Nichols Hazel J, Cant Michael A, Sanderson Jennifer L
School of Natural Science and Psychology, Liverpool John Moores University , Liverpool L3 3AF , UK and.
College of Life and Environmental Sciences, University of Exeter , Penryn TR10 9FE, UK.
Behav Ecol. 2015 Nov-Dec;26(6):1486-1494. doi: 10.1093/beheco/arv095. Epub 2015 Jul 3.
Females of many animal species seek mating opportunities with multiple males, despite being able to obtain sufficient sperm to father their offspring from a single male. In animals that live in stable social groups, females often choose to mate outside their group resulting in extra-group paternity (EGP). One reason proposed to explain female choice for extra-group males is to obtain compatible genes, for example, in order to avoid inbreeding depression in offspring. The benefits of such extra-group paternities could be substantial if they result in fitter, outbred offspring. However, avoiding inbreeding in this way could be costly for females, for example, through retaliation by cuckolded males or through receiving aggression while prospecting for extra-group mating opportunities. We investigate the costs and benefits of EGP in the banded mongoose , a cooperatively breeding mammal in which within-group mates are sometimes close relatives. We find that pups born to females that mate with extra-group males are more genetically heterozygous are heavier and are more likely to survive to independence than pups born to females that mate within their group. However, extra-group matings also involve substantial costs as they occur during violent encounters that sometimes result in injury and death. This appears to lead femalebanded mongooses to adaptively adjust EGP levels according to the current risk of inbreeding associated with mating within the group. For group-living animals, the costs of intergroup interactions may help to explain variation in both inbreeding rates and EGP within and between species.
许多动物物种的雌性会寻求与多个雄性交配的机会，尽管与单个雄性交配就能获得足够的精子来孕育后代。在生活在稳定社会群体中的动物里，雌性常常选择与群体外的雄性交配，从而产生群体外父权现象（EGP）。人们提出的一个解释雌性选择群体外雄性的原因是为了获得相容的基因，例如，以避免后代出现近亲繁殖衰退。如果这种群体外父权能产生更健康、非近亲繁殖的后代，那么其益处可能是巨大的。然而，以这种方式避免近亲繁殖对雌性来说可能代价高昂，比如，可能会遭到被戴绿帽的雄性的报复，或者在寻找群体外交配机会时受到攻击。我们研究了缟獴中群体外父权的成本和益处，缟獴是一种合作繁殖的哺乳动物，群体内的配偶有时是近亲。我们发现，与群体外雄性交配的雌性所生的幼崽基因上更具杂合性，体重更重，并且比在群体内交配的雌性所生的幼崽更有可能存活至独立生活。然而，群体外交配也涉及巨大成本，因为这些交配发生在激烈冲突期间，有时会导致受伤甚至死亡。这似乎导致雌性缟獴根据当前群体内交配相关的近亲繁殖风险来适应性地调整群体外父权水平。对于群居动物来说，群体间互动的成本可能有助于解释物种内部和物种之间近亲繁殖率及群体外父权的差异。
