Bergmüller Ralph, Taborsky Michael
Department of Behavioural Ecology, Institute of Zoology, University of Bern, Wohlenstr, 50a, CH-3032 Hinterkappelen, Switzerland.
BMC Ecol. 2007 Oct 12;7:12. doi: 10.1186/1472-6785-7-12.
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).
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.
行为综合征，即在不同功能情境下相关的行为中存在的一致个体差异，对进化推理构成挑战，因为个体应使其行为适应每种情况的要求。行为综合征常被解释为限制导致可塑性有限和行为缺乏灵活性的结果。或者，如果相关的生态或社会挑战在功能上整合了明显独立的行为，它们可能是适应性的。为了检验后一种假设，我们对合作繁殖鱼类美丽新亮丽鲷中的帮手进行了多次测试，以考察其探索行为以及两种类型的帮助行为。如果存在适应性行为综合征，我们预测探索行为与攻击性帮助行为（领地防御）之间呈正相关，而这些行为与非攻击性帮助行为（领地维护）之间呈负相关。
正如预期的那样，更多参与领地防御的帮手始终更具探索性，且较少参与领地维护，后者仅在有优势繁殖者在场时出现。与我们的预测相反，探索行为与领地维护之间不存在负相关。
我们的结果表明，我们测量的这三种行为是行为综合征的一部分。这些行为可能具有适应性，因为它们反映了帮手在两种不同生活史策略之一上的策略性专业化，即（a）留在原生领地提供帮助以便继承繁殖地位，或（b）早早扩散以便独立繁殖。
