排卵,排精前后文昌鱼体内GnRH的研究

利用放射免疫分析法测定了排卵、排精前后青岛文昌鱼体内促性腺激素释放激素（ＧｎＲＨ）的含量变化,并通过高效液相色谱比较了雌、雄文昌鱼性腺及除性腺外体部ＧｎＲＨ的种类和含量的异同。结果表明：１）生殖过程中雌、雄文昌鱼体内ＧｎＲＨ含量的变化规律不同;雌性文昌鱼体内ＧｎＲＨ总含量在排卵时有所下降,排后１２小时政策最为明显,以后逐渐上升到排前水平;雄性文昌鱼仅在排精时有所下降,２小时后即稳定在排水平。２）文     

三宝鸟繁殖期领域性的初步研究

鸟类领域性是鸟类生态学研究中一个引人入胜而又争议颇多的课题(Nice,1941;Hinde,1956)由于对鸟类的领域性与生态因素、种群密度之间关系的深入讨论(Davies,1978;Brown,1969;Wesolowski,1981),使得这一课题已成为鸟类种群生态学研究的重要内容之一。了解各种鸟类的领域性表现和特点,无论在理论上和实践上都是有一定的意义的。 我国鸟类生态学研究工作主要集中在鸟类繁殖习性和区系分布等方面,个体行为生态学     

SEX AND AGE SEGREGATION BY PHOCA VITULINA CONCOLOR AT HAUL-OUT SITES DURING THE BREEDING SEASON IN THE PASSAMAQUODDY BAY REGION, NEW BRUNSWICK

The size and composition of groups of harbor seals at two haul-out sites were studied during the breeding season of 1989, in the Passamaquoddy Bay region of Atlantic Canada. Evidence of segregation both by age and sex was found in the distinct composition of the two groups. One group contained mainly males and no pups, and the other had a sex ratio not significantly different from one and contained pups. The proportion of females increased at the nursery site with the onset of birthing in the region while the proportion of males increased through the breeding season at the other site. No increase in the number of adults, in total, was detected over the study period, suggesting that sexual segregation and not a change in haul-out frequency was responsible for the disparity in the sex structure of the two groups. The proportion of juveniles was significantly greater at the male dominated site than at the nursery site.     

繁殖期黄喉鹀的领域鸣唱及其种内个体识别

在镜泊湖自然保护区收录黄喉鹀(Emberiza elegans)的鸣唱声,室内作出鸣唱的语图和声谱图。繁殖期黄喉鹀领域鸣唱的频率范围2.4—6KHz,有13—28个音节,2—3个泛音,鸣唱持续时间2.2—4.0秒;具相似的频谱结构,但种内个体间亦存在差异。野外对比实验的结果可说明,黄喉鹀有识别邻鸟和陌生鸟领域鸣唱的能力,有对声音的记忆和定位的能力。     

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     

THE SIGNIFICANCE OF KLEPTOPARASITISM DURING THE BREEDING SEASON IN A COLONY OF ARCTIC SKUAS STERCORARIUS PARASITICUS IN ICELAND

Breeding and kleptoparasitism of Arctic Skuas was studied at Vik, Iceland, in 1973. Hatching success was 88.9%; fledging success was 0.27 fledglings per pair. The heavy chick mortality occurred mostly in the first week after hatching. In the early part of the breeding season skuas fed by robbing kittiwakes of their food at sea and by eating arthropods at the breeding grounds. At the time of hatching of skua eggs, which coincided with the hatching of Puffin eggs, skuas switched their feeding activities to kleptoparasitism of Puffins and fish so obtained was the principal item of most skuas' diet thereafter. In the first week post-hatching, the energy balance of an average adult skua pirating Puffins was estimated to be negative, but changed to positive a week later, although later, coinciding with an influx of non-breeders it turned back to negative. Arctic Terns which normally breed at Vik, and are exploited by skuas, failed to breed in 1973, and the abnormally heavy chick loss is therefore attributed to this failure of the terns. The success of the skuas kleptoparasitizing Puffins depends on the proximity of the interactions to the cliff or to the ocean, where Puffins seck refuge. Skuas catch fish mostly in the air, especially if it is dropped from high. Fish dropped from low is mostly taken by competing gulls and Ravens, which mostly control the ground and lower airspace. Skuas chasing in groups enhance their success, but the average success per member decreased with group increase. However, the success of the group-member in the ‘best’ position was equal to that of a single skua. Puffins carry 1 (large)-6 (smaller) fish, an approximately equal load irrespective of number of fish. Skuas preferentially chase Puffins carrying ‘large’ fish, thus maximizing their yield per effort. Arctic Skuas responded to changes in the numbers of arriving Puffins with a functional response, but their monitoring of the food supply was far from perfect.     

THE BREEDING SEASON IN S.W. ECUADOR

The breeding season on the Santa Elena peninsula in S.W. Ecuador is described on the basis of 1761 nests found in the four years 1955 to 1958. The environment and climate are outlined—a cool, dry season from about May to November and a warm, variable wet season from December to April, when alone rain may fall. It is shown that each year the general breeding season is closely correlated with the rainfall. The peak of breeding varies from year to year by at least a month and its length from about six weeks to three and a half months.
Although all species for which there are enough data, are stimulated to breed after important falls of rain, most of those species of small land-birds which are completely resident, attempt to nest before the rain and often continue for some time afterwards. Some specific differences, between seed- and insect-eating finches, seem to be adaptations to food supply and the availability of nest sites and building material. Such evidence as there is suggests that raptors, waders and waterfowl also nest in the wet season (often late), rather than in the dry season. (Unfortunately herons and sea-birds do not nest in the area.)
Annual differences in the amount of breeding by the same species are thought not to be entirely due to differences in weather between years.
It is suggested that the late (August-September) breeding in the Galápagos Islands described by Lack (1950) and the apparent dry-season nesting of raptors, waders and waterfowl there might be found to be linked with variable or abnormally wet weather, if records of rainfall from the islands were available.     

内蒙古东部草原地区赤狐繁殖期对洞穴的选择

通过对内蒙古东部草原地区赤狐的２５个洞穴观测,运用系统聚类分析的方法,研究了赤狐繁殖期的洞穴选择。结果表明,影响赤狐繁殖期洞穴选择的主要因子是水源,其次是坡向、坡位和坡度,人为干扰、隐蔽程度及洞口朝向等因子对其影响作用不明显。繁殖期赤狐的最适洞穴选择为：阳坡或半阴半阳坡、下坡位、坡度５°～２５°、距水源５００～１０００ｍ。     

CRABEATER SEALS LOBODON CARCINOPHAGUS DURING THE BREEDING SEASON: OBSERVATIONS ON FIVE GROUPS NEAR ENDERBY LAND, ANTARCTICA

Observations on five groups of crabeater seals were conducted between 29 October and 17 November 1985 in the Antarctic pack ice near 66°S 50°E, off Enderby Land. The pups studied were born in the last half of October. Two of them increased in weight at a rate of approximately 4.2kg per day. Pups were weaned in the first half of November at 80–110 kg. The lactation period was 2–3 wk and thus is one of the briefest among pinnipeds. Pups decreased in weight after weaning. The only pup visited after it left the natal floe must have been feeding, as it had lost only 2 kg in a 10–day period during which it moved 13 km. Molt of lanugo appeared to be influenced more by a pup's weight than by whether or not it was weaned.     

中国石龙子繁殖季节血浆性类固醇激素水平的变化

本文研究了中国石龙子繁殖季节中性腺变化与血浆性类固醇激素水平波动间的相互关系.结果表明雌性中国石龙子卵黄生成需要雌二醇(17β-estradiol,E2)的刺激.体现在卵巢重量于4月底至5月中旬间达峰值,血浆E2水平于3月底至最高值,此后显著回落,并于排卵前再次回升;血浆孕酮(progesterone,P)的生理功能在于输卵管卵的维持、促进胚胎发育和卵壳的形成.从3月中旬至4月底间,血浆P水平在基础值附近波动.5月中旬,随动物的排卵,血浆P水平迅速上升,至该月底达最高值,于产卵后迅速下降;E2随P的上升而下降,两者呈反向变动.雄性血浆睾酮(testosterone,T)水平与生精作用、维持攻击、求偶及交配行为密切相关.血浆T水平于动物出眠后呈现显著的上升趋势,并于4月中旬达峰值.5月中旬后,随睾丸的萎缩,血浆T水平也缓慢下降,至6月底达最低值.     

PHOTORESPONSES OF THE WOODPIGEON COLUMBA PALUMBUS IN RELATION TO THE BREEDING SEASON

• 1 The gametogenetic response following photo-stimulation was tested in Woodpigeons under controlled laboratory and aviary conditions. Subjects were wild-caught adult or first-winter birds or were hand-reared from wild-taken nestlings. The natural seasonal gonad cycle is described and experiments were related to this cycle.
• 2 Gonad recrudescence could be initiated in adults with regressed organs by exposure to summer photoperiods, while the normal vernal recrudescence could be prevented if birds were artificially kept on short (winter) daylengths. Thus Woodpigeons could be stimulated towards reproductive condition at seasons when the gonads of wild-living birds remained inactive, viz. late September to mid-February.
• 3 Juvenile males were unresponsive to extra photo-stimulation until they were about six months old. This meant that some spermatogonial division could be procured in a few individuals in late February, but juveniles were not very noticeably affected by an extended photoperiod until mid-late March. This is the time when juveniles first begin gametogenetic development in the wild, though spermatogenesis normally accelerates in April after which time the rate of gonad development is constant. First-winter females were judged to resemble males in their photoperiodic responses but the sample examined was small.
• 4 The results confirm that the natural gonad cycle in the Woodpigeon is controlled (via gonadotrophic hormones) by seasonal changes in daylength. More important is the finding that the species appears to possess no post-nuptial refractory period. Thus, at the end of the breeding season in September birds kept on summer daylengths were maintained in full reproductive condition until December. The testes of controls placed on winter daylengths regressed within one month, but they were immediately responsive to a summer daylength which stimulated spermatogenesis within a month.
• 5 The discussion argues that the avian refractory period is not a necessary period for gonad rehabihtation and reorganization and that it has not evolved as a fixed period serving to time the breeding season; views which until now have been current. Instead, it functions only as a safety mechanism, preventing unseasonal reproduction in those species for which natural selection favours seasonal breeding. In such species the evolution of sensitivity to a particular daylength could result in breeding taking place at the wrong time, for example spring responding species might also respond in the autumn. Because natural selection permits Woodpigeons to remain in breeding condition from March until September, without disadvantage, a direct response to natural daylength can regulate the cycle, and there is no need for a period of pituitary refractoriness. It is not known if some pigeons have lost the refractory period or whether they never possessed one.