Toward a Unifying Theory of Social Evolution: Testing Competing Models of Reproductive Skew in an Avian Cooperative Breeder

走向社会进化的统一理论：测试鸟类合作饲养者的繁殖偏差竞争模型

• 批准号: 0133795
• 负责人: Stephen Emlen
• 金额: $ 39.76万
• 依托单位: Cornell Univ - State: AWDS MADE PRIOR MAY 2010
• 依托单位国家: 美国
• 项目类别: Continuing grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-02-01 至 2006-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0133795&HistoricalAwards=false
• 关键词: Toward; Unifying; Theory; Social; Evolution

TOWARD A UNIFYING THEORY OF SOCIAL EVOLUTION: TESTING COMPETING MODELS OF REPRODUCTIVE SKEW IN AN AVIAN COOPERATIVE BREEDER.STEPHEN T. EMLENPROJECT SUMMARY (IN LAY TERMS)The family (defined as a multi-generation assemblage of genetic relatives) is among the least understood of all forms of social organization. Yet, because it is the basic social organization of our own species, it is arguably the most important for us to understand. Only about 3% of birds and mammals live in family-based societies, and only a few of these have been studied in detail.Families come in various sizes and forms. The most common form in both birds and mammals is the nuclear family, formed when grown young remain with their parents, but only the parents reproduce. Most so-called 'cooperative breeders' fit this category, with grown sons and daughters remaining as helpers at the nest or den of their parents. Less common, but of greater interest, is the extended family, formed when reproduction is shared among many family members. When multiple pairs within a single family breed, the result is a mixture not only of parents and offspring, but also of grandparents, uncles and aunts, nieces and nephews, and cousins as well as unrelated in-laws. Until very recently, we humans lived predominantly in groups comprised of such extended family units. The difference between extended and nuclear families is one of shared versus monopolized breeding. A rapidly growing number of evolutionary models, known collectively as reproductive skew theory, attempt to explain the variability of reproductive suppression found in nature. Skew models incorporate a small number of factors (two ecological, one genetic, and one social) to predict 1) when stable family groups will form, 2) what their stable size will be, and 3) how reproduction will be shared among family members.Reproductive skew they is generating considerable interest among behavioral ecologists and evolutionary biologists because it links many major features of animal societies to their ecological, genetic, and social underpinnings. Because of this breadth, some workers believe that skew theory may provide a unifying framework for viewing much of social evolution. However, the development of the theory has far outpaced the testing of its assumptions and predictions with real animals in the field. There is an urgent need for detailed observational and experimental studies of skew theory on birds and mammals that live in family-based societies.The proposed research will provide such a test. The study species is the Grey capped social weaver (Pseudonigrita arnaudi), a common inhabitant of the whistling thorn savanna of East Africa. This species was chosen because it lives in both extended and nuclear family units, background knowledge of its behavior and ecology is already well-known, and it possesses many features that make it logistically easy to collect data and perform experiments. A study population of over 50 family units has been captured and the birds individually marked. Molecular markers (microsatellite loci) have been developed that will allow genetic determination of family structures (e.g. who is the father, or aunt, of whom). The research program will help to train numerous Kenyan professionals in modern methods of behavioral research. It will also combine the talents of several senior investigators whose expertise ranges from field studies of behavior, to molecular studies of social organization, to theoretical modeling of social evolution. As such, it constitutes one of the first integrated tests of the applicability of recent skew models to a complex vertebrate society.The results should enhance our understanding of 1) the factors that favor the evolution of family groups, 2) the reasons why extended families develop when they do, and 3) the behaviors that family members use in their cooperative and competitive interactions with one another (so-called 'family dynamics'). This, in turn, should provide insights into the conditions that favored the evolution and maintenance of extended family groupings in our own species as well.

走向社会进化的一个可验证的理论：在一只合作繁殖的鸟类中检验生殖偏斜的竞争模型。家庭（被定义为遗传亲属的多代组合）是所有社会组织形式中最不为人所知的。 然而，因为它是我们自己物种的基本社会组织，它可以说是我们理解的最重要的。 只有大约3%的鸟类和哺乳动物生活在以家庭为基础的社会中，其中只有少数得到了详细的研究。家庭有各种各样的大小和形式。 在鸟类和哺乳动物中最常见的形式是核心家庭，当成长的年轻人留在父母身边时形成，但只有父母繁殖。 大多数所谓的“合作繁殖者”都属于这一类，成年的儿子和女儿留在父母的巢穴或巢穴中帮忙。 不太常见，但更令人感兴趣的是大家庭，它是由许多家庭成员共同生育而形成的。 当一个家庭中的多对夫妇繁殖时，结果不仅是父母和后代的混合，而且还有祖父母，叔叔和阿姨，侄女和侄女，堂兄弟姐妹以及无关的姻亲。 直到最近，我们人类主要生活在由这种大家庭单位组成的群体中。大家庭和核心家庭之间的区别在于共享与垄断的繁殖。 越来越多的进化模型，统称为生殖偏斜理论，试图解释自然界中发现的生殖抑制的变异性。 偏态模型包含了少量的因素（两个生态的，一个遗传的，一个社会的）来预测1）什么时候稳定的家庭群体将形成，2）他们的稳定规模将是什么，以及3）繁殖将如何在家庭成员之间共享。繁殖偏斜正在引起行为生态学家和进化生物学家的极大兴趣，因为它将动物社会的许多主要特征与它们的生态，基因和社会基础。 由于这种广度，一些工作者认为，偏斜理论可能提供一个统一的框架来观察社会进化的大部分。 然而，该理论的发展已经远远超过了在野外用真实的动物对其假设和预测的检验。 目前迫切需要对生活在以家庭为基础的社会中的鸟类和哺乳动物的偏斜理论进行详细的观察和实验研究。 研究物种是灰帽社会编织者（Pseudonigrita arnaudi），东非呼啸荆棘稀树草原的常见居民。 选择这个物种是因为它生活在扩展和核心家庭单元中，其行为和生态学的背景知识已经众所周知，并且它具有许多特征，使得在逻辑上易于收集数据和进行实验。 一个超过50个家庭单位的研究人口已被抓获，并单独标记的鸟类。 分子标记（微卫星基因座）已经开发出来，可以从遗传学上确定家庭结构（例如谁是谁的父亲或姑姑）。 该研究计划将有助于培训许多肯尼亚专业人员的现代行为研究方法。 它还将联合收割机结合几位高级研究人员的才能，他们的专业知识范围从行为的实地研究到社会组织的分子研究，再到社会进化的理论建模。 因此，它构成了最近的偏斜模型对复杂脊椎动物社会的适用性的第一个综合测试之一。结果应该增强我们对1）有利于家庭群体进化的因素，2）为什么大家庭发展的原因，3）家庭成员在相互合作和竞争的互动中使用的行为（所谓的“家庭动力”）。 反过来，这也应该为我们提供一些见解，以了解有利于我们自己物种进化和维持大家庭群体的条件。