Level Of Social Complexity Research Articles

Social complexity, life-history and lineage influence the molecular basis of castes in vespid wasps

A key mechanistic hypothesis for the evolution of division of labour in social insects is that a shared set of genes co-opted from a common solitary ancestral ground plan (a genetic toolkit for sociality) regulates caste differentiation across levels of social complexity. Using brain transcriptome data from nine species of vespid wasps, we test for overlap in differentially expressed caste genes and use machine learning models to predict castes using different gene sets. We find evidence of a shared genetic toolkit across species representing different levels of social complexity. We also find evidence of additional fine-scale differences in predictive gene sets, functional enrichment and rates of gene evolution that are related to level of social complexity, lineage and of colony founding. These results suggest that the concept of a shared genetic toolkit for sociality may be too simplistic to fully describe the process of the major transition to sociality.

What is really social about social insect cognition?

It is often assumed that social life imposes specific cognitive demands for animals to communicate, cooperate and compete, ultimately requiring larger brains. The “social brain” hypothesis is supported by data in primates and some other vertebrates, but doubts have been raised over its applicability to other taxa, and in particular insects. Here, we review recent advances in insect cognition research and ask whether we can identify cognitive capacities that are specific to social species. One difficulty involved in testing the social brain hypothesis in insects is that many of the model species used in cognition studies are highly social (eusocial), and comparatively little work has been done in insects that live in less integrated social structures or that are solitary. As more species are studied, it is becoming clear that insects share a rich cognitive repertoire and that these abilities are not directly related to their level of social complexity. Moreover, some of the cognitive mechanisms involved in many social interactions may not differ from those involved in non-social behaviors. We discuss the need for a more comparative and neurobiologically grounded research agenda to better understand the evolution of insect brains and cognition.

Measuring social determinants of health and their impact on service use and medical complexity

IntroductionPopulation based data on the social determinants of health are not widely available, despite a wide body of evidence pointing to their importance. The Mantioba Population Research Data Repository offers a unique opportunity to leverage data from multiple government departments to assess the relationship between measurable social determinants and health.
 Objectives and ApproachUsing population based data from health, small area level census survey questions, social assisitance, education, social housing, child protective services and justice, linked at the individual level, we measured indicators of social complexity and mapped them in the province of Manitoba. Individuals with high level of social complexity were then compared with indicators of medical complexity and/or high use of medical services to determine the degree of overlap between these attributes of individuals. A matched group of individuals without any of the measured social complexities was developed and the number and reason for visits to primary care providers was compared.
 ResultsThe rate of individuals having three or more social complexities varied from a low of ~7% to a high of 35%, depending on the geographic location. High residential mobiity, involvement with the justice system and history of social assistance were the most frequent (>15%). Individuals with social complexities tended to be younger and live in poorer neighbourhoods than medically complex individuals or high users of health services. Socially complex persons had on average 5.5 primary care visits annually, compared to only ~3.5 for matched individuals with no social complexities. The overlap with high users of health services was slight (14.4%) and depended on the characteristics of the population. The overlap with medically complex patients ws higher (16.2%), particularly when medical complexity included mental health related diagnoses (20.4%).
 Conclusion/ImplicationsThe proportion of individuals with social complexities is large, and a substantial number have multiple risk factors. These individuals are for the most part a unique group, distinct from medically complex patients. Different strategies for care may be necessary to promote and sustain mental and physical health and wellbeing.

Molecular signatures of plastic phenotypes in two eusocial insect species with simple societies

Phenotypic plasticity is important in adaptation and shapes the evolution of organisms. However, we understand little about what aspects of the genome are important in facilitating plasticity. Eusocial insect societies produce plastic phenotypes from the same genome, as reproductives (queens) and nonreproductives (workers). The greatest plasticity is found in the simple eusocial insect societies in which individuals retain the ability to switch between reproductive and nonreproductive phenotypes as adults. We lack comprehensive data on the molecular basis of plastic phenotypes. Here, we sequenced genomes, microRNAs (miRNAs), and multiple transcriptomes and methylomes from individual brains in a wasp (Polistes canadensis) and an ant (Dinoponera quadriceps) that live in simple eusocial societies. In both species, we found few differences between phenotypes at the transcriptional level, with little functional specialization, and no evidence that phenotype-specific gene expression is driven by DNA methylation or miRNAs. Instead, phenotypic differentiation was defined more subtly by nonrandom transcriptional network organization, with roles in these networks for both conserved and taxon-restricted genes. The general lack of highly methylated regions or methylome patterning in both species may be an important mechanism for achieving plasticity among phenotypes during adulthood. These findings define previously unidentified hypotheses on the genomic processes that facilitate plasticity and suggest that the molecular hallmarks of social behavior are likely to differ with the level of social complexity.

Trade as a Premise for Social Complexity

The argument of this paper is that trade is an important causal factor for the origins of social complexity, not just a co-evolutionary process. Ancient trade has played a crucial role for the origins of the first state level society (Early Uruk) and was a premise for social complexity between 9000 and 3000 BC. Due to the comparative advantage for clay and water transportation and to a series of innovations (pottery wheel and the tokens system), during the first state level polity there emerged a series of institutions, such as money, redistribution and wage payments. These subsequently increased the level of social complexity and economic development of the Early Uruk from city to the status of first political economy. A secondary hypothesis of this paper is concerned with the type of organization of this first political economy. The argument is that Uruk was more an entrepreneurial organization that paid wages according to the division of labor and had less central governance for the redistribution of the public goods. It was a “political enterprise” with more entrepreneurial attributes than political attributes. Thus, the necessary and sufficiency conditions for trade as a premise for social complexity are being fulfilled.

Population genomics of eusocial insects: the costs of a vertebrate‐like effective population size

The evolution of reproductive division of labour and social life in social insects has lead to the emergence of several life-history traits and adaptations typical of larger organisms: social insect colonies can reach masses of several kilograms, they start reproducing only when they are several years old, and can live for decades. These features and the monopolization of reproduction by only one or few individuals in a colony should affect molecular evolution by reducing the effective population size. We tested this prediction by analysing genome-wide patterns of coding sequence polymorphism and divergence in eusocial vs. noneusocial insects based on newly generated RNA-seq data. We report very low amounts of genetic polymorphism and an elevated ratio of nonsynonymous to synonymous changes – a marker of the effective population size – in four distinct species of eusocial insects, which were more similar to vertebrates than to solitary insects regarding molecular evolutionary processes. Moreover, the ratio of nonsynonymous to synonymous substitutions was positively correlated with the level of social complexity across ant species. These results are fully consistent with the hypothesis of a reduced effective population size and an increased genetic load in eusocial insects, indicating that the evolution of social life has important consequences at both the genomic and population levels.

From Aggregation to Dispersion: How Habitat Fragmentation Prevents the Emergence of Consensual Decision Making in a Group

In fragmented landscape, individuals have to cope with the fragmentation level in order to aggregate in the same patch and take advantage of group-living. Aggregation results from responses to environmental heterogeneities and/or positive influence of the presence of congeners. In this context, the fragmentation of resting sites highlights how individuals make a compromise between two individual preferences: (1) being aggregated with conspecifics and (2) having access to these resting sites. As in previous studies, when the carrying capacity of available resting sites is large enough to contain the entire group, a single aggregation site is collectively selected. In this study, we have uncoupled fragmentation and habitat loss: the population size and total surface of the resting sites are maintained at a constant value, an increase in fragmentation implies a decrease in the carrying capacity of each shelter. For our model organism, Blattella germanica, our experimental and theoretical approach shows that, for low fragmentation level, a single resting site is collectively selected. However, for higher level of fragmentation, individuals are randomly distributed between fragments and the total sheltered population decreases. In the latter case, social amplification process is not activated and consequently, consensual decision making cannot emerge and the distribution of individuals among sites is only driven by their individual propensity to find a site. This intimate relation between aggregation pattern and landscape patchiness described in our theoretical model is generic for several gregarious species. We expect that any group-living species showing the same structure of interactions should present the same type of dispersion-aggregation response to fragmentation regardless of their level of social complexity.

Consistent social structure and optimal clique size revealed by social network analysis of feral goats, Capra hircus

Social network analysis has become a valuable tool for the measurement of social bonds and can give insight into the level of social complexity in a species. However, most studies have focused on a single social group or community, and we have a rather limited understanding of the extent to which a species' network structure varies across groups and across habitats. We investigated the strength and structure of social bonds in feral goat groups in two geographical locations that differ in ecological and climatic conditions. We found that a range of strengths of social bonds existed between female goats, with behavioural and spatial measures being highly correlated. Levels of aggression between spatially proximate individuals reflected the intrinsic costs of social living, but lower rates between more strongly bonded individuals indicated a degree of social tolerance. We found a consistent social structure despite differences in demography and ecology and we propose that associations are driven by social benefits as well as by ecological requirements. We suggest that a clique size of 12–13 individuals may be optimal for goats; beyond this threshold, the system may be less stable and susceptible to fission.

Colony Size Evolution and the Origin of Eusociality in Corbiculate Bees (Hymenoptera: Apinae)

Recently, it has been proposed that the one of the main determinants of complex societies in Hymenoptera is colony size, since the existence of large colonies reduces the direct reproductive success of an average individual, given a decreased chance of being part of the reproductive caste. In this study, we evaluate colony size evolution in corbiculate bees and their relationship with the sociality level shown by these bees. Specifically i) the correlation between colony size and level of sociality considering the phylogenetic relationship to evaluate a general evolutionary tendency, and ii) the hypothetical ancestral forms of several clades within a phylogeny of corbiculate bees, to address idiosyncratic process occurring at important nodes. We found that the level of social complexity in corbiculate bees is phylogenetically correlated with colony size. Additionally, another process is invoked to propose why colony size evolved concurrently with the level of social complexity. The study of this trait improves the understanding of the evolutionary transition from simple to complex societies, and highlights the importance of explicit probabilistic models to test the evolution of other important characters involved in the origin of eusociality.

The Proboscis Extension Reflex Not Elicited in Megachilid Bees

A honey bee will reflexively extend its proboscis in response to antennal stimulation with sucrose solution (Bitterman et al, 1983). For decades the proboscis extension reflex (PER) of honey bees {Apis mellifera L., Hymenoptera: Apidae) has been used as a tool to further the understanding of their cognitive processes, such as learning and memory (Takeda, 1961; Bitterman et al, 1983), and revealing their neural and molecular foundations (reviewed in Giurfa, 2007). The PER has also been used to demonstrate learning abilities of bumble bees (Hymenoptera: Bombus spp.) (Laloi et al, 1999; Laloi and PhamDelegue, 2004) and stingless bees (Hymenoptera: Apidae) (Abramson et al, 1999; McCabe et al, 2007). We were interested in using the PER to answer questions about the cognitive processes of solitary bees, especially Osmia lignaria Say (blue orchard bee) and Megachile rotundata Fabricius (alfalfa leafcutting bee) (Hymenoptera: Megachildae). Our initial attempts to use simple PER elicitation procedures with O. lignaria failed, although honey bees readily responded. The lack of response in O. lignaria could have been due to procedural factors, such as method of bee restraint (Robin L. Foster, pers. comm.), or speciesspecific factors, such as level of social complexity. To determine whether the technique used to elicit the PER from honey bees can be adapted for use with other bees, we tested variations of the traditional PER elicitation technique on several species of Hymenoptera.

Who is Responsible?

On a continent crazed with litigation, it is sometimes easy to get carried away. This is a plea for taking responsibility in the outdoors. One of the great beauties of the so called 'pure' outdoor adventure experience is that it provides us with clear successes in a simplified world; a world over which we can exercise a higher than usual degree of control. Here the connection between actions and consequences are unmistakable. You reach for a handhold on a rock wall, or pick a break in the surf to make your landing and the feedback is immediate. Either you continue with confidence or you take a hit and hopefully learn something. This dynamic is a big part of wilderness adventure and it sets it apart from the experience of the tourist on a railed broad-walk at a roadside park where the most serious risk is likely to be an accidental slip or getting mugged. The 'pure' outdoor experience is probably an unattainable ideal, but a solo rock-climber approaches it when climbing without protection on a challenging wall. For the sea kayaker it may be the solo crossing in marginal conditions while for the back country skier, the moment likely comes from being utterly committed in the sort of conditions that stretch every nerve and sinew to survive. This moment may not last long, but it feeds the soul long after you've returned to civilization. My examples are mostly solo situations. This is because the intensity of the experience frequently has an inverse relationship to the number of people in your group. Also any ambiguity about exactly who is responsible is removed. For sure, group travel provides its own moments of intensity but the elegant simplicity of being alone is absent and often responsibility is passed off to a guide or leader. Solo ventures unfortunately tend to be frowned upon by peers and society in general, often on the basis of safety, but also because people who choose to act alone like that make the rest of us feel just a little bit uncomfortable. "Who are they to think they don't need 'us'?" Between the tourist on the railed broad-walk and the solo rock-climber, the field is graded unevenly and we select our comfort zones according to the situation and our familiarity with the activity. In North American society there are entire industries populated by people who need to be needed, including the medical and legal professions, police, coast guard, search and rescue, regulating bureaucracies, and many more. They are there to share the load, control the masses and catch us when we stumble, and they perform extraordinarily valuable services, for which we willingly pay privately or with our taxes. Each time we buy into one of these services, however, we assign them a little of our own personal responsibility and in exchange we agree to play the game by their rules. This leads in turn to a mind-numbing level of social complexity and an ever increasing sense of individual powerlessness that leads eventually to alienation. Enter the outdoor adventure. Here you get to choose your risk and the level that is manageable for you, and through the process of managing this risk, you regain some of the self-respect and empowerment lost in the social grinder. You look at the weather, check the conditions, then commit to the move. For the first time in months, you are totally responsible for your actions and what's that barely remembered sensation? An exhilarating sense of freedom sweeps over you. You realize there's a link between freedom and being responsible for your actions. As with all freedom, it is seldom handed to you on a plate, and when it is, it can be quickly lost. What was it JFK said about that? Vigilance is the price of freedom, or was freedom the price of vigilance? Of course, both are right in different circumstances. We need a measure of vigilance to maintain the source of freedom we've discovered. Vigilance against what, you may ask? Vigilance against losing our right to take these risks. …

Burnished Pottery and Gender Hierarchy in Iron Age Israelite Society

One of the typical characteristics of Iron Age II pottery in ancient Israel is slip and burnish, which was applied to many vessels, especially bowls, jugs and juglets. No functional explanation can account for the phenomenon, and the reason for the (re)appearance of this treatment at the turn of the first millennium BC should be sought in the social realm. Vessels that received this treatment were used for food consumption, while vessels used for food preparation and storage remained in their -natural- form. In ancient Israel, like many other societies, food preparation was regarded as women-s work and was conducted by them in the private part of the dwelling, while public food consumption was regarded as men-s business. It is suggested that the level of social complexity, which peaked around 1000 BC with the formation of the monarchy, also deepened gender inequalities, which were symbolized by an elaborated treatment of vessels used for masculine activities. It is also possible that, while vessels used for women's activities remained within the realm of nature (earthenwares), the slip and burnish transformed the vessels used for masculine activities and brought them into the realm of culture.

Managing Infidelity: A Cross-Cultural Perspective

Anthropologists have not systematically examined extramarital affairs. Our cross-cultural study found that within every culture men and women actively resort to mate-guarding tactics to control their mate's extramarital behavior. A person's level of interest and involvement does not change with a culture's notion of descent, level of social complexity, or the degree to which a culture is normatively permissive or restrictive in sexual matters. In effect, sexual propriety is the presumed right of both sexes. Our findings are consistent with both the sexual jealousy and the pair-bond hypotheses, which hold that every marriage or love relationship is organized around a presumption of sexual propriety. (Extramarital affair, pair bond, sexual jealousy, human universal) ********** Conventional wisdom holds that in many societies women express relative indifference to their spouse's infidelities. Many social-science researchers ascribe this indifference to either male's propensity for psychological violence (Bourdieu 2001; MacKinnon 1988) or women's structural marginality (Freeman 1990; Harris 1993; Leacock 1993; Ressner 1987; Rosaldo and Lamphere 1974). These theories link patriarchy with male superiority to account for institutionalizing a double standard. A constant life lesson for women in these societies is their inability to forestall their spouse's infidelities. Reinforced by folk ideology, social convention, and common practices, men come to believe that it is their right to have extramarital affairs, while women become indifferent to their spouse's infidelity. From this theoretical perspective, it is axiomatic that men believe that they have ownership of women's bodies, whereas women own neither their own bodies nor that of their spouse. The strength of this axiom derives in part from a kind of folklore of professional anthropologists and not from empirical documentation. To date, there is no comparative study that systematically examines how husbands and wives respond to a spouse's infidelity. Thus, the conventional wisdom of ownership and indifference remains untested anthropological assertion. This article examines the similarities and differences in women's and men's responses to a mate's infidelity. It explores the significance of structural factors--degree of social complexity, type of descent ideology, the degree to which sexual practices are restrictive or permissive, etc.--on the way men and women respond to an act of infidelity. It also questions if there are sex-linked factors shaping men's and women's perception of and response to spousal infidelity. SOCIAL-SCIENCE EXPLANATIONS FOR EXTRAMARITAL AFFAIRS Half a century ago, Ford and Beach's (1951) pioneering cross-cultural study of human sexuality found that less than 39 per cent (54 out of 139) of societies approved of some form of infidelity. Although not explored in any depth, the study determined that cultures overwhelmingly prefer to circumscribe [extramarital affairs] in one way or another (Ford and Beach 1951:114). A more recent cross-cultural survey of human sexuality found that extramarital affairs ranked just below incest the most strictly prohibited type of sexual relationships (Frayser 1985:20). This finding was reaffirmed in a study that found no society, not even America during the permissive 1960s, condoning extramarital affairs (Harrell 1997:475). In spite of these holocultural surveys, cultural anthropology has yet to develop a theory accounting for extramarital sex's nearly universal approbation. There are theories that focus on some aspect of the phenomenon. The most prevalent explanation is sociological. This perspective offers a gender-specific explanation for why men's extramarital affairs are tolerated more than women's. Focusing exclusively on stratified societies, Collins (1975) argues that men are the beneficiaries of a patriarchal ideology and a set of social practices that ensure and validate men's perception of women as their sexual property. …

Genetic Correlations and Matrilineal Structure in a Population of Spermophilus richardsonii

We analyzed nine matrilines within a single population of Richardson's ground squirrels ( Spermophilus richardsonii ) from southern Alberta, Canada, for genetic variability at six allozymic loci. Significant genetic differentiation was found among matrilines. The matrix of genetic distance between each pair of individuals was randomly associated with geographic distance, but matrices of genetic distance and coancestry, as well as coancestry and geographic distance, were significantly negatively correlated. Neighboring females tended to be more related than would be expected due to chance, not only within the entire population, but within individual matrilines as well. Correlation of coancestry and genetic distance values indicates that the predictability of kinship from genotypic data alone is unreliable. Female philopatry gives rise to non-random spatial and genetic associations of related individuals. This is the first documented genetic difference between matrilines for a sciurid species with a relatively low level of social complexity.

Architectural Patterns at Three Aztec-Period Sites in Morelos, Mexico

AbstractExcavations conducted by the Postclassic Morelos Archaeological Project in western Morelos, Mexico, have recovered data on stone architecture during the Late Postclassic, or Aztec, period at three sites: Cuexcomate (a town settlement); Capilco (a village); and Site 3 (a farmstead). Whereas the village site exhibits only one class of structures (ground-level houses), the town has a diversity of architectural classes including ground-level houses, platform houses, temple platforms, circular structures, and rock piles. These categories are described and the nature of inter-class and intra-class architectural variability is explored. Our results shed light on the nature of the Aztec peasantry, suggesting a high level of social complexity in rural provincial areas.