Mahidol University; Bangkok, Thailand. Address requests for reprints to: Professor N.J. White, FRCP, Faculty of Tropical Medicine, Mahidol University, 420/6 Rajvithi, Bangkok 10400, Thailand.
In many animal societies, subordinates exhibit down-regulated reproductive endocrine axes relative to those of dominants, but whether this ‘physiological suppression’ arises from active interference by dominants or subordinate self-restraint is a matter of debate. Here we investigate the roles that these processes play in precipitating physiological suppression among subordinate female meerkats, Suricata suricatta. We show that, while subordinate females are known to suffer stress-related physiological suppression during periodic temporary evictions by the dominant female, their low estrogen levels while within their groups cannot be readily attributed to chronic stress, as their fecal glucocorticoid metabolite levels during this time are comparable to those of dominants. The low estrogen levels of subordinate females also cannot be explained simply by self-restraint due to factors that could reduce their payoff from maintaining their fertility regardless of the presence of the dominant female (young age, a lack of unrelated mates, poor body condition and limited breeding experience), as substantial rank-related differences in fecal total-estrogen metabolite levels remain when such factors are controlled. We suggest that this residual difference in estrogen levels may reflect a degree of subordinate restraint due in part to the dominant female's ability to kill their young. Accordingly, subordinate female estrogen levels vary in association with temporal variation in the likelihood of infanticide by the dominant. Attempts to identify the causes of physiological suppression should be cautious if rejecting any role for dominant interference in favor of subordinate restraint, as the dominant's capacity to interfere may often be the reason why subordinates exercise restraint.
Robert Hinde led the study of animal behaviour for much of his long working life, drawing on his expertise in zoology and ethology to build bridges with psychology, psychiatry and the social sciences. He pioneered the application of a quantitative scientific approach to observations of behaviour, making important contributions to understanding underlying mechanisms, behavioural development and the dynamics of relationships between individuals. His influence on the field of animal behaviour was deep and pervasive, he was held in exceptionally high regard by others and his students and their students occupy many key positions in behavioural studies today. He went on to develop a science of personal relationships in humans, ranging from child development to the nature of aggression. Robert's dedication to research was combined with a commitment to promoting peace, including key roles in the Pugwash Conferences in Science and World Affairs. In retirement, he applied his ethological perspective to writing on the origins of religion and morality, the bases of war, and our culture of greed. Throughout his academic life he was a devoted member of St John's College, Cambridge—serving as teaching fellow, tutor and eventually Master.
In the past ten years, the rich world has begun to get serious about tackling the diseases that predominantly affect poor people, diseases that impose an enormous humanitarian and economic burden upon those least able to bear it. Infections comprise the majority of this burden, and three have been singled out for particular attention: HIV/AIDS, tuberculosis, and malaria. Of these, malaria is probably the easiest to attack. But how should we attack it?
