Adaptive behavioural syndromes due to strategic niche specialization

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.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.Evolutionary theory predicts that animals will behave adaptively, which means that their behavioural phenotype should on average converge towards an optimum. Hence, variation in behaviour has typically been interpreted as random variation around an adaptive mean or as a reflection of environmental or intrinsic constraints. However, studies on animal behaviour at the level of individuals have suggested that the observed variation can itself be adaptive [1-3]. More recently, individual differences in behaviours have been found to sometimes correlate across functionally unrelated contexts, a phenomenon termed 'behavioural syndromes', 'animal personalities' or 'animal temperaments' [4-7].Apart from humans, behavioural syndromes have, for instance, been reported in mammals, birds, lizards, amphibians, fish, molluscs and arthropods [8] suggesting they are common in animals and reflect individual differences in coping styles [9]. Although the question why individual differences should be consistent over time has received some theoretical attention [[10], and cited references], a conceptual framework to explain the functional significance of correlations between different behaviours (or cross context correlations of the same behaviour) is only gradually emerging [6,11].Currently, two non-exclusive hypotheses seek to e