scholarly journals Group size effect caused by food competition in nutmeg mannikins (Lonchura punctulata)

2008 ◽  
Vol 20 (2) ◽  
pp. 421-425 ◽  
Author(s):  
Guillaume Rieucau ◽  
Luc-Alain Giraldeau
Keyword(s):  
Size Effect ◽  
Group Size ◽  
Food Competition ◽  
Group Size Effect ◽  
Lonchura Punctulata

scholarly journals Group size effect in nutmeg mannikin: between-individuals behavioral differences but same plasticity

2010 ◽  
Vol 21 (4) ◽  
pp. 684-689 ◽  
Author(s):  
G. Rieucau ◽  
J. Morand-Ferron ◽  
L.-A. Giraldeau
Keyword(s):  
Size Effect ◽  
Group Size ◽  
Behavioral Differences ◽  
Group Size Effect

scholarly journals Modes of Collective Action in Village Economies: Evidence from Natural and Artefactual Field Experiments in a Developing Country

2013 ◽  
Vol 30 (1) ◽  
pp. 31-51 ◽  
Author(s):  
Yasuyuki Sawada ◽  
Ryuji Kasahara ◽  
Keitaro Aoyagi ◽  
Masahiro Shoji ◽  
Mika Ueyama
Keyword(s):  
Collective Action ◽  
Size Effect ◽  
Public Goods ◽  
Group Size ◽  
Field Experiments ◽  
Free Riding ◽  
Free Rider ◽  
Individual Contribution ◽  
Free Rider Problem ◽  
Group Size Effect

In a canonical model of collective action, individual contribution to collective action is negatively correlated with group size. Yet, empirical evidence on the group size effect has been mixed, partly due to heterogeneities in group activities. In this paper, we first construct a simple model of collective action with the free rider problem, altruism, public goods, and positive externalities of social networks. We then empirically test the theoretical implications of the group size effect on individual contribution to four different types of collective action, i.e., monetary or nonmonetary contribution to directly or indirectly productive activities. To achieve this, we collect and employ artefactual field experimental data such as public goods and dictator games conducted in southern Sri Lanka under a natural experimental situation where the majority of farmers were relocated to randomly selected communities based on the government lottery. This unique situation enables us to identify the causal effects of community size on collective action. We find that the levels of collective action can be explained by the social preferences of farmers. We also show evidence of free riding by self-interested households with no landholdings. The pattern of collective action, however, differs significantly by mode of activity—collective action that is directly rather than indirectly related to production is less likely to suffer from the free rider problem. Also, monetary contribution is less likely to cause free riding than nonmonetary labor contribution. Unlike labor contributions, monetary contributions involve collection of fees which can be easily tracked and verified, possibly leading to better enforcement of collective action.

scholarly journals The group size effect and synchronization of vigilance in the Tibetan wild ass

2020 ◽  
Author(s):  
Xinxin Wang ◽  
Le Yang ◽  
Yumeng Zhao ◽  
Cong Yu ◽  
Zhongqiu Li
Keyword(s):  
Size Effect ◽  
Group Size ◽  
Nature Reserve ◽  
Prey Species ◽  
The Other ◽  
Effective Strategy ◽  
Positive Correlation ◽  
Group Size Effect ◽  
Wild Ass ◽  
Group Members

Abstract Vigilance behavior is considered as an effective strategy for prey species to detect predators. An individual benefits from living in a group by reducing the time spent being vigilant without affecting the probability of detecting a predator. However, the mechanism producing a decrease in vigilance with increasing group size is unclear. Many models of vigilance assume that group members scan independently of one another. Yet in recent studies, the other 2 patterns of vigilance, coordination and synchronization, were reported in some species. In 2 summers (2018 and 2019), we studied the group-size effect on vigilance and foraging of Tibetan wild ass in Chang Tang Nature Reserve of Tibet. We also tested whether individuals scan the environment independently, tend to coordinate their scans, or tend to synchronize their vigilance. The results showed that individuals decreased the time spent on vigilance with increasing group size, while increased the time spent foraging. Group members scanned the environment at the same time more frequently and there was a positive correlation between group members’ behaviors, indicating that Tibetan wild asses tend to synchronize their vigilance.

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