原文: Female Taste in Men is Fickle by Nature

A new study of birds has caused a rethink of some explanations of evolution, and suggests that the female prerogative to change her mind about men is a natural gift.

A lark bunting

The study looked at the mating habits of migratory songbirds in Colorado’s prairies. It turned out that what females considered attractive, i.e. plumage, beak size, etc., varied from year to year. Just like human fashions, which might promote a slim, hairless build as the embodiment of sexy one year and suggest beefed up macho men are all the rage the next, birds’ tastes change.

This is causing scientists to revise some of their ideas on the evolution of “attractiveness” so to speak. Some of the more classical ideas about the evolution of sexual selection suggest that the behaviours and physical traits exhibited for mating by males evolved as the result of a female preference for those behaviours, plumage, etc., over time. One example is the peacock’s tail. Researchers had believed the brilliantly feathered plumage evolved over time as the result of female peacock’s preference for brilliant plumage.

The researchers studied 5 different characteristics of the male’s plumage and three of their size, as well as the male’s success in reproduction. They found that the success of a male depended on which of the 5 characteristics was in fashion in a particular year. For example, one year the size of a male’s wing patch was an indicator of success, the larger the better apparently.

Dr. Alexis Chaine of the University of California-Santa Cruz explained the behaviour, saying: “If the prairie is overrun by ground snakes, for example, female birds might choose the most protective males — signalled by, say, wing-patch size,”

Dr. Chaine added: “The traits the female is choosing somehow predict how successful the pair will be in nesting. One possibility is that certain traits are associated with the male being a good forager, and other traits predict how well he could defend the nest from predators. So, if there are lots of ground squirrels, which are a major nest predator, she wants a good defender, but in a year when grasshopper populations are low, she needs a good provider. These are ideas we still need to test.”

The researchers said that the ideas are applicable to humans as well, although the applications would be very different as the birds they studied are monogamous for only one mating season before choosing a new partner.

译文: 女性之见异思迁源自本能

 

   女性之见异思迁源自本能

   关于鸟类的一项新研究使人们对如何解释进化论有了新的思考，并且表明了对男性品位的转变是女性独有的天赋。

   百灵鸟（美国科罗拉多州州鸟）

   这项研究观察了科罗拉多大草原上迁徙鸟类的交配习惯。结果表明，吸引雌鸟的因素，如羽翼，鸟嘴的形状等逐年变化。如同人类追逐时尚潮流一样：今年苗条、稀发成为性感的代言词，而明年风行一时的却是魁梧、男人味十足的一类，鸟类的品位也会发生变化

   这个结果使科学家们对所谓的“魅力”一词的演变有了新的认识。一些有关性取向演变的传统理论认为，雄性交配时的行为和所展示的自然特征随着雌性长期以来对这些行为，羽毛等的偏好而变化。孔雀的尾巴就是一个例子。研究人员认为孔雀漂亮而丰满的羽翼是因雌性对此的偏好随时间进化而来。

   研究人员对雄鸟的五个羽翼特征、三项外形指标以及繁殖成功率做了调查。他们发现雄性繁殖的成功率取决于该年哪五种羽翼特征较受青睐。例如某一年，雄鸟羽毛上斑点的尺寸是成功的象征，显然，斑点越大越受欢迎。

   圣塔克鲁兹加州大学的教授Alexis Chaine对这种行为作出解释时说：“比如在草原被地蛇占领的情况下，雌鸟就可能选择最能保护他们的雄性，而羽翼斑点是这种保护能力的标志。”

   Chaine博士补充道：“雌性鸟类的喜好特征某种程度上预测了该对配偶筑巢的成功率。可能有些因素与雄性是否具备优良的捕食能力相关，另一些因素则关及他是否能抵御掠食者、安全守卫家园。所以，如果某个时候松鼠数量较多（松鼠是破坏鸟巢的罪魁祸首），雌鸟就要一个优秀的守巢者，但某一年蝗虫数量较少的话，她需要一个优秀的捕食者。我们还需用进一步实验来验证这些想法。”