučan RK, Bartonička T, Jedlička P, Řeřucha Š, Šálek M, Čížek M, Nicolaou H, Horáček I. Spatial activity and feeding ecology of the endangered northern population of the Egyptian fruit bat (Rousettus aegyptiacus). J Mammal 2016. [DOI: 10.1093/jmammal/gyw014] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Yurkowski DJ, Ferguson S, Choy ES, Loseto LL, Brown TM, Muir DCG, Semeniuk CAD, Fisk AT. Latitudinal variation in ecological opportunity and intraspecific competition indicates differences in niche variability and diet specialization of Arctic marine predators. Ecol Evol 2016; 6:1666-78. [PMID: 26909143 PMCID: PMC4752956 DOI: 10.1002/ece3.1980] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Revised: 11/29/2015] [Accepted: 01/05/2016] [Indexed: 11/21/2022] Open
Abstract
Individual specialization (IS), where individuals within populations irrespective of age, sex, and body size are either specialized or generalized in terms of resource use, has implications on ecological niches and food web structure. Niche size and degree of IS of near‐top trophic‐level marine predators have been little studied in polar regions or with latitude. We quantified the large‐scale latitudinal variation of population‐ and individual‐level niche size and IS in ringed seals (Pusa hispida) and beluga whales (Delphinapterus leucas) using stable carbon and nitrogen isotope analysis on 379 paired ringed seal liver and muscle samples and 124 paired beluga skin and muscle samples from eight locations ranging from the low to high Arctic. We characterized both within‐ and between‐individual variation in predator niche size at each location as well as accounting for spatial differences in the isotopic ranges of potential prey. Total isotopic niche width (TINW) for populations of ringed seals and beluga decreased with increasing latitude. Higher TINW values were associated with greater ecological opportunity (i.e., prey diversity) in the prey fish community which mainly consists of Capelin (Mallotus villosus) and Sand lance (Ammodytes sp.) at lower latitudes and Arctic cod (Boreogadus saida) at high latitudes. In beluga, their dietary consistency between tissues also known as the within‐individual component (WIC) increased in a near 1:1 ratio with TINW (slope = 0.84), suggesting dietary generalization, whereas the slope (0.18) of WIC relative to TINW in ringed seals indicated a high degree of individual specialization in ringed seal populations with higher TINWs. Our findings highlight the differences in TINW and level of IS for ringed seals and beluga relative to latitude as a likely response to large‐scale spatial variation in ecological opportunity, suggesting species‐specific variation in dietary plasticity to spatial differences in prey resources and environmental conditions in a rapidly changing ecosystem.
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Affiliation(s)
- David J Yurkowski
- Great Lakes Institute for Environmental Research University of Windsor Windsor ON N9B 3P4 Canada
| | - Steve Ferguson
- Freshwater Institute Fisheries and Oceans Canada Winnipeg MB R3T 2N6 Canada
| | - Emily S Choy
- Department of Biological Sciences University of Manitoba Winning MB R3T 2N6 Canada
| | - Lisa L Loseto
- Freshwater Institute Fisheries and Oceans Canada Winnipeg MB R3T 2N6 Canada
| | - Tanya M Brown
- Department of Geography Memorial University of Newfoundland St. John's NF A1B 3X9 Canada
| | - Derek C G Muir
- Environment Canada Aquatic Ecosystem Protection Research Division Burlington ON L7R 4A6 Canada
| | - Christina A D Semeniuk
- Great Lakes Institute for Environmental Research University of Windsor Windsor ON N9B 3P4 Canada
| | - Aaron T Fisk
- Great Lakes Institute for Environmental Research University of Windsor Windsor ON N9B 3P4 Canada
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14
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Kernaléguen L, Cherel Y, Knox TC, Baylis AMM, Arnould JPY. Sexual Niche Segregation and Gender-Specific Individual Specialisation in a Highly Dimorphic Marine Mammal. PLoS One 2015; 10:e0133018. [PMID: 26244371 PMCID: PMC4526469 DOI: 10.1371/journal.pone.0133018] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Accepted: 06/22/2015] [Indexed: 11/18/2022] Open
Abstract
While sexual segregation is expected in highly dimorphic species, the local environment is a major factor driving the degree of resource partitioning within a population. Sexual and individual niche segregation was investigated in the Australian fur seal (Arctocephalus pusillus doriferus), which is a benthic foraging species restricted to the shallow continental shelf region of south-eastern Australia. Tracking data and the isotopic values of plasma, red blood cells and whiskers were combined to document spatial and dietary niche segregation throughout the year. Tracking data indicated that, in winter, males and females overlapped in their foraging habitat. All individuals stayed within central Bass Strait, relatively close (< 220 km) to the breeding colony. Accordingly, both genders exhibited similar plasma and red cell δ13C values. However, males exhibited greater δ13C intra-individual variation along the length of their whisker than females. This suggests that males exploited a greater diversity of foraging habitats throughout the year than their female counterparts, which are restricted in their foraging grounds by the need to regularly return to the breeding colony to suckle their pup. The degree of dietary sexual segregation was also surprisingly low, both sexes exhibiting a great overlap in their δ15N values. Yet, males displayed higher δ15N values than females, suggesting they fed upon a higher proportion of higher trophic level prey. Given that males and females exploit different resources (mainly foraging habitats), the degree of individual specialisation might differ between the sexes. Higher degrees of individual specialisation would be expected in males which exploit a greater range of resources. However, comparable levels of inter-individual variation in δ15N whisker values were found in the sampled males and females, and, surprisingly, all males exhibited similar seasonal and inter-annual variation in their δ13C whisker values, suggesting they all followed the same general dispersion pattern throughout the year.
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Affiliation(s)
- Laëtitia Kernaléguen
- School of Life and Environmental Sciences, Deakin University, Burwood, Victoria, Australia
- * E-mail:
| | - Yves Cherel
- Centre d'Etudes Biologiques de Chizé, UMR 7372 du CNRS-Université de La Rochelle, Villiers-en-Bois, France
| | - Travis C. Knox
- School of Life and Environmental Sciences, Deakin University, Burwood, Victoria, Australia
| | - Alastair M. M. Baylis
- School of Life and Environmental Sciences, Deakin University, Burwood, Victoria, Australia
- South Atlantic Environmental Research Institute, Stanley, FIQQ1ZZ, Falkland Islands
| | - John P. Y. Arnould
- School of Life and Environmental Sciences, Deakin University, Burwood, Victoria, Australia
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Abstract
The "niche variation hypothesis" (NVH) predicts that populations with wider niches should display higher among-individual variability. This prediction originally stated at the intra-specific level may be extended to the inter-specific level: individuals of generalist species may differ to a greater extent than individuals of a specialist species. We tested the NVH at intra- and inter-specific levels based on a large diet database of three large herbivore feces collected in the field and analyzed using DNA metabarcoding. The three herbivores (roe deer Capreolus capreolus, chamois Rupicapra rupicapra and mouflon Ovis musimon) are highly contrasted in terms of sociality (solitary to highly gregarious) and diet. The NVH at the intraspecific level was tested by relating, for the same population, diet breadth and inter-individual variation across the four seasons. Compared to null models, our data supported the NVH both at the intra- and inter-specific levels. Inter-individual variation of the diet of solitary species was not larger than in social species, although social individuals feed together and could therefore have more similar diets. Hence, the NVH better explained diet breadth than other factors such as sociality. The expansion of the population niche of the three species was driven by resource availability, and achieved by an increase in inter-individual variation, and the level of inter-individual variability was larger in the generalist species (mouflon) than in the specialist one (roe deer). This mechanism at the base of the NVH appears at play at different levels of biological organization, from populations to communities.
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16
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Kernaléguen L, Arnould JPY, Guinet C, Cherel Y. Determinants of individual foraging specialization in large marine vertebrates, the Antarctic and subantarctic fur seals. J Anim Ecol 2015; 84:1081-91. [PMID: 25649011 DOI: 10.1111/1365-2656.12347] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Accepted: 01/23/2015] [Indexed: 11/29/2022]
Abstract
The degree of individual specialization in resource use differs widely among wild populations where individuals range from fully generalized to highly specialized. This interindividual variation has profound implications in many ecological and evolutionary processes. A recent review proposed four main ecological causes of individual specialization: interspecific and intraspecific competition, ecological opportunity and predation. Using the isotopic signature of subsampled whiskers, we investigated to what degree three of these factors (interspecific and intraspecific competition and ecological opportunity) affect the population niche width and the level of individual foraging specialization in two fur seal species, the Antarctic and subantarctic fur seals (Arctocephalus gazella and Arctocephalus tropicalis), over several years. Population niche width was greater when the two seal species bred in allopatry (low interspecific competition) than in sympatry or when seals bred in high-density stabilized colonies (high intraspecific competition). In agreement with the niche variation hypothesis (NVH), higher population niche width was associated with higher interindividual niche variation. However, in contrast to the NVH, all Antarctic females increased their niche width during the interbreeding period when they had potential access to a wider diversity of foraging grounds and associated prey (high ecological opportunities), suggesting they all dispersed to a similar productive area. The degree of individual specialization varied among populations and within the annual cycle. Highest levels of interindividual variation were found in a context of lower interspecific or higher intraspecific competition. Contrasted results were found concerning the effect of ecological opportunity. Depending on seal species, females exhibited either a greater or lower degree of individual specialization during the interbreeding period, reflecting species-specific biological constraints during that period. These results suggest a significant impact of ecological interactions on the population niche width and degree of individual specialization. Such variation at the individual level may be an important factor in the species plasticity with significant consequences on how it may respond to environmental variability.
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Affiliation(s)
- Laëtitia Kernaléguen
- School of Life and Environmental Sciences, Deakin University, 221 Burwood Highway, 3125 Burwood, Vic., Australia.,Centre d'Etudes Biologiques de Chizé, UMR 7372 du CNRS-Université de La Rochelle, BP 14, 79360, Villiers-en-Bois, France
| | - John P Y Arnould
- School of Life and Environmental Sciences, Deakin University, 221 Burwood Highway, 3125 Burwood, Vic., Australia
| | - Christophe Guinet
- Centre d'Etudes Biologiques de Chizé, UMR 7372 du CNRS-Université de La Rochelle, BP 14, 79360, Villiers-en-Bois, France
| | - Yves Cherel
- Centre d'Etudes Biologiques de Chizé, UMR 7372 du CNRS-Université de La Rochelle, BP 14, 79360, Villiers-en-Bois, France
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17
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The interaction of intraspecific competition and habitat on individual diet specialization: a near range-wide examination of sea otters. Oecologia 2015; 178:45-59. [PMID: 25645269 DOI: 10.1007/s00442-015-3223-8] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2014] [Accepted: 12/15/2014] [Indexed: 10/24/2022]
Abstract
The quantification of individuality is a common research theme in the fields of population, community, and evolutionary ecology. The potential for individuality to arise is likely context-dependent, and the influence of habitat characteristics on its prevalence has received less attention than intraspecific competition. We examined individual diet specialization in 16 sea otter (Enhydra lutris) populations from southern California to the Aleutian Islands in Alaska. Because population histories, relative densities, and habitat characteristics vary widely among sites, we could examine the effects of intraspecific competition and habitat on the prevalence of individual diet specialization. Using observed diet data, we classified half of our sites as rocky substrate habitats and the other half containing a mixture of rocky and unconsolidated (soft) sediment substrates. We used stable isotope data to quantify population- and individual-level diet variation. Among rocky substrate sites, the slope [±standard error (SE)] of the positive significant relationship between the within-individual component (WIC) and total isotopic niche width (TINW) was shallow (0.23 ± 0.07) and negatively correlated with sea otter density. In contrast, the slope of the positive WIC/TINW relationship for populations inhabiting mixed substrate habitats was much higher (0.53 ± 0.14), suggesting a low degree of individuality, irrespective of intraspecific competition. Our results show that the potential for individuality to occur as a result of increasing intraspecific competition is context-dependent and that habitat characteristics, which ultimately influence prey diversity, relative abundance, and the range of skillsets required for efficient prey procurement, are important in determining when and where individual diet specialization occurs in nature.
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Lučan RK, Bartonička T, Benda P, Bilgin R, Jedlička P, Nicolaou H, Reiter A, Shohdi WM, Šálek M, Řeřucha Š, Uhrin M, Abi-Said M, Horáček I. Reproductive seasonality of the Egyptian fruit bat (Rousettus aegyptiacus) at the northern limits of its distribution. J Mammal 2014. [DOI: 10.1644/14-mamm-a-035] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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19
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Araújo MS, Costa-Pereira R. Latitudinal gradients in intraspecific ecological diversity. Biol Lett 2013; 9:20130778. [PMID: 24335269 DOI: 10.1098/rsbl.2013.0778] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The increase in the number of species with decreasing latitude is a striking pattern of global biodiversity. An important feature of studies of this pattern up to now has been the focus on species as the fundamental unit of interest, neglecting potential within-species ecological diversity. Here, we took a new perspective on this topic by measuring the degree to which individuals within populations differ in niche attributes across a latitudinal gradient (range: 54.01° S to 69.12° N). We show that 156 populations of 76 species across a wide range of vertebrate and invertebrate animal taxa contain more ecologically diverse assemblages of individuals towards lower latitudes. Our results add a new level of complexity to our understanding of global patterns of biodiversity and suggest the possibility that niche variation is partly responsible for the latitudinal gradients of species diversity.
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Affiliation(s)
- Márcio S Araújo
- Departamento de Ecologia, Universidade Estadual Paulista 'Julio de Mesquita Filho', , Rio Claro, São Paulo, Brazil
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20
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Abstract
Many generalist populations are composed of specialised individuals, whose niches are small subsets of the population niche. This 'individual specialisation' is a widespread phenomenon in natural populations, but until recently few studies quantified the magnitude of individual specialisation and how this magnitude varies among populations or contexts. Such quantitative approaches are necessary for us to understand how ecological interactions influence the amount of among-individual variation, and how the amount of variation might affect ecological dynamics. Herein, we review recent studies of individual specialisation, emphasising the novel insights arising from quantitative measures of diet variation. Experimental and comparative studies have confirmed long-standing theoretical expectations that the magnitude of among-individual diet variation depends on the level of intra and interspecific competition, ecological opportunity and predation. In contrast, there is little empirical information as to how individual specialisation affects community dynamics. We discuss some emerging methodological issues as guidelines for researchers studying individual specialisation, and make specific recommendations regarding avenues for future research.
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Affiliation(s)
- Márcio S Araújo
- Marine Sciences Program, Department of Biological Sciences, Florida International University, Miami, FL 33181, USA.
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Ramírez-Hernández G, Herrera M. LG. Nutritional importance of seeds and arthropods to painted spiny pocket mice (Lyomis pictus): the effects of season and forest degradation. CAN J ZOOL 2010. [DOI: 10.1139/z10-087] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Temporal and spatial fluctuations in food abundance may affect the feeding habits of vertebrates in tropical dry forests. We explored the effects of season and forest degradation in dietary patterns of the painted spiny pocket mouse ( Lyomis pictus (Thomas, 1893)) (Heteromyidae) in a Mexican tropical dry forest. We used carbon (13C, 12C) and nitrogen (15N, 14N) stable isotope analyses to test the hypotheses that (i) L. pictus would increase its use of arthropods during the rainy season when seeds are less available on the forest floor and (ii) that L. pictus would increase its use of arthropods in degraded forest compared with conserved forest. Our hypotheses were wrong because assimilated biomass was derived almost exclusively from seeds in both seasons and the importance of arthropods was marginal in both sites. Examination of food remains in feces and cheek pouches confirmed these trophic patterns. Seed hoarding during the season of high seed availability probably allows L. pictus to subsist on a seed-based diet throughout the year in conserved and disturbed forests. This behavioral trait would enable L. pictus to maintain its specialized feeding habit in environments threatened by habitat degradation.
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Affiliation(s)
- Gustavo Ramírez-Hernández
- Posgrado en Ciencias Biológicas, Instituto de Biología, Universidad Nacional Autónoma de México, México D.F. 04510, México
- Estación de Biología de Chamela, Instituto de Biología, Universidad Nacional Autónoma de México, Apartado Postal 21, San Patricio, Jalisco, 48980, México
| | - L. Gerardo Herrera M.
- Posgrado en Ciencias Biológicas, Instituto de Biología, Universidad Nacional Autónoma de México, México D.F. 04510, México
- Estación de Biología de Chamela, Instituto de Biología, Universidad Nacional Autónoma de México, Apartado Postal 21, San Patricio, Jalisco, 48980, México
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Voigt CC, Zubaid A, Kunz TH, Kingston T. Sources of Assimilated Proteins in Old and New World Phytophagous Bats. Biotropica 2010. [DOI: 10.1111/j.1744-7429.2010.00632.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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