title: Slime moulds use heuristics based on within-patch experience to decide when to leave.
abstract: Animals foraging in patchy, non-renewing or slowly renewing environments must make decisions about how long to remain within a patch. Organisms can use heuristics ('rules of thumb') based on available information to decide when to leave the patch. Here, we investigated proximate patch-departure heuristics in two species of giant, brainless amoeba: the slime moulds Didymium bahiense and Physarum polycephalum. We explicitly tested the importance of information obtained through experience by eliminating chemosensory cues of patch quality. In P. polycephalum, patch departure was influenced by the consumption of high, and to a much lesser extent low, quality food items such that engulfing a food item increased patch-residency time. Physarum polycephalum also tended to forage for longer in darkened, 'safe' patches. In D. bahiense, engulfment of any food item increased patch residency irrespective of that food item's quality. Exposure to light had no effect on the patch-residency time of D. bahiense. Given that these organisms lack a brain, our results illustrate how the use of simple heuristics can give the impression that individuals make sophisticated foraging decisions.
authors.affiliation: Department of Plant and Food Science, Faculty of Agriculture and the Environment, University of Sydney, Sydney, NSW 2015, Australia tanya.latty@sydney.edu.au.
authors.forename: Tanya
authors.initials: T
authors.lastname: Latty
authors.affiliation: Behaviour and Genetics of Social Insects Lab, Centre for Mathematical Biology, School of Biological Sciences A12, University of Sydney, Sydney, NSW 2006, Australia.
authors.forename: Madeleine
authors.initials: M
authors.lastname: Beekman
mesh_terms: D000818:Animals; D005247:Feeding Behavior; D000066506:Heuristics; D008027:Light; D009068:Movement; D009235:Myxomycetes / Q000502:physiology; D016839:Physarum polycephalum / Q000502:physiology*; D013045:Species Specificity
keywords: Decision making; Foraging; Protist; Rules of thumb; Sampling; Unicellular