人類社會的家庭結(jié)構(gòu)和居住形式多種多樣。在大多數(shù)社會的婚姻中,，女性通常離開自己父母的家庭與配偶居住在一起,，即所謂的女性擴散模式,。在少數(shù)的母系社會中則是丈夫到妻子家與其親屬一起居住,，也稱男性擴散。在極少數(shù)社會中,，無論男女都不擴散,，他們一生居住在自己出生的家庭中。例如生活在我國西南部的少數(shù)民族-摩梭人,，他們終生居住在母系大家庭中,，與兄弟姐妹共同生活，其婚姻形式為“走婚”婚姻,。
中科院動物研究所陶毅研究組研究了在這種較為罕見的家庭結(jié)構(gòu)和居住形式中家庭成員的生育（繁殖）沖突,，分析了影響摩梭男性和女性繁殖成功的主要因素。其主要研究結(jié)果表明：（1）共同居住的女性親屬之間（姐妹間或表姐妹間）存在生育（繁殖）競爭,，并且共同居住的女性親屬數(shù)量越多，平均每一女性個體的繁殖成功率越低,；（2）男性的繁殖成功則與家庭內(nèi)的親屬數(shù)量無關(guān),，共同居住的男性與他們的兄弟之間不存在繁殖競爭；（3）女性表親之間的繁殖競爭比同母姐妹之間的競爭更為激烈,。研究人員還使用“tug-of-war”模型研究了姐妹間及表姐妹間的競爭模式及可能導(dǎo)致的繁殖后果,。該模型假設(shè)將資源用于競爭可以被看作是一種“自私”的行為。結(jié)果表明，當兩個女性親屬競爭繁殖資源時,，占優(yōu)勢的姐姐（或年長的個體）比占劣勢的妹妹（或年幼的個體）用于競爭的資源投入較少（更為合作）,，且會獲得較多的繁殖成功；而在競爭中利用資源的能力較弱的妹妹則須為競爭中投入更多的資源（更少合作）,，但仍獲得較低的繁殖成功,。實際的觀測數(shù)據(jù)支持了理論模型的預(yù)測。在需要母系大家庭的所有成員合作勞動的農(nóng)忙季節(jié)中,，研究人員發(fā)現(xiàn),，在平均意義上，妹妹比姐姐更少在土地中勞動,。這應(yīng)當是妹妹競爭行為的一種體現(xiàn),，也可能是由于與姐姐相比她與整個家庭的平均親緣關(guān)系較低。
此項研究結(jié)果已在線發(fā)表在英國皇家學(xué)會刊物Philosophical Transactions of the Royal Society B,。第一作者為季婷,；通信作者為陶毅，Ruth Mace,。（生物谷Bioon.com）
生物谷推薦的英文摘要
Philosophical Transactions of the Royal Society B doi: 10.1098/rstb.2013.0081
Reproductive competition between females in the matrilineal Mosuo of southwestern China
Ting Ji1,， Jia-Jia Wu2， Qiao-Qiao He1,， Jing-Jing Xu3,， Ruth Mace2 and Yi Tao1
The matrilineal Mosuo of southwestern China live in communal households where brothers and sisters of three generations live together (duolocal residence)， and men visit their wives,， who reside elsewhere,， only at night in ‘visiting’ marriages. Here we show that these communally breeding sisters are in reproductive conflict， in the sense that they share the resources needed to reproduce. We analyse determinants of reproductive success in females and males,， and show that co-resident female kin are in competition,； the more female kin reside in the household， the more reproductive success is reduced. Male reproductive success,， however,， is not determined by the kin in his natal household； duolocal males are not in reproductive conflict with their siblings. Competition with female cousins can be worse than that between sisters. We also find that female work on the farm (which is the main communal resource) is not equal. We use a ‘tug-of-war’ model of reproductive skew generated by incomplete control,， to model the patterns of effort put into competition between sisters and cousins. The model predicts that more dominant (older) sisters will put less effort into reproductive conflict than will less dominant (younger) sisters,； but younger sisters will also have lower reproductive success because they are less efficient at gaining access to the shared resource. Both predictions are consistent with our data. Younger sisters work less in the fields than do older sisters， which may represent a form of conflict or may be because their average relatedness to the household is lower than that of their more fertile older sisters.
