Colony size affects division of labour in the ponerine ant Rhytidoponera metallica

2003 ◽  
Vol 90 (2) ◽  
pp. 88-92 ◽  
Author(s):  
Melissa L. Thomas ◽  
Mark A. Elgar
1994 ◽  
Vol 6 (4) ◽  
pp. 507-517 ◽  
Author(s):  
S.J. Davies ◽  
M.H. Villet ◽  
T.M. Blomefield ◽  
R.M. Crewe

1999 ◽  
Vol 46 (1) ◽  
pp. 29-33 ◽  
Author(s):  
Y. Komene ◽  
S. Higashi ◽  
F. Ito ◽  
H. Miyata
Keyword(s):  

2013 ◽  
Vol 9 (3) ◽  
pp. 20130125 ◽  
Author(s):  
Heikki Helanterä ◽  
Oliver Aehle ◽  
Maurice Roux ◽  
Jürgen Heinze ◽  
Patrizia d'Ettorre

High relatedness promotes the evolution of sociality because potentially costly cooperative behaviours are directed towards kin. However, societies, such as those of social insects, also benefit from genetic diversity, e.g. through enhanced disease resistance and division of labour. Effects of genetic diversity have been investigated in a few complex eusocial species. Here, we show that genetically based division of labour may also be important in ‘simple societies’, with fewer individuals and limited morphological caste differentiation. The ponerine ant Pachycondyla inversa has small colonies, headed by several unrelated queens. We show that nest-mate workers from different matrilines engage in different tasks, have distinct chemical profiles and associate preferentially with kin in the nest, while queens and brood stay together. This suggests that genetically based division of labour may precede the evolution of complex eusociality and facilitate the existence of low relatedness societies functioning as associations of distinct families that mutually benefit from group living.


2015 ◽  
Vol 282 (1801) ◽  
pp. 20142502 ◽  
Author(s):  
Sabrina Amador-Vargas ◽  
Wulfila Gronenberg ◽  
William T. Wcislo ◽  
Ulrich Mueller

Group size in both multicellular organisms and animal societies can correlate with the degree of division of labour. For ants, the task specialization hypothesis (TSH) proposes that increased behavioural specialization enabled by larger group size corresponds to anatomical specialization of worker brains. Alternatively, the social brain hypothesis proposes that increased levels of social stimuli in larger colonies lead to enlarged brain regions in all workers, regardless of their task specialization. We tested these hypotheses in acacia ants ( Pseudomyrmex spinicola ), which exhibit behavioural but not morphological task specialization. In wild colonies, we marked, followed and tested ant workers involved in foraging tasks on the leaves (leaf-ants) and in defensive tasks on the host tree trunk (trunk-ants). Task specialization increased with colony size, especially in defensive tasks. The relationship between colony size and brain region volume was task-dependent, supporting the TSH. Specifically, as colony size increased, the relative size of regions within the mushroom bodies of the brain decreased in trunk-ants but increased in leaf-ants; those regions play important roles in learning and memory. Our findings suggest that workers specialized in defence may have reduced learning abilities relative to leaf-ants; these inferences remain to be tested. In societies with monomorphic workers, brain polymorphism enhanced by group size could be a mechanism by which division of labour is achieved.


2014 ◽  
Vol 281 (1793) ◽  
pp. 20141411 ◽  
Author(s):  
Henry Ferguson-Gow ◽  
Seirian Sumner ◽  
Andrew F. G. Bourke ◽  
Kate E. Jones

Division of labour is central to the ecological success of eusocial insects, yet the evolutionary factors driving increases in complexity in division of labour are little known. The size–complexity hypothesis proposes that, as larger colonies evolve, both non-reproductive and reproductive division of labour become more complex as workers and queens act to maximize inclusive fitness. Using a statistically robust phylogenetic comparative analysis of social and environmental traits of species within the ant tribe Attini, we show that colony size is positively related to both non-reproductive (worker size variation) and reproductive (queen–worker dimorphism) division of labour. The results also suggested that colony size acts on non-reproductive and reproductive division of labour in different ways. Environmental factors, including measures of variation in temperature and precipitation, had no significant effects on any division of labour measure or colony size. Overall, these results support the size–complexity hypothesis for the evolution of social complexity and division of labour in eusocial insects. Determining the evolutionary drivers of colony size may help contribute to our understanding of the evolution of social complexity.


Author(s):  
Tetiana Petrushyna ◽  
Anatolii Arseienko

Globalization remains the most common and quite controversial concept in modern social discourse. Within the theoretical and conceptual sociological dimension, the authors analyzed the essence of economic globalization (EG) as its defining type. They studied globalization as an objective process (first of all, the international division of labour) and the subjective process of forming a global capitalist economy under the auspices of leading Western countries, supranational financial and economic institutions (primarily the World Bank and the IMF), TNCs. As the main drivers of globalization, they determine its forms and directions in the interests of the "core" of global capitalism. Within the empirical sociological dimension of EG (which involves measuring the various manifestations of the EG process itself as well as its social consequences), the authors paid particular attention to the analysis of social changes in Ukrainian society. The capitalization of the Ukrainian economy, which took place in parallel with Ukraine’s entry into the global economic space, led to degradation of the national economy, significant deterioration of living standards of most citizens, creation of anti-social state with the systemic crisis as its main attribute. To prove these conclusions, the authors analyzed the dynamics of the principal macroeconomic and sociological indicators of Ukrainian society’s life for almost 30 years of drift to the roadside of the global capitalist world, based on the study of numerous domestic and foreign sources. The authors focused on the research of eight critical areas of social changes: deindustrialization of the economy, global competitiveness and innovation, GDP dynamics, employment, income and welfare of the population, socioeconomic inequality, debt dependence and degradation of Ukrainian science. The analysis shows the need to abandon the neoliberal paradigm of development and search for the alternative and more fair models of EG.


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