不同性别和年龄的大仓鼠对黄鼬气味的反应

将雌性成体和雌雄亚成体大仓鼠 (Cricetulustriton)长期 (4周 )暴露给过量的黄鼬 (Mustelasibirica)肛腺分泌物 ,观察其行为和生理状态的变化 ,并通过与我们以前有关黄鼬气味对成年雄鼠影响的研究结果进行比较 ,表明黄鼬气味对不同性别和不同年龄大仓鼠的胁迫效应和生殖抑制存在差异。发现黄鼬气味对雌性大仓鼠的影响较雄性小 ,对亚成体的影响较成体小 ,这与雌性和未成年动物对各种胁迫因素的反应更敏感的普遍现象相反。在成年鼠中 ,雌雄鼠的攻击行为都受到黄鼬气味的抑制 ;但天敌气味使雌性的胁腺膨大 ,对胁腺标记和肾上腺大小无影响 ;成年雄鼠的肾上腺膨大 ,胁腺萎缩 ,标记减少。在亚成体中 ,除了雄性胁腺受到抑制(与成年雄鼠相同 )外 ,雌雄鼠的肾上腺和雌性的胁腺未受影响。亚成体实验鼠的体重都比对照组低 ,但成年鼠的体重未受影响。另外 ,与以往对其它鼠类的研究结果一致 ,天敌气味并不影响成年鼠的生殖器官 ,却抑制了未成年雄鼠的附睾和未成年雌鼠的子宫。这些差异可能和生理基础的性二态以及可能面临的被捕食风险大小有关     

布氏田鼠标志种群的社群等级及其季节变化

在内蒙古锡林郭勒地区,通过标志重捕、染色标记和直接观测法对布氏田鼠社群等级的季节变化进行了研究。结果表明:在繁殖季节,布氏田鼠洞群内存在明显的社群等级。越冬雄鼠在社群内社群序位最高,其次是越冬雌鼠、当年成体雌鼠、当年成体雄鼠,亚成体鼠和幼鼠的社群地位最低。在繁殖末期,越冬雄鼠的地位明显下降,而当年成体雄鼠的等级序位逐渐上升。在繁殖季节,当年雄鼠在洞群中的等级序位依然很低,很少能有机会进行有效的交配,有效交配主要由越冬雄鼠来完成,因而越冬雄鼠对种群繁殖的贡献较大。本实验倾向于支持该鼠的婚配制度为一雄多雌制的观点。     

注射胸腺依赖和非胸腺依赖抗原雄性黑线毛足鼠的内分泌状态和气味吸引力

作者研究了胸腺依赖抗原 (SRBC) (羊红血细胞 ,sheepredbloodcells ,SRBC)和非胸腺依赖抗原 (细菌脂多糖 ,lipopolysaccharide ,LPS)的免疫活化对黑线毛足鼠气味信号和内分泌状态的影响。成年雄鼠注射SRBS5天后 ,其气味的性吸引力下降 ,这种结果伴随着粪便中睾酮含量的下降。SRBC处理后 ,雄性气味吸引力降低 ,这在体液免疫反应低的雄性个体中最明显。与SRBC的作用相反 ,注射LPS的雄性个体的气味吸引力增加 ,成熟雌性个体用于嗅闻嗅觉刺激上的时间差异与经LPS和盐处理过的雄鼠的粪便中睾酮浓度的差异呈正相关。作者讨论了这两种相反的嗅觉效应的适应性意义     

黑线仓鼠殴斗行为模式及其与生理状态的关系

本文以分布于鲁西南山区的黑线仓鼠雄体为对象,通过测定重复遭遇战(repeated encounters)对黑线仓
鼠体重、生理指标等参数的作用,以期阐明社群冲突(social conflict)对黑线仓鼠生理状态的影响。研究结果表
明:在4 周的重复遭遇战过程中,参与冲突个体的体重增长率略有降低,但未达到显著水平;粪便肾上腺皮质
激素(GCs)含量呈现波动性变化,在整个遭遇战过程中,优势个体与从属个体的GCs 含量交替显著升高,与
冲突时间及个体社群地位均有关;优势个体保持较高的睾酮水平,利于其增强攻击行为和获得优势地位;从属
组雄体的肾上腺显著增大,但生殖腺间差异不显著;HPA 轴对HPG 轴具有显著的抑制效应,肾上腺分泌的皮质
醇可显著抑制个体的睾酮分泌,二者呈显著的负相关关系。这些数据表明,黑线仓鼠雄体可通过斗殴行为建立
明确的优势- 从属关系,睾酮可促进个体优势地位的形成并受到肾上腺皮质醇抑制;HPA 轴对HPG 轴的抑制未
能在器官指数方面得到证实。从属个体受到胁迫,对优势雄性黑线仓鼠野外生存和繁殖有重要意义。     

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。     

布氏田鼠社会行为对光周期的适应格局

对实验室内不同光周期条件下的布氏田鼠陌生成体—亚成体间社会行为模式的初步研究显示:不同光周期下成体对亚成体（特别是对雄性亚成体）的行为反应具性二型特征,长光照周期下（light:dark,14L:10D)成体与亚成体同性组合间的争斗较异性组合间的明显,容忍性低,其中成体雄对亚成体雄尤甚。短光照周期下（light:dark,10L:14D）成体雄对亚成体雄、成体雌对亚成体雌及亚成体雄的相容性均较成体雄对亚成体雌的容忍性低,尤成体雌对亚成体雄的排斥表现更为突出,其容忍性也较长光照条件下对应组的低。结果表明,不同光周期条件下布氏田鼠成体与亚成体间的社会行为模式不同。在自然条件下,这些行为模式是其对环境季节变化的一种有效适应,它影响种群中未成年个体存活、补充、扩散重组以及社群结构、种群空间格局季节变化,对该鼠的生存和繁殖有利。     

雄性小鼠的社会优势地位、性吸引和信息素通讯

以前对小鼠的研究表明,优势雄鼠的尿液对雌性的吸引力比从属雄鼠大;同时,包皮腺分泌到尿液中的两个雄性信息素E-β-法尼烯和E, E- α-法尼烯含量相应升高,而尿液本身产生的两个雄性信息素成分--脱氢小蠹素和S-2-仲丁基- 二氢噻唑没有出现有效差异.为研究我们最近从小鼠(Mus musculus)包皮腺发现的两个雄性信息素16碳醇和16碳乙酸酯与雄性小鼠社会等级的关系, 我们将雄性小鼠两两配对饲养30天,让它们经历足够的社会争斗,建立起稳定的优势和从属关系.双项选择测试表明, 优势雄鼠的尿液对雌鼠的吸引比配对(组内)的从属鼠的强,优势雄鼠和来自另一配对组( 组间)的从属鼠尿液对雌鼠的吸引无差异.这说明优势和从属关系是相对于同一社群内的个体存在的.我们进一步用二氯甲烷分别萃取包皮腺分泌物和尿液,然后用气质联用(GC-MS )来定性和定量地分析组内优势和从属个体气味的化学组成的差异.结果表明:只有优势雄鼠的包皮腺产生的E-β-法尼烯和E, E-α-法尼烯含量一致高于从属雄鼠,而1 6碳醇和16碳乙酸酯以及尿液本身的脱氢小蠹素和丁基-二氢噻唑两个雄性信息素都无差异 .说明小鼠只利用包皮腺产生的两个分子量较小的雄性信息素浓度的相对升高传递社会优势地位的信息[动物学报 54(3):399-406,2008].     

布氏田鼠在不同光周期下对陌生个体尿液和粪便的气味辨别

研究了成年布氏田鼠在10min内,对不同光照周期下（长光照：LD;短光照：SD）陌生雌／雄个体尿液和粪便两种单一个体气味源的气味行为反应,实验发现：所有雌雄被试鼠对LD气味源比SD气味源表现出更多的嗅闻行为。LD和SD被试鼠对同性／异性尿液气味的嗅闻行为没有表现出明显的差别,但LD被试雄鼠对陌生雌鼠粪便的嗅闻频次显多于SD被试雄鼠,从嗅闻行为特征量（嗅闻行为占所有行为的百分比）来看,所有LD和SD被试雌,雄鼠对尿液的嗅 明显多于粪便,除SD粪便气味外,被试鼠对异性气味源的嗅闻明显多于同性,实验结果表明：作为两种个体气味源,尿液和粪便都带有季节性信息,而且是具有性别特性的。异性的个体气味源比同性的个体气味源更具吸引力;长光照动物的个体气味比短光照动物的气味更具吸引力。     

雄性弯角长角羚和普通大羚羊激素分泌模式与社会等级和季节的关系

为了确定羚羊类固醇激素分泌模式与行为和社群等级的关系,我们检测了成年雄性弯角长角羚(n=15)和普通大羚羊(n=11)的粪样皮质酮和睾酮浓度.采用随意取样和目标取样法记录了共650 h的行为.结果发现,两种羚羊的睾酮水平在雌性的发情时段里都是最高的.两种羚羊皮质激素水平有季节性变化,表现为雨季皮质酮水平高于干旱季节.优势胁迫作用明显存在于普通大羚羊,而在弯角长角羚不明显.没有证据表明从属个体压力的存在,一只弯角长角羚曾经是优势个体,但是后来有两年不是优势个体,与其他雄羚相比,这只雄羚在雌性发情期的睾酮和皮质酮水平有3个交迭出现的峰值.     

繁殖盛期雄性普通东方小蛙的个体大小不影响交配成功率

通过比较抱对和非抱对普通东方小蛙(Crinia signifera) 的吻尾干骨长(体长) 和检测个体较大或状态较好的雄体是否为成功繁殖个体, 检测雌蛙体长与交配成功的雄蛙的体长和相对状态(体重/体长) 之间是否存在线形关系, 评估交配与个体大小之间的关系。在实验室内, 令未交配雌体选择随机选出的雄体, 观测雌体是否与最大的雄体交配; 将抱对的蛙暴露于其它雄蛙, 观测其它较大或较小的雄蛙是否取代已抱对的雄蛙。结果表明: 抱对雄蛙和雌蛙的个体大小无显著的关系, 成功交配的雄蛙并不比未交配的雄蛙大, 其它雄蛙不能取代已抱对的雄蛙。在这一C. signifera种群中, 繁殖盛期雄性个体的大小似乎不影响交配成功率, 在此期间即便存在配偶选择, 亦决定于与雄性个体大小无关的其它因素。在更长的繁殖期内, 雄性个体大小则与交配成功率有关, 这是该种的典型特征。     

Social environment and morpho-physiological status of young males in the fall groups of great gerbil (Rhombomys opimus Licht). Effect of adults' presence

The dependence of stress and sex hormone levels, size of mid-ventral skin gland, and body mass of young males on the presence in social groups of adult gerbils (>1 year old) were studied during the fall of 1999 in the non-breeding high density population of the great gerbil (Rhombomys opimus Licht; Bukhara region, Uzbekistan). Contents of corticosterone and testosterone in fecal samples collected from young males in the field were analyzed by non-invasive radioimmunoassay. The fall gerbil groups with adults were of larger size than those without adults. The total number of individuals in a group is positively correlated with concentration of corticosterone in feces of young males. Presence of adult male and especially of adult female suppresses maturation of juvenile males indicated by size of the androgene-dependent mid-ventral gland, but accelerates their total growth. Thus, the social environment influences morpho-physiological characters of young males, effecting rate of their maturation directly or indirectly through the density dependent stress.     

Social correlates of stress in adult males of the great gerbil,Rhombomys opimus,in years of high and low population densities

The great gerbil, Rhombomys opimus, is the most social species in the Gerbillinae. The social structure consists of family groups that occupy isolated systems of burrows consisting of one breeding male, from one to seven females, and juveniles. During a year of peak density and one of density decline, we studied the influence of group size, group composition, local density, and distance to the nearest groups on fecal corticosterone and testosterone concentrations in breeding males. We also examined the relationship of hormone concentrations to the survival of males during the summer drought between the spring and the fall. We found that males differed in concentrations of steroid hormones. Concentrations of testosterone were lower whereas those of corticosterone tended to be higher in a year of high population densities compared with higher testosterone and lower corticosterone in a year with a lower density. This finding suggests that stress may be greater in higher densities because of increased social contact. Stepwise regression analysis revealed a positive and significant influence of the number of adult females in a family group on concentrations of fecal corticosterone and testosterone in adult males. Concentrations of corticosterone were also significantly higher in males that disappeared from family groups between the spring and the fall compared with males still alive in family groups in the fall. There was no change in concentrations of testosterone. These results suggest that social interactions within large family groups may be an important source of stress for adult males.     

Social stress decreases marking behavior independently of testosterone in Mongolian gerbils

This study examined the endogenous androgen regulation of the marking behavior in Mongolian gerbils (Meriones unguiculatus). In the first experiment, developmental changes of fecal testosterone levels, ventral gland growth, and the marking frequency of male gerbils were investigated. From 9 weeks of age, marking frequency increased with increases in fecal testosterone levels and ventral gland size. The ventral gland size and marking frequency were significantly correlated to the fecal testosterone level. In the second experiment, we hypothesized that reduction in the marking frequency of subordinate males after social confrontations was controlled by a decrease in the circulating testosterone level, and we followed changes in marking frequency, endocrine status, and ventral gland size after social confrontations in which two adult male gerbils established their social ranks by fighting. As expected, marking frequency and ventral gland size were significantly related to social rank, that is, marking frequency was higher among dominant gerbils and lower among subordinates. In addition, fecal corticosterone levels among subordinates were higher than those of dominant animals. However, neither the fecal and plasma testosterone levels, nor testis size, differed between dominant and subordinate gerbils. These results revealed that endogenous androgen played a role in regulating marking behavior and ventral gland size during the developmental stage and that the reductions in marking frequency and ventral gland size occurring in subordinate males after social confrontations were not directly regulated by androgen changes.     

Foraging ecology of the California gnatcatcher deduced from fecal samples

The California gnatcatcher is a threatened species essentially restricted to coastal sage scrub habitat in southern California. Its distribution and population dynamics have been studied intensely, but little is known about its diet. We identified arthropod fragments in 33 fecal samples of the California gnatcatcher to gain insight into its foraging ecology and diet. Fecal samples were collected from adult males, adult females, fledglings, and nestlings. Leaf- and planthoppers (Homoptera) and spiders (Araneae) predominated numerically in samples. Spider prey was most diverse, with eight families represented. True bugs (Hemiptera) and wasps, bees, and ants (Hymenoptera) were only minor components of the gnatcatcher diet. Gnatcatcher adults selected prey to feed their young that was larger than expected given the distribution of arthropod size available in their environment, and chicks were provisioned with larger prey items and significantly more grasshoppers and crickets (Orthoptera) and spiders than adults consumed themselves. Both adults and young consumed more sessile than active prey. Further studies are needed to determine whether arthropods sampled in coastal sage scrub that are common in fecal samples are good indicators of California gnatcatcher habitat. Received: 30 December 1998 / Accepted: 28 April 1999     

Social and hormonal mechanisms underlying male reproductive strategies in black howler monkeys (Alouatta pigra)

We investigated the social and hormonal mechanisms underlying male reproductive strategies in two multimale-multifemale groups of black howler monkeys (Alouatta pigra) during a 14-month study in Palenque National Park, Mexico. Fecal glucocorticoid (fGC) and androgen (fA) levels were analyzed for 343 fecal samples collected from 14 males during their presence in the study groups. Neither immigrating males nor resident males that remained in the group had elevated fGC and fA levels during 11 observed male migration events, suggesting that competition over group membership was not associated with variation in the fecal hormonal levels of males. Instead, fGC and fA levels were significantly higher in males who maintained a central position in the group and had almost exclusive access to fertile females than in other resident males. These “central” males were responsible for maintaining close spatial associations and cultivating strong affiliative relationships with cycling, sexually active females but not with noncycling, sexually inactive females. “Noncentral” males did not form strong social relationships with either cycling or noncycling females and had no or very few mating opportunities. Our findings suggest that male black howler monkeys compete nonaggressively by fostering relationships with cycling females and that the elevated fGC levels of central males may be indicative of the social challenges involved in their indirect competition.     

Influence of reproductive season and rank on fecal glucocorticoid levels in free-ranging male Verreaux's sifakas (Propithecus verreauxi)

Studies in anthropoid primates and other mammals suggest that reproductive season, rank, reproductive skew, aggression received, and social support are the major factors influencing glucocorticoid output. In which way these are also affecting adrenal function in lemurid primates has been studied rarely. Here, we examine the influence of reproductive season and rank on glucocorticoid output in male sifakas (Propithecus verreauxi), a species characterized by high breeding seasonality, a hierarchy among males and extreme reproductive skew towards dominant males. We established a fecal assay for non-invasively monitoring adrenal activity and collected 315 fecal samples during the reproductive and birth season from 10 male sifakas living in 5 groups in Western Madagascar. We found a significant effect of season on glucocorticoid output, with males exhibiting higher fecal glucocorticoid levels during the reproductive compared to the birth season in conjunction with an increase in overall aggression rates during the former period. Moreover, our data indicate a significant effect of rank on adrenocortical activity with dominant males exhibiting higher glucocorticoid levels than subordinate males in the reproductive season. However, dominant males did not differ significantly in rates of initiated or received aggression and rates of affiliative behavior from subordinates but showed significantly lower rates of submission. Given their highly formalized dominance relationships, we conclude that higher glucocorticoid output in dominant males during the 4-month reproductive season is likely related to higher energetic demands necessary to cope with the challenges of male reproduction rather than to physical demands of increased fighting frequency to maintain dominance status. High rank in sifakas may thus carry high costs, which, however, may be outweighed by monopolization of almost all paternities. In sum, our data generally support the findings on the relationship between environmental and social factors and glucocorticoid output found in non-lemurid primates.     

The population characteristics of howler monkeys (Alouatta caraya) in Northern Argentina

Howler monkeys, Alouatta caraya, were collected in family groups from islands in the Rio Parana in northern Argentina. The body weights, lens weights, dental age and reproductive status of 261 individuals illustrated sexually dimorphic body weights after a period of accommodation as young adults, a large proportion of older females (even though there are more young adult males than females) and a higher percentage of pregnancies among these older females. Seventeen families, representing the entire social system of one island, showed that about three quarters were adult (equally divided between the sexes but with fewer older males than females) and the remaining quarter were immature (with an equal sex ratio). Half of the adult females were either pregnant or suckling young. The mean family size is seven which includes peripheral males. Group size and composition as well as adult to immature proportions compared closely with data on A. caraya in the Chaco of Argentina and the 1951 census of A. palliata on Barro Colorado Island. It can be said that when these two species of Alouatta occur in small size families, they have in common: a high proportion of adults to immature, a low proportion of infants, and can have either an equal sex ratio (A. caraya) or preponderance of females (A. palliata).     

The effects of group size and reproductive status on vigilance in captive Callithrix jacchus

Previous work on mammals and birds has often demonstrated a negative relationship between group size and individual vigilance. However, this relationship has received only weak support in nonhuman primates. This result may be due to the failure to distinguish different forms of vigilance such as antipredatory vigilance and social monitoring. Here, we tested the effects of group size, reproductive status (breeding vs. nonbreeding), and sex on antipredatory vigilance and social monitoring in captive common marmosets (Callithrix jacchus). Behavioral observations using one-zero sampling were conducted on adult members of three captive groups of small, medium, and large size. Data were analyzed using a series of general linear models (GLMs) analyses of covariance (ANCOVAs). We found an overall negative group size effect on antipredatory vigilance and that breeders, especially breeding males, were significantly more vigilant than nonbreeders. Conversely, we found that social monitoring increased with group size. Unlike the results for antipredatory vigilance, neither breeders and nonbreeders nor males and females differed in their amounts of social monitoring. However, the effect of group size appeared to differ for nonbreeding males compared to all other adults. Our results generally support the idea that individuals in larger groups are safer with breeding males likely playing a prominent role in protection from predation. The increase in social monitoring may be related to increased reproductive competition with the presence of adult offspring, but future studies need to clarify the target of social monitoring in both breeders and nonbreeders. Overall, the study underlines the importance of distinguishing different forms of vigilance and other factors as they may confound the effects of group size on antipredatory vigilance.     

Diffusion of foraging innovations in the guppy

The way in which novel learned behaviour patterns spread through animal populations remains poorly understood, despite extensive field research and the recognition that such processes play an important role in the behavioural development, social interactions and evolution of many animal species. We conducted a series of controlled diffusions of foraging information in replicate experimental populations of the guppy, Poecilia reticulata. We presented novel foraging tasks over 15 trials to mixed-sex groups, made up of food-deprived and nonfood-deprived adults (experiment 1) or small, young fish and old, large adults (experiment 2). In these diffusions, knowledge of a route to a feeder could spread through the group by subjects learning from others, discovering the route for themselves, or, most likely, by some combination of these social and asocial learning processes. We found a striking sex difference, with novel foraging information spreading at a significantly faster rate through subgroups of females than of males. Females both discovered the goal and learned the route more quickly than males. Food-deprived individuals were faster at completing the tasks over the 15 trials than nonfood-deprived guppies, and there was a significant interaction between sex and size, with a sex difference in adults but not young individuals. There was also an interaction between sex and hunger level, with food deprivation having a stronger effect on male than female performance. We suggest that information may diffuse in a similar nonrandom or 'directed' manner through many natural populations of animals. Copyright 2000 The Association for the Study of Animal Behaviour.     

Fecal testosterone immunoreactivity as a non-invasive index of functional testosterone dynamics in male Japanese macaques (Macaca fuscata)

Validation of a simple method for the extraction and quantification of testosterone (T) from the excreta of male Japanese macaques (Macaca fuscata) is presented. Radioimmunoassay of paired fecal and serum samples collected from four intact sexually mature males during the breeding season provided profiles that were significantly correlated when samples were offset by approximately 48 hr. Additionally, no significant differences were observed in the pattern of temporal variation of T levels in serum and feces. Two castrated males were injected with radioinert T, and the patterns of excretion were observed by analysis of serial fecal and urine samples. Approximately 48 hr after the steroid was administered, a significant peak in the average fecal T levels was apparent. The injection event was also registered in the urine of both males, although qualitative differences were observed. These data suggest that measures of fecal T provide a reliable and non-invasive means of assessing gonadal function in this species. As the analysis of hormone levels in feces allows for frequent, stress-free sampling with minimal disruption, this method should be preferred in long-term orin situ applications requiring endocrine monitoring.