@article{d75009d770254d7b8dff7a19ea710ba6,
title = "Divergent water requirements partition exposure risk to parasites in wild equids",
abstract = "For grazing herbivores, dung density in feeding areas is an important determinant of exposure risk to fecal-orally transmitted parasites. When host species share the same parasite species, a nonrandom distribution of their cumulative dung density and/or nonrandom ranging and feeding behavior may skew exposure risk and the relative selection pressure parasites impose on each host. The arid-adapted Grevy's zebra (Equus grevyi) can range more widely than the water-dependent plains zebra (Equus quagga), with which it shares the same species of gastrointestinal nematodes. We studied how the spatial distribution of zebra dung relates to ranging and feeding behavior to assess parasite exposure risk in Grevy's and plains zebras at a site inhabited by both zebra species. We found that zebra dung density declined with distance from water, Grevy's zebra home ranges (excluding those of territorial males) were farther from water than those of plains zebras, and plains zebra grazing areas had higher dung density than random points while Grevy's zebra grazing areas did not, suggesting a greater exposure risk in plains zebras associated with their water dependence. Fecal egg counts increased with home range proximity to water for both species, but the response was stronger in plains zebras, indicating that this host species may be particularly vulnerable to the elevated exposure risk close to water. We further ran experiments on microclimatic effects on dung infectivity and showed that fewer nematode eggs embryonated in dung in the sun than in the shade. However, only 5% of the zebra dung on the landscape was in shade, indicating that the microclimatic effects of shade on the density of infective larvae is not a major influence on exposure risk dynamics. Ranging constraints based on water requirements appear to be key mediators of nematode parasite exposure in free-ranging equids.",
keywords = "Parasite exposure risk, equid parasitology, fecal egg counts, gastrointestinal nematodes, helminth transmission risk, zebra habitat use",
author = "Tombak, {Kaia J.} and Easterling, {Laurel A.} and Lindsay Martinez and Seng, {Monica S.} and Wait, {Liana F.} and Rubenstein, {Daniel I.}",
note = "Funding Information: We thank the Kenya Wildlife Service, the National Commission for Science, Technology, and Innovation of Kenya, and Mpala Research Centre for permission to conduct this work and for logistical support (NACOSTI permit no. P16708610679). We would like to thank Mpala Research Centre for hosting this research and providing generous support in logistics and facilities. Many thanks to our wonderful team of research staff, including Rosemary Warungu, Margaret Mwangi, Anthony Mwangi, Timothy Sisanya, and Josphat Mwangi. Special thanks to Emily Nonnamaker, Lily Reisinger, and Madison Spinelli for their hard work in the field and in the laboratory. This research was funded by the National Science Foundation (IBN-0309233, CNS-025214, IOB-9874523, IIS-0705822, IIS-0747369), the Princeton Environmental Institute, Princeton University, and by the Global Health Program, Office of Undergraduate Research, and the Department of Ecology and Evolutionary Biology of Princeton University. Funding Information: We thank the Kenya Wildlife Service, the National Commission for Science, Technology, and Innovation of Kenya, and Mpala Research Centre for permission to conduct this work and for logistical support (NACOSTI permit no. P16708610679). We would like to thank Mpala Research Centre for hosting this research and providing generous support in logistics and facilities. Many thanks to our wonderful team of research staff, including Rosemary Warungu, Margaret Mwangi, Anthony Mwangi, Timothy Sisanya, and Josphat Mwangi. Special thanks to Emily Nonnamaker, Lily Reisinger, and Madison Spinelli for their hard work in the field and in the laboratory. This research was funded by the National Science Foundation (IBN‐0309233, CNS‐025214, IOB‐9874523, IIS‐0705822, IIS‐0747369), the Princeton Environmental Institute, Princeton University, and by the Global Health Program, Office of Undergraduate Research, and the Department of Ecology and Evolutionary Biology of Princeton University. Publisher Copyright: {\textcopyright} 2022 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd.",
year = "2022",
month = mar,
doi = "10.1002/ece3.8693",
language = "English (US)",
volume = "12",
journal = "Ecology and Evolution",
issn = "2045-7758",
publisher = "John Wiley and Sons Ltd",
number = "3",
}