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Klosterneuburg, Austria

Morin O.,Konrad Lorenz Institute
Behavioral and Brain Sciences | Year: 2016

I argue that demographic selection migration and cultural diffusion three mechanisms of institutional change have little in common. Two of these lack the key features associated with group selection: they do not present us with group-level selection pressures counteracting individual-level ones need not produce behavioral altruism and do not require competition between groups whose members cooperate preferentially with one another. Cultural norms vary change and influence cooperation; but that is not group selection. © Cambridge University Press 2016.

Archetti M.,Harvard University | Scheuring I.,A.P.S. University | Scheuring I.,Konrad Lorenz Institute
Evolution | Year: 2011

The production of public goods by the contribution of individual volunteers is a social dilemma because an individual that does not volunteer can benefit from the public good produced by the contributions of others. Therefore it is generally believed that public goods can be produced only in the presence of repeated interactions (which allow reciprocation, reputation effects and punishment) or relatedness (kin selection). Cooperation, however, often occurs in the absence of iterations and relatedness. We show that when the production of a public good is a Volunteer's Dilemma, in which a fixed number of cooperators is necessary to produce the public good, cooperators and defectors persist in a mixed equilibrium, without iterations and without relatedness. This mixed equilibrium is absent in the N-person Prisoner's Dilemma, in which the public good is a linear function of the individual contributions. We also show that the Prisoner's Dilemma and the Volunteer's Dilemma are the two opposite extremes of a general public goods game, and that all intermediate cases can have a mixed equilibrium like the Volunteer's Dilemma. The coexistence of cooperators and defectors, therefore, is a typical outcome of most social dilemmas, which requires neither relatedness nor iterations. © 2010 The Author(s). Evolution© 2010 The Society for the Study of Evolution.

Dvorak M.,BirdLife Austria | Fessl B.,Charles Darwin Foundation | Nemeth E.,Konrad Lorenz Institute | Nemeth E.,Max Planck Institute for Ornithology (Seewiesen) | And 2 more authors.
ORYX | Year: 2012

Population monitoring is a vital tool for conservation management and for testing hypotheses about population trends in changing environments. Darwin's finches on Santa Cruz Island in the Galápagos archipelago have experienced habitat alteration because of human activity, introduced predators, parasites and disease. We used point counts to conduct systematic quantitative surveys of Darwin's finches and other land birds between 1997 and 2010. The temporal analysis revealed that six of the nine species investigated declined significantly and that this decline was most pronounced at higher elevations in humid native forest and agricultural areas; the highland areas have been most affected by introduced species or direct human impact. Five of the six declining species are insectivorous, which suggests that changes in insect abundance or insect availability are a critical factor in the declines. Further study is required to test this idea. Other factors including habitat alteration and introduced parasites or pathogens may be contributing to the observed declines. © 2012 Fauna & Flora Internationa.

Scheuring I.,Hungarian Academy of Sciences | Scheuring I.,Konrad Lorenz Institute
BioSystems | Year: 2010

Evolution of cooperative norms is studied in a population where individual and group level selection are both in operation. Individuals play indirect reciprocity game within their group and follow second order norms. Individuals are norm-followers, and imitate their successful group mates. Aside from direct observation individuals can be informed about the previous actions and reputations by information transferred by others. A potential donor estimates the reputation of a potential receiver either by her own observation or by the opinion of the majority of others (indirect observation). Following a previous study (Scheuring, 2009) we assume that norms determine only the probabilities of actions, and mutants can differ in these probabilities. Similarly, we assume that individuals follow a stochastic information transfer strategy. The central question is whether cooperative norm and honest social information transfer can emerge in a population where initially only non-cooperative norms were present, and the transferred information was not sufficiently honest. It is shown that evolution can lead to a cooperative state where information transferred in a reliable manner, where generous cooperative strategies are dominant. This cooperative state emerges along a sharp transition of norms. We studied the characteristics of actions and strategies in this transition by classifying the stochastic norms, and found that a series of more and more judging strategies invade each other before the stabilization of the so-called generous judging strategy. Numerical experiments on the coevolution of social parameters (e.g. probability of direct observation and the number of indirect observers) reveal that it is advantageous to lean on indirect observation even if information transfer is much noisier than for direct observation, which is because to follow the majorities' opinion suppresses information noise meaningfully. © 2010 Elsevier Ireland Ltd.

Nemeth E.,Max Planck Institute for Ornithology (Seewiesen) | Nemeth E.,Konrad Lorenz Institute | Brumm H.,Max Planck Institute for Ornithology (Seewiesen)
American Naturalist | Year: 2010

In cities with intense low-frequency traffic noise, birds have been observed to sing louder and at a higher pitch. Several studies argue that higher song pitch is an adaptation to reduce masking from noise, and it has even been suggested that the song divergence between urban and nonurban songs might lead to reproductive isolation. Here we present models of signal transmission to compare the benefits of raised song amplitude and song pitch in terms of sound transmission. We chose two bird species that sing with higher pitch in urban areas, the great tit (Parus major) and the blackbird (Turdus merula). For both species, we calculated communication distances in response to different levels of urban noise and in their natural forest habitats. We found that an increase in vocal pitch increased communication distance only marginally. In contrast, vocal amplitude adjustments had a strong and significantly larger effect. Our results indicate that frequency changes of urban songs are not very effective in mitigating masking from traffic noise. Increased song pitch might not be an adaptation to reduce signal masking but a physiological side effect of singing at high amplitudes or an epiphenomenon of urbanization that is not related to signal transmission. © 2010 by The University of Chicago.

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