Philosophical Transactions of the Royal Society B: Biological Sciences最新文献

Post-Marx, social scientists have tended to define 'labour' as working for others in return for a wage rather than as a harmonious Durkheimian-style interdependency. This mini-review of recent anthropological literature considers whether, in a world where the 'standard employment contract' is dwindling and many are out of work, 'division of labour' has any continuing relevance.This article is part of the theme issue 'Division of labour as key driver of social evolution'.

An important advantage to sociality is division of labour, which is often associated with specialization of group members, such as the polymorphic subcastes of ant workers. Given this advantage, it is puzzling that many social groups do not show clear specialization. Among ants, workers of closely related species have one, two or even three polymorphisms. The degree of specialism of asocial animals depends on environmental variability because specialists will perform poorly in some conditions. Here, we use a numeric model to consider whether the magnitude and type of environmental variability can help to explain the diversity of specialism in cooperative groups. By finding the optimal distribution of group members along a single dimension of specialization for two tasks, we predict when groups should be composed of specialists, generalists, both of these (trimodal) or moderate specialists. Generalism is predicted more when environments are unstable and when task importance-rather than demand-varies but depends on the likelihood that the group can complete all tasks in the range of experienced conditions. The benefit of sociality is strongest in invariable environments and there is selection for redundancy in the workforce, which may explain the widely observed inactivity in social insects.This article is part of the theme issue 'Division of labour as key driver of social evolution'.

Division of Labour (DoL) among group members reflects the pinnacle of social complexity. The synergistic effects created by task specialization and the sharing of duties benefitting the group raise the efficiency of the acquisition, use, management and defence of resources by a fundamental step above the potential of individual agents. At the same time, it may stabilize societies because of the involved interdependence among collaborators. Here, I review the conditions associated with the emergence of DoL, which include the existence of (i) sizeable groups with enduring membership; (ii) individual specialization improving the efficiency of task performance; and (iii) low conflict of interest among group members owing to correlated payoffs. This results in (iv) a combination of intra-individual consistency with inter-individual variance in carrying out different tasks, which creates (v) some degree of mutual interdependence among group members. DoL typically evolves 'bottom-up' without external regulatory forces, but the latter may gain importance at a later stage of the evolution of social complexity. Owing to the involved feedback processes, cause and effect are often difficult to disentangle in the evolutionary trajectory towards structured societies with well-developed DoL among their members. Nevertheless, the emergence of task specialization and DoL may entail a one-way street towards social complexity, with retrogression getting increasingly difficult the more individual agents depend on each other at progressing stages of social evolution.This article is part of the theme issue 'Division of labour as key driver of social evolution'.

The social organization of Damaraland and naked mole-rats is often suggested to resemble the societies of eusocial insects more closely than that of any other vertebrate. Eusocial insects feature queens that hardly contribute to the workforce, and specialized worker castes. However, in Damaraland and naked mole-rats, which live in family groups with a single breeding pair and multiple non-breeding helpers, the work division is still unclear. Previous studies, largely confined to laboratory settings, could not quantify their primary cooperative behaviour, which is digging extensive foraging tunnels. Here, we studied the distribution of workload in 11 wild Damaraland mole-rat groups, using body acceleration loggers to evaluate behavioural time budgets of 86 individuals. We found behavioural differences between breeders and non-breeders that emerged with increases in group size, such that in large groups, breeders spent less time digging, more time resting, and were overall less active than non-breeders. We did not find any indication of a caste system among non-breeders, though the amount of time individuals spent digging varied with age and sex. Overall, the lower contribution by breeders to the group's workload is a pattern rarely observed in other cooperative vertebrates; nevertheless, the lack of evidence for castes suggests that eusociality may be limited to invertebrates.This article is part of the theme issue 'Division of labour as key driver of social evolution'.

Eusocial insects are characterized by reproductive division of labour, with one (or a few) individuals specialized in reproduction (queen and in termites, also a king) and the other individuals performing all other tasks (workers). Among workers, further division of labour can occur. Termites have three main castes: reproductives, comprising a queen and king; morphologically differentiated sterile soldiers; and workers. Task division among workers varies greatly depending on lifestyle and degree of workers' reproductive potential, which varies from totipotency to reproduce up to sterility. In wood-dwelling species, which do not forage outside the nest, all tasks are performed by totipotent workers, comprising multiple-instars with less further division of labour. Foraging species with pluripotent workers also have a multi-instar worker caste, but some division of labour between brood care versus foraging and defence exists. The first task seems mainly to be done by smaller-and potentially younger-instars, while the latter two tasks are performed by larger-and potentially older-workers. The highest degree of division of labour occurs in foraging species with sterile workers. Here, morphological worker castes with defined tasks and age polyethism occur. Comparisons with Metazoa reveal striking similarities with termites concerning gradients in germline/soma differentiation and cell totipotency.This article is part of the theme issue 'Division of labour as key driver of social evolution'.

While ecological specialization, social differentiation and division of labour are found in many species, extensive and irreversible interdependence among culturally specialized producers is a characteristic feature of humans. By extending the concept of cultural ratcheting (or the evolution of cultural products of such complexity that they become very unlikely to be recreated from scratch by naive individuals), we present simulation models showing how cumulative cultural evolution may have engendered a parallel process of 'social ratcheting' or the origin of culturally differentiated and irreversible interdependent individuals and groups. We provide evidence that the evolution of cultural division of labour in humans may have been associated with social network structures splitting the cognitive costs of cultural production across differentiated specialists, significantly reducing the burden of cultural learning on individual cognition and memory. While previous models often assumed agents with unlimited memories, we show that limiting individual memories to a fraction of available cultural repertoires has a noticeable accelerating effect on both cultural evolution and social differentiation among producers. We conclude that cultural and social ratcheting may have been two linked outcomes of cultural evolution in the hominin lineage.This article is part of the theme issue 'Division of labour as key driver of social evolution'.

The social division of labour (DoL) has been renowned as a key driver of the economic success of human societies dating back to ancient philosophers such as Plato (in The Republic, ca 380 BCE), Xenophon (in Cyropaedia, ca 370 BCE) and Aristotle (in Politics, ca 350 BCE, and Nicomachean Ethics, ca 340 BCE). Over time, this concept evolved into a cornerstone of political economic thought, most prominently expressed in Smith (in The Wealth of Nations, 1776). In his magnum opus, Adam Smith posited that DoL has caused a greater increase in production than any other factor in human history. There is little doubt that DoL immensely increases productive output, both in humans and in other organisms, but it is less clear how it comes about, how it is organized and what the biological roots are of this human 'turbo enhancer'. We address these questions here using results from studies of a wide range of organisms and various modelling approaches.This article is part of the theme issue 'Division of labour as key driver of social evolution'.

The evolution of primitive eusociality from non-social ancestors in organisms such as bees and wasps is often regarded as a major evolutionary transition. The division of labour between reproductives that specialize on egg production and workers that specialize on tasks such as foraging is the key feature defining eusociality and is why social insects are so successful ecologically. In taxa with morphological castes, individuals are often irreversibly specialized for particular roles when they reach adulthood. At the origin of sociality, however, such adaptations were absent, and we must consider why selection would favour individuals specializing when they are undifferentiated from the ancestral, non-social phenotype. Here, I focus on constraints based on life-history tradeoffs and plasticity that would be faced by ancestral females when specializing. These include limited efficiency of within-individual tradeoffs between reproductive and worker functions, imperfect matching of the productivities of social partners and lack of coordination. I also discuss the possibility that payoffs through specialization could be condition dependent. Eusocial taxa lacking morphological castes have traditionally been the testing grounds to understand the origin of eusociality, but significant adaptation has occurred since helping first evolved. Investigating role specialization at the origin of eusociality therefore requires utilizing non-social taxa.This article is part of the theme issue 'Division of labour as key driver of social evolution'.

Recent advances in the fields of RNA translation and ribosome biology have demonstrated the heterogeneous nature of ribosomes. This manifests not only across different cellular contexts but also within the same cell. Such variations in ribosomal composition, be it in ribosomal RNAs or proteins, can significantly influence cellular processes and responses by altering the mRNAs being translated or the dynamics of ribosomes during the translation process. Therefore, identifying this heterogeneity is crucial for unravelling the complexity of gene expression across different fields of biology. Here we provide an overview of recent advances in high-throughput techniques for identifying ribosomal heterogeneity. We cover methodologies for probing both rRNA and protein components of the ribosome and encompass the most recent next-generation sequencing and computational analyses, as well as a diverse array of mass spectrometry techniques.This article is part of the discussion meeting issue 'Ribosome diversity and its impact on protein synthesis, development and disease'.

Since the framing of the Central Dogma, it has been speculated that physically distinct ribosomes within cells may influence gene expression and cellular physiology. While heterogeneity in ribosome composition has been reported in bacteria, protozoans, fungi, zebrafish, mice and humans, its functional implications remain actively debated. Here, we review recent evidence demonstrating that expression of conserved variant ribosomal DNA (rDNA) alleles in bacteria, mice and humans renders their actively translating ribosome pool intrinsically heterogeneous at the level of ribosomal RNA (rRNA). In this context, we discuss reports that nutrient limitation-induced stress in Escherichia coli leads to changes in variant rRNA allele expression, programmatically altering transcription and cellular phenotype. We highlight that cells expressing ribosomes from distinct operons exhibit distinct drug sensitivities, which can be recapitulated in vitro and potentially rationalized by subtle perturbations in ribosome structure or in their dynamic properties. Finally, we discuss evidence that differential expression of variant rDNA alleles results in different populations of ribosome subtypes within mammalian tissues. These findings motivate further research into the impacts of rRNA heterogeneities on ribosomal function and predict that strategies targeting distinct ribosome subtypes may hold therapeutic potential.This article is part of the discussion meeting issue 'Ribosome diversity and its impact on protein synthesis, development and disease'.