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Sumasgutner P, Nilles T, Hykollari A, de Chapa MM, Isaksson C, Hochleitner L, Renner S, Fusani L. Integument colouration and circulating carotenoids in relation to urbanisation in Eurasian kestrels (Falco tinnunculus). Naturwissenschaften 2023; 110:48. [PMID: 37736824 PMCID: PMC10516791 DOI: 10.1007/s00114-023-01874-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Revised: 09/03/2023] [Accepted: 09/04/2023] [Indexed: 09/23/2023]
Abstract
Urbanisation is one of the biggest environmental challenges of our time, yet we still lack an integrative understanding of how cities affect behaviour, physiology and parasite susceptibility of free-living organisms. In this study, we focus on carotenoids, strictly dietary micronutrients that can either be used as yellow-red pigments, for integument colouration (signalling function), or as antioxidants, to strengthen the immune system (physiological function) in an urban predator, the Eurasian kestrel (Falco tinnunculus). Kestrels are specialised vole hunters but shift to avian prey in cities where diurnal rodents are not sufficiently available. This different foraging strategy might determine the quantity of carotenoids available. We measured integument colouration, circulating carotenoids in the blood and ectoparasite burden in kestrels along an urban gradient. Our results showed that nestlings that were raised in more urbanised areas displayed, unrelated to their ectoparasite burden, a paler integument colouration. Paler colours were furthermore associated with a lower concentration of circulating carotenoids. These findings support the hypothesis that the entire urban food web is carotenoid deprived and only prey of low quality with low carotenoid content is available (e.g. fewer carotenoids in urban trees, insects, small birds and finally kestrels). The alternative hypothesis that nestlings allocate carotenoids to reduce physiological stress and/or to cope with parasites rather than invest into colouration could not be supported. Our study adds to existing evidence that urban stressors negatively affect carotenoid production in urban areas, a deficiency that dissipate into higher trophic levels.
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Affiliation(s)
- Petra Sumasgutner
- Konrad Lorenz Research Center, Core Facility for Behavior and Cognition, University of Vienna, Grünau/Almtal, Vienna, Austria.
- Department of Behavioral and Cognitive Biology, University of Vienna, Vienna, Austria.
- Natural History Museum Vienna, Vienna, Austria.
| | - Tom Nilles
- Konrad Lorenz Research Center, Core Facility for Behavior and Cognition, University of Vienna, Grünau/Almtal, Vienna, Austria
- Department of Behavioral and Cognitive Biology, University of Vienna, Vienna, Austria
- Natural History Museum Vienna, Vienna, Austria
| | - Alba Hykollari
- Research Institute of Wildlife Ecology, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Manuela Merling de Chapa
- Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany
- Hessian Agency for Nature, Environment and Geology, Biodiversity Center, Giessen, Germany
| | | | - Lukas Hochleitner
- Natural History Museum Vienna, Vienna, Austria
- Research Institute of Wildlife Ecology, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Swen Renner
- Natural History Museum Vienna, Vienna, Austria
| | - Leonida Fusani
- Department of Behavioral and Cognitive Biology, University of Vienna, Vienna, Austria
- Konrad Lorenz Institute of Ethology, University of Veterinary Medicine, Vienna, Austria
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