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Author Ratcliffe, J.M.; Fenton, M.B.; Shettleworth, S.J.
Title Behavioral flexibility positively correlated with relative brain volume in predatory bats Type (up) Journal Article
Year 2006 Publication Brain, behavior and evolution Abbreviated Journal Brain Behav Evol
Volume 67 Issue 3 Pages 165-176
Keywords Adaptation, Psychological; Animals; Behavior, Animal/*physiology; Brain/*anatomy & histology/physiology; Chiroptera/*anatomy & histology/*physiology; Organ Size; Predatory Behavior/*physiology
Abstract We investigated the potential relationships between foraging strategies and relative brain and brain region volumes in predatory (animal-eating) echolocating bats. The species we considered represent the ancestral state for the order and approximately 70% of living bat species. The two dominant foraging strategies used by echolocating predatory bats are substrate-gleaning (taking prey from surfaces) and aerial hawking (taking airborne prey). We used species-specific behavioral, morphological, and ecological data to classify each of 59 predatory species as one of the following: (1) ground gleaning, (2) behaviorally flexible (i.e., known to both glean and hawk prey), (3) clutter tolerant aerial hawking, or (4) open-space aerial hawking. In analyses using both species level data and phylogenetically independent contrasts, relative brain size was larger in behaviorally flexible species. Further, relative neocortex volume was significantly reduced in bats that aerially hawk prey primarily in open spaces. Conversely, our foraging behavior index did not account for variability in hippocampus and inferior colliculus volume and we discuss these results in the context of past research.
Address Department of Zoology, University of Toronto, Toronto, Canada. jmr247@cornell.edu
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ISSN 0006-8977 ISBN Medium
Area Expedition Conference
Notes PMID:16415571 Approved no
Call Number refbase @ user @ Serial 358
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Author Skov-Rackette, S.I.; Shettleworth, S.J.
Title What do rats learn about the geometry of object arrays? Tests with exploratory behavior Type (up) Journal Article
Year 2005 Publication Journal of experimental psychology. Animal behavior processes Abbreviated Journal J Exp Psychol Anim Behav Process
Volume 31 Issue 2 Pages 142-154
Keywords Animals; Behavior, Animal; *Discrimination Learning; *Exploratory Behavior; Female; *Form Perception; Habituation, Psychophysiologic; Male; Rats; Rats, Long-Evans
Abstract Six experiments using habituation of exploratory behavior tested whether disoriented rats foraging in a large arena encode the shapes of arrays of objects. Rats did not respond to changes in position of a single object, but they responded to a change in object color and to a change in position of 1 object in a square array, as in previous research (e.g., C. Thinus-Blanc et al., 1987). Rats also responded to an expansion of a square array, suggesting that they encoded sets of interobject distances rather than overall shape. In Experiments 4-6, rats did not respond to changes in sense of a triangular array that maintained interobject distances and angles. Shapes of object arrays are encoded differently from shapes of enclosures.
Address Department of Psychology, University of Toronto, Toronto, ON M5S 3G3, Canada. shannon.skov.rackette@utoronto.ca
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Series Volume Series Issue Edition
ISSN 0097-7403 ISBN Medium
Area Expedition Conference
Notes PMID:15839772 Approved no
Call Number refbase @ user @ Serial 363
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Author Shettleworth, S.J.; Sutton, J.E.
Title Multiple systems for spatial learning: dead reckoning and beacon homing in rats Type (up) Journal Article
Year 2005 Publication Journal of experimental psychology. Animal behavior processes Abbreviated Journal J Exp Psychol Anim Behav Process
Volume 31 Issue 2 Pages 125-141
Keywords Animals; Behavior, Animal; Cues; *Feeding Behavior; Habituation, Psychophysiologic; *Homing Behavior; *Learning; Male; Rats; Rats, Long-Evans; *Space Perception
Abstract Rats homed with food in a large lighted arena. Without visual cues, they used dead reckoning. When a beacon indicated the home, rats could also use the beacon. Homing did not differ in 2 groups of rats, 1 provided with the beacon and 1 without it; tests without the beacon gave no evidence that beacon learning overshadowed dead reckoning (Experiment 1). When the beacon was at the home for 1 group and in random locations for another, there was again no evidence of cue competition (Experiment 2). Dead reckoning experience did not block acquisition of beacon homing (Experiment 3). Beacon learning and dead reckoning do not compete for predictive value but acquire information in parallel and are used hierarchically.
Address Department of Psychology, University of Toronto, Toronto, ON M5S 3G3, Canada. shettle@psych.utoronto.ca
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Series Volume Series Issue Edition
ISSN 0097-7403 ISBN Medium
Area Expedition Conference
Notes PMID:15839771 Approved no
Call Number refbase @ user @ Serial 364
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Author Gibson, B.M.; Shettleworth, S.J.
Title Competition among spatial cues in a naturalistic food-carrying task Type (up) Journal Article
Year 2003 Publication Learning & behavior : a Psychonomic Society publication Abbreviated Journal Learn Behav
Volume 31 Issue 2 Pages 143-159
Keywords Adaptation, Psychological; Animals; Appetitive Behavior; *Association Learning; *Attention; Choice Behavior; *Cues; *Discrimination Learning; Male; Rats; Rats, Long-Evans; Space Perception; *Spatial Behavior
Abstract Rats collected nuts from a container in a large arena in four experiments testing how learning about a beacon or cue at a goal interacts with learning about other spatial cues (place learning). Place learning was quick, with little evidence of competition from the beacon (Experiments 1 and 2). Rats trained to approach a beacon regardless of its location were subsequently impaired when the well-learned beacon was removed and other spatial cues identified the location of the goal (Experiment 3). The competition between beacon and place cues reflected learned irrelevance for place cues (Experiment 4). The findings differ from those of some studies of associative interactions between cue and place learning in other paradigms.
Address University of Toronto, Toronto, Ontario, Canada
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ISSN 1543-4494 ISBN Medium
Area Expedition Conference
Notes PMID:12882373 Approved no
Call Number refbase @ user @ Serial 368
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Author Nevin, J.A.; Shettleworth, S.J.
Title An analysis of contrast effects in multiple schedules Type (up) Journal Article
Year 1966 Publication Journal of the experimental analysis of behavior Abbreviated Journal J Exp Anal Behav
Volume 9 Issue 4 Pages 305-315
Keywords Animals; Birds; *Conditioning (Psychology); Conditioning, Operant; Discrimination Learning; *Extinction, Psychological; Male; Reaction Time; *Reinforcement (Psychology)
Abstract
Address
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Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0022-5002 ISBN Medium
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Notes PMID:5961499 Approved no
Call Number refbase @ user @ Serial 392
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Author Cameron, E.Z.
Title Facultative adjustment of mammalian sex ratios in support of the Trivers-Willard hypothesis: evidence for a mechanism Type (up) Journal Article
Year 2004 Publication Proceedings. Biological sciences / The Royal Society Abbreviated Journal Proc Biol Sci
Volume 271 Issue 1549 Pages 1723-1728
Keywords Age Factors; Animals; Body Constitution; *Evolution; Female; Glucose/metabolism/physiology; Litter Size; Male; Mammals/*physiology; *Models, Biological; Reproduction/physiology; Seasons; Sex Factors; *Sex Ratio; Time Factors
Abstract Evolutionary theory predicts that mothers of different condition should adjust the birth sex ratio of their offspring in relation to future reproductive benefits. Published studies addressing variation in mammalian sex ratios have produced surprisingly contradictory results. Explaining the source of such variation has been a challenge for sex-ratio theory, not least because no mechanism for sex-ratio adjustment is known. I conducted a meta-analysis of previous mammalian sex-ratio studies to determine if there are any overall patterns in sex-ratio variation. The contradictory nature of previous results was confirmed. However, studies that investigated indices of condition around conception show almost unanimous support for the prediction that mothers in good condition bias their litters towards sons. Recent research on the role of glucose in reproductive functioning have shown that excess glucose favours the development of male blastocysts, providing a potential mechanism for sex-ratio variation in relation to maternal condition around conception. Furthermore, many of the conflicting results from studies on sex-ratio adjustment would be explained if glucose levels in utero during early cell division contributed to the determination of offspring sex ratios.
Address Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Pretoria 0002, South Africa. ezcameron@zoology.up.ac.za
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ISSN 0962-8452 ISBN Medium
Area Expedition Conference
Notes PMID:15306293 Approved no
Call Number refbase @ user @ Serial 413
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Author Broom, M.
Title A unified model of dominance hierarchy formation and maintenance Type (up) Journal Article
Year 2002 Publication Journal of theoretical biology Abbreviated Journal J. Theor. Biol.
Volume 219 Issue 1 Pages 63-72
Keywords Animals; *Behavior, Animal; Feeding Behavior; *Models, Psychological; *Social Dominance; Social Environment
Abstract In many different species it is common for animals to spend large portions of their lives in groups. Such groups need to divide available resources amongst the individuals they contain and this is often achieved by means of a dominance hierarchy. Sometimes hierarchies are stable over a long period of time and new individuals slot into pre-determined positions, but there are many situations where this is not so and a hierarchy is formed out of a group of individuals meeting for the first time. There are several different models both of the formation of such dominance hierarchies and of already existing hierarchies. These models often treat the two phases as entirely separate, whereas in reality, if there is a genuine formation phase to the hierarchy, behaviour in this phase will be governed by the rewards available, which in turn depends upon how the hierarchy operates once it has been formed. This paper describes a method of unifying models of these two distinct phases, assuming that the hierarchy formed is stable. In particular a framework is introduced which allows a variety of different models of each of the two parts to be used in conjunction with each other, thus enabling a wide range of situations to be modelled. Some examples are given to show how this works in practice.
Address Centre for Statistics and Stochastic Modelling, School of Mathematical Sciences, University of Sussex, Falmer, Brighton, BN1 9QH, U.K. m.broom@sussex.ac.uk
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ISSN 0022-5193 ISBN Medium
Area Expedition Conference
Notes PMID:12392975 Approved no
Call Number refbase @ user @ Serial 439
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Author Hemelrijk, C.K.; Wantia, J.
Title Individual variation by self-organisation Type (up) Journal Article
Year 2005 Publication Neuroscience and biobehavioral reviews Abbreviated Journal Neurosci Biobehav Rev
Volume 29 Issue 1 Pages 125-136
Keywords Aggression; Animals; Behavior, Animal/*physiology; Competitive Behavior/*physiology; Female; Humans; *Individuality; Male; Models, Psychological; Sex Characteristics; *Social Dominance; Time Factors
Abstract In this paper, we show that differences in dominance and spatial centrality of individuals in a group may arise through self-organisation. Our instrument is a model, called DomWorld, that represents two traits that are often found in animals, namely grouping and competing. In this model individual differences grow under the following conditions: (1) when the intensity of aggression increases and grouping becomes denser, (2) when the degree of sexual dimorphism in fighting power increases. In this case the differences among females compared to males grow too, (3) when, upon encountering another individual, the tendency to attack is 'obligate' and not conditional, namely 'sensitive to risks'. Results resemble phenomena described for societies of primates, mice, birds and pigs.
Address Theoretical Biology, University of Groningen, NN Haren, The Netherlands. hemelrij@ifi.unizh.ch
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Series Volume Series Issue Edition
ISSN 0149-7634 ISBN Medium
Area Expedition Conference
Notes PMID:15652260 Approved no
Call Number refbase @ user @ Serial 443
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Author Johnson, D.D.P.; Stopka, P.; Knights, S.
Title Sociology: The puzzle of human cooperation Type (up) Journal Article
Year 2003 Publication Nature Abbreviated Journal Nature
Volume 421 Issue 6926 Pages 911-2; discussion 912
Keywords Altruism; *Cooperative Behavior; Evolution; Humans; *Models, Biological; Punishment; Reward; Risk
Abstract
Address Olin Institute for Strategic Studies, Harvard University, Cambridge, Massachusetts 02138, USA. dominic@post.harvard.edu
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ISSN 0028-0836 ISBN Medium
Area Expedition Conference
Notes PMID:12606989 Approved no
Call Number refbase @ user @ Serial 467
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Author Scheffer, M.; van Nes, E.H.
Title Self-organized similarity, the evolutionary emergence of groups of similar species Type (up) Journal Article
Year 2006 Publication Proceedings of the National Academy of Sciences of the United States of America Abbreviated Journal Proc. Natl. Acad. Sci. U.S.A.
Volume 103 Issue 16 Pages 6230-6235
Keywords Animals; *Competitive Behavior; *Ecosystem; *Evolution; *Models, Biological
Abstract Ecologists have long been puzzled by the fact that there are so many similar species in nature. Here we show that self-organized clusters of look-a-likes may emerge spontaneously from coevolution of competitors. The explanation is that there are two alternative ways to survive together: being sufficiently different or being sufficiently similar. Using a model based on classical competition theory, we demonstrate a tendency for evolutionary emergence of regularly spaced lumps of similar species along a niche axis. Indeed, such lumpy patterns are commonly observed in size distributions of organisms ranging from algae, zooplankton, and beetles to birds and mammals, and could not be well explained by earlier theory. Our results suggest that these patterns may represent self-constructed niches emerging from competitive interactions. A corollary of our findings is that, whereas in species-poor communities sympatric speciation and invasion of open niches is possible, species-saturated communities may be characterized by convergent evolution and invasion by look-a-likes.
Address Aquatic Ecology and Water Quality Management Group, Department of Environmental Sciences, Wageningen University, P.O. Box 8080, 6700 DD, Wageningen, The Netherlands. marten.scheffer@wur.nl
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Series Volume Series Issue Edition
ISSN 0027-8424 ISBN Medium
Area Expedition Conference
Notes PMID:16585519 Approved no
Call Number refbase @ user @ Serial 510
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