title: The importance of motivation, weapons, and foul odors in driving encounter competition in carnivores.
abstract: Encounter competition is interference competition in which animals directly contend for resources. Ecological theory predicts the trait that determines the resource holding potential (RHP), and hence the winner of encounter competition, is most often body size or mass. The difficulties of observing encounter competition in complex organisms in natural environments, however, has limited opportunities to test this theory across diverse species. We studied the outcome of encounter competition contests among mesocarnivores at deer carcasses in California to determine the most important variables for winning these contests. We found some support for current theory in that body mass is important in determining the winner of encounter competition, but we found that other factors including hunger and species-specific traits were also important. In particular, our top models were "strength and hunger" and "size and hunger," with models emphasizing the complexity of variables influencing outcomes of encounter competition. In addition, our wins above predicted (WAP) statistic suggests that an important aspect that determines the winner of encounter competition is species-specific advantages that increase their RHP, as bobcats (Lynx rufus) and spotted skunks (Spilogale gracilis) won more often than predicted based on mass. In complex organisms, such as mesocarnivores, species-specific adaptations, including strategic behaviors, aggressiveness, and weapons, contribute to competitive advantages and may allow certain species to take control or defend resources better than others. Our results help explain how interspecific competition shapes the occurrence patterns of species in ecological communities.
authors.affiliation: Center for Integrated Spatial Research, Environmental Studies Department, University of California, Santa Cruz, California, 95064, USA.|School of Biological Sciences, Victoria University of Wellington, PO Box 600, Wellington, 6140, New Zealand.|Department of Forest and Wildlife Ecology, University of Wisconsin, 1630 Linden Drive, Madison, Wisconsin, 53706, USA.
authors.forename: Maximilian L
authors.initials: ML
authors.lastname: Allen
authors.affiliation: Center for Integrated Spatial Research, Environmental Studies Department, University of California, Santa Cruz, California, 95064, USA.
authors.forename: Christopher C
authors.initials: CC
authors.lastname: Wilmers
authors.affiliation: Panthera Puma Program, Panthera, 18th Floor, 8 W 40th St, New York, New York, 10018, USA.
authors.forename: L Mark
authors.initials: LM
authors.lastname: Elbroch
authors.affiliation: College of Natural Resources, Utah State University, College of Natural Resources, Utah State University, 5200 Old Main Hill Logan, Utah, 84322, USA.
authors.forename: Julie M
authors.initials: JM
authors.lastname: Golla
authors.affiliation: School of Biological Sciences, Victoria University of Wellington, PO Box 600, Wellington, 6140, New Zealand.
authors.forename: Heiko U
authors.initials: HU
authors.lastname: Wittmer
mesh_terms: D000374:Aggression; D000818:Animals; D002140:California; D060435:Carnivory; D004463:Ecology; D009042:Motivation; D009812:Odorants; D011235:Predatory Behavior
keywords: California; carrion; encounter competition; foraging arenas; interference competition; interspecific interactions; mesocarnivore