Freeman Angela R, Wood Thomas J, Bairos-Novak Kevin R, Anderson W Gary, Hare James F
Department of Psychology, Cornell University, Ithaca, NY, USA.
Department of Biological Sciences, University of Manitoba, Winnipeg, Manitoba, Canada.
R Soc Open Sci. 2019 Sep 4;6(9):190904. doi: 10.1098/rsos.190904. eCollection 2019 Sep.
Within matrilineal societies, the presence of mothers and female kin can greatly enhance survival and reproductive success owing to kin-biased alarm calling, cooperation in territory defence, protection from infanticidal conspecifics, joint care of young and enhanced access to resources. The removal of mothers by predators or disease is expected to increase the stress experienced by offspring via activation of their hypothalamic-pituitary-adrenal axis, increasing circulating glucocorticoids and reducing offspring survival and reproductive success. Yet, few studies have removed mothers in the post-weaning period to examine the assumed physiological and fitness consequences associated with these mortality events. We examined how the loss of a mother affects juvenile Richardson's ground squirrels' () faecal glucocorticoid metabolites and their survival. Given that neighbours are often close kin, we further hypothesized that conspecific removal would similarly diminish the fitness of neighbouring individuals. Upon removing the mother, we detected no impact on offspring or neighbouring conspecific faecal glucocorticoid metabolites in the removal year, or on overwinter survival in the following year. Furthermore, no impact on neighbour reproductive success was detected. Given the high predation rates of ground squirrels in wild populations, resilience to a changing social environment would prove adaptive for both surviving kin and non-kin.
在母系社会中，母亲和女性亲属的存在能够极大地提高生存几率和繁殖成功率，这得益于亲属偏向的警报鸣叫、领地防御中的合作、免受杀婴同类的侵害、对幼崽的共同照料以及获取资源的机会增加。预计捕食者或疾病导致母亲离世会通过激活后代的下丘脑 - 垂体 - 肾上腺轴增加其经历的压力，从而增加循环糖皮质激素水平并降低后代的生存几率和繁殖成功率。然而，很少有研究在断奶后阶段移除母亲，以检验与这些死亡事件相关的假定生理和适应性后果。我们研究了母亲的缺失如何影响幼年理查森地松鼠（）的粪便糖皮质激素代谢物及其生存情况。鉴于邻居通常是近亲，我们进一步假设同种个体的移除同样会降低相邻个体的适应性。移除母亲后，我们在移除当年未检测到对后代或相邻同种个体粪便糖皮质激素代谢物的影响，也未检测到对次年越冬生存的影响。此外，未检测到对邻居繁殖成功率的影响。鉴于野生种群中地松鼠的高捕食率，对不断变化的社会环境的适应能力对幸存的亲属和非亲属来说都将是适应性的。
