布氏田鼠雄性的优势地位

在实验条件下对雄性成年布氏田鼠（Microtus brandti）相遇后的优势地位及生理指标的研究结果表明：布氏田鼠雄性之间存在严格的等级关系;优势雄鼠生理指标中睾丸重量和血清睾酮激素含量高于从属雄鼠,而血清中皮质醇激素的含量低于从属雄鼠。优势雄鼠的探究、攻击和修饰等行为频次显著高于从属雄鼠,而从属雄鼠在跳跃频次上多于优势雄鼠。随着观察时间的延长,不论优势个体还是从属个体,其探究频次都呈现明显的下降趋势,其他行为的频次则没有显著差异。相关性检验说明,除攻击行为可以作为判断区分雄鼠等级的依据之外,修饰行为也可以作为判断的依据。     

树鼠mtDNA限制性内切酶图谱及其与小家鼠褐家鼠的亲缘关系

本实验用ＡｐｅⅠ,ＡｖａⅠ,ＢａｍＨⅠ,ＢｃｌⅠ,ＢｇｌⅠ,ＣｌａⅠ,ＥｃｏＲⅠ,ＥｃｏＲＶ,ＨｐａⅠ,ＰｓｔⅠ,ＰｖｕⅡ,ＳｃａⅠ,ＸｂａⅠ等１３种限制性内切酶分析树鼠（Ｃｈｉｒｏｍｙｓｃｕｓｃｈｉｒｏｐｅｓ）的ｍｔＤＮＡ限制性片段长度多态性,并用双酶解法构建了其中８种酶的限制性内切酶图谱。根据限制性片段差异法和分子钟,计算并讨论树鼠和小家鼠（Ｍｕｓｍｕｓｃｕｌｕｓ）、褐家鼠（Ｒａｔｔｕｓｎｏｒｖｅｇｉｃｕｓ）的ｍｔＤＮＡ遗传距离和亲缘关系。结果表明树鼠与褐家鼠的关系较接近,两者的分歧时间在距今１５００─２０００万年前,即处于中新世早中期。     

非繁殖期成年雄性布氏四鼠对群体气味的辨别

本文研究了非繁殖期成年雄性布氏四鼠对陌生群体气味、本群体气味的社会探究行为和尿标记行为,探讨了布氏四鼠利用气味信号进行群体辨别的能力。在对熟悉相的辨别实验中,雄鼠对陌生群体气昧的社会探究和尿标记行为明显多于本群体气味和对照组,优势个体的探究和尿标记行为显著高于从属个体。实验结果表明：布氏田鼠具有对群体气味的辨别能力;在巢垫物中存在用于群体识别的化学通讯成分,优势鼠的气味标记可能在种内群体间的嗅觉通讯中起着重要的作用。     

非繁殖期成年雄性布氏田鼠对群体气体的辨别

本文研究了非繁殖期成年雄性布氏田鼠对陌生群本气味,本群体气体的社会探究行为和尿标记行为,探讨了布氏田鼠利用气味信号进行群体辨别的能力。在熟悉相的辨别实验中,雄鼠对陌生群体气味的社会探究和尿标记行为明显我于本群体气味和对照组,优势个体的探究和尿尿行为显著高于从属个体。实验结果表明,布氏田鼠具体对群体气味的辨别能力,在巢垫物中存在用于群体识别的化学通讯成分,优势鼠的气味标记可能性种内群体间的嗅觉通讯中     

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。     

重复遭遇战对雌性黑线仓鼠生理状态的影响

以独居型啮齿动物——黑线仓鼠(Cricetulus barabensis)为对象,主要测定了与优势-从属关系有关的体重、生理状态和粪便激素变化规律相关的参数。野生成年仓鼠捕获于鲁西南山区农田并于实验室内单独饲养。按照陌生和体重匹配的原则配对,实验动物在中立竞技场中每天进行15 m in的遭遇战并收集粪便,连续28 d。以攻击行为、防御行为、社会行为、非社会行为确定个体的优势-从属地位。用于实验的动物共33只。行为实验结束后,将动物解剖,确定其繁殖及生理状态。结果表明:4周重复遭遇战期间,(1)优势雌体体重显著增加;(2)肾上腺指数显著降低;(3)雌体肾上腺指数与卵巢指数无显著的相关关系;(4)雌体粪便皮质醇及雌二醇含量随时间表现出明显的波动,但优势与从属个体间差异不显著;(5)优势雌体的粪便雌二醇含量与皮质醇含量呈显著的正相关关系。研究结果提示,重复遭遇战未影响雌体的存活及潜在繁殖能力,这可能与黑线仓鼠的独居生活方式有关。     

南京湖山地区孤峰组硅质岩中的放射虫化石

南京湖山地区孔山下二叠统孤峰组硅质碉中含有丰富的放射虫化石。这些化石主要以Ｆｏｌｌｉｃｕｃｕｌｌｕｓ ｓｃｈｏｌａｓｔｉｃｕｓ,Ｐｓｅｕｄｏａｌｂａｉｌｌｅｌｌａ ｘｃａｌｐｒａｔａ,Ｌａｔｅｎｔｉｆｉｓｈｕｌ ｔｅｘａｎａ和Ｒｕｚｈｅｎｃｅｖｉｓｐｏｎｇｕｓ ｃｆ．ｕｒａｌｉｃｕｓ占优势。文章对这些化石进行了系统的描述,并建立一个组合带,即Ｒｕｚｈｅｎｃｅｖｉｓｐｏｎｇｕｓ ｃｆ．ｕｒａｌｉｃｕ     

大仓鼠在繁殖期的行为关系及交配行为

在Ｙ型迷宫中进行气味选择测定时,被试大仓鼠偏好异性的气味,证明身体气味有性吸引和性识别作用。在Ｙ型迷宫进行性别选择测定时,在雌雄靶鼠个体之间,被试大仓鼠不表现出性别偏好,这是攻击行为和交配行为共同影响的结果;与空白相比较,被试鼠都选择靶鼠,说明独居大仓鼠之间存在频繁的探究行为。通过观察箱内对两鼠间的行为关系的观察发现,异性之间主要有攻击行为和交配行为;同性之间主要发生攻击行为,同时胜鼠或优势鼠的胁腺标记行为显著多于从属鼠,说明胁腺标记可以表明优势地位;雄鼠与非性接受状态的雌鼠相遇时,攻击行为很少,但无友好行为,只有简单的雄鼠爬跨雌鼠的行为;任何陌生的雄鼠与性接受状态的雌鼠相遇发生交配行为,交配结束又相互攻击;交配行为表现为多次爬跨多次射精;雄鼠有库利奇（Ｃｏｏｌｉｄｇｅ）效应,雌鼠可以连续接受几只雄鼠的交配,表明大仓鼠为多配制的婚配制度。从行为关系和交配行为看大仓鼠在繁殖期独居,无固定的配偶     

苏皖南部孤峰组放射虫动物群

南京天宝山、安徽巢湖平顶山、泾县晏公堂和南陵丫山孤峰组中含有较丰富的放射虫化石,包括７属１６种（未定种）,分属于６个科,可以分成三个化石组合带,即下部的Ｐｓｅｕｄｏａｌｂａｉｌｌｅｌｌａｆｕｓｉｆｏｒｍｉｓ－Ｐｓ．ｌｏｎｇｔａｎｅｎｓｉｓ带,中部的Ｆｏｌｌｉｃｕｃｕｌｌｕｓｍｏｎａｃａｎｔｈｕｓ带和上部的Ｒｕｚｈｅｎｃｅｖｉｓｐｏｎｇｕｓｕｒａｌｉｃｕｓ－Ｆｏ．ｓｃｈｏｌａｓｔｉｃｕｓ带。这三个带分别可以同广西钦州地区的Ｐｓ．ｇｌｏｂｏｓａ带,Ｆｏ．ｍｏｎａｃａｎｔｈｕｓ带和Ｆｏ．ｓｃｈｏｌａｓｔｉｃｕｓ－Ｆｏ．ｖｅｎｔｒｉｃｏｓｕｓ带对比。根据孤峰组下伏地层栖霞组灰岩中所含类Ｐａｒａｆｕｓｕｌｉｎａｍｕｌｔｉｓｅｐｔａｔａ带和上覆地层堰桥组或武穴组灰岩中所含类Ｍｅｔａｄｏｌｉｏｌｉｎａ动物群证实,孤峰组与华南地区茅口组下部类Ｎｅｏｓｃｈｗａｇｅｒｉｎａ带大体相当。最近的古地磁和古生物资料证明,在华北板块与扬子板块之间,二叠纪时存在一个宽阔的海洋,孤峰组硅质岩中的这些放射虫动物群就是由这个洋中发育的上升洋流带入扬子板块断陷盆地中沉积的。     

中国毛霉的三个新记录种

报道了中国毛霉属的三个新记录并对它们进行了描述和简短的讨论。它们是：Ｍｕｃｏｒ ｈｉｅｍａｌｉｓ ｆ． ｌｕｔｅｕｓ,Ｍｕｃｏｒ ｒａｃｅｍｏｓｕｓ ｆ．ｃｈｉｂｉｎｅｎｓｉｓ．和Ｍｕｃｏｒ ｒａｃｅｍｏｓｕｓ ｆ．ｓｐｈａｅｒｏｓｐｏｒｕ．     

Effects of vomeronasal organ removal on the sperm motility in male mice

Odors play important roles in the communication of house mice. They release behaviors and prime changes of the physiological conditions of other individuals. In our previous study, we showed that sperm motility was lowered in the subordinate mice comparing with dominant mice. Our hypothesis is that the lowered sperm motility was due to some primer effects by odor substances derived from dominant mice. To test the hypothesis, we destroyed the vomeronasal organ (VNO) of male mice (VNX male) at 5 weeks of age and paired them with intact male mice (Experimental Group). As control group males, intact male mice were kept in pairs (Control Group). At 15 weeks of age, the sperm motility and weights of reproductive organs, and social dominance was analyzed. The subordinate VNX males were found to have high sperm motility comparable to the dominant males. It was suggested that there is male-to-male primer effects, mediated by VNO, that suppress sperm motility of the subordinate mice.     

Effects of social status, age, and season on androgen and cortisol levels in wild male golden lion tamarins (Leontopithecus rosalia)

This study examines factors affecting androgen and cortisol levels in wild, male golden lion tamarins (Leontopithecus rosalia). Golden lion tamarins are a cooperatively breeding species in which groups often contain two potentially breeding males. Brothers frequently emigrate together and develop a clear dominance hierarchy, but interactions between them are primarily affiliative. Duos in which the males are not related are less stable. In addition, reproductive skew theory predicts that dominant males will be less likely to share reproduction with related subordinates. As such, we predicted that both androgens and cortisol would be higher in subordinate males unrelated to the dominant male. We also predicted that androgens in breeding males would be higher during the mating season than the birth/infant care season, as per Wingfield's "challenge hypothesis" (1990). Fecal samples were collected from 24 males in 14 social groups and assayed by enzyme immunoassay. Androgen levels were higher in breeding males during the mating season, thus supporting the challenge hypothesis. However, while subordinate males unrelated to the dominant male had significantly lower androgens than any other group, cortisol levels were not correspondingly higher. These results suggest that unrelated subordinate males show measurable reproductive suppression and may use strategies such as infantilization to avert aggression from dominant males.     

Age-associated changes in plasma testosterone levels in male mice and their relation to social dominance or subordinance

Plasma testosterone (T) levels were determined in male mice of the CD-1 (ICR) strain from 30 to 680 days of age. The mean plasma T was 5.2 ± 1.0 ng/ml for adult male mice (70–400 days old, 102 mice) and 1.8 ± 0.9 ng/ml for old males (450–680 days old, 11 mice). Through 140 determinations, the highest T value obtained was 52.3 ng/ml in an 80-day-old individual while the lowest was 0.08 ng/ml in a 680-day-old animal. It was found that plasma T was significantly decreased in the old age, although individual variation in T levels was considerable. On the other hand, social dominance or subordinance was examined among male mice in each cage and its relation to plasma T was investigated. Dominance or subordinance was verified by frequency of chases or attacks delivered or received, or number of fights won or lost. It was observed that dominant-subordinate relationships were present in 6 out of 10 cages and that the dominant individual had a significantly higher T level than the subordinate male; the mean T level was 10.5 ± 2.5 ng/ml for the dominant individuals vs 2.2 ± 0.8 ng/ml for the subordinate ones. Marked individual variation in plasma T titers in male mice seems to be related to the dominance/subordinance rank within a group.     

The reproductive correlates of social hierarchy in laboratory male mice

In laboratory male mice the effects of social hierarchy on hormonal and spermatogenic testicular function, accessory organs and testicular weights, sexual behaviour have been investigated using an experimental model of social hierarchy, which is characterised by a minimal size (two male mice) and 5 days period of social interactions. The social rank of the partners was detected by asymmetry in aggressive behaviour. Using the experimental condition, when the both partners have no preferences for exclusive use of area we demonstrated that there were no rank differences in the number of mounts and testicular testosterone content. Nevertheless a rank asymmetry in the male sniffing behaviour towards a receptive female, weights of the testes, seminal vesicles, epididymes and the number of epididymal sperm was kept up in a stable social group. Social dominance was found to affect negatively on testicular testosterone increase in response to introduction of a receptive female and sexual attractiveness of male to a receptive female in both dominant and subordinate males. The results obtained demonstrate the impact of social hierarchy on reproduction in laboratory male mice, particular in respect of spermatogenesis and the testicular testosterone in response to a receptive female.     

Hormonal responses to removal of a breeding male in the cooperatively breeding white-browed sparrow weaver, Plocepasser mahali.

The white-browed sparrow weaver (Plocepasser mahali) is a cooperatively breeding Ploceid finch that lives in groups of up to 11 individuals. Each group consists of a dominant breeding male and female and a varying number of nonreproductive birds that help feed young and defend the group territory. Experimental removal of the dominant male resulted in attempts by other males to take over the group. Removal of a subordinate, nonbreeding male, as a control, resulted in no change of status among group members. During takeover, there was a transitory increase in plasma levels of luteinizing hormone in the new dominant male, but no change in testosterone levels. As reported in previous investigations, dominant males tended to have higher levels of testosterone than females or subordinate males, but this was not related to the heightened aggression of the takeover. Plasma levels of luteinizing hormone, testosterone, and corticosterone did not differ between the other status groups. The possibility that luteinizing hormone, or a hitherto unidentified androgen, may regulate aggression in the white-browed sparrow weaver is discussed.     

Effects of Dominant/Subordinate Social Status on Formalin-Induced Pain and Changes in Serum Proinflammatory Cytokine Concentrations in Mice

Current investigations regarding social stress primarily focus on the health consequences of being in stressful social hierarchies. The repetitive nature of social conflicts seems to favor an induction of hyperalgesia or hypoalgesia, both in rodents and humans. Additionally, social conflicts may affect the immune system. In order to better establish the pain and immune responses to stress, the present study implemented a sensory contact model on 32 male BALB/c mice. Subsequent to establishing a dominance/submissive social relationship, each mouse was injected with formalin (20 μl, 2%) and their pain behavior was scored and serum concentrations of proinflammatory cytokines IL-1 and IL-6, and corticosterone were also measured. Test results revealed that subordinate mice were hypoalgesic during chronic phase of formalin test compared to control and dominant mice (P<0.05). On the other hand, subordinate mice were hyperalgesic compared to dominant mice during the whole acute phase of formalin test (P<0.05). Corticosterone, IL-1 and IL-6 concentrations were much higher in serum of dominant and subordinate mice than in the control group (p<0.05). The results indicated that, although both dominant and subordinate animals displayed an increase in serum corticosterone and proinflammatory cytokines during social interactions, their response to pain perception differently was affected with the social status.     

A Trouble Shared Is a Trouble Halved: Social Context and Status Affect Pain in Mouse Dyads

In mice behavioral response to pain is modulated by social status. Recently, social context also has been shown to affect pain sensitivity. In our study, we aimed to investigate the effects of interaction between status and social context in dyads of outbred CD-1 male mice in which the dominance/submission relationship was stable. Mice were assessed for pain response in a formalin (1% concentration) test either alone (individually tested-IT), or in pairs of dominant and subordinate mice. In the latter condition, they could be either both injected (BI) or only one injected (OI) with formalin. We observed a remarkable influence of social context on behavioral response to painful stimuli regardless of the social status of the mice. In the absence of differences between OI and IT conditions, BI mice exhibited half as much Paw-licking behavior than OI group. As expected, subordinates were hypoalgesic in response to the early phase of the formalin effects compared to dominants. Clear cut-differences in coping strategies of dominants and subordinates appeared. The former were more active, whereas the latter were more passive. Finally, analysis of behavior of the non-injected subjects (the observers) in the OI dyads revealed that dominant observers were more often involved in Self-grooming behavior upon observation of their subordinate partner in pain. This was not the case for subordinate mice observing the pain response of their dominant partner. In contrast, subordinate observers Stared at the dominant significantly more frequently compared to observer dominants in other dyads. The observation of a cagemate in pain significantly affected the observer''s behavior. Additionally, the quality of observer''s response was also modulated by the dominance/submission relationship.     

Reproductive suppression in female Alpine marmots, Marmota marmota

We studied mechanisms responsible for reproductive skew in female Alpine marmots. In each social group, only dominant females produced weaned young although subordinate females had similar body condition, were fertile as indicated by high levels of oestradiol during the mating season, and occasionally started pregnancies. During the period of gestation, dominant females initiated significantly more agonistic interactions against subordinate females, resulting in significantly increased levels of glucocorticoids and decreased levels of progesterone in subordinates. Results suggested that reproductive suppression in female Alpine marmots is mediated by the negative effects of stress (glucocorticoids) on the activity of the hypothalamic-pituitary-gonadal axis. The strength of competition between subordinate and dominant females was affected by their relatedness. Dominant females attacked unrelated subordinate females more, whereas amicable behaviour was observed mainly between dominant females and their daughters. These differences could be explained by differences in indirect fitness: related subordinate females benefited from warming the offspring of the dominant female during hibernation. Reproductive suppression was apparently costly for dominant females, because their reproductive success decreased as the number of adult subordinate females in a group increased. Copyright 2003 Published by Elsevier Science Ltd on behalf of The Association for the Study of Animal Behaviour.      

Intra- and inter-group interactions of an all-male group of virunga mountain gorillas (Gorilla gorilla beringei)

Six unrelated male gorillas formed an all-male group within the Virunga mountain gorilla population. Frequent homosexual interactions characterized the high cohesiveness of this group. Such homosexual behavior reduced the inter-individual distances and increased the social tension between the two silverbacks in the group. The silverbacks retained “ownership” of the homosexual partners, but competed and fought with each other violently when the partners avoided or ignored their courtship. Neither submissive nor reassurance behavior was noted between the silverbacks. Thus, their relationships may not be explained in terms of dominance and subordinancy. However, the loser-support and mediating behavior observed in the group prevented them from engaging in severe fights. Aggression was always directed from the elder and dominant males to the younger and subordinate males, while supporting interactions occurred in the opposite direction. The blackbacks frequently supported the subadult aggressees by attacking the silverbacks, and the younger males displayed mediating behavior in violent fights between the silverbacks. The group's ranging was influenced by encounters with neighboring social units. The members avoided contact with other units and shifted their range after several encounters. On the other hand, when and after a subadult male had immigrated into their group, they frequently encountered other units and did not move away from the encounter site. An all-male group may not be a favorable unit for females to transfer to, but may be profitable for maturing males to associate with. Its formation is probably related to recent social change in the Virunga gorilla population.     

Male immigration triggers increased growth in subordinate female meerkats

There is increasing evidence that some vertebrates can adjust their growth rate in relation to changes in the social context that affect their probability of breeding. Here, we show that, in meerkats (Suricata suricatta), which are singular cooperative breeders, subordinate females increase in body mass after their father is replaced as the dominant male in their natal group by an immigrant male, giving them regular access to an unfamiliar and unrelated mating partner, while their brothers showed no similar increase nor did subordinate females living in other stable groups (where male immigration did not occur did) in this time period. Moreover, subordinate females showed a greater increase in growth rate when their father was succeeded by an unfamiliar immigrant male than when he was replaced by a familiar male who was already resident. These results suggest that female meerkats can adjust their rate of growth to changes in the kinship composition of their groups that provide them with increased access to unrelated breeding partners, which may occur in other mammals as well when breeding opportunities change.