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Individuals often differ from each other in how they respond to environmental events: a feature of behaviour often termed animal personality. Furthermore, animals often show unpredictability in how much they respond to these events over time leading to the suggestion that personality and intraindividual variability (IIV) might have important fitness consequences. We investigated this hypothesis by focusing on the tendency for individually identifiable male fallow deer, Dama dama, to escalate low-level (noncontact) agonistic interactions to fighting during the rut. Males differed in their tendency to escalate noncontact interactions to fighting; however, repeatability in escalation rates was unstable over the rut suggesting that escalation rate is a poor measure of personality. There was no difference in the level of IIV in escalation rate shown by males. A comparison of IIV recorded over two consecutive annual ruts showed that IIV was highly correlated between years; therefore, over an extended time period individuals were consistent in their willingness to engage in fighting. There was a nonlinear relationship between IIV and mating success; specifically, individuals that showed either low or high IIV in escalation rate had lower mating success than individuals that showed intermediate levels of IIV. Aggression and the willingness to commit to fighting are important fitness correlates; nevertheless, our understanding of how personality and IIV are related to aggression is poorly understood. This study shows that although escalation rate appears to be a poor measure of personality in the fallow deer, IIV is related to increased fitness in individuals that show intermediate levels of predictability in their willingness to fight over the rut. [ABSTRACT FROM AUTHOR]

Abstract: During contests, losing animals often show signals communicating submission. From an evolutionary viewpoint, however, it is not so obvious why the losing individual gives such a signal instead of running away and why the winning individual accepts the signal instead of inflicting more severe damage. We investigated factors influencing the evolution of signals of submission using a numerical ESS model. The present analysis reveals that there is much space for the evolution of signals of submission, even when the winner of an escalated contest gets some extra benefit. In most cases, signals of submission are given by animals which are slightly or moderately weaker than the opponent. Signals of submission are expected to occur frequently (1) when the value of contested resource does not differ greatly from the cost of injury, (2) when the extra benefit of winning an escalated contest is small, (3) when the opportunity for safe retreat by the losing animal is small, and (4) when the estimation of the difference in the resource holding potential (RHP) between the combatants is accurate but not perfect. [Copyright &y& Elsevier]

Examines the purpose of signals transmitted by short-term vocalization rates in male fallow bucks Dama dama. Analysis on signal representation as intrasexual threat or an intersexual advertisement; Impact of female and male association on groaning rates; Postcopulation call as the highest groaning rates produced by males.

Third-party interventions of dyadic contests are often explained by appealing to high-level cognitive processes such as coalition formation between group members. However, alternative accounts that do not appeal to sophisticated cognitive processes have been proposed. We tested predictions from two such models using the fallow deer, Dama dama, as the model taxon: (1) a random target model that argues that intervention is directed randomly towards a target and (2) a specific target model that assumes that targeting is directed at contestants that have low resource-holding potential. Contrary to predictions of the specific target model, we found no evidence that targeting following third-party intervention increased as the resource-holding potential of the target declined. Both models argue that intervention serves to prevent individuals from gaining a winner effect and advancing up the hierarchy. Being targeted did not result in a decline in dominance rank, although targeting was associated with investment in dominance-related fighting tactics. Fight intervention was associated with an increase in rank early in the rut and accounted for increased mating success. Therefore, interveners benefited beyond simply preventing rivals from advancing in the hierarchy. In theoretical terms, a random target as opposed to a specific target model explains intervention behaviour in the fallow deer. [Copyright &y& Elsevier]

According to life history theory, males of iteroparous species are expected to trade off investment between current and future reproduction based on age (mating strategy or terminal investment hypotheses) or body condition (individual quality hypothesis). However, although central to this latter model, the question concerning whether and to what extent condition regulates competitive investment in polygynous species is unknown. Consequently, we investigated this issue with reference to fight structure in fallow deer contests. Support for the individual quality hypothesis was limited: males with larger necks as determined by prerut neck girth fought for longer than males with smaller necks. However, prime-aged males had higher investment in fighting than preprime- or postprime-aged males indicating that investment in fighting might be age related. Other aspects of our results also failed to support condition-related predictions; although we found that jump clashing and vocal rate were related to weight loss and decline in neck girth, respectively, there was no relationship between investment in fighting and prerut measures of body size. Moreover, we also found that rank was predicted by investment in fighting (backward pushing) rather than body condition. Our results show that, in addition to body condition and age, variation in competitive investment between individuals also influences reproductive effort in the fallow deer. [Copyright &y& Elsevier]

We tested predictions of evolutionary game theory focusing on fight duration and intensity during contests between European fallow deer, Dama dama L. We examined the relation between contest duration and intensity and resource-holding potential (RHP; body weight and antler size), in an effort to reveal the assessment rules used by competing males. We examined other potential determinants of duration and intensity: resource value (the oestrous female) and experience of agonistic interactions. Asymmetry in body weight or antler length of contestants was not correlated with fight duration. Body weight and antler length of the fight winner or loser were also not correlated with fight duration. Neither were the body weight of the heavier or lighter animal or the antler length of the animal that had longer or shorter antlers. A measure of intensity (the jump clash) was positively related to the body weight of the losing animal and the lighter member of the dyad. These results are consistent with the hypothesis that opponents escalate contest intensity based on assessment of their own ability rather than through mutual assessment. There was no evidence that resource value is an important factor in either fight duration or intensity in this population. As the number of fights between pairs of males increased, there was a decrease in fight duration. Fights were longer when at least one member of a competing pair of males had previously experienced a victory. [Copyright &y& Elsevier]

During competitive encounters protagonists are expected to use signals of individual quality particularly if there is a risk of injury or death. Lateral presentation of body profile, by which information regarding phenotypic characteristics associated with individual quality are displayed, may represent such a strategy. During aggressive interactions, male fallow deer frequently engage in parallel walking which is assumed to represent a mutual display of quality, as mediated by exposure of the maximal profile of the body or antlers. We examined the context and role of the parallel walk during competitive encounters to investigate whether there was evidence that dyads of competing males were assessing differences in phenotypic characteristics. There was no evidence to support the hypotheses that the parallel walk is a lateral display of body size or weaponry or that its use is associated with a reduced level of escalated or risky behaviours during fighting. Total time spent fighting was not shorter when a parallel walk was present than when there was no parallel walk. The parallel walk was highly associated with fighting and it was more likely to be initiated by the subsequent loser. Furthermore, parallel walking frequently followed bouts of fighting and as such may represent a strategy that permits an animal the opportunity to decide whether to continue fighting. Parallel walking was also associated with a failure to resolve contests in favour of one animal indicating that it may be a means of withdrawing from further fighting without incurring a loss in dominance status. Copyright 2003 Published by Elsevier Science Ltd on behalf of The Association for the Study of Animal Behaviour. [Copyright &y& Elsevier]