title: Hoarding without reward: rodent responses to repeated episodes of complete cache loss.
abstract: For food-hoarding strategies to be maintained in a population, the benefits of hoarding must outweigh the costs. If rewards are too low to offset the costs of hoarding, hoarders might be expected to abandon hoarding and/or shift to an alternative storing strategy (e.g., increase food consumption). However the ability to adjust to such circumstances requires that animals anticipate long-term rewards and adjust storing strategies to modify future outcomes. To test this, we subjected three sympatric food-hoarding species (the Korean field mouse, Apodemus peninsulae, both a scatter and larder hoarder; the Chinese white-bellied rat, Niviventer confucianus, only a larder hoarder; and Père David's rock squirrel, Sciurotamias davidianus, predominantly a scatter hoarder) to repeated episodes of complete cache loss over nine sequential trials in semi-natural enclosures. Although these species increased harvest and consumption rates throughout the experiment, none of these three species ceased hoarding under these conditions. The variation in responses observed across species and gender suggest some degree of behavioural plasticity to compensate for such extreme losses, but a general inability to abandon hoarding or shift to an alternative strategy. Future studies should consider how such responses correspond to natural patterns of intensive pilferage in the field.
authors.affiliation: Molecular and Behavioural Research Group, School of Life Sciences, Central China Normal University, 152 Luoyu Av., Wuhan 430079, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Luo
authors.affiliation: Molecular and Behavioural Research Group, School of Life Sciences, Central China Normal University, 152 Luoyu Av., Wuhan 430079, China.
authors.forename: Zheng
authors.initials: Z
authors.lastname: Yang
authors.affiliation: Department of Biology, Wilkes University, Wilkes-Barre, PA 18766, USA.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Steele
authors.affiliation: State Key Laboratory of Integrated Management of Pest Insects and Rodents in Agriculture, Institute of Zoology, The Chinese Academy of Sciences, Beijing 100101, China.
authors.forename: Zhibin
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Department of Biology, Wilkes University, Wilkes-Barre, PA 18766, USA.
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Stratford
authors.affiliation: Molecular and Behavioural Research Group, School of Life Sciences, Central China Normal University, 152 Luoyu Av., Wuhan 430079, China. Electronic address: hongmaozhang@gmail.com.
authors.forename: Hongmao
authors.initials: H
authors.lastname: Zhang
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000502:physiology*; D005247:Feeding Behavior / Q000502:physiology; D005260:Female; D005502:Food; D008297:Male; D051379:Mice; D051381:Rats; D012201:Reward; D012377:Rodentia / Q000502:physiology*; D012589:Sciuridae; D061350:Sympatry
keywords: Apodemus peninsulae; Cache pilferage; Compensation hypothesis; Food hoarding; Niviventer confucianus; Sciurotamias davidianus