雄性川金丝猴睾酮分泌与其社群环境变化的关系

采用化学免疫发光法,跟踪测定了上海野生动物园一个半放养川金丝猴群中3只先后参与交配繁殖活动的成年雄猴一年中尿中睾酮含量,并结合行为学记录对其性激素和性行为间的相互影响关系进行了初步研究。发现成年雄猴睾酮分泌峰的出现更多的是由其社会因素的变化引起的,而且,睾酮分泌峰出现的时期并不与雌性受孕高峰期相重叠,提示雄性繁殖具非季节性特点。睾酮分泌峰的出现,一方面说明此时社群的社会关系处于不稳定状态,另一方面发现睾酮水平的提高对雄猴攻击能力的增强起促进作用。由此,本研究认为川金丝猴雌雄性个体在繁殖中采用了不尽相同的繁殖策略[动物学报49(3)：325—33l,2003]。     

雄性小熊猫粪便中睾酮水平的变化与繁殖周期的关系

1999 年12 月至2000 年9 月, 使用放射免疫分析法, 测定了成都动物园和成都大熊猫繁育研究基地的4 只雄性小熊猫粪样中睾酮水平变化情况, 同时对其行为进行了观察。研究结果表明, 雄性粪样中睾酮水平在繁殖期(12 月～3 月) 显著高于非繁殖期(4 月～9 月) (P < 0.01) , 且睾酮水平变化与繁殖行为密切相关。在非繁殖期,雄性小熊猫的睾酮水平处于基础的较低水平时, 其繁殖行为如蹭阴、舔阴、舔标记物和咩叫等几乎没有发生或很少发生; 而在繁殖期, 雄性小熊猫的睾酮水平明显升高, 这些繁殖行为频繁发生。以上结果说明, 睾酮是调节雄性小熊猫繁殖行为季节性变化的生理因子。     

雄性麋鹿胆量和侵犯耦合与等级序位变化的关系

发情期的雄性麋鹿根据序位分为群主、挑战者和单身汉3个等级,序位变化是雄性麋鹿应对环境压力的直 观体现。本文利用胆量和侵犯2个行为指标在麋鹿生活史不同阶段的耦合强弱,来解释幼体时麋鹿序位发育、亚 成体时雄性序位定型及发情期时挑战者对群体序位的扰动。行为取样采用焦点取样法和扫描取样法相结合;分 析个体间行为样本流的非同步化水平,以同类型行为中较早发生、同步化率较低的判断为胆大;侵犯则结合攻 击行为和取胜指数来判定;粪样睾酮水平测定采用放射免疫分析法。结果显示雄性麋鹿幼体胆量和侵犯耦合与 等级序位呈负相关(r=-0.111 8,P=0.018 3);成体胆量和侵犯耦合与等级序位的波动呈正相关(r=0.917 9,P= 0.002 6)。从亚成体到成体:4头雄性麋鹿序位上升(胆量和侵犯耦合r=0.852 3,P=0.000 3),其中1头成为鹿 王;4头序位未发生改变(胆量和侵犯耦合r=0.482 9,P=0.006 3);3头序位下降(胆量和侵犯耦合r=0.251 7, P=0.003 5)。雄性麋鹿幼体睾酮水平与等级序位呈正相关(r=0.860 7,P=0.005 5);亚成体睾酮水平与等级序 位呈正相关(r=0.845 7,P=0.004 4);成体睾酮水平与等级序位呈正相关(r=0.954 6,P=0.001 8)。结果表明雄 性麋鹿发情期胆量和侵犯耦合强度与等级序位波动呈正相关;等级序位上升与睾酮水平升高有关。     

雄性短尾猴的等级顺位、睾酮水平与肠道寄生虫感染强度的关系

在等级森严的非人灵长类群体中,睾酮对雄性顺位维持有着重要作用,且影响着体内寄生虫种类和荷虫量。本研究以栖息于安徽黄山的雄性短尾猴为研究对象,通过计算成年雄性的等级顺位,测定其粪便中睾酮含量以及寄生虫的荷虫量,探讨雄性等级顺位、睾酮水平与健康间的平衡关系。结果表明：共检测出10种肠道寄生虫,包括4种蠕虫、5种原虫和1种螨虫;其中雄性短尾猴个体间睾酮水平（1.00±0.42） ng/g和肠道寄生虫荷虫量（112.44±83.62）EPG均存在显著差异（Kruskal-Wallis H,P<0.05）;等级顺位与睾酮水平呈正相关（Spearman, N=8,ρ= 0.326, P<0.05）,与肠道原虫类的荷虫量呈负相关（Spearman, N=8,ρ= - 0.345, P<0.05）,与肠道蠕虫类的荷虫量无相关性（Spearman, N=8,ρ= 0.065, P>0.05）;睾酮水平与肠道原虫类寄生虫的荷虫量呈负相关（Spearman, N=8,ρ= -0.546, P<0.05）,与肠道蠕虫类的荷虫量无相关性（Spearman, N=8,ρ= -0.013, P>0.05）。本研究表明高顺位雄性拥有更高的睾酮水平,这不仅对其顺位的维持具有重要作用,对原虫类寄生虫也具有明显的抑制作用。     

昆虫激素对雄性和雌性果蝇的不同影响

尽管两性之间存在极大的行为差异,但令人吃惊的是,对任何物种,研究人员几乎都没有发现能够将雄性与雌性脑区分开来的解剖特征。现在,用果蝇所做的研究工作揭示了雄性和雌性之间对昆虫激素cVA的反应存在的差异。雄性释放该激素,而雄性和雌性都能探测到该激素,而且它们都是通过其     

圈养林麝社会等级与粪样类固醇激素水平的关系

动物社群的社会等级可对个体的资源分配、社群稳定及个体的行为对策产生重要影响,圈养动物的类固醇激素水平与饲养管理有关,可反映动物的社群紧张水平.深入理解圈养动物的社会等级与其类固醇激素水平的关系是进行濒危动物迁地保育和成功驯养的基础.2018年6月15日—8月15日,用焦点取样法对四川马尔康林麝繁育场的25头林麝进行了冲...     

普通小麦与长穗偃麦草杂种及其衍生材料的细胞遗传学特性

对十倍体长穗偃麦草(Thinopyrum ponticum)与普通小麦杂交F1及其与普通小麦回交BC1F1的形态学和细胞学特性进行了分析。结果表明,长穗偃麦草与普通小麦‘兰考矮早八’衍生F1(‘兰考小偃麦’)的根尖细胞染色体数为56条;花粉母细胞减数分裂中期Ⅰ染色体构型平均值为19.81Ⅰ+15.78Ⅱ+0.75Ⅲ+0.59Ⅳ;基因组荧光原位杂交(GISH)显示,兰考小偃麦中含有35条完整的长穗偃麦草和21条小麦染色体。‘兰考小偃麦’/‘科育818’和‘兰考小偃麦’/‘Cp02-3-5-5’杂交F1的根尖细胞染色体数及其所遗传的长穗偃麦草染色体数分别为50~52和16~22条,且存在染色体易位;花粉母细胞减数分裂中期Ⅰ平均染色体构型为14.54Ⅰ+17.40Ⅱ+0.55Ⅲ+0.14Ⅳ,平均49.4%的细胞出现多价体(三价体或四价体)。这些材料为创造小麦-长穗偃麦草新种质奠定了基础。     

食物蛋白含量对雄性长爪沙鼠社会行为和某些生理特征的影响

为确定食物蛋白对长爪沙鼠行为和生理特征的影响,我们采用两种不同蛋白含量(9% 和27% )的食物饲喂不同年龄的雄性长爪沙鼠,测定了不同食物条件下长爪沙鼠的体重、睾丸重、脾脏重、血清抗体、社会行为和气味吸引力等指标。结果发现,食物蛋白含量没有影响长爪沙鼠的社会行为、生理特征及幼体气味的选择,但对成体气味的被选择程度影响显著,提示食物质量与其配偶选择过程相关联。     

促性腺激素释放激素类似物对长臀(鱼危)脑垂体促性腺激素分泌的影响

采用离体灌流孵育技术和促性腺激素的放射免疫测定方法,对长臀(鱼危)(Cranoglanis bouderius)脑垂体碎片促性腺激素的分泌进行了研究.结果表明:持续的促性腺激素释放激素类似物(GnRH-A)能显著刺激退化期的长臀(鱼危)离体脑垂体碎片促性腺激素(GTH)的分泌,并且长臀(鱼危)脑垂体碎片对持续的GnRH-A刺激未表现出脱敏性,该结果与胡子鲇和鲇鱼相似,而与金鱼和鲤科鱼类不同;重复脉冲GnRH-A刺激对长臀(鱼危)脑垂体碎片GTH分泌具有促进作用,而且存在剂量依存关系,与鲇鱼和鲤科鱼类相类似.上述结果表明在长臀(鱼危)的人工繁殖中可以用持续高浓度GnRH-A刺激对长臀(鱼危)进行催熟和催产.     

池养雄性白鱀豚性自慰行为与血清睾酮浓度之间的关系

自 1996年 3月至 1998年 12月 ,作者采用放射免疫分析法每月 1次测定雄性白豚 (Lipotesvexillifer)“淇淇”血清睾酮浓度。春季每天 1次 ,其它季节每三天 1次 ,每次 1h ,用目标动物取样法观察“淇淇”的行为。结果发现 ,性自慰 (腹面贴池壁、伸出阴茎 )行为的发生频率和血清睾酮激素水平都有周期性变化 ,春季为高峰期 ,秋季有 1个小峰 ,性自慰行为与血清睾酮激素浓度两者的周期较为一致。从性自慰行为和血清睾酮激素水平季节变化 ,推测出“淇淇”性腺活动的周期性变化 ,活动期为 2～ 10月 ,血清睾酮浓度为 2 4 8～ 9 6 6ng/ml;春季高峰在 4月前后 ,血清睾酮浓度为 3 4 4～ 9 6 6ng/ml;秋季小峰在 10月 ,血清睾酮浓度为 3 33～4 2 5ng/ml;11月至次年 1月为性腺活动相对静止期 ,血清睾酮浓度为 1 2 4～ 2 85ng/ml。白豚是一种季节性繁殖动物 ,繁殖高峰期在 4月前后。     

Hormonal responses to different sexually related conditions in male rats

Plasma levels of corticosterone (C) and testosterone (T) increase after sexual activity in males of several species. However, the physiological significance of these increases has not been elucidated. In the present study, hormonal response to different conditions linked to sexual activity was assessed. In the first experiment, plasma levels of C and T were assessed both in sexually experienced and naive male rats after the following conditions: (A) control group, without sexual stimulation; (B) males exposed to ovariectomized females; (C) males exposed to intact, non-receptive females; (D) males exposed to receptive females with the vagina obstructed, to avoid intromission; (E) males exposed to receptive females: but separated by a grid that prevents physical contact; (F) males exposed to receptive females during 30 min. In a second experiment, experienced male rats were allowed to repeatedly copulate until reaching the criteria for sexual exhaustion, and 24 h later, they were allowed to copulate. Once sexually related conditions ended, males were killed and their blood was obtained. C and T plasma levels were assessed by HPLC with ultraviolet (UV) detection. Results indicate that T did not increase significantly in naive male in any sexual condition, while in the experienced males, significant increases were observed with the mere presence of a receptive female and also after ejaculation. These increases were significantly larger in experienced males. On the other hand, C also increased in all sexual conditions, both in experienced and naive rats; however, the increase observed was larger in experienced males. Regarding sexual satiety, both C and T increased after copulating ad libitum to satiety. T increased almost three-fold compared to control, while C increased two-fold. No significant changes were observed in either one of the steroids 24 h after sexual exhaustion, even though males remained with a receptive female during an hour. These results show that sexual experience has an important influence on the hormonal response to sexual activity. C rises could be directly related to sexual arousal involved in the different sexual conditions, while T rises seem to have a direct relationship with both the motivation and execution aspects of masculine sexual behavior.     

Temporal patterns in natality and mortality of three threatened antelope species in North Africa: Oryx dammah,Addax nasomaculatus and Nanger dama

Long‐term population studies on large mammals are rare. Here, we have examined the threatened scimitar‐horned oryx, addax and dama gazelle's populations over the last 20 years in Bou Hedma National Park. Using monthly count data of the three studied species collected since 1995, we examined their population trends. Using autocorrelation analyses, we discovered endogenous natural cyclical fluctuations in the numbers of each species, with a periodicity of approximately 3 years. For all three studied species which seem to be opportunistic breeders, births and deaths occurred throughout the year, although with notable seasonality. By means of cross‐correlation, we discovered that during the first 7 years for which data were available, addax numbers were positively correlated with those of dama and inversely correlated with numbers of oryx. This pattern reversed during the following 4‐year period. The number of oryx was negatively correlated with dama during the first 4 years and then became positively correlated during the subsequent 7‐year period. Thus, we draw attention to difference in response to environmental and anthropogenic factors. Incorporating fundamental long‐term population data into developing management approaches, especially for potentially competitive species, is vital for their future long‐term survival and the success of conservation actions.     

Impact of season and social challenge on testosterone and corticosterone levels in a year-round territorial bird

Plasma testosterone increases during breeding in many male vertebrates and has long been implicated in the promotion of aggressive behaviors relating to territory and mate defense. Males of some species also defend territories outside of the breeding period. For example, the European nuthatch (Sitta europaea) defends an all-purpose territory throughout the year. To contribute to the growing literature regarding the hormonal correlates of non-breeding territoriality, we investigated the seasonal testosterone and corticosterone profile of male (and female) nuthatches and determined how observed hormone patterns relate to expression of territorial aggression. Given that non-breeding territoriality in the nuthatch relates to the reproductive context (i.e., defense of a future breeding site), we predicted that males would exhibit surges in plasma testosterone throughout the year. However, we found that males showed elevated testosterone levels only during breeding. Thus, testosterone of gonadal origin does not appear to be involved in the expression of non-breeding territoriality. Interestingly, territorial behaviors of male nuthatches were stronger in spring than in autumn, suggesting that in year-round territorial species, breeding-related testosterone elevations may upregulate male-male aggression above non-breeding levels. In females, plasma testosterone was largely undetectable. We also examined effects of simulated territorial intrusions (STIs) on testosterone and corticosterone levels of breeding males. We found that STIs did not elicit a testosterone response, but caused a dramatic increase in plasma corticosterone. These data support the hypothesis that corticosterone rather than testosterone may play a role in the support of behavior and/or physiology during acute territorial encounters in single-brooded species.     

Effects of physiological and social challenges in different seasons on fecal testosterone and corticosterone in male domestic geese (Anser domesticus)

We investigated the reliability of the non-invasive approach of measuring steroid hormones from feces in the domestic goose (Anser domesticus), a mainly herbivorous bird with a short gut passage time (2–3 h). Groups of eight outdoor-housed male domestic geese were subjected to three different experiments, injection of either GnRH analogue or ACTH, or ”social stimulation” by confrontation with two alien males or females. These experiments were replicated in three different seasons, in spring, during peak reproductive activity, in summer, during long-day photorefractoriness and postnuptial molt, and in fall, during sexual reactivation. GnRH stimulation resulted in significant increases of mean response and peak fecal testosterone metabolites (TM) in spring and fall. Response TM concentrations excreted in spring were generally higher than in summer and fall. Social confrontation with two females, but not with two males, increased mean and peak TM in all seasons. In general, ACTH treatment resulted in a proportionally higher increase of fecal corticosterone metabolites (BM) than GnRH did in fecal TM (80- to 140-fold vs 6- to 8-fold). ACTH significantly increased mean and peak BM in all seasons. Social confrontation with two males significantly increased fecal BM in spring, but confrontation with two females increased fecal BM in fall. Our results indicate that determining steroids from feces is a generally valid approach. However, the sensitivity of the method may vary between different hormones and results may differ between seasons. BM results seemed more sensitive and seasonally robust than did TM. Received: 22 December 1999 / Received in revised form: 26 January 2000 / Accepted: 27 January 2000     

Homosexual behavior in male goats is more frequent during breeding season and in bucks isolated from females

Male homosexual behavior is observed in many ruminant species; seasonality and isolation from females may affect the display of male–male sexual behavior. Our objectives were to determine whether: 1) homosexual behavior has a seasonal pattern in male goats (Capra hircus); 2) isolation from female goats influences the frequency of the display of homosexual behavior; and 3) the frequency of homosexual behaviors is related to testosterone concentration. Bucks were housed in a pen adjacent to another pen with 3 estrous goats (FC group) or in complete isolation from females (IF group). Homosexual behaviors and testosterone concentrations were recorded in October, December, February and May. Frequencies of penile display and flehmen increased in May and were observed more frequently in the IF than in the FC group. Ano-genital sniffing was more frequent in February and May and was more frequent in IF than in FC bucks. Lateral approaches were more frequent in May, in which period this was more frequently observed in IF bucks. Mount attempts and mounts were only observed in IF bucks. Testosterone concentrations increased from December to February and decreased in May, although they were still greater than in October and December. In May IF bucks had greater testosterone concentrations than FC bucks. Testosterone concentrations were only related to the number of lateral approaches in IF bucks in December. In conclusion, homosexual behavior was more frequent during the late breeding season than during the early and the non-breeding seasons, and in males isolated from females than in males housed near estrous females. Testosterone concentrations appear to be unrelated to homosexual behavior.     

Behavioural and hormonal effects of social isolation and neophobia in a gregarious bird species, the European starling (Sturnus vulgaris)

Separating gregarious individuals from their group members often results in behavioural and physiological changes, like increased levels of corticosterone. Testosterone and corticosterone, in particular, have been implicated in the response of mammals to novelty. Data in birds are, however, rare. The presence or absence of group members may also influence an individual's response to novel stimuli. We assessed the behaviour and hormonal response of European starlings (Sturnus vulgaris) to a novel object in two different situations and seasons: each starling was tested when separated and when in contact with its group members in May/June (breeding season) and again in September/October (non-breeding season). Starlings are gregarious throughout the year, but as foraging flocks are small during the breeding season and large during the non-breeding season, we assumed that non-breeding starlings would be more affected by social isolation. Overall, starlings had higher levels of corticosterone, lost more body mass, and were more active when they were separated from their group. Isolated individuals, however, did not show a greater neophobic response than individuals in the presence of their group members in either season. Circulating levels of testosterone and corticosterone were higher after a test with novel object than after a test with only the familiar feeding dish in both sexes and seasons. However, control tests for handling effects confirmed only the increase in testosterone. Our study shows that social isolation is stressful for unrelated and unpaired members of a wild flocking bird species and demonstrates that novelty can lead to a rise in testosterone in birds.     

Hormonal correlates of social status and courtship display in the cooperatively lekking lance-tailed manakin

Though cooperative behavior has long been a focus of evolutionary biology, the proximate hormonal mechanisms underlying cooperative interactions remain poorly understood. Lance-tailed manakins (Chiroxiphia lanceolata) are tropical passerines that form long-term male-male partnerships and cooperate in paired male courtship displays. To elucidate patterns of natural hormonal variation in relation to cooperation and reproductive behavior, we examined circulating androgen levels of male lance-tailed manakins in relation to social status, display behavior, and time of year. We found significantly higher circulating androgen levels in alpha-ranked (breeding) males compared to non-alpha adult males in the population. Beta males, which participated in courtship displays but did not copulate, had androgen levels indistinguishable from those of unpaired adult males that never displayed for females, suggesting that an elevated concentration of plasma testosterone in tropical lekking birds may be associated primarily with copulatory behavior or other status-specific traits, and not the performance of courtship display. Androgens decreased throughout the breeding season for males of all status categories. Interestingly, alphas that displayed for females in the observation session prior to sampling had lower androgen levels than alphas that did not display for females. This pattern may result from female discrimination against alpha males at display areas with high levels of social conflict among males, as social disruption is linked to elevated testosterone in many species. However, recent change of a display partner was not related to alpha androgen levels. We discuss alternative explanations and the possible implications of these results, and generate several testable predictions for future investigations.     

Effect of age,pubertal stage and season on testosterone concentration in male dromedary camel

The present study was conducted in the Laboratory of Animal Physiology and Biotechnology, Department of Animal Production, Faculty of Agriculture, Mansoura University, Egypt. The present investigation aimed at studying effects of ages, pubertal stages and seasons of the year on testosterone concentrations in blood plasma and tissue homogenate of the testes. The testes used in the current study were collected from a total of 104 one-humped male camels (Camelus dromedarius). Samples were taken from pre (1–3.5 years) and post (3.5–13 years) pubertal camels. Testes were studied for a two consecutive seasons. The freshly prepared homogenate of the testicular tissue and blood plasma were used for determining the concentrations of testosterone in plasma and testicular extract. The concentrations of testosterone in blood plasma and testicular tissue were significantly increased during the breeding season compared with that of non-breeding season; the concentration of testosterone was higher in testicular tissue than in blood plasma.Testosterone concentrations in plasma and testicular tissue were increased in breeding than in non-breeding season. In addition, the testosterone concentrations were closely related with seasonal changes, stage of puberty and advancing age.