title: Energetic costs of mange in wolves estimated from infrared thermography.
abstract: Parasites, by definition, extract energy from their hosts and thus affect trophic and food web dynamics even when the parasite may have limited effects on host population size. We studied the energetic costs of mange (Sarcoptes scabiei) in wolves (Canis lupus) using thermal cameras to estimate heat losses associated with compromised insulation during the winter. We combined the field data of known, naturally infected wolves with a data set on captive wolves with shaved patches of fur as a positive control to simulate mange-induced hair loss. We predict that during the winter in Montana, more severe mange infection increases heat loss by around 5.2-12 MJ per night (1,240-2,850 kcal, or a 65-78% increase) for small and large wolves, respectively, accounting for wind effects. To maintain body temperature would require a significant proportion of a healthy wolf's total daily energy demands (18-22 MJ/day). We also predict how these thermal costs may increase in colder climates by comparing our predictions in Bozeman, Montana to those from a place with lower ambient temperatures (Fairbanks, Alaska). Contrary to our expectations, the 14°C differential between these regions was not as important as the potential differences in wind speed. These large increases in energetic demands can be mitigated by either increasing consumption rates or decreasing other energy demands. Data from GPS-collared wolves indicated that healthy wolves move, on average, 17 km per day, which was reduced by 1.5, 1.8, and 6.5 km for light, medium, and severe hair loss. In addition, the wolf with the most hair loss was less active at night and more active during the day, which is the converse of the movement patterns of healthy wolves. At the individual level, mange infections create significant energy demands and altered behavioral patterns, this may have cascading effects on prey consumption rates, food web dynamics, predator-prey interactions, and scavenger communities.
authors.affiliation: U.S. Geological Survey, Northern Rocky Mountain Science Center, 2327 University Way, Suite 2, Bozeman, Montana, 59715, USA.
authors.forename: P C
authors.initials: PC
authors.lastname: Cross
authors.affiliation: U.S. Geological Survey, Northern Rocky Mountain Science Center, 2327 University Way, Suite 2, Bozeman, Montana, 59715, USA.|Department of Biology, Center for Infectious Disease Dynamics, The Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, Pennsylvania, USA.
authors.forename: E S
authors.initials: ES
authors.lastname: Almberg
authors.affiliation: School of Natural Resources and Environment, University of Florida, Gainesville, Florida, 32611, USA.
authors.forename: C G
authors.initials: CG
authors.lastname: Haase
authors.affiliation: Department of Biology, Center for Infectious Disease Dynamics, The Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, Pennsylvania, USA.
authors.forename: P J
authors.initials: PJ
authors.lastname: Hudson
authors.affiliation: School of Anatomy, Physiology, and Human Biology, University of Western Australia, Crawley, Western Australia, 6009, Australia.
authors.forename: S K
authors.initials: SK
authors.lastname: Maloney
authors.affiliation: Yellowstone Wolf Project, Yellowstone National Park, Wyoming, USA.
authors.forename: M C
authors.initials: MC
authors.lastname: Metz
authors.affiliation: School of Biological Sciences, University of Wollongong, Northfields Avenue, Wollongong, New South Wales, 2522, Australia.
authors.forename: A J
authors.initials: AJ
authors.lastname: Munn
authors.affiliation: NWB Sensors, Inc., Bozeman, Montana, USA.
authors.forename: P
authors.initials: P
authors.lastname: Nugent
authors.affiliation: Chemical and Biological Engineering Department, Montana State University, Bozeman, Montana, 59717, USA.
authors.forename: O
authors.initials: O
authors.lastname: Putzeys
authors.affiliation: Yellowstone Wolf Project, Yellowstone National Park, Wyoming, USA.
authors.forename: D R
authors.initials: DR
authors.lastname: Stahler
authors.affiliation: Wyoming Game and Fish Department, Pinedale, Wyoming, 82941, USA.
authors.forename: A C
authors.initials: AC
authors.lastname: Stewart
authors.affiliation: Yellowstone Wolf Project, Yellowstone National Park, Wyoming, USA.
authors.forename: D W
authors.initials: DW
authors.lastname: Smith
mesh_terms: D000413:Alaska; D000818:Animals; D004463:Ecology; D004784:Environmental Monitoring / Q000379:methods*; D008924:Mite Infestations / Q000453:epidemiology*; D009009:Montana; D011235:Predatory Behavior; D013817:Thermography / Q000379:methods*; D019596:Wolves / Q000469:parasitology*
keywords: energy; metabolic costs; parasitism; trophic dynamics