19 resultados para domination and territory
em BORIS: Bern Open Repository and Information System - Berna - Suiça
Resumo:
In most species, some individuals delay reproduction or occupy inferior breeding positions. The queue hypothesis tries to explain both patterns by proposing that individuals strategically delay breeding (queue) to acquire better breeding or social positions. In 1995, Ens, Weissing, and Drent addressed evolutionarily stable queuing strategies in situations with habitat heterogeneity. However, their model did not consider the non - mutually exclusive individual quality hypothesis, which suggests that some individuals delay breeding or occupy inferior breeding positions because they are poor competitors. Here we extend their model with individual differences in competitive abilities, which are probably plentiful in nature. We show that including even the smallest competitive asymmetries will result in individuals using queuing strategies completely different from those in models that assume equal competitors. Subsequently, we investigate how well our models can explain settlement patterns in the wild, using a long-term study on oystercatchers. This long-lived shorebird exhibits strong variation in age of first reproduction and territory quality. We show that only models that include competitive asymmetries can explain why oystercatchers' settlement patterns depend on natal origin. We conclude that predictions from queuing models are very sensitive to assumptions about competitive asymmetries, while detecting such differences in the wild is often problematic.
Resumo:
BACKGROUND: Behavioural syndromes, i.e. consistent individual differences in behaviours that are correlated across different functional contexts, are a challenge to evolutionary reasoning because individuals should adapt their behaviour to the requirements of each situation. Behavioural syndromes are often interpreted as a result of constraints resulting in limited plasticity and inflexible behaviour. Alternatively, they may be adaptive if correlated ecological or social challenges functionally integrate apparently independent behaviours. To test the latter hypothesis we repeatedly tested helpers in the cooperative breeder Neolamprologus pulcher for exploration and two types of helping behaviour. In case of adaptive behavioural syndromes we predicted a positive relationship between exploration and aggressive helping (territory defence) and a negative relationship between these behaviours and non-aggressive helping (territory maintenance). RESULTS: As expected, helpers engaging more in territory defence were consistently more explorative and engaged less in territory maintenance, the latter only when dominant breeders were present. Contrary to our prediction, there was no negative relationship between exploration and territory maintenance. CONCLUSION: Our results suggest that the three behaviours we measured are part of behavioural syndromes. These may be adaptive, in that they reflect strategic specialization of helpers into one of two different life history strategies, namely (a) to stay and help in the home territory in order to inherit the breeding position or (b) to disperse early in order to breed independently.
Resumo:
Palestinians living in the West Bank, a territory occupied by the State of Israel according to International Law, face deprived access to land and a limited ability to move freely which pertains to the presence of Israeli settlements and other infrastructure (closures, restricted or forbidden roads, etc.). This confinement has significant impacts on their economic and social livelihoods, and it is even worsening with the on-going construction of a 709 km long Barrier which mainly runs inside the West Bank. With regard to this situation, there is a clear need to strengthen the capacity of civil society and its representatives to apply sound research processes as a basis for improved advocacy for Palestinian human rights. Monitoring processes and tools are needed to assess the impacts of the Palestinians’ confinement, particularly in relation to the Barrier’s construction. Reliable data has also to be collected, managed, and above all, shared. These challenges have been addressed within the Academic Cooperation Palestine Project (ACPP) that brings together academic partners from the occupied Palestinian territory (oPt) West Bank (WB), and Switzerland as well as other international academic institutions and Palestinian governmental and non-governmental agencies. ACPP started in early 2011 and is designed as a large cooperation networking platform involving researchers, students, public servants and experts from the oPt WB. A large set of actions have already been developed during the first year of the project, including courses, training, and research actions. First relevant results and impacts of the different actions are presented in this paper. Taken as a whole, the project produces valuable results for all partners: useful advocacy material for the Palestinian partners, and a unique “real-scale laboratory” where investigations are jointly conducted to develop novel confinement and change indicators.