Dantzer Ben, Goncalves Ines Braga, Spence-Jones Helen C, Bennett Nigel C, Heistermann Michael, Ganswindt Andre, Dubuc Constance, Gaynor David, Manser Marta B, Clutton-Brock Tim H
Department of Zoology, University of Cambridge, Cambridge, UK
Kalahari Meerkat Project, Kuruman River Reserve, Northern Cape, South Africa.
Proc Biol Sci. 2017 Sep 27;284(1863). doi: 10.1098/rspb.2017.1248.
In cooperative breeders, aggression from dominant breeders directed at subordinates may raise subordinate stress hormone (glucocorticoid) concentrations. This may benefit dominants by suppressing subordinate reproduction but it is uncertain whether aggression from dominants can elevate subordinate cooperative behaviour, or how resulting changes in subordinate glucocorticoid concentrations affect their cooperative behaviour. We show here that the effects of manipulating glucocorticoid concentrations in wild meerkats () on cooperative behaviour varied between cooperative activities as well as between the sexes. Subordinates of both sexes treated with a glucocorticoid receptor antagonist (mifepristone) exhibited significantly more pup protection behaviour (babysitting) compared to those treated with glucocorticoids (cortisol) or controls. Females treated with mifepristone had a higher probability of exhibiting pup food provisioning (pup-feeding) compared to those treated with cortisol. In males, there were no treatment effects on the probability of pup-feeding, but those treated with cortisol gave a higher proportion of the food they found to pups than those treated with mifepristone. Using 19 years of behavioural data, we also show that dominant females did not increase the frequency with which they directed aggression at subordinates at times when the need for assistance was highest. Our results suggest that it is unlikely that dominant females manipulate the cooperative behaviour of subordinates through the effects of aggression on their glucocorticoid levels and that the function of aggression directed at subordinates is probably to reduce the probability they will breed.
在合作繁殖的动物中，优势繁殖者对从属者的攻击可能会提高从属者的应激激素（糖皮质激素）浓度。这可能通过抑制从属者的繁殖而使优势者受益，但尚不确定优势者的攻击是否能提高从属者的合作行为，或者从属者糖皮质激素浓度的变化如何影响其合作行为。我们在此表明，在野生狐獴中操纵糖皮质激素浓度对合作行为的影响在不同的合作活动以及不同性别之间存在差异。与接受糖皮质激素（皮质醇）处理或作为对照的狐獴相比，接受糖皮质激素受体拮抗剂（米非司酮）处理的两性从属者表现出显著更多的幼崽保护行为（照看幼崽）。与接受皮质醇处理的雌性相比，接受米非司酮处理的雌性表现出为幼崽提供食物（喂幼崽）的可能性更高。在雄性中，处理对喂幼崽的可能性没有影响，但接受皮质醇处理的雄性将其找到的食物分给幼崽的比例高于接受米非司酮处理的雄性。利用19年的行为数据，我们还表明，在援助需求最高的时候，优势雌性并不会增加对从属者的攻击频率。我们的结果表明，优势雌性不太可能通过攻击对从属者糖皮质激素水平的影响来操纵从属者的合作行为，并且对从属者的攻击作用可能是降低它们繁殖的可能性。
