scholarly journals Variation in helper effort among cooperatively breeding bird species is consistent with Hamilton’s Rule

2016 ◽  
Vol 7 (1) ◽  
Author(s):  
Jonathan P. Green ◽  
Robert P. Freckleton ◽  
Ben J. Hatchwell
Keyword(s):  
Bird Species ◽  
Breeding Bird ◽  
Hamilton’S Rule ◽  
Cooperatively Breeding ◽  
Hamilton's Rule

scholarly journals Helping in cooperatively breeding long-tailed tits: a test of Hamilton's rule

2014 ◽  
Vol 369 (1642) ◽  
pp. 20130565 ◽  
Author(s):  
Ben J. Hatchwell ◽  
Philippa R. Gullett ◽  
Mark J. Adams
Keyword(s):  
Social Evolution ◽  
Inclusive Fitness ◽  
Empirical Studies ◽  
Alloparental Care ◽  
Hamilton’S Rule ◽  
Long Term Study ◽  
Inclusive Fitness Theory ◽  
Cooperatively Breeding ◽  
Helping Behaviour ◽  
Hamilton's Rule

Inclusive fitness theory provides the conceptual framework for our current understanding of social evolution, and empirical studies suggest that kin selection is a critical process in the evolution of animal sociality. A key prediction of inclusive fitness theory is that altruistic behaviour evolves when the costs incurred by an altruist ( c ) are outweighed by the benefit to the recipient ( b ), weighted by the relatedness of altruist to recipient ( r ), i.e. Hamilton's rule rb > c . Despite its central importance in social evolution theory, there have been relatively few empirical tests of Hamilton's rule, and hardly any among cooperatively breeding vertebrates, leading some authors to question its utility. Here, we use data from a long-term study of cooperatively breeding long-tailed tits Aegithalos caudatus to examine whether helping behaviour satisfies Hamilton's condition for the evolution of altruism. We show that helpers are altruistic because they incur survival costs through the provision of alloparental care for offspring. However, they also accrue substantial benefits through increased survival of related breeders and offspring, and despite the low average relatedness of helpers to recipients, these benefits of helping outweigh the costs incurred. We conclude that Hamilton's rule for the evolution of altruistic helping behaviour is satisfied in this species.

scholarly journals Climate predicts which sex acts as helpers among cooperatively breeding bird species

2017 ◽  
Vol 13 (1) ◽  
pp. 20160863 ◽  
Author(s):  
Guoyue Zhang ◽  
Qingtian Zhao ◽  
Anders Pape Møller ◽  
Jan Komdeur ◽  
Xin Lu
Keyword(s):  
Bird Species ◽  
Adult Survival ◽  
Sex Bias ◽  
Tropical Species ◽  
Ecological Constraints ◽  
Breeding Bird ◽  
Adult Females ◽  
Cooperatively Breeding ◽  
Demographic Response ◽  
Potential Determinant

Among avian cooperative breeders, help in raising offspring is usually provided by males or by both sexes. Sex bias in helping should evolve in response to sex-specific ecological constraints on independent reproduction, with mate shortage for males and breeding vacancy shortage for each sex. Given that male-biased adult sex ratios are prevalent among birds, we predict that male-only helping mainly occurs in temperate species where fast population turnovers deriving from low adult annual survival allow all adult females to hold breeding vacancies, whereas some males overflow as helpers, and both-sex helping in tropical species where saturated habitats prevent not only males, but also females from breeding themselves. As expected, we found that across species, adult survival increased towards tropical zones and warmer climates, and higher adult survival tended to be associated with both-sex helping. Furthermore, sex bias in helping was predicted by latitude and ambient temperature. Our findings of demographic response of species to climate as a potential determinant of bias in helper sex uncover how ecological constraints operate to limit independent reproduction in sex-specific ways.

Influence of Winter Ranging Behaviour on the Social Organization of a Cooperatively Breeding Bird Species, The Apostlebird

Ethology ◽  
2009 ◽  
Vol 115 (9) ◽  
pp. 888-896 ◽  
Author(s):  
Michael Griesser ◽  
Jonathan Barnaby ◽  
Nicole A. Schneider ◽  
Nina Figenschau ◽  
Jonathan Wright ◽  
...  
Keyword(s):  
Social Organization ◽  
Bird Species ◽  
Breeding Bird ◽  
Ranging Behaviour ◽  
The Social ◽  
Cooperatively Breeding

Functional evenness of bird communities varies along the elevational gradient in Europe: Conservation implications

2019 ◽  
Author(s):  
Federico Morelli ◽  
Yanina
Keyword(s):  
Species Richness ◽  
Elevation Gradient ◽  
Bird Species ◽  
Elevational Gradient ◽  
Negative Association ◽  
Bird Communities ◽  
Breeding Bird ◽  
Bird Species Richness ◽  
Large Spatial Scale ◽  
Functional Evenness

ContextThe negative association between elevation and species richness is a well-recognized pattern in macro-ecology. ObjectivesThe aim of this study was to investigate changes in functional evenness of breeding bird communities along an elevation gradient in Europe. MethodsUsing the bird data from the EBCC Atlas of European Breeding Birds we estimated an index of functional evenness which can be assumed as a measure of the potential resilience of communities.ResultsOur findings confirm the existence of a negative association between elevation and bird species richness in all European eco regions. However, we also explored a novel aspect of this relationship, important for conservation: Our findings provide evidence at large spatial scale of a negative association between the functional evenness (potential community resilience) and elevation, independent of the eco region. We also found that the Natura2000 protected areas covers the territory most in need of protection, those characterized by bird communities with low potential resilience, in hilly and mountainous areas.ConclusionsThese results draw attention to European areas occupied by bird communities characterized by a potential lower capacity to respond to strong ecological changes, and, therefore, potentially more exposed to risks for conservation.

Die Brutvogelfauna eines Nadelwaldes der nördlichen Voralpen nach dem Sturm Lothar

2017 ◽  
Vol 168 (2) ◽  
pp. 59-66
Author(s):  
Pierre Mollet ◽  
René Hardegger ◽  
Res Altwegg ◽  
Pius Korner ◽  
Simon Birrer
Keyword(s):  
Forest Succession ◽  
Coniferous Forest ◽  
Bird Species ◽  
Individual Species ◽  
Mountain Forest ◽  
Breeding Bird ◽  
Point Counts ◽  
Federal Institute ◽  
Central Switzerland ◽  
Bird Fauna

Breeding bird fauna in a coniferous forest in the northern Prealps after storm Lothar In a 70-hectare large coniferous forest located on the northern edge of the Alps in central Switzerland, Canton of Obwalden, at an altitude of 1260 to 1550 metres above sea level, we surveyed the local breeding bird fauna in 2002 and 2013 by means of point counts as well as additional area searches for rare species. In December 1999, hurricane Lothar caused two large windthrow areas and several smaller areas with scattered throws in the survey range. We found a total of 48 breeding bird species, which is a very diverse species composition for a mountain forest. In the eleven years between surveys, a decline in distribution or abundance was recorded for four species, while seven species showed an increase; a further four species showed no change. For the remaining species, the data sets were too small to reliably estimate changes. A comparison with forest structure data provided by the Swiss Federal Institute of Forest, Snow and Landscape Research WSL revealed that for five bird species, the changes in distribution or abundance could be explained at least partially by forest succession. In order to obtain realistic distribution and abundance values in this kind of breeding bird survey, it is essential to collect large enough samples and to consider the detection probability of each individual species using appropriate statistical methods.

Social Evolution, Hamilton’s Rule, and Inclusive Fitness

2018 ◽  
Author(s):  
Samir Okasha
Keyword(s):  
Social Behaviour ◽  
Social Evolution ◽  
Inclusive Fitness ◽  
Popular Approach ◽  
Hamilton’S Rule ◽  
Inclusive Fitness Theory ◽  
The Social ◽  
Social Encounters ◽  
The Individual ◽  
Hamilton's Rule

Inclusive fitness theory, originally due to W. D. Hamilton, is a popular approach to the study of social evolution, but shrouded in controversy. The theory contains two distinct aspects: Hamilton’s rule (rB > C); and the idea that individuals will behave as if trying to maximize their inclusive fitness in social encounters. These two aspects of the theory are logically separable but often run together. A generalized version of Hamilton’s rule can be formulated that is always true, though whether it is causally meaningful is debatable. However, the individual maximization claim only holds true if the payoffs from the social encounter are additive. The notion that inclusive fitness is the ‘goal’ of individuals’ social behaviour is less robust than some of its advocates acknowledge.

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