Dynamic foraging strategy adaptation to heterogeneous environments contributes to social aggregation in snub-nosed monkeys

The dynamics of animal social structures are heavily influenced by environmental patterns of competition and cooperation.In folivorous colobine primates,prevailing theories suggest that larger group sizes should be favored in rainforests with a year-round abundance of food,thereby reducing feeding competition.Yet,paradoxically,larger groups are frequently found in high-altitude or high-latitude montane ecosystems characterized by a seasonal scarcity of leaves.This contradiction is posited to arise from cooperative benefits in heterogeneous environments.To investigate this hypothesis,we carried out a six-year field study on two neighboring groups of golden snub-nosed monkey(Rhinopithecus roxellana),a species representing the northernmost distribution of colobine primates.Results showed that the groups adjusted their movement and habitat selection in response to fluctuating climates and spatiotemporal variability of resources,indicative of a dynamic foraging strategy.Notably,during the cold,resource-scarce conditions in winter,the large group occupied food-rich habitats but did not exhibit significantly longer daily travel distances than the smaller neighboring group.Subsequently,we compiled an eco-behavioral dataset of 52 colobine species to explore their evolutionary trajectories.Analysis of this dataset suggested that the increase in group size may have evolved via home range expansion in response to the cold and heterogeneous climates found at higher altitudes or latitudes.Hence,we developed a multi-benefits framework to interpret the formation of larger groups by integrating environmental heterogeneity.In cold and diverse environments,even smaller groups require larger home ranges to meet their dynamic survival needs.The spatiotemporal distribution of high-quality resources within these expanded home ranges facilitates more frequent interactions between groups,thereby encouraging social aggregation into larger groups.This process enhances the benefits of collaborative actions and reproductive opportunities,while simultaneously optimizing travel costs through a dynamic foraging strategy.

Social development and living environment changes in the Northeast Tibetan Plateau and contiguous regions during the late prehistoric period

The relationship between the evolution of human societies and their living environments has been discussed intensively in recent decades.It is important to understand the patterns and mechanisms of human–environment interaction and evolution in order to cope with rapidly changing environments in the modern world.We reviewed the results of dating,archaeobotanical,and zooarchaeological studies from 139 prehistoric sites in the Northeast Tibetan Plateau(NETP)and contiguous regions(NETP-CR:i.e.,the Hexi Corridor and western margin of the Chinese Loess Plateau)and compared them with paleoenvironmental records to study variations in spatiotemporal patterns of social development in the area and their relationships with climate and vegetation changes.Our results show that hunter-gatherer groups occupied vast areas of the NETP at low intensities during^15,000–5500 BP(years before present).This was directly related to forest cover and climate change.An increase in temperature and precipitation turnover of vegetation from desert steppe to alpine meadow/subalpine shrub,and recovery of animal population on the Tibetan Plateau created more food resources and space for hunter-gatherers.Millet farmers settled extensively below 2500 m a.s.l.(meters above sea level)in the NETP-CR between^5500 and 3600 BP,and might have coexisted with hunting groups above 2500 m a.s.l.via subsistence exchange.The distribution of human settlements during that period was affected by climate change,with the relatively warm and wet climate promoting the expansion of millet agriculture to the NETP-CR during 5500–4500 BP,while climate deterioration caused humans to retreat to lower altitudes.During 3600–2200 BP,a range of livelihoods emerged in different regions of the NETPCR.This was promoted by early trans-Eurasian exchange and the development of an agro-pastoral economy that utilized cold-tolerant crops and livestock.This eventually promoted the expansion of permanent human settlements to high-altitude areas in the NETP.This study found that human societies adopted various strategies to adapt to the changing living environment throughout late prehistoric times in the NETP-CR.The results provide a long-term perspective on the trajectory of regional socio-environmental co-evolution.

Social Scale and Collective Computation:Does Information Processing Limit Rate of Growth in Scale?

Collective computation is the process by which groups store and share information to arrive at decisions for collective behavior.How societies engage in effective collective computation depends partly on their scale.Social arrangements and technologies that work for small-and mid-scale societies are inadequate for dealing effectively with the much larger communication loads that societies face during the growth in scale that is a hallmark of the Holocene.An important bottleneck for growth may be the development of systems for persistent recording of information(writing),and perhaps also the abstraction of money for generalizing exchange mechanisms.Building on Shin et al.,we identify a Scale Threshold to be crossed before societies can develop such systems,and an Information Threshold which,once crossed,allows more or less unlimited growth in scale.We introduce several additional articles in this special issue that elaborate or evaluate this Thresholds Model for particular types of societies or times and places in the world.

Acromyrmex ameliae sp. n. （Hymenoptera： Formicidae）： A new social parasite of leaf-cutting ants in Brazil

The fungus-growing ants （Tribe Attini） are a New World group of〉 200 species, all obligate symbionts with a fungus they use for food. Four attine taxa are known to be social parasites of other attines. Acromyrmex （ Pseudoatta） argentina argentina and Acromyrmex （Pseudoatta） argentina platensis （parasites of Acromyrmex lundi）, and Acromyrmex sp. （a parasite of Acromyrmex rugosus） produce no worker caste. In contrast, the recently discovered Acromyrmex insinuator （a parasite of Acromyrmex echinatior） does produce workers. Here, we describe a new species, Acromyrmex ameliae, a social parasite of Acromyrmex subterraneus subterraneus and Acromyrmex subterraneus brunneus in Minas Gerais, Brasil. Like A. insinuator, it produces workers and appears to be closely related to its hosts. Similar social parasites may be fairly common in the fungus-growing ants, but overlooked due to the close resemblance between parasite and host workers.

Marx＇s Four Expositions of His Theory of Social Formation and Their Historico-philosophic Significance

An examination of Marx＇s exposition of the evolution of social formations on four occasions shows that the core content of his social formation theory consists in its affirmation of both the universality of the law of the development of social formations from lower to higher stages in different nations and the diversity of their developmental paths. The theoretical assumptions he put forward in the late 19th century about the possibility of late- developing modernizers being able to establish a socialist society without passing through the stage of capitalism represent a major development of his theory of social formations. The theory of the primary stage of socialism and the theory of building socialism with Chinese characteristics advanced by the Chinese Communists are the latest development of Marx＇s theory of social formations.

Hierarchical networks of food exchange in the black garden ant Lasius niger

In most eusocial insects,the division of labor results in relatively few individuals foraging for the entire colony.Thus,the survival of the colony depends on its efficiency in meeting the nutritional needs of all its members.Here,we characterize the network topology of a eusocial insect to understand the role and centrality of each caste in this network during the process of food dissemination.We constructed trophallaxis networks from 34 food-exchange experiments in black garden ants(Lasius niger).We tested the influence of brood and colony size on(i)global indices at the network level(i.e.,efficiency,resilience,centralization,and modularity)and(ii)individual values(i.e.,degree,strength,betweenness,and the clustering coefficient).Network resilience,the ratio between global efficiency and centralization,was stable with colony size but increased in the presence of broods,presumably in response to the nutritional needs of larvae.Individual metrics highlighted the major role of foragers in food dissemination.In addition,a hierarchical clustering analysis suggested that some domestics acted as intermediaries between foragers and other domestics.Networks appeared to be hierarchical rather than random or centralized exclusively around foragers.Finally,our results suggested that networks emerging from social insect interactions can improve group performance and thus colony fitness.

On ethics,the pursuit of knowledge,truth and status in the hallowed halls of academe

Advancement in academe is largely on the basis of research output;that is,refereed journal papers.This paper first explores pressures on academics,especially emerging researchers,when English is not a first language.We assess why,when faculty members rush to improve their station that they may elect to circumvent ethical protocols to accelerate their promotion and status.The resulting unethical behavior includes plagiarism and forms of duplication such as co-submission.Consideration is then given to the wider implications of both plagiarism and the theft of intellectual property,and the role these have played in the development of individuals,the university and society.