Social evolution.

Mode of access: Internet.

Women and economics; a study of the economic relation between men and women as a factor in social evolution,

Mode of access: Internet.

Intermediate types among primitive folk; a study in social evolution

Pt. 1 originally published in the American Journal of Religious Psychology, 1911, and in the Revue d'Ethnographie et de Sociologie, 1911

Thoughts and reflections on modern society, with an introduction on the gradual social evolution of primitive man,

Mode of access: Internet.

The making of Hawaii; a study in social evolution,

Bibliography: p. 257-262.

The function of socialization in social evolution

Mode of access: Internet.

Social evolution,

Mode of access: Internet.

Piaci rend és társadalmi normák. Hayek elmélete a társadalmi evolúcióról (Market order and social norms Hayek's theory of social evolution)

A hayeki szociokulturális evolúció elmélete a piaci rend elemzésének általánosítása. Hayek mind a piaci rend, mind a piaci rend alapzatául szolgáló társadalmi intézmények kialakulását és működését azonos logika alapján magyarázza. Ez a logika az egyéni cselekvések nem szándékolt következményeként értelmezi a spontán rend és a csoportszintű magatartásszabályok kialakulását és fennmaradását. A társadalmi normák magyarázatában a módszertani individualizmus elveinek érvényesítéséért az evolucionista perspektíva feladásával kellene fizetni. Hayek azonban a társadalmi normák magyarázatára is az evolucionista megközelítést alkalmazza, ezért egészíti ki a módszertani individualista megközelítést funkcionalista-evolucionista érvekkel. A szociokulturális evolúció hayeki elmélete példa arra, hogy a módszertani individualizmusra épülő magyarázat és a funkcionalista érvelés nem kiszorítja, hanem kiegészíti egymást. _____ Hayek's theory of socio-cultural evolution is a generalization of his theory of market order. He explains in the same way the development and operation of market order and those of the social institutions on which market order is based. This logic interprets the development and persistence of spontaneous order and group-level behaviour rules as an unintentional consequence of individual actions. In his explanation of social norms, enforcement of the principles of methodological individualism has to be paid for by abandoning the evolutionist perspective. But Hayek also employs an evolutionist approach in his explanation of social norms, and so he augments his methodological individualist approach with some functionalist-cum-evolutionist arguments. Hayek's theory of sociocultural evolution, for instance, exemplifies how an explanation resting on methodological individualism and a functionalist argument can complement, not preclude each other.

Ecology and evolution of social-organization: insights from fire ants and other highly eusocial insects

Social organisms exhibit conspicuous intraspecific variation in all facets of their social organization. A prominent example of such variation in the highly eusocial Hymenoptera is differences in the number of reproductive queens per colony, Differences in queen number in ants are associated with differences in a host of reproductive and social traits, including queen phenotype and breeding strategy, mode of colony reproduction, and pattern of sex allocation. We examine the causes and consequences of changes in colony queen number and associated traits using the fire ant Solenopsis invicta as a principal model. Ecological constraints on mode of colony founding may act as important selective forces causing the evolution of queen number in this and many other ants, with social organization generally perpetuated across generations by means of the social environment molding appropriate queen phenotypes and reproductive strategies. Shifts in colony queen number have profound effects on genetic structure within nests and may also influence genetic structure at higher levels (aggregations of nests or local demes) because of the association of queen number with particular mating and dispersal habits. Divergence of breeding habits between populations with different social organizations has the potential to promote genetic differentiation between these social variants. Thus, evolution of social organization can be important in generating intrinsic selective regimes that channel subsequent social evolution and in initiating the development of significant population genetic structure, including barriers to gene flow important in cladogenesis.

Evolution, société, éthique : darwinisme social versus éthique évolutionniste

L'éthique évolutionniste (EE) est une branche de la philosophie morale à la fois fascinante et génératrice de craintes, qui considère les mécanismes darwiniens et les données évolutives sur la socialité animale et humaine comme pertinents pour une réflexion éthique. Ce courant de pensée est souvent mal compris ; beaucoup de lecteurs critiques l'associent au darwinisme social et au cortège d'horreurs qu'il a servi à justifier. Il vaut cependant la peine de résister à la tentation de réduire l'EE au darwinisme social et de chercher à analyser objectivement l'intérêt d'adopter une approche évolutionnaire en éthique. L'objet de cet article est de 'dédiaboliser' l'EE tout en explorant ses limites. Je commencerai par mentionner deux manières d'intégrer un raisonnement darwinien dans le domaine des sciences politiques et sociales: le darwinisme social et ce que l'on pourrait appeler le darwinisme pro-social. Je mettrai ensuite en évidence les erreurs fondamentales sur lesquelles repose le darwinisme social afin de montrer qu'il n'est pas possible aujourd'hui pour un éthicien évolutionniste de défendre les idées propres à ce courant (à moins de faire preuve de malhonnêteté intellectuelle). Au contraire, l'EE semble s'approcher davantage de l'état d'esprit du darwinisme pro-social sans pour autant s'y assimiler car elle restreint sa réflexion au niveau de l'éthique théorique. Dans un second temps, il s'agira de présenter en quoi consiste précisément l'EE, quels sont ses domaines de réflexion, et quelle est sa pertinence au niveau des différents domaines de l'éthique. Une focale particulière sera mise sur les questions de la genèse de la moralité et du passage délicat des faits aux normes.

Social chromosome variants differentially affect queen determination and the survival of workers in the fire ant Solenopsis invicta.

Intraspecific variation in social organization is common, yet the underlying causes are rarely known. An exception is the fire ant Solenopsis invicta in which the existence of two distinct forms of social colony organization is under the control of the two variants of a pair of social chromosomes, SB and Sb. Colonies containing exclusively SB/SB workers accept only one single queen and she must be SB/SB. By contrast, when colonies contain more than 10% of SB/Sb workers, they accept several queens but only SB/Sb queens. The variants of the social chromosome are associated with several additional important phenotypic differences, including the size, fecundity and dispersal strategies of queens, aggressiveness of workers, and sperm count in males. However, little is known about whether social chromosome variants affect fitness in other life stages. Here, we perform experiments to determine whether differential selection occurs during development and in adult workers. We find evidence that the Sb variant of the social chromosome increases the likelihood of female brood to develop into queens and that adult SB/Sb workers, the workers that cull SB/SB queens, are overrepresented in comparison to SB/SB workers. This demonstrates that supergenes such as the social chromosome can have complex effects on phenotypes at various stages of development.

How life history and demography promote or inhibit the evolution of helping behaviours.

In natural populations, dispersal tends to be limited so that individuals are in local competition with their neighbours. As a consequence, most behaviours tend to have a social component, e.g. they can be selfish, spiteful, cooperative or altruistic as usually considered in social evolutionary theory. How social behaviours translate into fitness costs and benefits depends considerably on life-history features, as well as on local demographic and ecological conditions. Over the last four decades, evolutionists have been able to explore many of the consequences of these factors for the evolution of social behaviours. In this paper, we first recall the main theoretical concepts required to understand social evolution. We then discuss how life history, demography and ecology promote or inhibit the evolution of helping behaviours, but the arguments developed for helping can be extended to essentially any social trait. The analysis suggests that, on a theoretical level, it is possible to contrast three critical benefit-to-cost ratios beyond which costly helping is selected for (three quantitative rules for the evolution of altruism). But comparison between theoretical results and empirical data has always been difficult in the literature, partly because of the perennial question of the scale at which relatedness should be measured under localized dispersal. We then provide three answers to this question.

Social structure varies with elevation in an Alpine ant.

Insect societies vary greatly in social organization, yet the relative roles of ecological and genetic factors in driving this variation remain poorly understood. Identifying how social structure varies along environmental gradients can provide insights into the ecological conditions favouring alternative social organizations. Here, we investigate how queen number variation is distributed along elevation gradients within a socially polymorphic ant, the Alpine silver ant Formica selysi. We sampled low- and high-elevation populations in multiple Alpine valleys. We show that populations belonging to different drainage basins are genetically differentiated. In contrast, there is little genetic divergence between low- and high-elevation populations within the same drainage basin. Thus, elevation gradients in each of the drainage basins represent independent contrasts. Whatever the elevation, all well-sampled populations are socially polymorphic, containing both monogynous (= one queen) and polygynous (= multiple queen) colonies. However, the proportion of monogynous colonies per population increases at higher elevation, while the effective number of queens in polygynous colonies decreases, and this pattern is replicated in each drainage basin. The increased prevalence of colonies with a single queen at high elevation is correlated with summer and winter average temperature, but not with precipitation. The colder, unpredictable and patchy environment encountered at higher elevations may favour larger queens with the ability to disperse and establish incipient monogynous colonies independently, while the stable and continuous habitat in the lowlands may favour large, fast-growing polygynous colonies. By highlighting differences in the environmental conditions favouring monogynous or polygynous colonies, this study sheds light on the ecological factors influencing the distribution and maintenance of social polymorphism.

The robustness of the weak selection approximation for the evolution of altruism against strong selection.

The weak selection approximation of population genetics has made possible the analysis of social evolution under a considerable variety of biological scenarios. Despite its extensive usage, the accuracy of weak selection in predicting the emergence of altruism under limited dispersal when selection intensity increases remains unclear. Here, we derive the condition for the spread of an altruistic mutant in the infinite island model of dispersal under a Moran reproductive process and arbitrary strength of selection. The simplicity of the model allows us to compare weak and strong selection regimes analytically. Our results demonstrate that the weak selection approximation is robust to moderate increases in selection intensity and therefore provides a good approximation to understand the invasion of altruism in spatially structured population. In particular, we find that the weak selection approximation is excellent even if selection is very strong, when either migration is much stronger than selection or when patches are large. Importantly, we emphasize that the weak selection approximation provides the ideal condition for the invasion of altruism, and increasing selection intensity will impede the emergence of altruism. We discuss that this should also hold for more complicated life cycles and for culturally transmitted altruism. Using the weak selection approximation is therefore unlikely to miss out on any demographic scenario that lead to the evolution of altruism under limited dispersal.

Geographic patterns in the distribution of social systems in terrestrial arthropods.

The role of ecology in the evolution and maintenance of arthropod sociality has received increasing research attention in recent years. In some organisms, such as halictine bees, polistine wasps, and social spiders, researchers are investigating the environmental factors that may contribute to high levels of variation in the degree of sociality exhibited both among and within species. Within lineages that include only eusocial members, such as ants and termites, studies focus more on identifying extrinsic factors that may contribute to the dramatic variation in colony size, number of queens, and division of labour that is evident across these species. In this review, I propose a comparative approach that seeks to identify environmental factors that may have a common influence across such divergent social arthropod groups. I suggest that seeking common biogeographic patterns in the distribution of social systems or key social traits may help us to identify ecological factors that play a common role in shaping the evolution of sociality across different organisms. I first review previous studies of social gradients that form along latitudinal and altitudinal axes. Within families and within species, many organisms show an increasing degree of sociality at lower latitudes and altitudes. In a smaller number of cases, organisms form larger groups or found nests cooperatively at higher latitudes and altitudes. I then describe several environmental factors that vary consistently along such gradients, including climate variables and abundance of predators, and outline their proposed role in the social systems of terrestrial arthropods. Finally, I map distributions of a social trait against several climatic factors in five case studies to demonstrate how future comparative studies could inform empirical research.