不同社群条件下雄性布氏田鼠的行为

实验室内观察了布氏田鼠雄性个体之间在3 种不同社群条件下(社群1:2 只雄鼠;社群2:2 只雄鼠与1只非动情雌鼠,社群3:2 只雄鼠与1 只动情雌鼠)的相互行为,结果显示:(1)在嗅闻行为上,不论优势雄鼠还是从属雄鼠在3 组间都存在显著差异,它们的嗅闻频次都是在社群3 中最少、在社群2中居中,在社群1中嗅闻频次最多;(2)在攻击行为频次上,不论是优势雄鼠还是从属雄鼠在3 组中都不存在显著差异;(3)在上跳频次上,优势雄鼠在各组间存在显著差异,从属雄鼠在各组间不存在显著差异; (4) 在自我修饰行为频次上,不论是优势雄鼠还是从属雄鼠,在3 组之间不存在显著差异;(5)在相互友好行为上,3 组间存在显著差异。其中社群2 中的雄性之间的友好行为频次最高,社群3 中次之,社群1 中最低。结果表明,雄性之间的攻击行为并不因为雌性的存在而增强,反而会可能减少,我们推测这可能因为雄性要花费更多的时间用于社群探究和交配,从而减少了雄性之间的斗争。     

不同社群序位布氏田鼠的繁殖行为

在实验室条件下观察了捕自内蒙古草原的不同序位布氏田鼠的繁殖行为特征。结果表明, 雌鼠对雄性配偶存在着激烈的竞争, 高序位雌鼠获得被选择、交尾及产仔的机会最多, 较低序位雌鼠若被选择并且产仔, 则其序位将随之上升; 高序位雄鼠对各个序位雌鼠均可选择, 且在繁殖期间对同性个体表现很强的攻击性, 以获得更多的交配机会。在社群繁殖中高序位雌、雄个体的作用明显高于低序位个体, 这是布氏田鼠种群长期选择进化的生存策略。实验支持了布氏田鼠为混交制、一雄多雌的婚配制度推论。     

非人灵长类是否回避近亲繁殖?

近亲繁殖回避现象是人类学者、生物学者、心理学者和社会学者最关心的研究课题之一。针对灵长类的社会特点和近亲繁殖回避假说,本文引入了三个主要假设:假设1)近亲繁殖可能会导致个体繁殖适合度降低等损失;假设2)近亲繁殖有利有弊,但是弊端可能明显大于利益;假设3)如果弊大于利,那么动物应该进化形成回避近亲繁殖的机制,以减少该行为产生的损失。然后,本文综述分析了6科19个灵长类种群的现有繁殖数据,验证了灵长类的行为回避、迁移和繁殖抑制等机制,旨在强调灵长类回避近亲繁殖的必要性及其生物学背景,并为人类学、生物学和心理学的相关研究提供跨学科素材。     

The social gradient in health: The effect of absolute income and subjective social status assessment on the individual's health in Europe

Using data on individuals aged between 50 and 65 from 6 European countries, this study investigates the effect of absolute income and subjective social status assessment on health in the light of medical evidence indicating that the individual's position in the social hierarchy undermines his/her mental and physical health. The paper shows that individuals’ own income has a positive, but modest effect on health. Importantly, subjective social status assessment has a significant effect on all health measurements. Finally, the results show that individuals from deprived families (when at the age of 14) have poorer physical and mental health.     

Ontogeny of hydrocarbon profiles in the ant Aphaenogaster senilis and effects of social isolation

In ants, cuticular hydrocarbons are used for nestmate recognition; they are stored in the postpharyngeal gland and shared among the individuals. Newly emerged ants have a very small quantity of hydrocarbons. We studied the ontogeny of the hydrocarbon profile in Aphaenogaster senilis. The total quantities of both cuticular and postpharyngeal gland (PPG) hydrocarbons increased with age from 0 to 20 days after emergence and then stabilised. These quantities are correlated with the development of the ovary. Under individual social isolation, cuticular hydrocarbons increased as normal, but the total quantity of PPG hydrocarbons never increased from the initial low level. This effect of social isolation on the PPG hydrocarbon level indicates the importance of hydrocarbon transfer between nestmates through the PPG and lends support to the gestalt model of nestmate recognition. To cite this article: K. Ichinose, A. Lenoir, C. R. Biologies 332 (2009).     

Testing the social dog hypothesis: Are dogs also more skilled than chimpanzees in non-communicative social tasks?

Relative to non-human primates, domestic dogs possess a number of social skills that seem exceptional—particularly in solving problems involving cooperation and communication with humans. However, the degree to which dogs’ unusual skills are contextually specialized is still unclear. Here, we presented dogs with a social problem that did not require them to use cooperative-communicative cues and compared their performance to that of chimpanzees to assess the extent of dogs’ capabilities relative to those of non-human primates. We tested the abilities of dogs and chimpanzees to inhibit previously learned responses by using a social and a non-social version of a reversal learning task. In contrast to previous findings in cooperative-communicative social tasks, dogs were not more skilled on the social task than the non-social task, while chimpanzees were significantly better in the social paradigm. Chimpanzees were able to inhibit their prior learning better and more quickly in the social paradigm than they were in the non-social paradigm, while dogs took more time to inhibit what they had learned in both versions of the task. These results suggest that the dogs’ sophisticated social skills in using human social cues may be relatively specialized as a result of domestication.     

Investigating social discrimination of group members by laying hens

Social relationships in domestic fowl are commonly assumed to rely on social recognition and its pre-requisite, discrimination of group-mates. If this is true, then the unnatural physical and social environments in which commercial laying hens are typically housed, when compared with those in which their progenitor species evolved, may compromise social function with consequent implications for welfare. Our aims were to determine whether adult hens can discriminate between unique pairs of familiar conspecifics, and to establish the most appropriate method for assessing this social discrimination. We investigated group-mate discrimination using two learning tasks in which there was bi-directional exchange of visual, auditory and olfactory information. Learning occurred in a Y-maze task (p < 0.003; n = 7/8) but not in an operant key-pecking task (p = 0.001; n = 1/10). A further experiment with the operant-trained hens examined whether failure was specific to the group-mate social discrimination or to the response task. Learning also failed to occur in this familiar/unfamiliar social discrimination task (p = 0.001; n = 1/10). Our findings demonstrate unequivocally that adult laying hens kept in small groups, under environmental conditions more consistent with those in which sensory capacities evolved, can discriminate group members: however, appropriate methods to demonstrate discrimination are crucial.     

Whom do the sparrows follow? The effect of kinship on social preference in house sparrow flocks

Non-aggressive social interactions between group-mates, e.g. maintenance of spatial proximity or activity synchrony are basic elements of a species’ social structure, and were found to be associated with important fitness consequences in group-living animals. In the establishment of such affiliative relationships, kinship has often been identified as one of the key predictors, but this has rarely been studied in simple social groups such as flocks of gregarious birds. In this study we investigated whether kinship affects social preference, as measured by the tendency to associate with others during various social activities, in captive house sparrow (Passer domesticus) flocks where birds could interact with differently related flock-mates. We found that preference between flock-mates was correlated with familiarity from early nestling period: same-brood siblings followed their sib initiating new activities more often than non-sib birds. The strength of association between birds also tended to correlate with genetic relatedness, but this was mainly due to the effect of siblings’ affiliation. Thus we concluded that house sparrows prefer the company of their siblings during social activities even well after fledging, which may facilitate kin-biased behaviours.     

Bi-directional sex change and gonad structure in the gobiid fish <Emphasis Type="Italic">Trimma yanagitai</Emphasis>

Bi-directional sex change in the deep-water gobiid fish Trimma yanagitai was examined. The gonads of all individuals consisted of ovarian and testicular elements, and an accessory gonadal structure. In no gonads were both testicular and ovarian parts simultaneously active. Bi-directional sex changes occurred during the rearing experiments in aquaria under conditions of which there was co-existence of two males or plural females. The sex of individuals could be determined by their relative body size or social dominance: the largest individuals acting as male and the remainder as female.     

Experimental translocation of juvenile water voles in a Scottish lowland metapopulation

Population density affects dispersal success because residents can hinder or facilitate immigration into a new site, via a “social fence effect” or “social attraction” (or “conspecific attraction”), respectively. These mechanisms can affect the dynamics of fragmented populations and the success of translocations. However, information on the settlement behaviour of dispersers is rare. We conducted a manipulative field experiment using wild water voles, which exist in metapopulations along waterways in Scotland. We translocated 17 young of dispersal age into either an occupied site or a vacant site containing good habitat, which had recently become extinct due to a feral predator (American mink) moving through. We monitored the movements of translocated voles using radio telemetry. Translocated voles were less likely to settle in occupied sites with higher densities of residents, suggesting a possible social fence effect at high density. There was evidence of a social attraction mechanism, because voles never remained at new sites unless another individual arrived soon after translocation, and they were more likely to settle in occupied or colonised sites than vacant ones. Voles remained in the transient phase of dispersal for many days, and often followed a “stepping stone” trajectory, stopping for several days at successive sites. We suggest that trajectories followed by dispersing water voles, the time scale and long dispersal distances found in this species are conducive to locating conspecifics at low density and colonising vacant habitat. These results are encouraging for prospects of metapopulation persistence and future translocation success.