Alternative reproductive tactics and lifetime reproductive success in a polygynandrous mammal

The widespread occurrence of alternative reproductive tactics (ARTs) highlights the diverse ways in which sexual selection can operate within a population. We studied ARTs in Columbian ground squirrels (Urocitellus columbianus), evaluating paternity, lifetime reproductive success, and life histories. Reproductively mature male Columbian ground squirrels displayed either a territorial or satellite (non-territorial) tactic. Territorial males secured a higher proportion of copulations, were more likely to mate at earlier positions in females’ mating sequences and sired more offspring than satellite males. The tactic males adopted was largely a function of weight, age, and experience, with larger, older and more experienced males displaying the territorial tactic. At two years of age, males adopted the satellite tactic or deferred breeding for the season. Two-year-old satellite males were heavier than males that deferred breeding, but by age three there was no difference between their weigh...

替代繁殖策略（alternative reproductive tactics, ARTs）的广泛存在凸显了性选择在种群内运作方式的多样性。我们针对哥伦比亚地松鼠（Urocitellus columbianus）的替代繁殖策略展开研究，评估了父权、终生繁殖成功率及生活史特征。性成熟的雄性哥伦比亚地松鼠表现出领域型或卫星型（非领域性）两种繁殖策略。领域型雄性获得的交配比例更高，更可能在雌性交配序列中占据较早位置，且相比卫星型雄性，其后代数量更多。雄性所采用的策略在很大程度上取决于体重、年龄及经验——体型更大、年龄更长且经验更丰富的雄性倾向于采用领域型策略。两岁时，雄性会选择卫星型策略或推迟该繁殖季的繁殖活动。两岁的卫星型雄性比推迟繁殖的雄性体重更重，但到三岁时，二者的体重差异...