Adaptive suppression of subordinate reproduction in cooperative mammals

本计画将探讨哺乳动物合作繁殖之雌性间生殖成功变异的演化过程与生理机制。以前的研究要么假设，下属的女性繁殖，占主导地位的女性给予他们的生殖让步，以确保他们留在组中，并协助抚养他们的后代，或下属的繁殖，占主导地位的是无法阻止他们怀孕或抚养年轻。然而，他们在解释物种内部或物种之间的从属生殖分布方面取得了有限的成功。我们将测试备择假设，即从属女性繁殖的频率不同，因为占主导地位的调整，他们抑制从属生殖的可能的成本和收益的变化，以自己的健身从属繁殖的程度。在现有的喀拉哈里猫鼬研究种群中，已经有大量个体样本的完整生活史记录，该项目将使用一系列新颖的实验，包括操纵从属和主导雌性动物的繁殖，以及对现有数据的定量分析，以（1）通过在群体样本中阻止下属繁殖来衡量下属繁殖对主导雌性的成本;（2）确定在何种程度上的优势容忍的存在或繁殖企图的下属时，可能的成本下属繁殖自己的繁殖成功是低的，通过防止显性繁殖，并检查这如何影响他们的待遇下属女性和他们的后代（3）决定支配者是否监控下属的生长，并抑制体重接近他们的个体的生长，或（4）试图通过选择性地驱逐在等级制度中直接低于他们的远亲雌性（贝塔雌性）来操纵他们的继任者的身份。最后，我们将开发新的博弈理论模型的基础上，现实的成本和收益的估计，抑制或驱逐下属的优势，可用于预测频率下属的繁殖和结构的群体在其他合作育种。

This project will investigate the evolutionary processes and physiological mechanisms underlying variation in reproductive success among females in mammals that breed cooperatively. Previous studies have either assumed that subordinate females breed where dominant females grant them reproductive concessions to ensure that they remain in the group and assist in rearing their offspring or that subordinates breed where dominants are incapable of preventing them from conceiving or rearing young. However, they have had limited success in explaining the distribution of subordinate reproduction within or across species. We shall test the alternative hypothesis that the frequency with which subordinate females breed varies because dominants adjust the extent to which they suppress subordinate reproduction in relation to variation in the likely costs and benefits of subordinate breeding to their own fitness. In an existing study population of Kalahari meerkats Suricata suricatta, where full life-history records are already available for large samples of individuals, the project will use a combination of novel experiments involving the manipulation of reproduction by subordinate and dominant females and quantitative analyses of existing data to (1) measure the costs of subordinate breeding to dominant females by preventing subordinates from breeding in a sample of groups and (2) determine whether the extent to which dominants tolerate the presence or breeding attempts of subordinates when the likely costs of subordinate reproduction to their own breeding success are low by preventing dominants from breeding and examining how this affects their treatment of subordinate females and their offspring (3) determine whether dominants monitor the growth of subordinates and suppress the growth of individuals close to them in weight or (4) attempt to manipulate the identity of their successors by selectively evicting distantly related females immediately below them in the hierarchy (beta females). Finally, we shall develop novel game-theoretical models based on realistic estimates of the costs and benefits of suppressing or evicting subordinates to dominants that can be used to predict the frequency of subordinate reproduction and the structure of groups in other cooperative breeders.