Role Of Group Size Research Articles

Geographical indications' prices and marketing margins: the role of group size, longevity and production decisions

PurposeGeographical indication (GI) labels aim to improving farmers' and processors' income. This article studies how characteristics related to GI groups and their reputation (e.g. the producer group size, longevity and production decisions) are related to prices at the origin, final (consumption) prices and marketing margins.Design/methodology/approach The authors use 8 years of annual data for the Italian Extra Virgin Olive Oil (EVOO) GI market encompassing 46 GI EVOOs. Estimated parameters characterizing the relationship between the GI's group features and prices (at origin and at consumption) are obtained via Three-Stage Least Squares (3SLS).FindingsResults show that the number of GI operators is related to consumption prices, while is weakly related to prices at the origin. GIs' age is not associated with higher consumption prices, while origin prices are lower for older GIs compared to younger ones. Higher farmers' olive/oil conversion rate is associated with lower origin and consumption prices, whereas the extent of vertical integration is related to higher prices at the origin and a higher share of the marketing margins going to producers.Originality/valueTo the best of their knowledge, the authors offer the first empirical evidence on how structural characteristics and production decisions of a GI group relate to prices and marketing margins.

Social Group Size and Shelter Availability Influence Individual Metabolic Traits in a Social Fish.

SynopsisGroup living is widespread among animal species and yields both costs and benefits. Presence of conspecifics can restrict or enhance the expression of individual behavior, and the recent social environment is thought to affect behavioral responses in later contexts, even when individuals are alone. However, little is known about how social group size influences the expression of individual physiological traits, including metabolic rates. There is some evidence that shoaling can reduce fish metabolic rates but this variable may be affected by habitat conditions such as shelter availability via density-dependent processes. We investigated how social group size and shelter availability influence Eurasian minnow (Phoxinus phoxinus) metabolic rates estimated by respirometry. Respirometry trials were conducted on fish in isolation before and after they were housed for 3 weeks in a social treatment consisting in a specific group size (n = 4 or 8) and shelter availability (presence or absence of plant shelter in the experimental tank). Plant shelter was placed over respirometers for half of the duration of the respirometry trials, allowing estimation of minimum daytime and nighttime metabolic rates in both conditions (in the presence or absence of plant shelter). Standard metabolic rate (SMR), maximum metabolic rate (MMR), and aerobic scope were also estimated over the entire trial. Minimum daytime and nighttime metabolic rates estimated while in presence of plant shelter were lower than when estimated in absence of plant shelter, both before and after individuals were housed in their social treatment. After the social treatment, SMRs were higher for fish that were held in groups of 4 as compared with those of fish held in groups of 8, while MMR showed no difference. Plant shelter availability during the social treatments did not influence SMR or MMR. Our results suggest that social group size may directly influence energy demands of individuals, highlighting the importance of understanding the role of group size on variations in physiological traits associated with energy expenditure.

Group size and aquatic vegetation modulates male preferences for female shoals in wild zebrafish, Danio rerio

Shoaling decisions in the wild are determined by a combination of innate preferences of the individual along with the interplay of multiple ecological factors. In their natural habitat as well as in the laboratory, zebrafish is a shoaling fish. Here, we investigate the role of group size and associated vegetation in shaping shoaling preferences of wild male zebrafish. We studied the association preference of males to groups of female shoals in a multi-choice test design. We found that males made greater proportion of visits to an 8-female group compared to 2 and 4-female groups. However, males spent similar proportions of time across the three female-containing groups. When artificial vegetation was incorporated along with female number as an additional factor, we found that males prefer high and moderately vegetated patches compared to low or no-vegetation groups, irrespective of the number of females in these patches. Based on experiments using a novel multi-choice design, our results show that preference for group size can change due to interaction of two separate factors. This work is a first attempt to understand the role of aquatic flora in determining shoaling preferences in zebrafish, using an experimental paradigm consisting of a gradation in female and vegetation densities.

Trust or Control? The Role of Group Size in Governing Small‐scale Irrigation Facilities*

AbstractOne of the key issues in collective action is whether stakeholders are able to realize commons governance through a trust‐based mode or control‐based mode. This paper, examines whether trust and control affect the commons governance for small‐scale irrigation facilities, and the moderating effects of group size on the relationship between trust and control and cooperative performance. The data were collected from 504 households who participated in the collective action for small‐scale irrigation facilities in Shaanxi, Gansu Province, and Ningxia Hui Autonomous Region of Northwest China. The analysis was performed by Structural Equation modeling and hierarchical regression. The findings show that trust and control are contrasting forces that influence the participation degree and the cooperative performance, although their relationship is not of a simple supplementary character but could be moderated by the group size. Both trust‐based and control‐based modes of irrigation management are effective in small groups, whereas only a control‐based mode of management has an effect in big groups. The theoretical contribution of this paper clarifies the mechanisms through which the contrasting forces of group size are exerted on trust and control, directly and indirectly influences the participation degree and the cooperative performance in commons governance.

Social Capital: The Role of Group Size and Heterogeneity

Social Capital: The Role of Group Size and Heterogeneity

On the Role of Group Size in Tournaments: Theory and Evidence from Laboratory and Field Experiments

We explore how individual equilibrium effort in tournaments varies with the number of contestants. The probability of winning a tournament depends on both effort and luck, and we show that the distribution of the luck component is critical in determining individual equilibrium effort. Our theory predicts that equilibrium effort is an increasing (decreasing) function of the number of contestants if there is considerable (little) mass on favorable draws. We test our theory using both laboratory and field experiments, and find substantial support for our theory in both settings. This paper was accepted by Teck Ho, behavioral economics.

Breeding Phenology and Meteorological Conditions Affect Carer Provisioning Rates and Group-Level Coordination in Cooperative Chestnut-Crowned Babblers

Recent theoretical and empirical work suggests that coordinating offspring provisioning plays a significant role in stabilising cooperative care systems, with benefits to developing young. However, a warming and increasingly extreme climate might be expected to make contributions to, and so coordination of, care more challenging, particularly in cooperative breeding systems comprising multiple carers of varying age and pair-wise relatedness. Here we investigated the interplay between breeding phenology, meteorological conditions and carer number on the individual rates and group-level of coordination of nestling care in the cooperatively breeding chestnut-crowned babbler (Pomatostomus ruficeps) in outback south-eastern Australia. From three months since the last meaningful rain event, dominant male breeders and – to a lesser extent – related helpers showed reductions in their provisioning rates and increases in their day-to-day variation. On days with high mean wind speed, dominant males contributed less and helpers were less likely to visit the nest on such days, and also showed reduced visitation rates on days with high mean temperature. Provisioning rates were independent of the number of carers, and increasing numbers of carers failed to mitigate the detrimental effects of challenging environment on patterns of provisioning. Those helpers that were unrelated to broods often failed to help on a given day and tended to help at a low rate when they did contribute, with socio-environmental predictors having limited explanatory power. Given the marked variation in individual contributions to offspring care and the variable explanatory power of the socio-environmental predictors tested, babblers unsurprisingly had low levels of nest-visitation synchrony. Large groups visited the nest more asynchronously on days of high mean temperature, suggesting that meteorological impacts on individual provisioning have consequences for group-level coordination. Our study has implications for the consequences of climate change on patterns of provisioning, the minimal role of group size in buffering against these challenges and the stabilisation of cooperative care.

The Origins of Ethnic Activism: Caste Politics in Colonial India

AbstractExisting accounts of ethnic mobilization have focused on the role of group size or state policy. This paper suggests that narrow identity activism was also non-linearly related to education since poorly-educated groups are unlikely to have an educated elite to participate in activism, while in very educated groups this elite existed but participated in the colonial state or anti-colonial nationalism. This theory is tested using a historical panel dataset of Indian caste groups, with petitions to the colonial census authorities being used as an index of caste activism.

The role of group size in reactions to ostracism and inclusion

Three experiments examined the effects of group size on reactions to ostracism and inclusion. Participants engaged in an online introduction activity with 2 or 6 other people and received likes from everyone (inclusion) or no one (ostracism). In Studies 1 and 2, group size had a significant effect on need satisfaction only when participants were ostracized, with larger groups threatening needs to a greater extent. These effects were evident during and immediately after the task, but not after a reflection period and delay. In Study 3, being ostracized by a larger group increased sadness and anger only when ostracism was public. Together, these results indicate that people react more negatively to ostracism by larger groups, but do not reap greater benefits in terms of need satisfaction or affect when included by larger groups. Implications for the ostracism literature and social media use are discussed.

The Role of Group Size and Correlated Project Outcomes in Group Lending

This paper analyzes contract efficiency with regard to correlated project realization and the size of the borrowers in group lending. Firstly, I show that under the standard assumption of independent project payoffs, the expected group cost of default decreases with group size. Secondly, I show that small groups can also optimize group efficiency if individual payoffs and credit risks are correlated. The results outline that social cost minimization occurs due to a common interest in forming optimal borrower groups between lenders and borrowers.

The role of group size in group lending

This paper explores group size in joint liability lending, primarily in the adverse selection framework with local borrower information. A single, standardized contract that imposes full joint liability subject to a limited liability cap is optimal. Further, if gross returns to borrowing are moderately high, this contract results in perfectly efficient lending if groups are large enough. However, raising group size accomplishes nothing if there is no local borrower information. These results show that more is required for efficient lending than full within-group insurance, and highlight a complementarity between group size and social capital. Very similar results are shown in two different settings, ex ante and ex post moral hazard, though the type of social capital that complements group size varies across the settings. Taking a step toward modeling drawbacks of larger groups, it is shown that if information deteriorates sufficiently with group size, an intermediate group size does better than either extreme. Simulations suggest that most of the efficiency gains from larger groups are realized in group sizes below ten, and that outreach and efficiency can increase dramatically when a moderate group size threshold is crossed.

Too Much Work, Not Enough Tarsi: Group Size Influences <I>Bombus impatiens</I> (Hymenoptera: Apidae) Worker Reproduction With Implications for Sublethal Pesticide Toxicity Assessments

As bumble bees may routinely forage on pesticide-treated plants, it is imperative to apply pesticides that pose minimal risk. Identifying such reduced-risk pesticides requires toxicity tests using biologically relevant and standardized exposure methods. Our goal was to develop a functional and reliable queen-less micro-colony method for determining the sublethal effects of pesticides on Bombus impatiens Cresson, a species for which further toxicity assessments are needed. Originally developed using Bombus terrestris (L.), this method involves isolating three workers and allowing them to establish and maintain a colony. The workers and brood can then be exposed to pesticides and various effects measured simultaneously. Our preliminary work indicated that B. impatiens workers were unable to reproduce under the micro-colony conditions developed for B. terrestris. In the current study, we focused on the potential role of group size in B. impatiens worker reproduction by placing groups of three or five sister workers together and assessing their ability to establish a colony and rear males to adulthood. While both groups oviposited and produced males, significantly more males emerged from micro-colonies of five workers. We conclude that group size affects B. impatiens worker reproduction, and this effect in bumble bees varies interspecifically. In the context of toxicity testing, we recommend the use of at least five B. impatiens workers in micro-colonies to ensure a level of reproduction that allows the detection of potential sublethal changes to reproduction or development.

Stereotyping on the two fundamental content dimensions: The role of group size and consensual views on trait typicality in Finland and Sweden

Two alternative hypotheses regarding group differentiation on the two fundamental content dimensions of competence and warmth were tested in this study; the first one based on the stereotype content model (SCM) and the other combining SCM with social identity theory and acknowledging the neglected role of group size. In addition, the potential of consensual stereotypes to counter predictions based on SCM was explored. Nationwide, representative samples of high- and low-status Swedish- and Finnish-speaking minority and majority groups in Finland and Sweden (N = 2075) attributed stereotypic traits reflecting the two content dimensions of competence and warmth to the in- and outgroup. In contrast to predictions based on SCM minority groups favoured the ingroup on both competence and warmth, regardless of status, suggesting that the contextual variable group size should be acknowledged in future studies. Also against expectations based on SCM the high-status groups did not differentiate the ingroup on competence; however, only on warmth. Group ratings on specific traits revealed consensual stereotypes for Swedish- and Finnish-speakers across the countries. Results are discussed in relation to ideology, primacy of warmth and group history.

Group size, heterogeneity and collective action outcomes: Evidence from community forestry in Nepal

In the context of ongoing theoretical debate on the role of group size and heterogeneity in affecting collective action outcomes, this study analyzed associations of group size, and intra-group heterogeneities arising from ethnic, educational and livelihood-related differences with conditions of selected forests managed (formally or informally) by local user groups in the middle hills of Nepal. Four biological variables, basal area of trees, density of trees, density of saplings and richness of plant species, were chosen to represent the condition of the forests. The findings show significant differences in biological condition of the forests managed by different size forest user groups and levels of ethnic, educational and livelihood-related heterogeneities. These differences, however, are inconsistent across the dependent variables representing forest condition, indicating that they were not necessarily caused by the size of the user groups or the group heterogeneities, but could be the result of other factors, such as the history of forest land use and degradation, composition of tree species and institutional arrangements governing the forests.

The role of group size and environmental factors on survival in a cooperatively breeding tropical passerine

1. Variation in survival, a major determinant of fitness, may be caused by individual or environmental characteristics. Furthermore, interactions between individuals may influence survival through the negative feedback effects of density dependence. Compared to species in temperate regions, we have little knowledge about population processes and variation in fitness in tropical bird species. 2. To investigate whether variation in survival could be explained by population size or climatic variables we used capture-recapture models in conjunction with a long-term data set from an island population of the territorial, cooperatively breeding Seychelles warbler (Acrocephalus sechellensis). The lack of migration out of the study population means that our results are not confounded by dispersal. 3. Annual survival was high, both for adults (84%) and juveniles (61%), and did not differ between the sexes. Although there was significant variation in survival between years, this variation could not be explained by overall population size or weather variables. 4. For territorial species, resource competition will work mainly on a local scale. The size of a territory and number of individuals living in it will therefore be a more appropriate measure of density than overall population density. Consequently, both an index of territory quality per individual (food availability) and local density, measured as group size, were included as individual covariates in our analyses. 5. Local density had a negative effect on survival; birds living in larger groups had lower survival probabilities than those living in small groups. Food availability did not affect survival. 6. Our study shows that, in a territorial species, although density-dependent effects might not be detectable at the population level they can be detected at the individual territory level - the scale at which individuals compete. These results will help to provide a better understanding of the small-scale processes involved in the dynamics of a population in general, but in particular in tropical species living in relatively stable environments.

Cognitive and affective experiences of minority and majority members: The role of group size, status, and power

Four studies examined cognitive and affective experiences of minority and majority members. We predicted and found that minority members were more cognitively preoccupied with their group membership and experienced less positive affect as a consequence of their group membership than majority members. The first experiment established these effects with numerical minority and majority groups. The second experiment ruled out status as an explanatory variable, and the third experiment uncovered the role of power in the differential cognitive and affective experiences of minority and majority members. The final field study substantiated the ecological robustness of the experimental findings and provided further evidence for the role of power. The interrelation of status and power is discussed as well as the phenomenology of being a minority member.

Eat or be eaten: predator sensitive foraging among primates

Preface 1. An introduction to predator sensitive foraging Lynne E. Miller Part I. Biological Variables: 2. Dangers in the dark: are some nocturnal primates afraid of the dark? Simon K. Bearder, K. A. I. Nekaris and Courtney A. Buzzell 3. Predation sensitive foraging in captive tamarins Mark J. Prescott and Hannah M. Buchanan-Smith 4. Seeing red: consequence of individual differences in color vision in callitrichid primates Nancy G. Caine 5. Predator sensitive foraging in Thomas langurs Elisabeth H. M. Sterck Part II. Social Variables: 6. The role of group size in predator sensitive foraging decisions for wedge-capped capuchin monkeys (Cebus olivaceous) Lynne E. Miller 7. Group size effects on predation sensitive foraging in wild ring-tailed lemurs (Lemur catta) Michelle L. Sauther 8. Species differences in feeding in Milne Edward's sifakas (Propithecus diadema edwardsi), rufus lemurs (Eulemur fulvus rufus) and red-bellied lemurs (Eulemur rubriventer) in southeastern Madagascar: implications for predator avoidance Deborah J. Overdorff, Suzanne G. Strait and Ryan G. Seltzer 9. Evidence of predator sensitive foraging and traveling in single- and mixed-species tamarin troops Paul A. Garber and Julio Cesar Bicca-Marques 10. Predator (in)sensitive foraging in sympatric female vervets (Chlorocebus aethiops) and patas monkeys (Erythrocebus patas): a test of ecological models of group dispersion Lynne A. Isbell and Karen L. Enstam 11. Predation risk and anti-predator adaptions in white-faced sakis (Pithecia pithecia) Terrence M. Gleason and Marilyn A. Norconk Part III. Environmental Variables: 12. Foraging female baboons exhibit similar patterns of antipredator vigilance across two populations Russell A. Hill and Guy Cowishaw 13. Foraging and safety in adult female blue monkeys in the Kakamega Forest, Kenya Marina Cords 14. Predicting predation risk for foraging arboreal monkeys Adrian Treves 15. Predator sensitive foraging in ateline primates Anthony Di Fiore 16. Anti-predatory behaviour in gibbons (Hylobates lar, Yai/Thailand) Nicola L. Uhde and Volker Sommer.

Jury Verdicts: The Role of Group Size and Social Decision Rule.

Jury Verdicts: The Role of Group Size and Social Decision Rule.