Evolution & Ecology Research Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW, Australia.
J Evol Biol. 2013 Jan;26(1):76-87. doi: 10.1111/jeb.12028. Epub 2012 Nov 19.
In species where males provide neither direct benefits nor paternal care, it is typically assumed that female preferences are maintained by indirect selection reflecting genetic benefits to offspring of preferred males. However, it remains unclear whether populations harbour sufficient genetic variation in fitness to support costly female preferences - a problem called the 'lek paradox'. Here, we ask whether indirect selection on female preferences can be maintained by nongenetic inheritance. We construct a general model that can be used to represent either genetic or nongenetic inheritance, depending on the choice of parameter values. Interestingly, we find that costly preference is most likely to evolve and persist when fitness depends on an environmentally induced factor that can be transmitted over a single generation only, such as an environment-dependent paternal effect. Costly preference can also be supported when fitness depends on a highly mutable factor that can persist over multiple generations, such as an epigenetic mark, but the necessary conditions are more restrictive. Our findings show that nongenetic inheritance provides a plausible hypothesis for the maintenance of costly female preferences in species where males provide no direct benefits to females. Nongenetic paternal inheritance of fitness can occur in species lacking conventional forms of paternal care. Indeed, transmission of paternal condition via sperm-borne nongenetic factors may be more likely to evolve than conventional forms of paternal investment because sperm-borne effects are protected from cuckoldry. Our results furnish a novel example of an interaction between genetic and nongenetic inheritance that can lead to otherwise unexpected evolutionary outcomes.
在雄性既不提供直接利益也不提供亲代照顾的物种中，通常假设雌性偏好是通过反映对偏好雄性后代的遗传益处的间接选择来维持的。然而，目前尚不清楚种群中是否存在足够的适应性遗传变异来支持昂贵的雌性偏好——这一问题被称为“lek 悖论”。在这里，我们询问非遗传继承是否可以维持对雌性偏好的间接选择。我们构建了一个通用模型，该模型可以根据参数值的选择代表遗传或非遗传继承。有趣的是，我们发现，当适应性取决于只能通过一代传递的环境诱导因素（例如与环境相关的父本效应）时，昂贵的偏好最有可能进化和持续存在。当适应性取决于高度易变的因素（例如表观遗传标记）并且可以在多个世代中持续存在时，昂贵的偏好也可以得到支持，但必要条件更加严格。我们的研究结果表明，非遗传继承为雄性不向雌性提供直接利益的物种中维持昂贵的雌性偏好提供了一个合理的假设。缺乏传统形式的亲代照顾的物种可以通过非遗传的父本遗传来获得适应性。事实上，通过精子携带的非遗传因素传递父本状况可能比传统形式的亲代投资更容易进化，因为精子携带的效应不受“戴绿帽子”的影响。我们的研究结果提供了一个新颖的例子，即遗传和非遗传继承之间的相互作用可以导致否则意想不到的进化结果。
