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Gangoso L, Viana DS, Merchán M, Figuerola J. A new trophic specialization buffers a top predator against climate-driven resource instability. Behav Ecol 2024; 35:arae005. [PMID: 38287939 PMCID: PMC10824164 DOI: 10.1093/beheco/arae005] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 12/22/2023] [Accepted: 01/15/2024] [Indexed: 01/31/2024] Open
Abstract
Intraspecific phenotypic variability is key to respond to environmental changes and anomalies. However, documenting the emergence of behavioral diversification in natural populations has remained elusive due to the difficulty of observing such a phenomenon at the right time and place. Here, we investigated how the emergence of a new trophic strategy in a population subjected to high fluctuations in the availability of its main trophic resource (migrating songbirds) affected the breeding performance, population structure, and population fitness of a specialized color polymorphic predator, the Eleonora's falcon from the Canary Islands. Using long-term data (2007-2022), we found that the exploitation of an alternative prey (a local petrel species) was associated with the growth of a previously residual falcon colony. Pairs in this colony laid earlier and raised more fledglings than in the other established colonies. The specialization on petrels increased over time, independently of annual fluctuations in prey availability. Importantly, however, the positive effect of petrel consumption on productivity was stronger in years with lower food availability. This trophic diversification was further associated with the genetically determined color morph, with dark individuals preying more frequently on petrels than pale ones, which might promote the long-term maintenance of genotypic and phenotypic diversity. We empirically demonstrate how the emergence of an alternative trophic strategy can buffer populations against harsh environmental fluctuations by stabilizing their productivity.
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Affiliation(s)
- Laura Gangoso
- Department of Biodiversity, Ecology and Evolution, Faculty of Biological Sciences, Complutense University of Madrid, C/Antonio Novais 12, 28040, Madrid, Spain
| | - Duarte S Viana
- Estación Biológica de Doñana, CSIC, C/Américo Vespucio 26, 41092, Sevilla, Spain
| | - Marina Merchán
- Estación Biológica de Doñana, CSIC, C/Américo Vespucio 26, 41092, Sevilla, Spain
| | - Jordi Figuerola
- Estación Biológica de Doñana, CSIC, C/Américo Vespucio 26, 41092, Sevilla, Spain
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Avilés JM, Cruz-Miralles Á, Parejo D. Colour-specific diet specialization is associated with differences in owlet weight in a polymorphic owl: influence of the trophic quality variation. Oecologia 2023; 203:181-191. [PMID: 37815597 PMCID: PMC10615958 DOI: 10.1007/s00442-023-05460-4] [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: 03/23/2023] [Accepted: 09/25/2023] [Indexed: 10/11/2023]
Abstract
The niche divergence hypothesis proposes that the evolution and maintenance of colour polymorphism is based on a mechanism of disruptive selection. In a trophic context, the hypothesis predicts that individuals differing in colour vary in their trophic niche, either because they differ in foraging efficiency or feed in different habitats. A major evolutionary conundrum is how these expectations are affected by variation in trophic quality. Using an owl species with colour plumage polymorphism, the Eurasian scops owl Otus scops, we examined diet and habitat segregation during reproduction in relation to plumage colouration and trophic quality. Intensive sampling revealed that trophic quality for scops owls (i.e. abundance of grasshoppers and locusts) varied more among territories than between years, but scops owls did not segregate among territories of different quality by their colouration. However, we found that sex, plumage colouration and territory differences in trophic quality explained differences in the degree of dietary specialization. Brownish males delivered a higher diversity of prey to the nest than greyish ones in high trophic quality territories. We also found that the more diverse the diet provided by males, the heavier the owlets at fledging. Our study provides evidence for a different sensitivity to trophic quality of the colour morphs with potential fitness consequences in scops owls. We highlight the importance of studying the mechanisms leading to the persistence of colour polymorphism in patchy environments, since segregation may pass otherwise unnoticed if only habitats or years with similar conditions are considered.
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Affiliation(s)
- Jesús Miguel Avilés
- Departamento de Ecología Funcional y Evolutiva, EEZA-CSIC, La Cañada de San Urbano, Almería, Spain.
- Unidad Asociada (CSIC): Ecología en el Antropoceno, Facultad de Ciencias, Universidad de Extremadura, Badajoz, Spain.
| | - Ángel Cruz-Miralles
- Departamento de Anatomía, Biología Celular y Zoología, Facultad de Ciencias, Universidad de Extremadura, Badajoz, Spain
| | - Deseada Parejo
- Departamento de Ecología Funcional y Evolutiva, EEZA-CSIC, La Cañada de San Urbano, Almería, Spain
- Unidad Asociada (CSIC): Ecología en el Antropoceno, Facultad de Ciencias, Universidad de Extremadura, Badajoz, Spain
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Avilés JM, Cruz-Miralles Á, Parejo D. Moonlight influence on quality of nestlings of scops owls depends on paternal coloration. Behav Ecol 2021. [DOI: 10.1093/beheco/arab139] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Abstract
Lunar phases might favor the maintenance of color polymorphism via disruptive selection if the different color variants performed differently in terms of prey capture under different moonlight levels. Moonlight, however, may affect prey capture as a side effect of its influence on prey behavior. Here we combine data of parental provisioning and quality of owlets with one ex-situ study of grasshopper activity to test whether Eurasian scops owls (Otus scops) with different plumage color and their prey are differently affected by moonlight. Food provisioning increased from new- to full-moon. However, the effect of moonlight on owlet mass gain and immune response depended on paternal coloration. On the one hand, body mass gain of nestlings of the greyest fathers increased from nights with new- to full-moon, whereas it did not change with moonlight for the brownest fathers. On the other hand, PHA response of nestlings of the brownest fathers increased with high moonlight levels during the first week of life, whereas it did not change with moonlight levels for the greyest fathers. Grasshoppers were more active at new moon than at full or waning moon. Our study provides supporting evidence that moonlight influences the behavior of both scops owls and its prey and suggests that fluctuations in environmental conditions can modulate the advantages of morphs. These results are important because they provide a general insight into a little appreciated mechanism for the maintenance of color polymorphism in natural populations based on the interactive effect of different environmental factors.
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Affiliation(s)
- Jesús M Avilés
- Departamento de Ecología Funcional y Evolutiva, EEZA-CSIC, La Cañada de San Urbano, Almería E-04001, España
- Unidad Asociada (UNEX-CSIC): Ecología en el Antropoceno, Facultad de Ciencias, Universidad de Extremadura, Badajoz E-06006, España
| | - Ángel Cruz-Miralles
- Departamento de Anatomía, Biología Celular y Zoología, Facultad de Ciencias, Universidad de Extremadura, Badajoz E-04001, España
| | - Deseada Parejo
- Departamento de Ecología Funcional y Evolutiva, EEZA-CSIC, La Cañada de San Urbano, Almería E-04001, España
- Departamento de Anatomía, Biología Celular y Zoología, Facultad de Ciencias, Universidad de Extremadura, Badajoz E-04001, España
- Unidad Asociada (UNEX-CSIC): Ecología en el Antropoceno, Facultad de Ciencias, Universidad de Extremadura, Badajoz E-06006, España
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Nebel C, Sumasgutner P, Rodseth E, Ingle RA, Childs DZ, Curtis‐Scott O, Amar A. Multigenerational pedigree analysis of wild individually marked black sparrowhawks suggests that dark plumage coloration is a dominant autosomal trait. J Zool (1987) 2021. [DOI: 10.1111/jzo.12913] [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]
Affiliation(s)
- C. Nebel
- FitzPatrick Institute of African Ornithology DSI‐NRF Centre of Excellence University of Cape Town Cape Town South Africa
- Department of Biology University of Turku Turku Finland
| | - P. Sumasgutner
- FitzPatrick Institute of African Ornithology DSI‐NRF Centre of Excellence University of Cape Town Cape Town South Africa
- Department of Behavioral & Cognitive Biology Konrad Lorenz Research Centre (KLF) Core Facility for Behaviour and Cognition University of Vienna Vienna Austria
| | - E. Rodseth
- Department of Molecular and Cell Biology University of Cape Town Cape Town South Africa
| | - R. A. Ingle
- Department of Molecular and Cell Biology University of Cape Town Cape Town South Africa
| | - D. Z. Childs
- School of Biosciences University of Sheffield Sheffield UK
| | - O. Curtis‐Scott
- Department of Biological Sciences University of Cape Town Cape Town South Africa
| | - A. Amar
- FitzPatrick Institute of African Ornithology DSI‐NRF Centre of Excellence University of Cape Town Cape Town South Africa
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Abstract
Natural habitats are rapidly declining due to urbanisation, with a concomitant decline in biodiversity in highly urbanised areas. Yet thousands of different species have colonised urban environments. These organisms are exposed to novel urban conditions, which are sometimes beneficial, but most often challenging, such as increased ambient temperature, chemicals, noise and light pollution, dietary alterations and disturbance by humans. Given the fundamental role of physiological responses in coping with such conditions, certain physiological systems such as the redox system, metabolism and hormones are thought to specifically influence organisms' ability to persist and cope with urbanisation. However, these physiological systems often show mixed responses to urbanisation. Does this mean that some individuals, populations or species are resilient to the urban environmental challenges? Or is something missing from our analyses, leading us to erroneous conclusions regarding the impact of urbanisation? To understand the impact of urbanisation, I argue that a more integrated mechanistic and ecological approach is needed, along with experiments, in order to fully understand the physiological responses; without knowledge of their ecological and evolutionary context, physiological measures alone can be misinterpreted. Furthermore, we need to further investigate the causes of and capacity for individual plasticity in order to understand not only the impact of urbanisation, but also species resilience. I argue that abiotic and biotic urban factors can interact (e.g. pollution with micro- and macronutrients) to either constrain or relax individual physiological responses - and, thereby, plasticity - on a temporal and/or spatial scale, which can lead to erroneous conclusions regarding the impact of urbanisation.
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Nebel C, Sumasgutner P, McPherson SC, Tate GJ, Amar A. Contrasting parental color morphs increase regularity of prey deliveries in an African raptor. Behav Ecol 2020. [DOI: 10.1093/beheco/araa063] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Abstract
Disassortative mating in color-polymorphic raptors is a proposed mechanism for the maintenance of color polymorphism in populations. Selection for such a mating system may occur if there are fitness advantages of mating with a contrasting morph. In the black sparrowhawk (Accipiter melanoleucus), mixed-morph pairs may have a selective advantage because they produce offspring that have higher survival rates. Two hypotheses, which may explain the mechanism, are the “avoidance-image” and “complementarity” hypotheses. The first suggests that, within a predator’s territory, prey develop a search image for the more commonly encountered parental morph, for example, the male morph during incubation and brooding. Females of a contrasting morph to their partner would then have higher capture rates once they commence hunting in the later nestling phase. Thus, the “avoidance-image” hypothesis predicts higher provisioning rates for mixed-morph pairs. Alternatively, the “complementarity” hypothesis posits that different color morphs exploit different environmental conditions, allowing mixed-morph pairs to hunt under a wider range of conditions and predicts that food is delivered more consistently. We test these hypotheses using nest cameras to record prey delivery rates during the late nestling phase when both parents are hunting. We found support for the “complementarity” hypothesis, with mixed-morph pairs delivering food more consistently but not at a higher rate. This higher consistency in prey deliveries may explain the improved survival of the offspring of mixed-morph pairs and could, therefore, play a role in maintaining the stability of color polymorphism in this system.
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Affiliation(s)
- Carina Nebel
- FitzPatrick Institute of African Ornithology, DST-NRF Centre of Excellence, University of Cape Town, Private Bag X3, John Day Building, 7700 Rondebosch, Cape Town, Western Cape, South Africa
| | - Petra Sumasgutner
- FitzPatrick Institute of African Ornithology, DST-NRF Centre of Excellence, University of Cape Town, Private Bag X3, John Day Building, 7700 Rondebosch, Cape Town, Western Cape, South Africa
- Konrad Lorenz Research Centre, Core Facility for Behaviour and Cognition, University of Vienna, Fischerau 11, 4645 Grünau/Almtal, Austria
| | - Shane C McPherson
- FitzPatrick Institute of African Ornithology, DST-NRF Centre of Excellence, University of Cape Town, Private Bag X3, John Day Building, 7700 Rondebosch, Cape Town, Western Cape, South Africa
- Konrad Lorenz Research Centre, Core Facility for Behaviour and Cognition, University of Vienna, Fischerau 11, 4645 Grünau/Almtal, Austria
| | - Gareth J Tate
- FitzPatrick Institute of African Ornithology, DST-NRF Centre of Excellence, University of Cape Town, Private Bag X3, John Day Building, 7700 Rondebosch, Cape Town, Western Cape, South Africa
- Endangered Wildlife Trust, Birds of Prey Programme, Glen Austin AH, Midrand, 1685 Gauteng, South Africa
| | - Arjun Amar
- FitzPatrick Institute of African Ornithology, DST-NRF Centre of Excellence, University of Cape Town, Private Bag X3, John Day Building, 7700 Rondebosch, Cape Town, Western Cape, South Africa
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Nebel C, Sumasgutner P, Pajot A, Amar A. Response time of an avian prey to a simulated hawk attack is slower in darker conditions, but is independent of hawk colour morph. ROYAL SOCIETY OPEN SCIENCE 2019; 6:190677. [PMID: 31598248 PMCID: PMC6731706 DOI: 10.1098/rsos.190677] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Accepted: 07/08/2019] [Indexed: 06/10/2023]
Abstract
To avoid predation, many species rely on vision to detect predators and initiate an escape response. The ability to detect predators may be lower in darker light conditions or with darker backgrounds. For birds, however, this has never been experimentally tested. We test the hypothesis that the response time of avian prey (feral pigeon Columbia livia f. domestica) to a simulated hawk attack (taxidermy mounted colour-polymorphic black sparrowhawk Accipiter melanoleucus) will differ depending on light levels or background colour. We predict that response will be slower under darker conditions, which would translate into higher predation risk. The speed of response of prey in relation to light level or background colour may also interact with the colour of the predator, and this idea underpins a key hypothesis proposed for the maintenance of different colour morphs in polymorphic raptors. We therefore test whether the speed of reaction is influenced by the morph of the hawk (dark/light) in combination with light conditions (dull/bright), or background colours (black/white). We predict slowest responses to morphs under conditions that less contrast with the plumage of the hawk (e.g. light morph under bright light or white background). In support of our first hypothesis, pigeons reacted slower under duller light and with a black background. However, we found no support for the second hypothesis, with response times observed between the hawk-morphs being irrespective of light levels or background colour. Our findings experimentally confirm that birds detect avian predators less efficiently under darker conditions. These conditions, for example, might occur during early mornings or in dense forests, which could lead to changes in anti-predator behaviours. However, our results provide no support that different morphs may be maintained in a population due to differential selective advantages linked to improved hunting efficiencies in different conditions due to crypsis.
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Affiliation(s)
- Carina Nebel
- FitzPatrick Institute of African Ornithology, DST-NRF Centre of Excellence, University of Cape Town, Private Bag X3, Rondebosch, 7701 Cape Town, South Africa
| | - Petra Sumasgutner
- FitzPatrick Institute of African Ornithology, DST-NRF Centre of Excellence, University of Cape Town, Private Bag X3, Rondebosch, 7701 Cape Town, South Africa
| | - Adrien Pajot
- FitzPatrick Institute of African Ornithology, DST-NRF Centre of Excellence, University of Cape Town, Private Bag X3, Rondebosch, 7701 Cape Town, South Africa
- Bordeaux Sciences Agro, 1 Cours du Général de Gaulle, 33170 Gradignan, France
| | - Arjun Amar
- FitzPatrick Institute of African Ornithology, DST-NRF Centre of Excellence, University of Cape Town, Private Bag X3, Rondebosch, 7701 Cape Town, South Africa
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Amar A, Reynolds C, Van Velden J, Briggs CW. Clinal variation in morph frequency in Swainson’s hawk across North America: no support for Gloger’s ecogeographical rule. Biol J Linn Soc Lond 2019. [DOI: 10.1093/biolinnean/blz037] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- Arjun Amar
- Fitzpatrick Institute of African Ornithology, DST-NRF Centre of Excellence, University of Cape Town, Rondebosch, South Africa
| | - Chevonne Reynolds
- Fitzpatrick Institute of African Ornithology, DST-NRF Centre of Excellence, University of Cape Town, Rondebosch, South Africa
- Animal, Plant and Environmental Sciences, University of the Witwatersrand, Braamfontein, South Africa
| | - Julia Van Velden
- Fitzpatrick Institute of African Ornithology, DST-NRF Centre of Excellence, University of Cape Town, Rondebosch, South Africa
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Bosch J, Mestre J, Baiges C, Martínez JE, Calvo JF, Jiménez‐Franco MV. Colour plumage polymorphism in the Booted Eagle: inheritance pattern and temporal stability of the morph frequencies. J Zool (1987) 2019. [DOI: 10.1111/jzo.12666] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- J. Bosch
- Cra. de Navarcles 43, Santpedor Barcelona Spain
| | - J. Mestre
- Departament de Territori i Sostenibilitat Parc Natural dels Ports Tarragona Spain
| | - C. Baiges
- Departament de Territori i Sostenibilitat Parc Natural dels Ports Tarragona Spain
| | - J. E. Martínez
- Departamento de Ecología e Hidrología Universidad de Murcia Murcia Spain
- Bonelli′s Eagle Study and Conservation Group Murcia Spain
| | - J. F. Calvo
- Departamento de Ecología e Hidrología Universidad de Murcia Murcia Spain
| | - M. V. Jiménez‐Franco
- Departamento de Biología Aplicada Universidad Miguel Hernández Elche, Alicante Spain
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