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Pereszlényi Á, Száz D, Jánosi IM, Horváth G. A new argument against cooling by convective air eddies formed above sunlit zebra stripes. Sci Rep 2021; 11:15797. [PMID: 34349136 PMCID: PMC8339008 DOI: 10.1038/s41598-021-95105-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Accepted: 07/15/2021] [Indexed: 11/22/2022] Open
Abstract
There is a long-lasting debate about the possible functions of zebra stripes. According to one hypothesis, periodical convective air eddies form over sunlit zebra stripes which cool the body. However, the formation of such eddies has not been experimentally studied. Using schlieren imaging in the laboratory, we found: downwelling air streams do not form above the white stripes of light-heated smooth or hairy striped surfaces. The influence of stripes on the air stream formation (facilitating upwelling streams and hindering horizontal stream drift) is negligible higher than 1–2 cm above the surface. In calm weather, upwelling air streams might form above sunlit zebra stripes, however they are blown off by the weakest wind, or even by the slowest movement of the zebra. These results forcefully contradict the thermoregulation hypothesis involving air eddies.
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Affiliation(s)
- Ádám Pereszlényi
- Department of Biological Physics, ELTE Eötvös Loránd University, Pázmány sétány 1, 1117, Budapest, Hungary.,Deutsches Meeresmuseum, Katharinenberg 14-20, 18437, Stralsund, Germany
| | - Dénes Száz
- Department of Biological Physics, ELTE Eötvös Loránd University, Pázmány sétány 1, 1117, Budapest, Hungary.,Department of Physics, ELTE Eötvös Loránd University, BDPK, 9700, Szombathely, Hungary
| | - Imre M Jánosi
- Department of Water and Environmental Policy, University of Public Service, Ludovika tér 1, 1083, Budapest, Hungary.,Max Planck Institute for Physics of Complex Systems, Nöthnitzer Strasse 38, 01187, Dresden, Germany
| | - Gábor Horváth
- Department of Biological Physics, ELTE Eötvös Loránd University, Pázmány sétány 1, 1117, Budapest, Hungary.
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Larison B, Kaelin CB, Harrigan R, Henegar C, Rubenstein DI, Kamath P, Aschenborn O, Smith TB, Barsh GS. Population structure, inbreeding and stripe pattern abnormalities in plains zebras. Mol Ecol 2020; 30:379-390. [PMID: 33174253 DOI: 10.1111/mec.15728] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 10/23/2020] [Accepted: 10/30/2020] [Indexed: 01/14/2023]
Abstract
One of the most iconic wild equids, the plains zebra occupies a broad region of sub-Saharan Africa and exhibits a wide range of phenotypic diversity in stripe patterns that have been used to classify multiple subspecies. After decades of relative stability, albeit with a loss of at least one recognized subspecies, the total population of plains zebras has undergone an approximate 25% decline since 2002. Individuals with abnormal stripe patterns have been recognized in recent years but the extent to which their appearance is related to demography and/or genetics is unclear. Investigating population genetic health and genetic structure are essential for developing effective strategies for plains zebra conservation. We collected DNA from 140 plains zebra, including seven with abnormal stripe patterns, from nine locations across the range of plains zebra, and analyzed data from restriction site-associated and whole genome sequencing (RAD-seq, WGS) libraries to better understand the relationships between population structure, genetic diversity, inbreeding, and abnormal phenotypes. We found that genetic structure did not coincide with described subspecific variation, but did distinguish geographic regions in which anthropogenic habitat fragmentation is associated with reduced gene flow and increased evidence of inbreeding, especially in certain parts of East Africa. Further, zebras with abnormal striping exhibited increased levels of inbreeding relative to normally striped individuals from the same populations. Our results point to a genetic cause of stripe pattern abnormalities, and dramatic evidence of the consequences of habitat fragmentation.
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Affiliation(s)
- Brenda Larison
- Department of Ecology and Evolutionary Biology, UCLA, Los Angeles, CA, USA.,Center for Tropical Research, Institute of the Environment and Sustainability, UCLA, Los Angeles, CA, USA
| | - Christopher B Kaelin
- HudsonAlpha Institute for Biotechnology, Huntsville, AL, USA.,Department of Genetics, Stanford University, Stanford, CA, USA
| | - Ryan Harrigan
- Department of Ecology and Evolutionary Biology, UCLA, Los Angeles, CA, USA.,Center for Tropical Research, Institute of the Environment and Sustainability, UCLA, Los Angeles, CA, USA
| | | | - Daniel I Rubenstein
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA
| | - Pauline Kamath
- School of Food and Agriculture, University of Maine, Orono, ME, USA
| | - Ortwin Aschenborn
- School of Veterinary Medicine, University of Namibia, Neudamm Windhoek, Namibia
| | - Thomas B Smith
- Department of Ecology and Evolutionary Biology, UCLA, Los Angeles, CA, USA.,Center for Tropical Research, Institute of the Environment and Sustainability, UCLA, Los Angeles, CA, USA
| | - Gregory S Barsh
- HudsonAlpha Institute for Biotechnology, Huntsville, AL, USA.,Department of Genetics, Stanford University, Stanford, CA, USA
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