Kin selection in cooperative alliances of carrion crows

In most cooperative vertebrates, delayed natal dispersal is the mechanism that leads to the formation of kin societies. Under this condition, the possibility that kin-based cooperative breeding is an unselected consequence of dispersal patterns can never be ruled out because helpers can only help their relatives. Here we show that a population of carrion crows (Corvus corone corone) fully fits the central prediction of kin selection theory that cooperative breeding should arise among relatives. On their territory, resident breeders are aided not only by nonbreeding retained offspring but also by immigrants (mainly males), with whom they share matings. Philopatry cannot account, however, for the high degree of genetic relatedness found between breeders and immigrants of the same sex that cooperate at a nest, indicating that crows actively choose to breed cooperatively with their relatives.     

Wasp gene expression supports an evolutionary link between maternal behavior and eusociality

The presence of workers that forgo reproduction and care for their siblings is a defining feature of eusociality and a major challenge for evolutionary theory. It has been proposed that worker behavior evolved from maternal care behavior. We explored this idea by studying gene expression in the primitively eusocial wasp Polistes metricus. Because little genomic information existed for this species, we used 454 sequencing to generate 391,157 brain complementary DNA reads, resulting in robust hits to 3017 genes from the honey bee genome, from which we identified and assayed orthologs of 32 honey bee behaviorally related genes. Wasp brain gene expression in workers was more similar to that in foundresses, which show maternal care, than to that in queens and gynes, which do not. Insulin-related genes were among the differentially regulated genes, suggesting that the evolution of eusociality involved major nutritional and reproductive pathways.     

Kin discrimination and the benefit of helping in cooperatively breeding vertebrates

In many cooperatively breeding vertebrates, a dominant breeding pair is assisted in offspring care by nonbreeding helpers. A leading explanation for this altruistic behavior is Hamilton's idea that helpers gain indirect fitness benefits by rearing relatives (kin selection). Many studies have shown that helpers typically provide care for relatives, but relatively few have shown that helpers provide closer kin with preferential care (kin discrimination), fueling the suggestion that kin selection only poorly accounts for the evolution of cooperative breeding in vertebrates. We used meta-analysis to show that (i) individuals consistently discriminate between kin, and (ii) stronger discrimination occurs in species where the benefits of helping are greater. These results suggest a general role for kin selection and that the relative importance of kin selection varies across species, as predicted by Hamilton's rule.     

Haplodiploidy and the evolution of facultative sex ratios in a primitively eusocial bee

In eusocial Hymenoptera, the haplodiploid system of sex determination creates relatedness asymmetries such that workers are more closely related on average to their sisters than to their brothers. For such societies, kin-selection theory and sex-ratio theory predict that workers maximize their inclusive fitness by biasing the investment sex ratio toward females. To test the prediction of sex-ratio biasing, relatedness asymmetries were experimentally manipulated in colonies of the primitively eusocial bee Augochlorella striata (Halictidae: Hymenoptera) by removing or not removing foundress queens. Queenright colonies (relatedness asymmetry present) produced a more female-biased sex ratio than did queenless colonies (relatedness asymmetry absent). Worker reproduction and unmated replacement queens can be discounted as alternative explanations. Workers therefore facultatively adjusted their colony's sex ratio and, in the presence of a relatedness asymmetry, biased the investment sex ratio toward their more closely related sisters and away from their more distantly related brothers.     

关联和亲缘选择的概念·原理及其研究进展

就关联和亲缘选择的概念、原理作一总结,从模型建立、利他和协作方面综述了关联和亲缘的研究进展综述。     

基于动态粗集的农民工群体结构研究

首先基于动态粗集理论对农民工群体进行建模,将农民工群体动态的划分为4个层次,分别是核心农民工群体、现实农民工群体、边缘农民工群体和非农民工群体。其次提出依据农民工个体属性的迁移系数判定他位于农民工群体的层次。此过程不仅充分考虑了农民工个体在社会中的动态表现和各种不确定因素,还避免了主观因素的影响。最后通过一个公司农民工群体结构分析的应用举例验证了研究的实用性。     

Behavioral control of workers by queens in primitively eusocial bees

Queens of Lasioglossum zephyrum, a primitively eusocial bee, are considerably more active than workers. The queen's behavior stimulates worker activities; removal of the queen results in a marked reduction in activities of other bees. The queen not only activates workers but also directs them by a primitive recruitment behavior suggestive of tandem running of highly eusocial ants.     

Ancestral monogamy shows kin selection is key to the evolution of eusociality

Close relatedness has long been considered crucial to the evolution of eusociality. However, it has recently been suggested that close relatedness may be a consequence, rather than a cause, of eusociality. We tested this idea with a comparative analysis of female mating frequencies in 267 species of eusocial bees, wasps, and ants. We found that mating with a single male, which maximizes relatedness, is ancestral for all eight independent eusocial lineages that we investigated. Mating with multiple males is always derived. Furthermore, we found that high polyandry (>2 effective mates) occurs only in lineages whose workers have lost reproductive totipotency. These results provide the first evidence that monogamy was critical in the evolution of eusociality, strongly supporting the prediction of inclusive fitness theory.     

Breeding together: kin selection and mutualism in cooperative vertebrates

In cooperatively breeding vertebrates, nonbreeding helpers raise young produced by dominant breeders. Although the evolution of cooperative breeding has often been attributed primarily to kin selection (whereby individuals gain "indirect" benefits to their fitness by assisting collateral relatives), there is increasing evidence that helpers can be unrelated to the young they are raising. Recent studies also suggest that the indirect benefits of cooperative behavior may often have been overestimated while the direct benefits of helping to the helper's own fitness have probably been underestimated. It now seems likely that the evolutionary mechanisms maintaining cooperative breeding are diverse and that, in some species, the direct benefits of helping may be sufficient to maintain cooperative societies. The benefits of cooperation in vertebrate societies may consequently show parallels with those in human societies, where cooperation between unrelated individuals is frequent and social institutions are often maintained by generalized reciprocity.     

Migration strategies of insects

Physiological and ecological results from a variety of species are consistent with what seem to be valid general statements concerning insect migration. These are as follows: (i)During migration locomotory functions are enhanced and vegetative functions such as feeding and reproduction are suppressed. (ii) Migration usually occurs prereproductively in the life of the adult insect (the oogenesis-flight syndrome). (iii)Since migrant individuals are usually prereproductive, their reproductive values, and hence colonizing abilities, are at or near maximum. (iv) Migrants usually reside in temporary habitats. (v)Migrants have a high potential for population increase, r, which is also advantageous for colonizers. (vi)Both the physiological and ecological parameters of migration are modifiable by environmental factors (that is, phenotypically modifiable)to suit the prevailing conditions. Taken together, these criteria establish a comprehensive theory and adumbrate the basic strategy for migrant insects. This basic strategy is modified to suit the ecological requirements of individual species. Comparative studies of these modifications are of considerable theoretical and practical interest, the more so since most economically important insects are migrants. No satisfactory general statements can as yet be made with respect to the genotype and migration. Certainly we expect colonizing populiations to possess genotypes favoring a high r, but genotypic variation in r depends on the heritabilities of life table statistics, and such measurements are yet to be made (10, 53). The fact that flight duration can be increased by appropriate selection in Oncopeltus fasciatus, and the demonstration of additive genetic variance for this trait in Lygaeus kalmii, suggest that heritability studies of migratory behavior would also be worth pursuing. Most interesting of course, will be possible genetic correlations between migration and life history parameters. Also, migration often transports genotypes across long distances with considerable mixing of populations. An understanding of its operation therefore carries with it implications for population genetics, zoogeography, and evolutionary theory. Finally, at least parts of the above general theory would seem to be applicable to forms other than insects. Bird and insect migrations, for example, are in many respects ecologically and physiologically similar. Birds, like insects, emphasize locomotory. as opposed to vegetative functions during long-distance flight; the well-known Zugenruhe or migratory restlessness is a case in point. Further, many birds migrateat nigt at a time when they would ordinarily roost(vegetative activity). Because their life spans exceed single seasons, bird migrants are not prereproductive in the same sense that insect migrants are, and hence reproductive values do not have the same meaning(but note that some insects are also interreproductive migrants). The situaion is complicated further by the fact that in many birds adult survivorship is virtually independent of age so that colonizing ability tends to be also (10, 54). Nevertheless, birds arrive on their nesting grounds in reproductive condition with the result that migration is a colonizing episode. It is also phenotypically modifiable by environmental factors, some of which, for example, photoperiod, influence insects as well (55). The similarities between birds and insects thus seem sufficient to indicate, at least provisionally, that the theory developed for insects applies also to birds with appropriate modifications for longer life span and more complex social behavior; comparisons between insects and fish (56) lead to the same conclusion. In birds especially, and also in other forms, various functions accessory to migration such as reproductive endocrinology, energy budgets, and orientation mechanisms have been studied extensively (55, 56). But there is need in vertebrates for more data andtheoy on the ecology and physiology of migratory behavior per se in order tobetter understand its evolution and its role in ecosystem function (5, 57). Migration in any animal cannot be understood until viewed in its entirety as a physiological, behavioral, and ecological syndrome.     

农民工性亚文化研究——基于珠三角的实地调研分析

基于对珠三角地区东莞、珠海、惠州3市农民工的问卷调查,分析了农民工性文化的独特特征:他们已脱离了传统生殖功能观,将性与爱联系在一起;对性行为的结果有担忧,但对性病的担忧较少,且呈现年龄差异;他们在日常中对性语言的使用较为宽容,但对性越轨行为的宽容局限于婚姻;他们不排斥商业性行为,其性规范体现出了较为宽松特点,且具有群体传染性,通过群体压力稳固化。这要求全社会加强对农民工的关爱,营造一个宽松的性交流氛围。     

人工巢箱条件下两种山雀鸟类的同域共存机制

种间竞争会导致鸟类对自身的生存策略进行多方面调整,将多种因素结合起来分析不同鸟类的同域共存机制具有十分重要的意义.2009-2011年的3-7月,在辽宁省东部山区以悬挂人工巢箱的方法招引杂色山雀(Parus varius)和大山雀(Parus major),通过比较这两种鸟类在繁殖时间、繁殖参数和巢址选择上的差异,分析其繁殖期的栖息地选择及繁殖对策,探讨这两种鸟类同域共存的机制.结果表明,生态位的部分分离是大山雀和杂色山雀能够长期共存的基础.两者都是在繁殖期到来立即开始繁殖,均出现两次繁殖高峰,采用消减窝卵数的对策来适应环境质量的下降.对繁殖参数的分析表明,两种鸟类的繁殖对策都为k-选择,但大山雀略偏向r端,大山雀倾向高窝卵数、低繁殖成功率的繁殖策略;杂色山雀倾向低窝卵数、高繁殖成功率的繁殖策略.两种鸟类都选择在林龄较长的森林中筑巢,但是大山雀较注重巢址的安全性能,巢距地面较高,周围乔木密集;杂色山雀较为注重植被类型的选择,巢址多选择在植被多样、灌木生长茂盛的针阔混交林中,推测可能与杂色山雀的食物构成有关.     

Hormonal and genetic control of behavioral integration in honey bee colonies

The ability of insect colonies to adjust the division of labor among workers in response to changing environmental and colony conditions, coupled with research showing genetic effects on the division of labor in honey bee colonies, led to an investigation of the role of genetics and the environment in the integration of worker behavior. Measurements of juvenile hormone(JH) titers and allozyme analyses of worker honey bees suggest that two processes are involved in colony-level regulation of division of labor: (i) plasticity in age-dependent behavior is a consequence of modulation of JH titers by extrinsic factors, and (ii) stimuli that can affect JH titers and age-dependent behavior do elicit variable responses among genetically distinct subpopulations of workers within a colony. These results provide a new perspective on the developmental plasticity of insect colonies and support the emerging view that colony genetic structure affects behavioral organization.     

基于自然选择理论的动物利他行为研究

介绍了学术界关于动物利他行为的一些理论,包括群体选择理论、基因选择理论、亲缘选择理论、互惠利他理论、纯粹利他行为、操纵假说、相互依赖假说以及＂自私的基因＂理论。研究表明,自然选择学说能够很好地解释动物的利他行为,除此之外的其他学说只能用于利他行为的分类,而不能用来解释动物的利他行为。     

Caste in a primitive ant: absence of age polyethism in amblyopone

Polyethism, the divison of labor among members of a colony, is based on worker age and size in ants. In the ponerine species Amblyopone pallipes worker behavior is independent of age, therefore temporal castes, or groups of age-related task specialists, do not exist. This primitive caste system, previously unknown in ants, appears to be correlated with the peculiar characteristics of the life history and ecology of Amblyopone.     

意蜂来源的微孢子虫感染对中蜂工蜂血淋巴蛋白的影响

为探讨微孢子虫交叉感染对中蜂工蜂血淋巴蛋白的影响,用意蜂来源的微孢子虫经口侵染不同日龄的中蜂和意蜂工蜂,在(30±0.5)℃、60%-80%RH的温箱内,用蔗糖液隔离饲养8 d后,提取工蜂血淋巴,测量其蛋白含量,并对其进行了SDS-PAGE.结果表明:(1)感染微孢子虫的8日龄中蜂及意蜂工蜂的血淋巴蛋白含量均比对照组高;而11、14日龄中蜂工蜂血淋巴蛋白含量均比对照组低.(2)无论感染与否,8日龄中蜂工蜂血淋巴蛋白含量均比同龄意蜂工蜂的高.(3)SDS-PAGE图谱显示,微孢子虫感染主要造成一些蛋白量上的差异.其中47、38、35 ku蛋白可能是8日龄意蜂工蜂感染微孢子虫后出现的特征条带.     

Broadly neutralizing antibodies present new prospects to counter highly antigenically diverse viruses

Certain human pathogens avoid elimination by our immune system by rapidly mutating the surface protein sites targeted by antibody responses, and consequently they tend to be problematic for vaccine development. The behavior described is prominent for a subset of viruses--the highly antigenically diverse viruses--which include HIV, influenza, and hepatitis C viruses. However, these viruses do harbor highly conserved exposed sites, usually associated with function, which can be targeted by broadly neutralizing antibodies. Until recently, not many such antibodies were known, but advances in the field have enabled increasing numbers to be identified. Molecular characterizations of the antibodies and, most importantly, of the sites of vulnerability that they recognize give hope for the discovery of new vaccines and drugs.     

Self-recognition in social amoebae is mediated by allelic pairs of tiger genes

Free-living cells of the social amoebae Dictyostelium discoideum can aggregate and develop into multicellular fruiting bodies in which many die altruistically as they become stalk cells that support the surviving spores. Dictyostelium cells exhibit kin discrimination--a potential defense against cheaters, which sporulate without contributing to the stalk. Kin discrimination depends on strain relatedness, and the polymorphic genes tgrB1 and tgrC1 are potential components of that mechanism. Here, we demonstrate a direct role for these genes in kin discrimination. We show that a matching pair of tgrB1 and tgrC1 alleles is necessary and sufficient for attractive self-recognition, which is mediated by differential cell-cell adhesion. We propose that TgrB1 and TgrC1 proteins mediate this adhesion through direct binding. This system is a genetically tractable ancient model of eukaryotic self-recognition.     

鸡传染性支气管炎病毒分离株与疫苗株抗原相关性和S1基因序列分析

本实验挑选8株近年来山东省IBV分离株与疫苗株H120和491,利用SPF鸡分别制备了高免阳性血清,进行鸡胚交叉中和试验,计算其抗原相关系数,鉴定其血清型,并结合S1基因序列分析,研究其血清型和基因型之间的关系.结果显示:SDWF0608、SDLY0612、SDLY0701与疫苗株H120同属Mass血清型的不同亚型,其它5个分离株与H120和491不属于同一个血清型.结合S1基因序列分析发现,S1基因序列分析与血清中和结果二者不具有明显的相关性,8个分离株分属三个基因群,其中SDTA06111与H120等同属一个基因群,但血清中和实验显示它们不属于一个血清型;CK/CH/SD09/005与一个参考株独自构成一个基因群,其S1基因变异程度较大,并且能够与两个疫苗株发生交叉中和实验,但不属于一个血清型,它可能是一个基因重组后病毒.     

Migratory flight of insect pests within a year-round distribution: European corn borer as a case study

Insect migratory flight differs fundamentally from most other kinds of flight behavior, in that it is non-appetitive. The adult is not searching for anything, and migratory flight is not terminated by encounters with potential resources. Many insect pests of agricultural crops are long-distance migrants, moving from lower latitudes where they overwinter to higher latitudes in the spring to exploit superabundant, but seasonally ephemeral, host crops. The migratory nature of these pests is somewhat easy to recognize because of their sudden appearance in areas where they had been absent only a day or two earlier. Many other serious pests survive hostile winter conditions by diapausing, and therefore do not require migration to move between overwintering and breeding ranges. Yet there is evidence of migratory behavior engaged in by several pest species that inhabit high latitudes year-round. In these cases, the consequences of migratory flight are not immediately noticeable at the population level, because migration takes place for the most part within their larger year-round distribution. Nevertheless, the potential population-level consequences can be quite important in the contexts of pest management and insect resistance management. As a case study, I review the evidence for migratory flight behavior by individual European corn borer adults, and discuss the importance of understanding it. The kind of migratory behavior posited for pest species inhabiting a permanent distribution may be more common than we realize.