scholarly journals Lack of experience-based stratification in homing pigeon leadership hierarchies

2016 ◽  
Vol 3 (1) ◽  
pp. 150518 ◽  
Author(s):  
Isobel Watts ◽  
Benjamin Pettit ◽  
Máté Nagy ◽  
Theresa Burt de Perera ◽  
Dora Biro
Keyword(s):  
Prior Experience ◽  
Release Site ◽  
Homing Pigeon ◽  
Fundamental Question ◽  
Leadership Roles ◽  
Homing Pigeons ◽  
Adaptive Value ◽  
Collective Decisions ◽  
Group Members ◽  
The Individual

In societies that make collective decisions through leadership, a fundamental question concerns the individual attributes that allow certain group members to assume leadership roles over others. Homing pigeons form transitive leadership hierarchies during flock flights, where flock members are ranked according to the average time differences with which they lead or follow others' movement. Here, we test systematically whether leadership ranks in navigational hierarchies are correlated with prior experience of a homing task. We constructed experimental flocks of pigeons with mixed navigational experience: half of the birds within each flock had been familiarized with a specific release site through multiple previous releases, while the other half had never been released from the same site. We measured the birds' hierarchical leadership ranks, then switched the same birds' roles at a second site to test whether the relative hierarchical positions of the birds in the two subsets would reverse in response to the reversal in levels of experience. We found that while across all releases the top hierarchical positions were occupied by experienced birds significantly more often than by inexperienced ones, the remaining experienced birds were not consistently clustered in the top half—in other words, the network did not become stratified. We discuss our results in light of the adaptive value of structuring leadership hierarchies according to ‘merit’ (here, navigational experience).

scholarly journals Group decisions and individual differences: route fidelity predicts flight leadership in homing pigeons ( Columba livia )

2010 ◽  
Vol 7 (1) ◽  
pp. 63-66 ◽  
Author(s):  
Robin Freeman ◽  
Richard Mann ◽  
Tim Guilford ◽  
Dora Biro
Keyword(s):  
Individual Differences ◽  
Individual Variation ◽  
Columba Livia ◽  
Homing Pigeon ◽  
Scientific Interest ◽  
Homing Pigeons ◽  
Collective Decisions ◽  
The Subject ◽  
Leadership Decisions

How social-living animals make collective decisions is currently the subject of intense scientific interest, with increasing focus on the role of individual variation within the group. Previously, we demonstrated that during paired flight in homing pigeons, a fully transitive leadership hierarchy emerges as birds are forced to choose between their own and their partner's habitual routes. This stable hierarchy suggests a role for individual differences mediating leadership decisions within homing pigeon pairs. What these differences are, however, has remained elusive. Using novel quantitative techniques to analyse habitual route structure, we show here that leadership can be predicted from prior route-following fidelity. Birds that are more faithful to their own route when homing alone are more likely to emerge as leaders when homing socially. We discuss how this fidelity may relate to the leadership phenomenon, and propose that leadership may emerge from the interplay between individual route confidence and the dynamics of paired flight.

scholarly journals Tracking clock-shifted homing pigeons from familiar release sites

2000 ◽  
Vol 203 (2) ◽  
pp. 207-212 ◽  
Author(s):  
F. Bonadona ◽  
R. Holland ◽  
L. Dall'Antonia ◽  
T. Guilford ◽  
S. Benvenuti
Keyword(s):  
Large Scale ◽  
Release Site ◽  
Homing Pigeon ◽  
Homing Pigeons ◽  
Pigeon Navigation ◽  
Wrong Direction ◽  
Terrain Features ◽  
Clock Shift

Clock-shifted homing pigeons were tracked from familiar sites 17.1 km and 23.5 km from the home loft in Pisa, Italy, using an on-board route recorder. At the first release site, north of home, the majority of clock-shifted birds had relatively straight tracks comparable with those of control birds. At the second release site, south of home, the clock-shifted birds deflected in the direction predicted for the degree of clock shift, with many birds travelling some distance in the wrong direction before correcting their course. The possible role of large-scale terrain features in homing pigeon navigation is discussed.

The Epistemology of Groups

2020 ◽  
Author(s):  
Jennifer Lackey
Keyword(s):  
Group Level ◽  
Social Significance ◽  
Individual Group ◽  
Key Concepts ◽  
Normative Requirements ◽  
Group Members ◽  
The Individual ◽  
Belief Justification ◽  
In Virtue Of ◽  
Trump Administration

Groups are often said to bear responsibility for their actions, many of which have enormous moral, legal, and social significance. The Trump Administration, for instance, is said to be responsible for the U.S.’s inept and deceptive handling of COVID-19 and the harms that American citizens have suffered as a result. But are groups subject to normative assessment simply in virtue of their individual members being so, or are they somehow agents in their own right? Answering this question depends on understanding key concepts in the epistemology of groups, as we cannot hold the Trump Administration responsible without first determining what it believed, knew, and said. Deflationary theorists hold that group phenomena can be understood entirely in terms of individual members and their states. Inflationary theorists maintain that group phenomena are importantly over and above, or otherwise distinct from, individual members and their states. It is argued that neither approach is satisfactory. Groups are more than their members, but not because they have “minds of their own,” as the inflationists hold. Instead, this book shows how group phenomena—like belief, justification, and knowledge—depend on what the individual group members do or are capable of doing while being subject to group-level normative requirements. This framework, it is argued, allows for the correct distribution of responsibility across groups and their individual members.

scholarly journals Decentralised sweetpotato (Ipomoea batatas) vine multiplication in Lake Zone, Tanzania: Five years later

2020 ◽  
Vol 5 (1) ◽  
pp. 677-689
Author(s):  
Margaret A. McEwan ◽  
Conny J. M. Almekinders ◽  
Moses S. Matui ◽  
Dorothy Lusheshanija ◽  
Mariana Massawe ◽  
...  
Keyword(s):  
Group Dynamics ◽  
Ipomoea Batatas ◽  
Water Access ◽  
Qualitative And Quantitative ◽  
Factors Influencing ◽  
Lake Zone ◽  
Norms And Values ◽  
Group Members ◽  
Market Factors ◽  
The Individual

AbstractFarmer-based seed multiplication is widely promoted by development practitioners, but there is limited understanding of the individual or collective motivations of farmers to engage or disengage in specialised seed production. The objective of this study is to understand the factors influencing the continuity of sweetpotato vine multiplication enterprises in the Lake Zone of Tanzania, five years after support from a project ended. A total of 81 out of 88 trained group or individual decentralised vine multipliers (DVMs) were traced to assess their vine multiplication activities. Qualitative and quantitative data were collected through telephone and field interviews. Our data showed that 40% of the 81 DVMs had sold vines in the year prior to the study and 20% had maintained the improved varieties for their own use. Some group members had continued vine sales as individuals. The DVMs’ reasons for abandoning vine multiplication included climatic and water access issues, market factors and group dynamics. The DVMs did not engage in high volumes of commercial sales. Socio-economic norms and values underpin the transactions of sweetpotato vines. These norms may undermine the emergence of commercially viable enterprises yet seem navigable for a substantial number of the DVMs. Group DVMs seem less commercially successful than individuals.

scholarly journals Task allocation and site fidelity jointly influence foraging regulation in honeybee colonies

2017 ◽  
Vol 4 (8) ◽  
pp. 170344 ◽  
Author(s):  
Thiago Mosqueiro ◽  
Chelsea Cook ◽  
Ramon Huerta ◽  
Jürgen Gadau ◽  
Brian Smith ◽  
...  
Keyword(s):  
Site Fidelity ◽  
Collective Behaviour ◽  
Trade Off ◽  
Agent Based ◽  
Resource Collection ◽  
Group Members ◽  
Collective Foraging ◽  
The Individual ◽  
Colony Level ◽  
And Task

Variation in behaviour among group members often impacts collective outcomes. Individuals may vary both in the task that they perform and in the persistence with which they perform each task. Although both the distribution of individuals among tasks and differences among individuals in behavioural persistence can each impact collective behaviour, we do not know if and how they jointly affect collective outcomes. Here, we use a detailed computational model to examine the joint impact of colony-level distribution among tasks and behavioural persistence of individuals, specifically their fidelity to particular resource sites, on the collective trade-off between exploring for new resources and exploiting familiar ones. We developed an agent-based model of foraging honeybees, parametrized by data from five colonies, in which we simulated scouts, who search the environment for new resources, and individuals who are recruited by the scouts to the newly found resources, i.e. recruits. We varied the persistence of returning to a particular food source of both scouts and recruits and found that, for each value of persistence, there is a different optimal ratio of scouts to recruits that maximizes resource collection by the colony. Furthermore, changes to the persistence of scouts induced opposite effects from changes to the persistence of recruits on the collective foraging of the colony. The proportion of scouts that resulted in the most resources collected by the colony decreased as the persistence of recruits increased. However, this optimal proportion of scouts increased as the persistence of scouts increased. Thus, behavioural persistence and task participation can interact to impact a colony's collective behaviour in orthogonal directions. Our work provides new insights and generates new hypotheses into how variations in behaviour at both the individual and colony levels jointly impact the trade-off between exploring for new resources and exploiting familiar ones.

scholarly journals Major Evolutionary Transitions in Social Insects, the Importance of Worker Sterility and Life History Trade-Offs

2021 ◽  
Vol 9 ◽  
Author(s):  
Abel Bernadou ◽  
Boris H. Kramer ◽  
Judith Korb
Keyword(s):  
Life History ◽  
Social Insects ◽  
Division Of Labour ◽  
Evolutionary Transitions ◽  
Individual Level ◽  
Individual Fitness ◽  
Trade Offs ◽  
Group Members ◽  
The Individual ◽  
Worker Sterility

The evolution of eusociality in social insects, such as termites, ants, and some bees and wasps, has been regarded as a major evolutionary transition (MET). Yet, there is some debate whether all species qualify. Here, we argue that worker sterility is a decisive criterion to determine whether species have passed a MET (= superorganisms), or not. When workers are sterile, reproductive interests align among group members as individual fitness is transferred to the colony level. Division of labour among cooperating units is a major driver that favours the evolution of METs across all biological scales. Many METs are characterised by a differentiation into reproductive versus maintenance functions. In social insects, the queen specialises on reproduction while workers take over maintenance functions such as food provisioning. Such division of labour allows specialisation and it reshapes life history trade-offs among cooperating units. For instance, individuals within colonies of social insects can overcome the omnipresent fecundity/longevity trade-off, which limits reproductive success in organisms, when increased fecundity shortens lifespan. Social insect queens (particularly in superorganismal species) can reach adult lifespans of several decades and are among the most fecund terrestrial animals. The resulting enormous reproductive output may contribute to explain why some genera of social insects became so successful. Indeed, superorganismal ant lineages have more species than those that have not passed a MET. We conclude that the release from life history constraints at the individual level is a important, yet understudied, factor across METs to explain their evolutionary success.

scholarly journals The analysis of individual Visegrad group members’ agrarian export sensitivity in relation to selected macroeconomic aggregations

2011 ◽  
Vol 59 (4) ◽  
pp. 327-342
Author(s):  
Miroslav Svatoš ◽  
Luboš Smutka
Keyword(s):  
Agricultural Trade ◽  
Added Value ◽  
The Czech Republic ◽  
Grocery Industry ◽  
Agricultural Exports ◽  
Group Members ◽  
The Subject ◽  
The Individual ◽  
High Degree ◽  
Visegrad Group

This paper analyzes the development of agricultural trade of the countries of the Visegrad Group with emphasis on development of the value of agricultural exports of the individual countries. The subject matter of the analysis is the sensitivity of the commodity structure of agricultural exports of individual countries and the identification of aggregations that are the least and the most sensitive to changes to the external and internal economic environment. From the conducted research, agricultural trade in the V4 countries was found to have developed very dynamically from 1993 to 2008, while the commodity structure of exports has constantly narrowed as the degree of specialization of the individual countries has increased (this applies especially to the Czech Republic, Slovakia and Hungary). From the results of analysis of sensitivity to changes of selected variables relating to the development of the value of agricultural exports of the individual V4 countries, it appears that the aggregations that react most sensitively to changes are those that are the subject of re-exports, followed by the aggregations that are characterized by a high degree of added value. In general it can be said that products of agricultural primary production exhibit less sensitivity in comparison with grocery industry products. This is confirmed by the general trend arising from the very nature of consumer behaviour.

scholarly journals Media Baru dan Potensi Terorisme Virtual

2012 ◽  
Vol 1 (1) ◽  
pp. 59-70
Author(s):  
Rulli Nasrullah
Keyword(s):  
Mental Representations ◽  
Multiple Identities ◽  
The Internet ◽  
Internet Users ◽  
Group Members ◽  
The Individual ◽  
Internet Medium ◽  
Police Commissioner ◽  
Different Characteristics ◽  
National Police

It is interesting to look at the Head of Criminal Investigation statement of the Indonesian National Police Commissioner General Ito Sumardi (Kompas, 22/9/2010), which warns that the crime of terrorism is closely related to ideology. Sociologist Van Dijk (1993) states that ideology is basically a mental system that is exchanged, represented both in the level of discourse and action to achieve certain goals or desires in a groups (defi ned as the system of mental representations and processes of group members). Why (technology) Internet so powerful in spreading the message of terrorism? First, the interaction happens on internet can be done anywhere and anytime. Second, Internet users in Indonesia, which is increasingly growing in number, allows access to the site or content to be easily obtained terrorism. Third, Internet medium provides access not only cheap but free. Fourth, the Internet allows anyone to construct new identity. In a fact proves that the identities of individuals in cyber world are individuals who have two possibilities, it could be the same or different identities as in the real world. Furthermore, the individual does not only have one identity per se on the internet, they could have multiple identities as well as different characteristics from each other. In according to Gilmore (1996), those on the Internet nobody knows you at all, not either knows your race or your sex. This is the opportunities that could be used by the perpetrators of terrorism to spread the ideology of terrorism and violence in the name of religion without worried their identity will be revealed. Key words: cybermedia, virtual terorism, internet, identity.

scholarly journals Flight Tracks of Homing Pigeons Measured with GPS

2001 ◽  
Vol 54 (2) ◽  
pp. 167-175 ◽  
Author(s):  
Karen von Hünerbein ◽  
Wolfgang Wiltschko ◽  
Eckhard Rüter
Keyword(s):  
Power Supply ◽  
Sampling Rate ◽  
Operating Time ◽  
Release Site ◽  
Gps Receiver ◽  
Homing Pigeons ◽  
Flight Duration ◽  
Ground Speed ◽  
Animal Navigation ◽  
The Village

This and the following paper were first presented at the RIN01 Conference held in Oxford under the auspices of the Animal Navigation Special Interest Group, April 2001.Flight paths of homing pigeons were measured with a newly developed recorder based on GPS. The device consists of a GPS receiver board, a logging facility, an antenna, a power supply, a DC-DC converter and a casing. It has a weight of 33 grams and works reliably with a sampling rate of 1 Hz for an operating time of about three hours, providing time-indexed data on geographic positions, ground speed and altitude. The devices are fixed to the birds with a harness, and the data are downloaded when the bird is re-captured. The measured flight paths show many details : for example, initial loops flown immediately after release and large detours flown by some pigeons. Three examples of flight paths are presented from a release site 17·3 km northeast of the home loft in Frankfurt. Mean speed in flight, duration of breaks and total length of the flight path were calculated. The pigeons chose different routes and have different individual tendencies to fly loops over the village close to the release site.

Membership Rights: The Individual Rights of Group Members

2019 ◽  
Vol 32 (02) ◽  
pp. 343-364
Author(s):  
Adi Goldiner
Keyword(s):  
Human Rights ◽  
Legal Protection ◽  
Moral Rights ◽  
Social Categories ◽  
Group Rights ◽  
Reasonable Accommodations ◽  
Theoretical Inquiry ◽  
Group Members ◽  
The Individual ◽  
Distinct Features

AbstractIndividuals often invoke the moral rights that they hold as members of certain groups or social categories. Yet, there is ambiguity in both terminology and theorizing surrounding the nature of those rights. Focusing on the paradigmatic case of disabled people’s right to reasonable accommodations, this paper develops a descriptive account of those group-related rights, as a distinct category of rights which I call ‘membership rights’. Membership rights neither fit the concept of ‘human rights’, as not all people hold them, nor are they typical ’group rights’, as they are held by members of some group as individuals, not by groups collectively. In addition, the grounding of membership rights is linked to the distinct features of group members, be it their special interests or special circumstances. Finally, the content of membership rights includes distinct entitlements and correlating duties, which are not secured by human rights, group rights, or any combination thereof. Recognizing the distinct features of membership rights may have practical implications by strengthening efforts to secure legal protection to membership rights. It also invites further theoretical inquiry, for example, towards identifying other specific rights that fit into this category.

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