title: Niche-specific cognitive strategies: object memory interferes with spatial memory in the predatory bat Myotis nattereri.
abstract: Related species with different diets are predicted to rely on different cognitive strategies: those best suited for locating available and appropriate foods. Here we tested two predictions of the niche-specific cognitive strategies hypothesis in bats, which suggests that predatory species should rely more on object memory than on spatial memory for finding food and that the opposite is true of frugivorous and nectivorous species. Specifically, we predicted that: (1) predatory bats would readily learn to associate shapes with palatable prey and (2) once bats had made such associations, these would interfere with their subsequent learning of a spatial memory task. We trained free-flying Myotis nattereri to approach palatable and unpalatable insect prey suspended below polystyrene objects. Experimentally naïve bats learned to associate different objects with palatable and unpalatable prey but performed no better than chance in a subsequent spatial memory experiment. Because experimental sequence was predicted to be of consequence, we introduced a second group of bats first to the spatial memory experiment. These bats learned to associate prey position with palatability. Control trials indicated that bats made their decisions based on information acquired through echolocation. Previous studies have shown that bat species that eat mainly nectar and fruit rely heavily on spatial memory, reflecting the relative consistency of distribution of fruit and nectar compared with insects. Our results support the niche-specific cognitive strategies hypothesis and suggest that for gleaning and clutter-resistant aerial hawking bats, learning to associate shape with food interferes with subsequent spatial memory learning.
authors.affiliation: Sound and Behaviour Group, Department of Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark khulgard@biology.sdu.dk j.ratcliffe@utoronto.ca.
authors.forename: Katrine
authors.initials: K
authors.lastname: Hulgard
authors.affiliation: Sound and Behaviour Group, Department of Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, ON M5S 3B2, Canada Department of Biology, University of Toronto Mississauga, 3359 Mississauga Road, Mississauga, ON L5L 1C6, Canada khulgard@biology.sdu.dk j.ratcliffe@utoronto.ca.
authors.forename: John M
authors.initials: JM
authors.lastname: Ratcliffe
mesh_terms: D000818:Animals; D002685:Chiroptera / Q000502:physiology*; D005260:Female; D008297:Male; D008568:Memory / Q000145:classification* / Q000502:physiology*; D011235:Predatory Behavior / Q000502:physiology*
keywords: Echolocation; Foraging behaviour; Object memory; Predatory bats; Spatial memory