Alternative reproductive tactics occur when conspecifics of the same sex use different behavioral processes to maximize reproductive success. Resource availability can have significant impacts on the proximate factors impacting the success and persistence of alternative tactics, such as an individual’s physiology, immunity, and body condition. Male Cape ground squirrels (Xerus inauris) display two alternative tactics, with some mature males dispersing from their natal groups and joining bands of nonrelated males (band males), whereas others do not disperse and remain philopatric in their natal groups past sexual maturation (natal males). Despite differences in metabolism, home ranges, and behavior, there is no difference in reproductive success between the two tactics, allowing us to test if rainfall (as a measure of primary productivity) influences body condition and physiological indices in tactics when fitness is equal. Over a period of 6 years, rainfall was positively related to body condition (mass–spine length residuals) in band males (N = 76), but not in natal males (N = 75). When we followed 18 males prior to and after dispersal, we also found a positive relationship between body condition and age following dispersal, but not prior to dispersal, and natal males maintained a better body condition in low rainfall years. During 2 years of low rainfall, band males (N = 39) had higher total ectoparasite abundance, and white blood cell differentials, implying they are less able to tolerate parasitic infection than natal males (N = 31). We found no difference in bacterial growth inhibition between tactics, suggesting that band and natal males both are equally resistant to parasites. The poorer body condition of band males during lower rainfall suggests they are less tolerant to parasites in these years. Dispersal during years of low rainfall thus may increase the costs to body condition and parasite infection, but the reproductive benefit of overlapping with more females may contribute to maintaining equal fitness between tactics.

中文翻译：

---

非洲雄性地松鼠的另类策略：降雨变化对条件和生理的影响

当同性别的同种异形使用不同的行为过程来最大程度地实现生殖成功时，就会出现替代性的生殖策略。资源的可用性可能对影响替代策略的成功和持久性的直接因素产生重大影响，例如个人的生理机能，免疫力和身体状况。雄海角松鼠（Xerus inauris）展示了两种替代策略，其中一些成熟的男性从其出生群体中分散出来，并加入不相关的男性群体（乐队男性），而另一些则没有分散，并且在性成熟后（其成年男性）在他们的出生群体中保持成语性。尽管在新陈代谢，家庭活动范围和行为方面存在差异，但两种策略在生殖成功方面没有差异，这使我们能够测试在相等的情况下降雨（作为初级生产力的量度）是否会影响战术中的身体状况和生理指标。在6年的时间里，带状男性（N = 76）的降雨与身体状况（质量-脊柱长度残差）呈正相关，而与成年男性（N= 75）。当我们追踪散布前后的18位男性时，我们还发现散布后身体状况与年龄之间呈正相关，但散布前却没有，而且在低降雨量年份，成年男性保持较好的身体状况。在2年的低降雨期间，带状雄性（N = 39）具有较高的总体外寄生虫丰度和白细胞差异，这意味着与成年雄性相比，它们对寄生虫感染的耐受性较弱（N= 31）。我们发现战术之间的细菌生长抑制没有差异，这表明带状和成年男性均对寄生虫具有同等的抵抗力。降雨较少时，带状雄性的身体状况较差，这表明这些年它们对寄生虫的耐受性较弱。因此，在多年降雨不足的情况下驱散可能会增加身体状况和寄生虫感染的成本，但与更多雌性交配产生的生殖效益可能有助于维持战术之间的平等适应性。