1
|
Schalcher K, Milliet E, Séchaud R, Bühler R, Almasi B, Potier S, Becciu P, Roulin A, Shepard ELC. Landing force reveals new form of motion-induced sound camouflage in a wild predator. eLife 2024; 12:RP87775. [PMID: 39046781 PMCID: PMC11268889 DOI: 10.7554/elife.87775] [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] [Indexed: 07/25/2024] Open
Abstract
Predator-prey arms races have led to the evolution of finely tuned disguise strategies. While the theoretical benefits of predator camouflage are well established, no study has yet been able to quantify its consequences for hunting success in natural conditions. We used high-resolution movement data to quantify how barn owls (Tyto alba) conceal their approach when using a sit-and-wait strategy. We hypothesized that hunting barn owls would modulate their landing force, potentially reducing noise levels in the vicinity of prey. Analysing 87,957 landings by 163 individuals equipped with GPS tags and accelerometers, we show that barn owls reduce their landing force as they approach their prey, and that landing force predicts the success of the following hunting attempt. Landing force also varied with the substrate, being lowest on man-made poles in field boundaries. The physical environment, therefore, affects the capacity for sound camouflage, providing an unexpected link between predator-prey interactions and land use. Finally, hunting strike forces in barn owls were the highest recorded in any bird, relative to body mass, highlighting the range of selective pressures that act on landings and the capacity of these predators to modulate their landing force. Overall, our results provide the first measurements of landing force in a wild setting, revealing a new form of motion-induced sound camouflage and its link to hunting success.
Collapse
Affiliation(s)
- Kim Schalcher
- Department of Ecology and Evolution, University of LausanneLausanneSwitzerland
| | - Estelle Milliet
- Department of Ecology and Evolution, University of LausanneLausanneSwitzerland
| | - Robin Séchaud
- Department of Ecology and Evolution, University of LausanneLausanneSwitzerland
- Agroecology and Environment, AgroscopeZurichSwitzerland
| | - Roman Bühler
- Swiss Ornithological InstituteSempachSwitzerland
| | | | - Simon Potier
- Department of Biology, Lund UniversityLundSweden
- Les Ailes de l’UrgaMarcilly-la-CampagneFrance
| | - Paolo Becciu
- Department of Ecology and Evolution, University of LausanneLausanneSwitzerland
| | - Alexandre Roulin
- Department of Ecology and Evolution, University of LausanneLausanneSwitzerland
| | - Emily LC Shepard
- Department of Biosciences, Swansea UniversitySwanseaUnited Kingdom
| |
Collapse
|
2
|
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.
Collapse
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
| |
Collapse
|
3
|
Sabal MC, Workman ML, Merz JE, Palkovacs EP. Shade affects magnitude and tactics of juvenile Chinook salmon antipredator behavior in the migration corridor. Oecologia 2021; 197:89-100. [PMID: 34355272 PMCID: PMC8445879 DOI: 10.1007/s00442-021-05008-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 08/01/2021] [Indexed: 11/26/2022]
Abstract
Environmental conditions strongly affect antipredator behaviors; however, it is less known how migrating prey adjust antipredator behavior in migration corridors, in part, because active migrants are difficult to observe and study. Migrants are vulnerable and encounter many predators in the corridor, and their propensity to travel towards their destination ties antipredator behavior with movement. We evaluated how environmental risk cues in the migration corridor including in-water habitat structure (present, absent) and overhead shade (sun, shade), and salmon origin (hatchery, wild) affected how juvenile Chinook salmon (Oncorhynchus tshawytscha) reacted to a live predator. We measured how salmon react to predation risk as the difference in time to swim downstream through a 9.1-m long field enclosure with or without a live predatory largemouth bass (Micropterus salmoides). Shade significantly modified the reaction to the predator, and it did so in two ways. First, the magnitude of antipredator behavior was larger in shade compared to direct sun, which suggests salmon perceived shade to be a riskier environment than sun. Second, the escape tactic also varied; salmon slowed down to be cautious in shade and sped up in sun. Structure did not significantly affect behavior and hatchery and wild salmon behaved similarly. Our study suggests that environmental risk cues can shape the magnitude and tactics of how migrants react to predation risk and illustrates how these responses relate to movement with potential to scale up and affect migration patterns.
Collapse
Affiliation(s)
- Megan C Sabal
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, 130 McAllister Way, Santa Cruz, CA, 95060, USA.
| | - Michelle L Workman
- East Bay Municipal Utility District, 1 Winemaster Way, Lodi, CA, 95240, USA
| | - Joseph E Merz
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, 130 McAllister Way, Santa Cruz, CA, 95060, USA
- Cramer Fish Sciences, 3300 Industrial Blvd #100, West Sacramento, CA, 95691, USA
| | - Eric P Palkovacs
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, 130 McAllister Way, Santa Cruz, CA, 95060, USA
| |
Collapse
|
4
|
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.
Collapse
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
| |
Collapse
|
5
|
Nebel C, Harl J, Pajot A, Weissenböck H, Amar A, Sumasgutner P. High prevalence and genetic diversity of Haemoproteus columbae (Haemosporida: Haemoproteidae) in feral pigeons Columba livia in Cape Town, South Africa. Parasitol Res 2020; 119:447-463. [PMID: 31883048 PMCID: PMC6985069 DOI: 10.1007/s00436-019-06558-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Accepted: 11/19/2019] [Indexed: 02/08/2023]
Abstract
In this study, we explore blood parasite prevalence, infection intensity, and co-infection levels in an urban population of feral pigeons Columba livia in Cape Town. We analyze the effect of blood parasites on host body condition and the association between melanin expression in the host's plumage and parasite infection intensity and co-infection levels. Relating to the haemosporidian parasite itself, we study their genetic diversity by means of DNA barcoding (cytochrome b) and show the geographic and host distribution of related parasite lineages in pigeons worldwide. Blood from 195 C. livia individuals was collected from April to June 2018. Morphometric measurements and plumage melanism were recorded from every captured bird. Haemosporidian prevalence and infection intensity were determined by screening blood smears and parasite lineages by DNA sequencing. Prevalence of Haemoproteus spp. was high at 96.9%. The body condition of the hosts was negatively associated with infection intensity. However, infection intensity was unrelated to plumage melanism. The cytochrome b sequences revealed the presence of four Haemoproteus lineages in our population of pigeons, which show high levels of co-occurrence within individual birds. Three lineages (HAECOL1, COLIV03, COQUI05) belong to Haemoproteus columbae and differ only by 0.1% to 0.8% in the cytochrome b gene. Another lineage (COLIV06) differs by 8.3% from the latter ones and is not linked to a morphospecies, yet. No parasites of the genera Leucocytozoon and Plasmodium were detected.
Collapse
Affiliation(s)
- Carina Nebel
- FitzPatrick Institute of African Ornithology, DST-NRF Centre of Excellence, University of Cape Town, Cape Town, South Africa
| | - Josef Harl
- Institute of Pathology, University of Veterinary Medicine, Vienna, Austria
| | - Adrien Pajot
- FitzPatrick Institute of African Ornithology, DST-NRF Centre of Excellence, University of Cape Town, Cape Town, South Africa
- Bordeaux Sciences Agro, 1 Cours du Général de Gaulle, Gradignan, France
| | | | - Arjun Amar
- FitzPatrick Institute of African Ornithology, DST-NRF Centre of Excellence, University of Cape Town, Cape Town, South Africa
| | - Petra Sumasgutner
- FitzPatrick Institute of African Ornithology, DST-NRF Centre of Excellence, University of Cape Town, Cape Town, South Africa
- Konrad Lorenz Forschungsstelle, Core Facility for Behaviour and Cognition, University of Vienna, Vienna, Austria
| |
Collapse
|