Behavioural type affects dominance and growth in staged encounters of cooperatively breeding cichlids Thomas Riebli * , Batur Avgan, Anna-Maria Bottini, Caroline Duc, Michael Taborsky, Dik Heg Department of Behavioural Ecology, Institute of Ecology and Evolution, University of Bern article info Article history: Received 1 June 2010 Initial acceptance 29 July 2010 Final acceptance 1 November 2010 Available online xxx MS. number: 10-00388R Keywords: behavioural syndrome body condition Neolamprologus pulcher personality reserves strategic growth submission In animals, behavioural properties such as aggressive propensity are often consistent over a life span, and they may form part of a behavioural syndrome. We studied how aggressive propensity influences dominance, contest behaviour and growth in the cooperatively breeding cichlid fish Neolamprologus pulcher. We tested whether intrinsic aggressive propensity (1) influences dominance in paired contests, (2) causes different aggression levels in contests with partners matched for aggressive propensity compared to unmatched partners, and how it (3) affects growth rate in groups that were either matched or unmatched for aggressive propensity. Intrinsic aggressive propensity was first scored with a mirror test and classified as high, medium or low. Thereafter we tested fish with either high or low aggressive propensity with partners matched for size and either matched or unmatched for aggressive type in a paired contest for a shelter. We scored dominance, aggression and submission. As predicted, (1) dominance was more clearly established in unmatched than in matched contests and (2) individuals with high aggressive propensity launched more attacks overall than fish with low intrinsic aggressive- ness, suggesting a higher propensity to escalate independently of winning or losing the paired contest. However, contrary to expectation, (3) individuals with low aggressiveness grew faster than aggressive ones in unmatched groups, whereas the opposite occurred in matched groups. This suggests that indi- viduals with low aggressive propensity may benefit from conflict evasion, which might allow them to gain dominance in the future owing to larger body size. Ó 2010 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved. Individuals in natural populations often show consistent differences in how their behaviour responds to environmental and social challenges. These consistent differences have been termed behavioural syndromes, animal personalities, coping styles or temperaments (reviewed in Gosling & John 1999; Sih et al. 2004a; Bergmüller & Taborsky 2010). Typically, different behavioural axes are correlated with each other, for instance aggressiveness, novelty seeking and exploratory propensity. The strength of these behav- ioural correlations and the frequency of occurrence of different behavioural types may differ between populations (Coleman & Wilson 1998; Dingemanse et al. 2009). Behavioural correlations may exist between different situations within a certain behavioural context, for instance in foraging across a range of different habitats, or between different contexts, for instance among behavioural traits related to predator evasion, mating or resource competition (Sih et al. 2004a, b). Although research on animal personality has proceeded rapidly, the social consequences of the coexistence of different behavioural types in group-living species have been underexplored (Armitage & Johns 1982; Armitage 1986a, b; McGuire et al. 1994; Capitanio 1999; Gosling & John 1999; Bergmüller et al. 2007; Schürch & Heg 2010a, b). For instance, it has not been tested whether individuals with a high aggressive propensity gain dominance in social groups, and whether individ- uals with a low aggressive propensity accept a subordinate position instead. Moreover, more tests are needed that relate high and low levels of aggressiveness to social behaviour in general, for example energy expenditure, expulsion risk or costly conflicts within groups (i.e. escalated fights resulting in injuries), and subdominant - dominant interactions (Schürch & Heg 2010b). So far most studies of behavioural syndromes have focused either on risk-taking behaviour or exploration (van Oers et al. 2005; Brown et al. 2007). However, in group-living animals, especially when novel groups are formed and dominance relationships are established, other behaviours might be more important, such as aggressiveness, which can affect dominance and access to food, shelter and mates. Recent work provides evidence that behavioural traits such as aggressive propensity are positively correlated with life history traits such as food intake and growth rates (Stamps 2007; Biro & Stamps 2008). In group-living species * Correspondence: T. Riebli, Department of Behavioural Ecology, Institute of Ecology and Evolution, University of Bern, Wohlenstrasse 50a, CH-3032 Hinterkappelen, Switzerland. E-mail address: thomas.riebli@iee.unibe.ch (T. Riebli). Contents lists available at ScienceDirect Animal Behaviour journal homepage: www.elsevier.com/locate/anbehav 0003-3472/$38.00 Ó 2010 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.anbehav.2010.11.001 Animal Behaviour xxx (2010) 1e11 Please cite this article in press as: Riebli, T., et al., Behavioural type affects dominance and growth in staged encounters of cooperatively breeding cichlids, Animal Behaviour (2010), doi:10.1016/j.anbehav.2010.11.001