Detalhes bibliográficos
| Ano de defesa: |
2012 |
| Autor(a) principal: |
Guedes, Danusa
 |
| Orientador(a): |
Bicca-marques, Júlio César
|
| Banca de defesa: |
Não Informado pela instituição |
| Tipo de documento: |
Tese
|
| Tipo de acesso: |
Acesso aberto |
| Idioma: |
por |
| Instituição de defesa: |
Pontifícia Universidade Católica do Rio Grande do Sul
|
| Programa de Pós-Graduação: |
Programa de Pós-Graduação em Zoologia
|
| Departamento: |
Faculdade de Biociências
|
| País: |
BR
|
| Palavras-chave em Português: |
|
| Área do conhecimento CNPq: |
|
| Link de acesso: |
http://tede2.pucrs.br/tede2/handle/tede/270
|
Resumo: |
Anthropoid primates stand out among mammals because of their advanced cognitive skills resulting from the evolution of a relatively larger brain. Their ability to use social tactics to solve ecological and group-living challenges has been proposed by some experts as the major selective pressure that drove their brain evolution and increase in cognitive skills. Yet, little is known about how differences in social intelligence affect individual fitness within primate groups, including those of New World species. Previous studies have shown that tamarins (Saguinus) and capuchin monkeys (Sapajus) integrate ecological and social information in their group foraging decision-making, thereby suggesting that they adopt efficient cognitive mechanisms for coping with the social network. However, these studies did not analyze individual behavior from a Game Theory perspective, which provides an appropriate theoretical framework for evaluating individual decisions within a social context. In this research we tested whether black tufted-ear marmosets (Callithrix penicillata) are capable of integrating social and ecological information for making economical foraging decisions as predicted by the Producer-Scrounger Game. Specifically, we tested whether the members of social groups adjust their foraging strategies (producer and scrounger) in response to changes in the productivity and density of food resources and whether the individual choice of strategy and foraging success are age-sex and social rank dependent. The study was conducted with two wild groups living in a forest fragment at Fazenda Cauaia, Matozinhos, State of Minas Gerais, Brazil, from October 2009 to October 2011. The experimental design involved the establishment of two feeding stations (one in the home range of each group) composed of five platforms in a circular arrangement. The behavior of the marmosets, including the amount of food reward (arabic gum) eaten by each individual, was recorded with a closed-circuit television (CCTV). We ran four experiments controlling the amount of food available in the station (productivity) and the number of rewarded feeding apparatuses (density). The experimental conditions were: low density-low productivity, low density-high productivity, high density-low productivity and high density-high productivity. Individuals differed in their investment in producing resources (that is, searching for food rewards in platforms) in both groups throughout the study, indicating the use of the Producer-Scrounger Game. As predicted by this model, the finder s advantage (amount of food eaten by the producer of a resource before the arrival of scroungers), the foraging success of producers and the proportion of individuals playing producer in the group were higher under conditions of low productivity. Changes in resource density also influenced the proportion of individuals adopting each strategy. Again, more individuals played producer under conditions of low resource density. The latency to the arrival of the first scrounger was lower under conditions of low density and low productivity. Adult males also tended to play scrounger more often than adult females under these circumstances. Social rank did not have a significant relationship with individual foraging strategy and success. We conclude that black tufted-ear marmosets use ecological and social information to make foraging decisions within their groups and suggest that the strategy to be played is chosen by the individual prior to the arrival of the group at the food patch. Finally, we confirmed that the Game Theory and the Producer-Scrounger model are useful theoretical frameworks for analyzing the individual foraging decisions of black tufted-ear marmosets within a social context |
