Harassment is also often used by subordinates to modify the behaviour of dominants. For example, hungry individuals sometimes harass successful foragers or hunters for a share of the food that selleck kinase inhibitor they have acquired and adolescents of either sex may harass copulating couples (Clutton-Brock & Harvey, 1976; Clutton-Brock & Parker, 1995b). More generally, the stress induced by social conflicts varies across species depending on the structure

of societies as well as within societies depending on social dynamics, and may be higher in dominants than in subordinates when the costs of acquiring and maintaining dominance are very high (Goymann & Wingfield, 2004; Rubenstein & Shen, 2009). In many social mammals where selleck compound females are philopatric, female group members (who are often close kin) compete with each other

to breed and raise young (Clutton-Brock, 2009b; Clutton-Brock & Lukas, 2011). Regular aggression directed by dominant females at subordinates or their offspring is common, especially in species living in large groups, where average coefficients of relatedness are relatively low and females belonging to different kin groups compete with each other to breed and rear young. Competition between females often inhibits females from mating and can depress the fertility of subordinates, disrupting their reproductive cycles and causing them to down-regulate their reproductive systems (Wasser & Barash, 1983; Young, 2009). For example, in yellow baboons, dominant females direct frequent aggression at cycling subordinate females in the follicular phase and these attacks can increase the number of cycles before conception (Wasser & Starling, Pazopanib datasheet 1988), while in other species (including several rodents, some carnivores and almost all of the marmosets and tamarins) subordinates are temporarily infertile (Young, 2009). As well as disrupting reproduction, regular aggression can lead to increased rates of abortion and reductions in juvenile survival (Silk, 2007a; Stockley & Bro-Jorgensen, 2011). For example, in

hamsters, interactions between subordinate and dominant females shortly after mating increase implantation failures in subordinates, while interactions later in pregnancy lead to increased rates of foetal mortality (Huck, 1988a, b). Studies of several species suggest that reproductive suppression intensifies when resources are limited and eases when they are abundant (Young, 2009; Clutton-Brock et al., 2010). For example, in Damaraland mole rats, physiological suppression of subordinate females is relaxed during the annual rains when ecological constraints are relaxed (Young et al., 2010) while, in meerkats, dominant females are more likely to tolerate subordinate reproduction when food is abundant (Clutton-Brock et al., 2010).