Males have more pronounced personalities than females across a range of species - from humans to house sparrows - according to new research. Consistent personality traits, such as aggression and daring, are also more important to females when looking for a mate than they are to males. Research from the University of Exeter draws together a range of studies to reveal the role that sexual selection plays in this disparity between males and females.
The study shows that in most species males show more consistent, predictable behaviours, particularly in relation to parental care, aggression and risk-taking. Females, on the other hand, are more likely to vary their behaviour. They are also more likely to respond to these traits and therefore seem to be 'choosier' about the personality of a potential mate.
The research, which is published in the journal Biological Reviews (18 November 2009) draws on several studies, dating back to 1972. It is the latest study in a growing body of research from a University of Exeter team that links gender personality differences to sexual selection.
The authors believe sexual selection may hold the key to this variation. A concept originally developed by Charles Darwin, sexual selection is the theory that evolutionary traits can be explained by competition between one sex - usually males - for mates and by (female) mate choice. While the physical attributes resulting from sexual selection - from dazzling peacocks tails to over-sized antler horns - are well known, there has been much less of a focus on the impact on personality.
Lead author Dr Wiebke Schuett of the University of Exeter says: "Our study is the first to bring together research about the impact of sexual selection on personality in humans and other animals. Our study suggests that, while males tend to exhibit more pronounced personalities, including more predictable behaviour, in a range of different contexts, females are more receptive to these traits in males. We found a surprising level of similarity across a range of species."
This paper supports research carried out by the same team, published in the journal Animal Behaviour (February 2009). The team studied the social and feeding behaviours of a population of zebra finches. They found that although the male zebra finches did not explore their environment more than the females, they were more consistent in their exploratory behaviour. The team concluded that males are more likely to be selected as mates if they are consistent in any behaviour that would be beneficial to a partnership and its offspring. This would include finding food or seeing off predators.
Dr Sasha Dall of the University of Exeter, the team leader, says: "This body of research suggests that male personality could have evolved in much the same way as signs of physical attractiveness - to help attract a mate. Scientists have not given the role of sexual selection in shaping animal personality much consideration in the past. We hope that our work will pave the way for further research in this rather overlooked subject."
Dr Wiebke Schuett was funded by the European Social Fund.
The paper, entitled Sexual Selection and Animal Personality, can be accessed at http://www3.