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Author Scheffer, M.; van Nes, E.H. doi  openurl
  Title Self-organized similarity, the evolutionary emergence of groups of similar species Type 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  
  Corporate Author (up) Thesis  
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  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0027-8424 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:16585519 Approved no  
  Call Number refbase @ user @ Serial 510  
Permanent link to this record
 

 
Author Hirsch, B.T. doi  openurl
  Title Costs and benefits of within-group spatial position: a feeding competition model Type Journal Article
  Year 2007 Publication The Quarterly review of biology Abbreviated Journal Q Rev Biol  
  Volume 82 Issue 1 Pages 9-27  
  Keywords Animals; Competitive Behavior/*physiology; Dominance-Subordination; Feeding Behavior/*physiology/*psychology; Population Dynamics; Predatory Behavior/*physiology  
  Abstract An animal's within-group spatial position has several important fitness consequences. Risk of predation, time spent engaging in antipredatory behavior and feeding competition can all vary with respect to spatial position. Previous research has found evidence that feeding rates are higher at the group edge in many species, but these studies have not represented the entire breadth of dietary diversity and ecological situations faced by many animals. In particular the presence of concentrated, defendable food patches can lead to increased feeding rates by dominants in the center of the group that are able to monopolize or defend these areas. To fully understand the tradeoffs of within-group spatial position in relation to a variety of factors, it is important to be able to predict where individuals should preferably position themselves in relation to feeding rates and food competition. A qualitative model is presented here to predict how food depletion time, abundance of food patches within a group, and the presence of prior knowledge of feeding sites affect the payoffs of different within-group spatial positions for dominant and subordinate animals. In general, when feeding on small abundant food items, individuals at the front edge of the group should have higher foraging success. When feeding on slowly depleted, rare food items, dominants will often have the highest feeding rates in the center of the group. Between these two extreme points of a continuum, an individual's optimal spatial position is predicted to be influenced by an additional combination of factors, such as group size, group spread, satiation rates, and the presence of producer-scrounger tactics.  
  Address Department of Anthropology, Stony Brook University Stony Brook, New York 11794, USA. BTHIRSCH@IC.SUNYSB.EDU  
  Corporate Author (up) Thesis  
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  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0033-5770 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:17354992 Approved no  
  Call Number refbase @ user @ Serial 803  
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Author Li, F.-H.; Zhong, W.-Q.; Wang, Z.; Wang, D.-H. doi  openurl
  Title Rank in a food competition test and humoral immune functions in male Brandt's voles (Lasiopodomys brandtii) Type Journal Article
  Year 2007 Publication Physiology & behavior Abbreviated Journal Physiol. Behav.  
  Volume 90 Issue 2-3 Pages 490-495  
  Keywords Animals; Antibody Formation/*physiology; Arvicolinae/immunology/*physiology; Competitive Behavior/*physiology; *Dominance-Subordination; Feeding Behavior/physiology; Hydrocortisone/blood; Male; *Social Dominance; Spleen/immunology/physiology  
  Abstract Social status can influence an animal's immune and reproductive functions, eventually leading to alterations in immunocompetence and reproductive success. Here, we report that rank assessed in a food competition test, considered as an index of social status, has significant influences on humoral immune functions in male Brandt's voles (Lasiopodomys brandtii) living in a group. Our data reveal a negative correlation of the spleen mass and serum antibody levels with social status, as well as a positive correlation of serum cortisol levels with social status. Males winning in food competition had a smaller spleen, a lower level of serum antibodies, and a higher level of serum cortisol than did their conspecific counterparts. These data indicate interactions between social status and humoral immune functions and might illustrate a trade-off between infection risks and reproductive success in male Brandt's voles.  
  Address State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, The Chinese Academy of Sciences, No. 25 Beisihuan Xilu, Zhongguancun, Haidian, Beijing 100080, China  
  Corporate Author (up) Thesis  
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  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0031-9384 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:17141282 Approved no  
  Call Number refbase @ user @ Serial 804  
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Author Hrdy, S.B. openurl 
  Title Male-male competition and infanticide among the langurs (Presbytis entellus) of Abu, Rajasthan Type Journal Article
  Year 1974 Publication Folia Primatologica; International Journal of Primatology Abbreviated Journal Folia Primatol (Basel)  
  Volume 22 Issue 1 Pages 19-58  
  Keywords Aggression; Animals; Animals, Newborn; Coitus; *Competitive Behavior; Estrus; Feeding Behavior; Female; *Haplorhini; Homing Behavior; Humans; India; Infanticide; Leadership; Male; Maternal Behavior; Population Density; Pregnancy; Rain; Seasons; Sex Factors; Sexual Behavior, Animal; Social Behavior; Temperature; Vocalization, Animal  
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  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0015-5713 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:4215710 Approved no  
  Call Number Serial 2051  
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Author Fujita, K.; Kuroshima, H.; Masuda, T. doi  openurl
  Title Do tufted capuchin monkeys (Cebus apella) spontaneously deceive opponents? A preliminary analysis of an experimental food-competition contest between monkeys Type Journal Article
  Year 2002 Publication Animal Cognition Abbreviated Journal Anim. Cogn.  
  Volume 5 Issue 1 Pages 19-25  
  Keywords Animals; Cebus/*psychology; *Competitive Behavior; *Deception; Dominance-Subordination; Feeding Behavior/*psychology; Female; Male; Predatory Behavior; Social Behavior  
  Abstract A new laboratory procedure which allows the study of deceptive behavior in nonhuman primates is described. Pairs of tufted capuchin monkeys faced each other in a food-competition contest. Two feeder boxes were placed between the monkeys. A piece of food was placed in one of the boxes. The subordinate individual was able to see the food and to open the box to obtain the bait. A dominant male was unable to see the food or to open the box but was able to take the food once the box was opened by the subordinate. In experiment 1, two of four subordinate monkeys spontaneously started to open the unbaited box first with increasing frequency. Experiment 2 confirmed that this “deceptive” act was not due to a drop in the rate of reinforcement caused by the usurping dominant male, under the situation in which food sometimes automatically dropped from the opened box. In experiment 3, two subordinate monkeys were rerun in the same situation as experiment 1. One of them showed some recovery of the “deceptive” act but the other did not; instead the latter tended to position himself on the side where there was no food before he started to open the box. Although the results do not clearly indicate spontaneous deception, we suggest that operationally defined spontaneous deceptive behaviors in monkeys can be analyzed with experimental procedures such as those used here.  
  Address Department of Psychology, Graduate School of Letters, Kyoto University, Yoshida-honmachi, Sakyo, Kyoto 606-8501, Japan. fujita@psy.bun.kyoto-u.ac.jp  
  Corporate Author (up) Thesis  
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  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1435-9448 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:11957398 Approved no  
  Call Number Equine Behaviour @ team @ Serial 2614  
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