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Author (down) Bergstrom,C. T.; Lachmann, M.
Title Signalling among relatives. I. Is costly signalling too costly? Type Journal Article
Year 1997 Publication Proceedings of the National Academy of Sciences of the United States of America Abbreviated Journal Proc. Natl. Acad. Sci. U.S.A.
Volume 352(1353) Issue Pages 609-617
Keywords Signalling
Abstract ahavi's handicap principle,originally proposed as an explanation for sexual selection ofelaborate male traits, suggests that a sufficient cost to dishonest signals can outweigh the rewards of deception and allow individuals to communicate honestly. Maynard Smith (1991) and Johnstone and Grafen (1992) introduce the Sir Philip Sidney game in order to extend the handicap principle to interactions among related individuals, and to demonstrate that stable costly signalling systems can exist among relatives.

In this paper we demonstrate that despite the benefits associated with honest information transfer, the costs incurred in a stable costly signalling system may leave all participants worse off than they would be in a system with no signalling at all. In both the discrete and continuous forms of the Sir Philip Sidney game, there exist conditions under which costly signalling among relatives, while stable, is so costly that it is disadvantageous compared with no signalling at all. We determine the factors which dictate signal cost and signal benefit in a generalized version of this game, and explain how signal cost can exceed signal value. Such results raise concerns about theevolutionary pathways which could have led to the existence of signalling equilibria in nature. The paper stresses the importance of comparing signalling equilibria with other possible strategies, beforedrawing conclusions regarding the optimality of signalling.
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Call Number refbase @ user @ Serial 559
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Author (down) Bergstrom, C.T.; Lachmann, M.
Title Signaling among relatives. III. Talk is cheap Type Journal Article
Year 1998 Publication Proceedings of the National Academy of Sciences of the United States of America Abbreviated Journal Proc. Natl. Acad. Sci. U.S.A.
Volume 95 Issue 9 Pages 5100-5105
Keywords Animal Communication; Animals; Costs and Cost Analysis; *Evolution; Interpersonal Relations; Models, Biological
Abstract The Sir Philip Sidney game has been used by numerous authors to show how signal cost can facilitate honest signaling among relatives. Here, we demonstrate that, in this game, honest cost-free signals are possible as well, under very general conditions. Moreover, these cost-free signals are better for all participants than the previously explored alternatives. Recent empirical evidence suggests that begging is energetically inexpensive for nestling birds; this finding led some researchers to question the applicability of the costly signaling framework to nestling begging. Our results show that cost-free or inexpensive signals, as observed empirically, fall within the framework of signaling theory.
Address Department of Biological Sciences, Stanford University, Stanford, CA 94305, USA. carl@charles.stanford.edu
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ISSN 0027-8424 ISBN Medium
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Notes PMID:9560235 Approved no
Call Number refbase @ user @ Serial 561
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Author (down) Begall, S.; Cervený, J.; Neef, J.; Vojtech, O.; Burda, H.
Title Magnetic alignment in grazing and resting cattle and deer Type Journal Article
Year 2008 Publication Proceedings of the National Academy of Sciences of the United States of America Abbreviated Journal Proc. Natl. Acad. Sci. U.S.A.
Volume 105 Issue 36 Pages 13451-13455
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Abstract We demonstrate by means of simple, noninvasive methods (analysis of satellite images, field observations, and measuring “deer beds” in snow) that domestic cattle (n = 8,510 in 308 pastures) across the globe, and grazing and resting red and roe deer (n = 2,974 at 241 localities), align their body axes in roughly a north–south direction. Direct observations of roe deer revealed that animals orient their heads northward when grazing or resting. Amazingly, this ubiquitous phenomenon does not seem to have been noticed by herdsmen, ranchers, or hunters. Because wind and light conditions could be excluded as a common denominator determining the body axis orientation, magnetic alignment is the most parsimonious explanation. To test the hypothesis that cattle orient their body axes along the field lines of the Earth's magnetic field, we analyzed the body orientation of cattle from localities with high magnetic declination. Here, magnetic north was a better predictor than geographic north. This study reveals the magnetic alignment in large mammals based on statistically sufficient sample sizes. Our findings open horizons for the study of magnetoreception in general and are of potential significance for applied ethology (husbandry, animal welfare). They challenge neuroscientists and biophysics to explain the proximate mechanisms.
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Notes 10.1073/pnas.0803650105 Approved no
Call Number Equine Behaviour @ team @ Serial 5316
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Author (down) Ballew, R.M.; Sabelko, J.; Gruebele, M.
Title Direct observation of fast protein folding: the initial collapse of apomyoglobin Type Journal Article
Year 1996 Publication Proceedings of the National Academy of Sciences of the United States of America Abbreviated Journal Proc. Natl. Acad. Sci. U.S.A.
Volume 93 Issue 12 Pages 5759-5764
Keywords Animals; Apoproteins/*chemistry; Circular Dichroism; Horses; Kinetics; Muscle, Skeletal/chemistry; Myoglobin/*chemistry; *Protein Folding; Spectrometry, Fluorescence; Spectrophotometry, Infrared; Temperature
Abstract The rapid refolding dynamics of apomyoglobin are followed by a new temperature-jump fluorescence technique on a 15-ns to 0.5-ms time scale in vitro. The apparatus measures the protein-folding history in a single sweep in standard aqueous buffers. The earliest steps during folding to a compact state are observed and are complete in under 20 micros. Experiments on mutants and consideration of steady-state CD and fluorescence spectra indicate that the observed microsecond phase monitors assembly of an A x (H x G) helix subunit. Measurements at different viscosities indicate diffusive behavior even at low viscosities, in agreement with motions of a solvent-exposed protein during the initial collapse.
Address School of Chemical Sciences and Beckman Institute for Advanced Science and Technology, University of Illinois, Urbana, 61801, USA
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Notes PMID:8650166 Approved no
Call Number Equine Behaviour @ team @ Serial 3798
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Author (down) Amé, J.-M.; Halloy, J.; Rivault, C.; Detrain, C.; Deneubourg, J.L.
Title Collegial decision making based on social amplification leads to optimal group formation 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 15 Pages 5835-5840
Keywords Animals; Blattellidae/*physiology; Choice Behavior; Decision Making; Leadership; *Social Behavior
Abstract Group-living animals are often faced with choosing between one or more alternative resource sites. A central question in such collective decision making includes determining which individuals induce the decision and when. This experimental and theoretical study of shelter selection by cockroach groups demonstrates that choices can emerge through nonlinear interaction dynamics between equal individuals without perfect knowledge or leadership. We identify a simple mechanism whereby a decision is taken on the move with limited information and signaling and without comparison of available opportunities. This mechanism leads to optimal mean benefit for group individuals. Our model points to a generic self-organized collective decision-making process independent of animal species.
Address Service d'Ecologie Sociale CP231, Universite Libre de Bruxelles, Avenue F. D. Roosevelt 50, B-1050 Brussels, Belgium
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ISSN 0027-8424 ISBN Medium
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Notes PMID:16581903 Approved no
Call Number Equine Behaviour @ team @ Serial 2042
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