Mixed roosts in the Montagu’s harrier Circus pygargus during courtship

Mixed communal roosting of Montagu’s harrier Circus pygargus in the pre-laying period was observed on Calcareous Marshes in Eastern Poland from 1992 to 1995. To my knowledge, this behaviour was described in literature for the first time. The communal roosting in Montagu’s harrier during courtship can help in estimation of mate attraction and finally in mate choice. Harriers from communal roosts start egg laying earlier when compared to the outside roosts. Communal roosting as anti-predator behaviour can help with predator detection and provides benefits to all members of the group. The pair formation process has led to disintegration of communal roosting. Males were more common in the roosting places than females. The time of roosting was correlated with the photoperiod. The weather and predators impact delayed the formation of mixed roosting places.     

Genetic information and insurance: some ethical issues.

Life is risky, and insurance provides one of the best developed ways of controlling risks. By pooling, and so transferring risks, those who turn out to suffer antecedently uncertain harms can be assured in advance that they will be helped if those harms arise; they can then plan their lives and activities with confidence that they are less at the mercy of ill fortune. Both publicly organized and commercial insurance can organize the pooling of risk in ways that are beneficial for all concerned. They provide standard ways of securing fundamental ethical values such as solidarity and mutuality. Although policy holders do not know or contract with one another, each benefits from the contribution of others to a shared scheme for pooling and so controlling risk. Although there is a limit to the degree to which commercially-based insurance, where premiums depend on risk level, can go beyond mutuality towards solidarity, in practice it too often achieves a measure of solidarity by taking a broad brush approach to pooling risk. However, the ordinary practices of insurance, and in particular of commercial insurance, also raise ethical questions. These may be put in simple terms by contrasting the way in which an insurance market discriminates between different people, on the basis of characteristics that (supposedly) determine their risk level, and our frequent abhorrence of discrimination, in particular on the basis on religious, racial and gender characteristics. Are the discriminations on which insurance practice relies upon as standard acceptable or not? The increasing availability of genetic information, which testing (of individuals) and screening (of populations) may provide, could lend urgency to these questions. Genetic information may provide a way of obtaining more accurate assessment of individual risks to health and life. This information could be used to discriminate more finely between the risk levels of different individuals, and then to alter the availability and the costs of health, life and unemployment insurance to them. Since all of these forms of insurance bear very directly on the way most people live, it will matter to them how (if at all) insurers take account of genetic information. Will use of this information improve or damage the capacity of insurance to provide confidence in the face of uncertain harms, and help if they happen? Will it discriminate in acceptable or in unacceptable ways? Will it support or damage the sorts of mutuality and solidarity various sorts of insurance schemes have successfully institutionalized?     

Changes in woody community structure and composition under constrasting landuse systems in a semi-arid savanna, South Africa

We aimed to explore the farm scale effects of three landuse types, communal grazing, wildlife management and commercial cattle farming, on the woody vegetation of a semiarid savanna. Location The study farms were located within a single bioclimatic zone in semiarid savanna, South Africa. Methods The species composition and structure of woody vegetation on three farms of each of three landuse types were sampled. Results We found that communal grazing land sites were classified outside the topland-bottomland vegetation dichotomy characteristic of this region. Comparisons of size class distributions showed the communal grazing lands had fewer small and large individuals; suggesting both lower levels of regeneration and regenerative capacity in the communal grazing lands. The species richness and biomass of woody plants was lower on communal grazing lands than on private game reserves and commercial cattle farms. The longevity of tree species explains the observed lag between changes in abundance and species loss; we consequently predict that there will be future losses of species in the communal grazing lands. By classifying species into a range of use-categories we showed that utilization and species loss was not limited to certain plant use categories. Higher levels of wood harvesting measured in the communal grazing lands are likely to be responsible for the observed differences. Main conclusions It is concluded that communal grazing management at this study site has substantially changed the composition and structure of woody plant communities, and that these changes have reduced the current availability of natural resources and will reduce resource production in the future.     

Impact of land use on vegetation composition, diversity, and selected soil properties of wetlands in the southern Drakensberg mountains, South Africa

Wetlands provide the ecosystem services of enhancing water quality, attenuating floods, sequestrating carbon and supporting biodiversity. In southern Africa, the pattern and intensity of land use is influenced by whether land tenure is public (state), private (individual ownership), or communal (shared agricultural and grazing resources). The influence of land tenure and its associated use on service provision was compared for communal tenure (grazing, maize production), wildlife conservation, and commercial agriculture (grazing, planted pastures) in the southern Drakensberg. Ordination analyses revealed that oxbow marshes, hill slope seepages and hygrophilous grasslands, the main hydro-geomorphic units, supported distinct plant communities that differed in their response to land use because of wetness or slope. Oxbows, uncultivated because of wetness, were inherently species poor with few exotics. Composition of hill slope seepages, uncultivated because of saturated slopes, varied among tenure types most likely in relation to grazing pressure. Seepages were threatened by the exotic invasive Rubus cuneifolius. Eighty-five percent of hygrophilous grassland had been cultivated by 1953, most of which was subsequently abandoned to secondary grassland. Primary hygrophilous grassland and hill slope seepages were the main repository for indigenous plant diversity, while communal maize fields supported a diverse mixture of mainly exotic species. Soil carbon concentrations decreased from oxbows to pastures, seepages, primary hygrophilous grassland, secondary grassland, and maize on former grassland (7.0, 4.1, 4.0, 3.5, 2.4, and 1.7%, respectively). The pattern for total soil nitrogen and sulphur were the same. Cultivation of hygrophilous grassland was estimated to have reduced soil carbon stocks to 69% of pre-settlement levels by 1953 (∼150 years BP). Stocks then increased by 8% to 2001 following crop abandonment. Cultivation has impaired water quality enhancement and flood attenuation because of greater amounts of bare ground and shorter vegetation. Further improvement of ecosystem services will depend on the influence of socio-economic factors on communal cropping.     

Rangeland as a Common Property Resource: Contrasting Insights from Communal Areas of Central Eastern Cape Province,South Africa

This paper explores the grazing management systems in operation in communal areas of central Eastern Cape Province, South Africa, through two contrasting case studies from the region. Considerable differences in current management systems are identified and are shown to depend primarily on the degree of control that can be exercised by communities over communal grazing resources. This in turn can be related to the social and ecological heterogeneity that characterises the region and how this influences pressure on grazing resources at the local level. On the basis of this study three broad levels of grazing management system are identified in these communal areas. These are: complete lack of management with grazing taking place in an ‘open-access’ manner; grazing being controlled on a community basis and grazing taking place on private land and being controlled entirely by the landowner. Many aspects of these scenarios find reflection in struggles over common property which are taking place in other parts of Africa. Understanding the variation in these systems from both a social and ecological perspective will be fundamental in challenging previous management paradigms, and facilitating the development of effective common property institutions for grazing management systems in communal areas of South Africa.     

The Moral Economy of Water: Equity and Antiquity in the Andean Commons

This article focuses on irrigation and water use in a community in the Peruvian Andes, one of numerous villages in the region where these activities are carried out in an unusual way. The practices and principles that make up this tradition, defining the rights and duties of community members in making use of the resource most vital for life, are identified and evaluated based on comparative ethnographic research. It is argued that they provide a highly effective way of managing a scarce and fluctuating resource that is held in common, an older Andean tradition that may have been adopted by the Incas and endorsed as an official policy—all of which might help to account for its wide distribution in the region today. In this particular case, the principles help to create an extraordinary kind of community, a transparent and equitable one in which a basic material symmetry or proportionality is expressed at many levels. This symmetry is closely related to other basic commonalities among community members, but of particular interest are its effects on social solidarity and cooperation and its association with a strong sense of ethnic identity. The implications of this tradition for solving contemporary problems in water management are also briefly discussed, [sociocultural anthropology, irrigation, Andes, common-property]     

The evolution of communal roosting in birds: origin and secondary losses

Three main benefits are thought to underlie communal roostingin birds: a reduction in thermoregulation demands, a decreasein predation risk, and an increase in foraging efficiency. Iinvestigated interspecific variation in communal roosting tendenciesacross categories of several ecological factors to examine therelevance of each functional hypothesis in the evolutionary transitionto communal roosting and the secondary reversal to solitary roostinghabits. The study phylogenetic tree included 30 families and437 species. Evolutionary transitions to communal roosting occurredmore often on branches with flocking species and with largerspecies but were not associated with diet, territoriality, geographicalarea, or time of day. The association with flocking activitiessuggests that increased foraging efficiency, a factor thoughtto operate through the formation of flocks, may have been akey factor in the origin of avian communal roosting. However,several transitions to communal roosting occurred on brancheswith nonflocking species, indicating that foraging efficiencymay not be the only factor involved in the evolution of communalroosting. Secondary losses of communal roosting habits occurredon several branches, with a concomitant loss of flocking behaviorand a tendency to exhibit territorial behavior and nocturnalforaging. Secondary losses suggest that communal roosting iscostly to perform and maintain and may be lost when an asocialselection regime operates. The large number of exceptions tothe above patterns may force a reevaluation of current functional hypothesesabout communal roosting in birds.     

High warning colour polymorphism in Heliconius hybrid zone roosts

1. Communal roosting behaviour has been documented among a wide range of taxa, particularly among groups of butterflies that display warning colourations. These aggregations of conspecifics and/or other species that share mimetic warning colour patterns can have a large impact on predator learning, and thus the survival of an aposematic form. Yet there has been limited investigation of communal roosting within areas where new and diverse warning colour forms are generated, such as hybrid zones. 2. Here, roosting behaviour was examined in a Heliconius erato hybrid zone in French Guiana between races with divergent warning colourations on their wings. In this hybrid zone, native individuals with nine distinct warning colourations, as well as individuals with altered forms that are not native in the French Guiana population, were marked and observed to determine if divergently coloured individuals participated in communal roosting, and if the proportions of colour pattern forms at roosts differed from the proportions that are found in the population. 3. The results demonstrated that divergently coloured individuals of the same species, including altered, non‐native forms, will readily and repeatedly participate in nocturnal communal roosting, often with extreme fidelity to specific perch locations. 4. These findings suggest that roosts composed of polymorphic warning patterns may be common in phenotypic transition zones, which could have major implications on predator training and selection dynamics in hybrid zones.     

Sibling solidarity in a polygamous community in the USA: unpacking inclusive fitness

This pilot study explores the degree of solidarity felt between full and half siblings who are raised in a Mormon Fundamentalist polygamous community. The community under study is unique in that, at the level of official culture, it actively promotes full and half sibling solidarity through an ethos that strives to downplay genetic differences in favor of a harmonious family living together in one household. This community is an ideal cultural setting in which to examine the suitability of inclusive fitness theory for understanding the factors that promote family cohesion, sibling solidarity, and rivalry. Our main question becomes: is the degree of sibling solidarity a manifestation of genetic closeness or a natural byproduct of emotional closeness that arises from being raised together? We found evidence for more solidarity between full siblings than between half siblings. Our data suggest that, despite the force of religious ideals, and notwithstanding the continued close physical proximity of half siblings in the polygamous family, there is a pronounced clustering of feeling and affection in the polygamous family that is consistent with inclusive fitness theory.     

The crisis seen from below,within, and against: from solidarity economy to food distribution cooperatives in Greece

Anthropological literature on crises and social and solidarity economies can benefit from integrated approaches that assess grassroots cooperatives formed during critical periods of capitalist recession. This article debates on why it is problematic to conceptualize the Greek crisis as exceptional and then examines the relationship between the solidarity economy and cooperatives and argues that the latter is a development of the former in the future plans of people struggling against the crisis being witnessed in Greece. It moreover makes a case for there being a need to pay more attention to the distribution sector. Its main aim is to point out how participants engaged in initiatives related to the solidarity economy tend to imagine that their activities are inspired by larger aims and claims than the immediate significance of their material actions. This is done by ethnographically analyzing organized social responses against crises through the rise of popular solidarity economies associated with distribution of food without middlemen.     

OBSERVATIONS ON THE COMMUNAL ROOSTING OF AFRICAN BLACK OYSTERCATCHERS

Hockey P. A. R. 1985. Observations on the communal roosting of African Black Oystercatchers. Ostrich 56: 52–57.

There are currently three main hypotheses for the adaptive significance of avian communal roosts: physiological advantages, predator avoidance and information centres. The African Black Oystercatcher Haematopus moquini is territorial throughout the year and forms communal roosts during the nonbreeding season, but does not breed communally. Roosts generally are small, and site fidelity is high. Roosts are normally sited on a rocky promontory with adjacent offshore rocks (west coast), or in flat areas with extensive all-round visibility. The main predators of African Black Oystercatchers are nocturnal terrestrial mammals and nocturnal communal roosts are larger and more tightly packed than daytime roosts. Breeding birds do not roost communally during the breeding season and at this time of year mortality due to mammal predators at a study site in Saldanha Bay was greatest (X² = 9.46; p<0.01). It appears therefore that predator avoidance is an important adaptive feature of communal roosting in this species.     

Sacrifice, Plants, and Western Pharmaceuticals: Money and Health Care in Northern Ghana

In this article I discuss the role of money vis-à-vis health care among the Dagomba, an agrarian people living in northern Ghana, whose pluralistic medical culture involves the use of both plants and Western pharmaceuticals in the treatment of various symptoms. In Dagomba society monetary exchanges in the domain of healing cannot be equated with self-interest, and nonmonetary exchanges cannot be compared with altruism in any straightforward fashion. Exchanges and their purposes are made meaningful by the contexts in which they occur. Exchanges may involve money and be commoditized. However, the very fact that such an exchange is made in a "benevolent and considerate manner" (which often means selling/buying on credit) transforms otherwise impersonal relationships between medicine sellers and their customers into displays of solidarity with the communal (collective) goals of Dagomba society.     

Thicket expansion in a South African savanna under divergent land use: local vs. global drivers?

Woody plant increase in grassy biomes has been widely reported over the last century. Increases have been attributed to local drivers associated with land use change, such as heavy grazing or fire suppression, or, controversially, to global drivers such as increased atmospheric carbon dioxide (CO₂). Here, we report a comparison of woody increase since the 1930s in three neighbouring areas with highly contrasting land use systems to help distinguish between local and global causes of woody increase. Aerial photography was used to measure changes in tree cover for three time intervals (1937, 1960, 2004) for three adjacent 25 km² sites which remained under radically different tenure (conservation, commercial farms, and communal rangeland) over the study period. From previous studies on drivers affecting savanna dynamics, we predicted a decrease in tree cover for the conservation and communal sites and an increase in tree cover at the commercial site. The analyses showed highly significant increases in tree cover at all sites. Total tree cover increased from 14% in 1937 to 58% in 2004 at the conservation site, 3–50% in the commercial ranching area and 6–25% in the communal farming area. Reconstruction of past land use practices showed large differences in stocking rates, herbivore species, burning practices, human population densities and natural resource harvesting between the three sites. These land use differences are reflected in differences in woody cover among the three sites in 2004. However, despite major differences in land use, tree cover also increased significantly in all three areas. This suggests global drivers favouring woody plant increase in grassy vegetation regardless of land use practises. In our study area the most likely candidates are increased CO₂ and/or atmospheric nitrogen deposition.     

Between the individual and the community: the impact of genetics on ethical models

This paper discusses how genetics is influencing ethical frameworks with particular focus on the effectiveness and appropriateness of individual and communal models. It suggests that genetics supports a relational understanding of the person and therefore that genetic ethics requires ethical models which respect both individuals and groups. First, the inadequacy of individualistic frameworks – at conceptual, ethical and practical levels – is outlined. Second, the “communal turn” in genetic ethics in both clinical and population ethics is considered. Third, it is claimed that this communal turn is applicable to genetic ethics in general and to illustrate this two further examples are explored: those of UK Biobank and personalized medicine. The paper concludes that ethical frameworks in genetic ethics must accommodate both group and individual concerns.     

白蚁诱食信息素研究进展

白蚁为社会性昆虫,其组织结构和联系方式主要由白蚁外分泌腺产生的起诱导和调节白蚁行为反应作用的信息素来获得。由白蚁下唇腺产生的诱食信息素,能够在白蚁巢体的群体性食物采集中诱使取食白蚁形成聚集,并且取食食物的相同位置,从而提高白蚁巢体采集食物的效率。目前,已确定对苯二酚为白蚁诱食信息素,且认为整个等翅目昆虫都产生和使用对苯二酚作为诱食信息素,与分类地位和生物学特性无关。该文概述了白蚁诱食信息素的分泌器官、种特异性、生物学意义、生物合成途径及其在白蚁防治中的应用等方面的研究进展。     

Molecular and dendrochronological analysis of natural root grafting in Populus tremuloides (Salicaceae)

Trembling aspen (Populus tremuloides) is a clonal tree species, which regenerates mostly through root suckering. In spite of vegetative propagation, aspen maintains high levels of clonal diversity. We hypothesized that the maintenance of clonal diversity in this species can be facilitated by integrating different clones through natural root grafts into aspen's communal root system. To verify this hypothesis, we analyzed root systems of three pure aspen stands where clones had been delineated with the help of molecular markers. Grafting between roots was frequent regardless of their genotypes. Root system excavations revealed that many roots were still living below trees that had been dead for several years. Some of these roots had no root connections other than grafts to living ramets of different clones. The uncovered root systems did not include any unique genotypes that would not occur among stems. Nevertheless, acquiring roots of dead trees helps to maintain extensive root systems, which increases the chances of clone survival. Substantial interconnectivity within clones as well as between clones via interclonal grafts results in formation of large genetically diverse physiological units. Such a clonal structure can significantly affect interpretations of diverse ecophysiological processes in forests of trembling aspen.     

Uniform and Complementary Social Interaction: Distinct Pathways to Solidarity

We examine how different forms of co-action give rise to feelings of solidarity. We propose that (a) coordinated action elicits a sense of solidarity, and (b) the process through which such solidarity emerges differs for different forms of co-action. We suggest that whether solidarity within groups emerges from uniform action (e.g. synchronizing, as when people speak in unison) or from more complementary forms of action (e.g. alternating, when speaking in turns) has important consequences for the emergent position of individuals within the group. Uniform action relies on commonality, leaving little scope for individuality. In complementary action each individual makes a distinctive contribution to the group, thereby increasing a sense of personal value to the group, which should contribute to the emergence of solidarity. The predictions receive support from five studies, in which we study groups in laboratory and field settings. Results show that both complementary and uniform co-action increase a sense of solidarity compared to control conditions. However, in the complementary action condition, but not in the uniform action (or synchrony) condition, the effect on feelings of solidarity is mediated by a sense of personal value to the group.     

The benefit of being a social butterfly: communal roosting deters predation

Aposematic passion-vine butterflies from the genus Heliconius form communal roosts on a nightly basis. This behaviour has been hypothesized to be beneficial in terms of information sharing and/or anti-predator defence. To better understand the adaptive value of communal roosting, we tested these two hypotheses in field studies. The information-sharing hypothesis was addressed by examining following behaviour of butterflies departing from natural roosts. We found no evidence of roost mates following one another to resources, thus providing no support for this hypothesis. The anti-predator defence hypothesis was tested using avian-indiscriminable Heliconius erato models placed singly and in aggregations at field sites. A significantly higher number of predation attempts were observed on solitary models versus aggregations of models. This relationship between aggregation size and attack rate suggests that communally roosting butterflies enjoy the benefits of both overall decreased attack frequency as well as a prey dilution effect. Communal roosts probably deter predators through collective aposematism in which aggregations of conspicuous, unpalatable prey communicate a more effective repel signal to predators. On the basis of our results, we propose that predation by birds is a key selective pressure maintaining Heliconius communal roosting behaviour.     

A resynthesis of the primordial and circumstantial approaches to ethnic group solidarity: Towards an explanatory model

Social scientists who have attempted to explain ethnic group solidarity have tended to use either the primordial or the circumstantial approach. The first approach accounts for strong ethnic attachments on the basis of their ineffable affective significance. Moreover, this affective significance most often surrounds images of the group's distinctive past, thus giving a historical dimension to the concept of primordialism. The second approach views ethnic group solidarity as resulting from certain social circumstances, both internal and external, under which the members of the group exist. It is argued that neither approach alone offers a sufficient explanation ‐ i.e., that the primordial approach cannot readily account for fluctuating ethnic group solidarity and that the circumstantial approach tends to ignore the affective significance of ethnic ties ‐ and that previous attempts to synthesize them have been inadequate as explanatory models. Such a synthetic model is offered, which is based on the oppositional approach originated by Edward Spicer and which maintains that fluctuating ethnicity, along with fluctuating primordial sentiments, can be best explained on the basis of the circumstance of fluctuating opposition.     

Solidarity and justice as guiding principles in genomic research

In genomic research the ideal standard of free, informed, prior and explicit consent is sometimes difficult to apply. This has raised concern that important genomic research will be restricted. Different consent procedures have therefore been proposed. This paper explicitly examines the question how, in genomic research, the principles of solidarity and justice can be used to justify forms of diminished individual control over personal data and bio-samples. After a discussion of the notions of solidarity and justice and how they can be related to health care and genomic research, we examine how and in which situations these notions can form a strong moral basis for demanding certain financial sacrifices. Then we examine when these principles can justify consent procedures which diverge from the ideal standard. Because much genomic research is not expected to lead to immediate (clinical) benefits we also discuss the question of whether we can be obliged to make any sacrifices for future (not yet existing) patients. We conclude with the formulation of a number of conditions that have to be met before autonomy sacrifices can be reasonably demanded in genomic research.