"占群"还是"挑战"?不同时间限制条件下麋鹿个体的交配计策

在麋鹿的发情交配季节 ,雄性麋鹿可区分为 3种类型 :“群主”、“挑战者”和“单身汉”。“群主”是一头圈占并控制雌鹿活动的优势雄性。“挑战者”不占有雌性繁殖群 ,但在发情场附近地点展示炫耀。当雌性繁殖群的雌鹿外出采食靠近“挑战者”的展示炫耀地点时 ,“挑战者”会积极地寻求机会与之交配。“单身汉”在繁殖季节不表现发情行为。他们像非繁殖季节一样采食 ,采食后蹲在水塘中休息。我们对何种因素决定麋鹿个体的发情交配计策感兴趣。 1996至 1998年夏天 ,我们在北京麋鹿苑观察麋鹿发情交配行为以分析导致这些行为差异的原因。结果发现 ,“群主”、“挑战者”和“单身汉”用于维持生命的时间预算与用于发情的时间预算成反比 ,并且 ,“群主”、“挑战者”和“单身汉”用于维持生命的时间预算与用于发情的时间预算差异显著。“群主”的绝大部分时间用于发情占群 ,而用于采食、饮水的时间很少 ,所以 ,“群主”在发情期间基本上处于禁食状态 ,靠消耗体内脂肪维持生命。“单身汉”则相反 ,绝大部分时间用于采食、休息和反刍 ,基本上没有发情行为。“挑战者”在发情行为与维持生命行为之间的时间则居于“群主”与“单身汉”之间。交配次数是偏态分布的 ,与雄性发情时间呈正比。“群主”的交配概率最高     

雄性麋鹿的交配机会、社会等级和皮质醇水平

我们在北京麋鹿苑研究了发情期雄性麋鹿的社会行为、社会等级和血清皮质醇水平,并分析了三者间的相互关系。按照雄性麋鹿的行为,将雄性麋鹿分为优势群和从属群。优势群包括群主和挑战者,从属群包括单身汉和被淘汰群主。使用SJ—Ⅰ型事件记录器进行常规行为取样,用放射免疫分析法测定血清皮质醇含量。发现：(1)优势雄鹿的发情行为频次明显高于从属雄鹿;(2)攻击行为的发生频次在两组间无显著差异;(3)血清皮质醇含量在两组间也无显著差异。由此我们认为,发情期雄性麋鹿的社会等级序位影响许多行为的表达,优势雄鹿成功交配的机会比从属雄鹿多。而攻击行为和肾上腺皮质醇的分泌与社群等级无明显相关,可能是麋鹿在圈养状态下的一种适应策略,这将有利于缓解发情期雄鹿的紧张,从而允许更多的能量投放在发情交配上。     

社会等级和食物供给会影响搔痒行为？麋鹿中的验证

先前的研究表明,性别、年龄、蜱虫密度、季节等因素会影响大丰自然保护区中重引入麋鹿的口部搔痒行为,因此野生动物重引入需要考虑该种群是否仍保留瘙痒行为以便有效抵御皮外寄生虫尤其是蜱虫的侵扰。在本次研究中,我们进一步探讨了两个可能会影响麋鹿搔痒行为的因素：社会等级和食物供给。在发情季节,麋鹿群主通常具有较高水平的睾酮水平,进而抑制搔痒行为,所以我们预测群主的搔痒频率应该会低于单身汉。但是群主和单身汉的搔痒频率并没有差别,这可能是因为观察期处于发情末期,睾酮水平已经下降。食物供给也可能会影响搔痒行为,因为其可以减轻采食压力,从而释放了其他行为如搔痒的时间。然而我们也没有发现食物供给的影响,这可能是因为围栏小种群的游客较多,使得警戒行为占据了采食压力释放后的行为时间。我们建议未来改变行为观察时间,并排除游客干扰,从而进一步探讨这两个因素对麋鹿搔痒行为的影响。     

Behavioural factors affecting male reproductive success in red deer (Cervus elaphus)

Variation in reproductive success among adult red deer stags was related to harem size, and the duration and timing of breeding access. All three factors were affected by dominance (fighting success) during the rut. The number of hinds using a stag's rutting area and the duration of individual rutting activity also affected breeding access. Dominance rank in bachelor herds, which may affect access to hinds conceiving after the rut, was correlated with rank in the preceding but not the following rut.     

麋鹿鹿角脱落、群主更替、产仔的年节律及其环境影响因子

本文在2014—2016年三个冬季(12月—翌年2月)收集了北京南海子麋鹿苑半散放麋鹿自然脱落的角,并观察和记录了2015—2017年发情期(5—9月)群主更替和2016—2018年产仔期(3—7月)麋鹿幼仔出生情况,结合2014—2018年年平均气温、季平均气温、月平均气温、年降雨量、雨季开始时间、种群密度等环境因子,对鹿角脱落、群主更替、产仔等繁殖特征的年节律及其环境影响因子进行了研究。结果表明：1)麋鹿鹿角脱落、群主更替、产仔的年节律均存在年际差异。2)鹿角脱落时间为12月开始,1月下旬或2月上旬结束。3)发情期为5月下旬或6月上旬开始,9月上旬结束;2015—2017年发情期时间有延长的趋势。4)产仔期为3月中旬或4月中旬开始,5月下旬或7月下旬结束。5)麋鹿鹿角脱落、群主更替、产仔的年节律存在明显的同步关系,其中鹿角脱落开始时间、鹿角脱落高峰期、鹿角脱落结束时间、第一次发情期开始时间、群主更替高峰期、产仔期开始时间、产仔高峰期、产仔期结束时间与前一年度比较均出现同步提前的现象。6)鹿角脱落年节律存在随着12月平均气温升高而提前的现象;产仔期开始时间和产仔高峰期存在随着前一年9月平均气温的升高而提前的现象。7)鹿角脱落年节律表现出随着年降雨量的增多而提前的现象;第一次发情期开始时间、群主更替高峰期的年节律表现出随着前一年度年降雨量的增多而提前的现象。8)麋鹿鹿角脱落、群主更替、产仔的年节律均不存在随着种群密度升高或降低而提前或延迟的现象。麋鹿繁殖特征的年节律是一个复杂的过程,受气候、营养、种群密度、纬度等环境因子的影响。     

Seasonal changes of reproductive behavior and fecal steroid concentrations in Père David's deer.

From July 1997 to September 1997 and from March 1998 to July 1998, we studied reproductive behaviors of Père David's deer in Dafeng, China. During the field behavioral observations, we collected fresh voided fecal samples from the Père David's stags and hinds periodically and kept those samples under -20 degrees C until laboratory analysis. We analyzed the fecal testosterone, estradiol, and progesterone concentrations in those samples using radioimmunoassay. During this study, we also recorded 17 types of male reproductive behaviors and nine types of female reproductive behaviors. Reproductive behaviors and the fecal steroid concentrations showed overt seasonal fluctuations. There were statistically significant correlations between some male reproductive behaviors, such as anogenital sniffing, urine sniffing, urine spraying, wallowing, bellowing, antler adorning, Antler swags mud, chasing, herding hinds, chin resting, mounting and copulating, with the fecal testosterone concentrations. These results suggested that seasonal reproductive behaviors in stags are strongly associated with circulating testosterone. We also found that some female reproductive behaviors fluctuate corresponding with changes in fecal estrogen concentrations. Although there was no direct evidence to confirm the correlations between female reproductive behaviors and fecal estrogen in our experiment, we could not rule out that reproductive activities of hinds were largely related to ovarian estrogen secretion, and estrogen is necessary for inducing female reproductive behaviors.     

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。     

Evidence of effects of human disturbance on alert response in Père David's deer (Elaphurus davidianus)

To understand effects of human disturbance on alert response of Père David's deer, we carried out an experiment in the Dafeng Père David's Deer Reserve (32°59′–33°03′N, 120°47′–120°53′E), China. In the spring and summer, we observed alert responses (including stare, walking away, and flee) of deer and recorded the intensity of tourist disturbance in a small display pen using a laser‐range finder to measure the alert distance of a free‐ranging group in a large enclosure. We also recorded the pattern of head orientation when deer were resting in these two deer groups. After statistical analysis, we found that: 1) in small pen, the frequency of alert response was significantly different among different intensities of human disturbance; strong disturbance resulted in higher frequency of alert response; 2) stare distance in the free‐ranging group in summer was significantly longer than that in spring, but the distance of walking away and the distance of flee showed no significant difference between the two seasons; and 3) in free‐ranging group, there was no significant directional difference in head orientation, whereas in display group, there was a significant directional difference in head orientation. We suggest that: 1) under the captive situation, human disturbance may be one of the factors that affect alert response in Père David's deer; and 2) Père David's deer adopted different alert response to adapt to human disturbance under different circumstance. We recommended that relationships between alert response and human disturbance should be considered in ex situ conservation of this field extinct deer. Zoo Biol 26:461–470, 2007. © 2007 Wiley‐Liss, Inc.     

Relationships between Behaviour and Antler Cycle Timing in Red Deer

The factors affecting the stag social hierarchy and antler cycle timing in a herd of red deer were analysed. The analysis was based on behaviour records of the herd between 1972 and 1983. The alpha stag was not usually the oldest stag present. Changes in rank were commoner in periods of hard antler than during velvet periods. The frequency of rank changes was correlated with the number of stags present but not with the number of hinds; it was also positively related to indicators of the level of aggression such as the incidence of antler breakage, the number of harem-holding stags per rut and the incidence of post-casting rank loss. The number of stags killed in fights was not correlated to any of the indicators of aggression except the number of harem-holders per rut. Rank loss after antler casting and the change of harem-holding stags during the rut were both relatively rare events indicating year-round, stable social relationships in the herd. The relationships between rank and casting date and between rank and cleaning date previously reported were related to the level of aggression among the deer. The higher the level of aggression, the closer the relationship between rank and the timing of the antler cycle. The small difference in the level of aggression between the periods of casting and cleaning is thought to be the result of the seasonally different social background. The number of hinds present did not appear to affect antler casting, antler cleaning or the general indicators of the level of aggression. It is concluded that the results support the previously advanced hypothesis that behaviour modulates antler cycle timing in Cervids.     

The induction of male sexual behavior in red deer (Cervus elaphus) by the administration of testosterone to hinds and estradiol-17β to stags

One-gram implants of testosterone were placed subcutaneously in two adult intact and one castrated red deer hinds, and 100-mg implants of estradiol-17β were given to three castrated and two intact red deer stags. Their sexual behavior was then observed in the wild and in captivity for up to 3 years. Testosterone initially produced prolonged and intense estrous behavior in the hinds; this gradually gave way to behavior normally shown only by rutting stags, such as flehmen, herding threats, and roaring. Testosterone-implanted hinds rose in the dominance hierarchy as measured by competition for food. Pregnancy, or the administration of progestagens, suppressed most of this testosterone-induced behavior. Testosterone also induced development of male secondary sexual characteristics such as formation of small antler pedicles (but not antlers), hypertrophy of the clitoris and neck musculature, and development of a neck mane and male rutting odor. Estradiol-17β mimicked the behavioral effects of testosterone when given to castrated stags, stimulating all components of rutting behavior. In intact stags, the only effects were to abolish antler casting and stimulate roaring; normal rutting behavior continued unchanged. In contrast to the effects of testosterone, estradiol-17β did not influence the social status of either intact or castrated stags. The distinctions between the behavioral effects of androgens and estrogens are ill defined and are determined more by the prior sexual differentiation of the brain and the duration of steroid treatment, than by the nature of the steroid.     

Diet composition and selection of Père David's deer in Hubei Shishou Milu National Nature Reserve,China

Hubei Shishou Milu National Nature Reserve is an ideal place to restore the wild population of Père David's deer (Elaphurus davidianus). Understanding foraging ecology and diet composition is essential for assessing population development or establishing long-term effective conservation measures for endangered species. However, little is known about the diet composition of Père David's deer and its diet selection mechanism. In this study, we used stable isotope technology to investigate the diet composition of Père David's deer according to various tissues (i.e., fur, muscle, liver, heart, and feces) and seasons, and evaluated the correlation between the nutrient composition of plants and diet composition. Bayesian isotope analysis showed that the autumn and winter diet estimated by fur and fecal samples indicated a diet dominated by C₃ grasses (42.7%–57.2%, mean), while the summer diet estimated by muscle and liver samples was dominated by C₃ forbs (30.9%–41.6%, mean). The Pearson correlation test indicated that the contribution of winter diet composition reflected by fur and fecal samples was associated with correlations with crude protein (r = .666, p < .01) and soluble sugars (r = .695, p < .01). The results indicated that crude protein and soluble sugars were important factors influencing the winter diet selection of Père David's deer. In the context of the current reintroduction facing many challenges, such as habitat fragmentation, wetland degradation, and human disturbance, comprehensively evaluating the diet selection mechanism of Père David's deer under different resource specificities and temporal changes should be considered in the future.     

江苏盐城湿地麋鹿冬季食性研究

2017年12月至2018年3月在江苏盐城湿地珍禽国家级自然保护区,利用粪便显微组织学分析技术结合野外直接观察法对麋鹿(Elaphurus davidianus)冬季食性和食物营养成分进行了分析。野外调查在7条样线上共收集228堆麋鹿粪便,组成14个复合样本进行分析。结果表明,麋鹿冬季食物来源于14科51种植物,其中,芦苇(Phragmites australis,23.09%)和互花米草(Spartina alterniflora,17.58%)为最主要食物,其次为盐地碱蓬(Suaeda salsa,6.50%)、白茅(Imperata cylindrica,5.36%)、獐毛(Aeluropus sinensis,4.90%)、苇状羊茅(Festucas arundinacea,3.83%)、扁秆藨草(Scirpus planiculmis,3.45%)、碱蓬(Suaeda glauca,3.27%)、碱茅(Puccinellia distans,3.12%)、黑麦草(Lolium perenne,2.60%)和茵陈蒿(Artemisia capillaris,2.60%)。麋鹿冬...     

Pater Davids Hirsch oder Milu (Elaphurus davidianus Milne Edwards, 1866), 150 Jahre, 1865 bis 2015

The population of the Père David's deer or milu (Elaphurus davidianus), which was discovered in China by Père Armand David in 1866, has grown from five, or even merely three individuals, imported from China to approximately 5000 during a time-span of 140 years. We tried to find out more about the origin of the 18 individuals which formed the original herd of the 11^th Duke of Bedford at Woburn Abbey. His breeding-group was the only safeguard for this species between the years 1900 and 1946. Of the 18 individuals three were offspring of Berlin Zoo, three originated from Cologne Zoo and probably all the rest came from the Jardin d‘Acclimatation in Paris. The origin of the breeding herd at the Jardin d‘Acclimatation is not clear. The first individuals either came from Berlin Zoo or were imported directly from China in the years between 1876 and 1886. In Berlin Zoo's breeding records there is a remarkable gap for the years 1879 and 1880. If they came from Berlin Zoo, the imported male and two females would be the sole founders of the herd, and if the Jardin d‘Acclimatation had done an own import, then there would be at least five founders. At Berlin Zoo at least 18 milu calves were born between the years 1878 and 1895. The final destinations of most of these could be traced in literature. Some of them are not quite conclusive yet. We sketched the development of the worldwide zoo-stock of Père David's deer, the return to China and the re-settlement in the original habitat in newly established reserves and finally even outside the reserves. After centuries the milu has again gained the status of a free-living species thanks to the efforts of several zoological gardens, the Dukes of Bedford and the Chinese conservation authorities.     

Relative Effect of Food Supplementation and Natural Resources on Female Red Deer Distribution in a Mediterranean Ecosystem

ABSTRACT Supplementary feeding is a widespread game management practice in several red deer (Cervus elaphus) populations, with important potential consequences on the biology of this species. In Mediterranean ecosystems food supplementation occurs in the rutting period, when it may change mating system characteristics. We studied the role of food supplementation relative to natural resources in the spatial distribution, aggregation, and mean harem size of females in Iberian red deer (Cervus elaphus hispanicus) during the rut. We studied 30 red deer populations of southwestern Spain, 63% of which experienced supplementary feeding. Using multivariate spatial analyses we found that food supplementation affected distribution of females in 95% of the populations in which it occurred. Green meadows present during the mating season acted as an important natural resource influencing female distribution. Additionally, the level of female aggregation and mean harem size were significantly higher in those populations in which food supplementation determined female distribution than in populations in which female distribution did not depend on supplementary feeding. Because female aggregation and mean harem size are key elements in sexual selection, supplementary feeding may constitute an important anthropogenic element with potential evolutionary implications for populations of Iberian red deer.     

Do Père David's Deer Lose Memories of Their Ancestral Predators?

Whether prey retains antipredator behavior after a long period of predator relaxation is an important question in predator-prey evolution. Père David''s deer have been raised in enclosures for more than 1200 years and this isolation provides an opportunity to study whether Père David''s deer still respond to the cues of their ancestral predators or to novel predators. We played back the sounds of crows (familiar sound) and domestic dogs (familiar non-predators), of tigers and wolves (ancestral predators), and of lions (potential naïve predator) to Père David''s deer in paddocks, and blank sounds to the control group, and videoed the behavior of the deer during the experiment. We also showed life-size photo models of dog, leopard, bear, tiger, wolf, and lion to the deer and video taped their responses after seeing these models. Père David''s deer stared at and approached the hidden loudspeaker when they heard the roars of tiger or lion. The deer listened to tiger roars longer, approached to tiger roars more and spent more time staring at the tiger model. The stags were also found to forage less in the trials of tiger roars than that of other sound playbacks. Additionally, it took longer for the deer to restore their normal behavior after they heard tiger roars, which was longer than that after the trial of other sound playbacks. Moreover, the deer were only found to walk away after hearing the sounds of tiger and wolf. Therefore, the tiger was probably the main predator for Père David''s deer in ancient time. Our study implies that Père David''s deer still retain the memories of the acoustic and visual cues of their ancestral predators in spite of the long term isolation from natural habitat.     

Antler size and fluctuating asymmetry in red deer (Cervus elaphus) stags and probability of becoming a harem holder in rut

Red deer hinds play a significant role in selecting stags for mating. We tested the hypotheses that in red deer ( Cervus elaphus ) the probability of becoming a harem holder (and hence achieving reproductive success) occurs in stags bearing larger, branched antlers and showing low fluctuating asymmetry (FA). Eleven antler characteristics were measured; absolute and relative FA were calculated on 51 cast antler sets from 19 individually recognized stags. Probability of becoming a harem holder (PBHH) was originally analysed separately, i.e. for antler size and FA of each antler characteristic and calculated factors for both antler size and FA. If analysed separately, large antler size and low relative but high absolute FA increased PBHH. When we combined antler size and FA of antler characteristics in one model using antler size and FA factors, however, PBHH and achieving reproductive success were mainly dependent on increasing antler size and enhanced antler branching rather than on FA. We conclude that in contrast to antler size, FA is unlikely to play any significant role in sexual selection as an indicator of individual quality.  © 2006 The Linnean Society of London, Biological Journal of the Linnean Society , 2006, 87 , 59–68.     

Behavioral estimates of male mating success tested by DNA fingerprinting in a polygynous mammal

We used DNA fingerprinting to determine paternity of 80 calvesborn into the individually monitored population of red deer(Cervus elaphus) on the Isle of Rum, Scotland. Using the paternityinformation, we investigated the assumptions and predictionsof behavioral estimates of male mating success, on which previousstudies in this population have relied. Over an 11- day intervalin the rut centered on a female's estimated date of conception,the probability that a male fathers a calf is closely relatedto the number of days he holds the female in his harem, increasingfrom 0.12 for 1 day to 1.0 for 6 days or more. We compared threemethods for estimating the reproductive success of individualmales from field observations of harem membership with truesuccess revealed by DNA fingerprinting. All three methods accuratelyidentified the relative success of individual males but werepoor predictors of absolute success: the behavioral methodsunderestimate the true success of successful males and overestimatethe success of many males who, in fact, fail to father any calves.In consequence, variance in male mating success is greater thanprevious behavioral estimates for this population suggested.Both harem membership data and observations of mating and otherestrous behavior can be used to identify males most likely tofather a specific calf.     

Estimating Neospora caninum prevalence in wildlife populations using Bayesian inference

Prevalence of disease in wildlife populations, which is necessary for developing disease models and conducting epidemiologic analyses, is often understudied. Laboratory tests used to screen for diseases in wildlife populations often are validated only for domestic animals. Consequently, the use of these tests for wildlife populations may lead to inaccurate estimates of disease prevalence. We demonstrate the use of Bayesian latent class analysis (LCA) in determining the specificity and sensitivity of a competitive enzyme‐linked immunosorbent assay (cELISA; VMRD^®, Inc.) serologic test used to identify exposure to Neospora caninum (hereafter N. caninum) in three wildlife populations in southeastern Ohio, USA. True prevalence of N. caninum exposure in these populations was estimated to range from 0.1% to 3.1% in American bison (Bison bison), 51.0% to 53.8% in Père David's deer (Elaphurus davidianus), and 40.0% to 45.9% in white‐tailed deer (Odocoileus virginianus). The accuracy of the cELISA in American bison and Père David's deer was estimated to be close to the 96% sensitivity and 99% specificity reported by the manufacturer. Sensitivity in white‐tailed deer, however, ranged from 78.9% to 99.9%. Apparent prevalence of N. caninum from the test results is not equal to the true prevalence in white‐tailed deer and Père David's deer populations. Even when these species inhabit the same community, the true prevalence in the two deer populations differed from the true prevalence in the American bison population. Variances in prevalence for some species suggest differences in the epidemiology of N. caninum for these colocated populations. Bayesian LCA methods could be used as in this example to overcome some of the constraints on validating tests in wildlife species. The ability to accurately evaluate disease status and prevalence in a population improves our understanding of the epidemiology of multihost pathogen systems at the community level.     

麋鹿沧桑命运与未来保护展望

麋鹿作为中国特有的鹿科动物,经历129年的保护努力,种群数量恢复到10000多头。因近亲繁殖严重,表面上看已无灭绝危险,但仍存在巨大隐忧。通过对麋鹿种群变迁、灭绝、重引入、恢复现状及四大种群(乌邦寺、南海子、大丰、石首野化种群)的发展趋势进行追踪分析,探究近千年来困扰麋鹿种群发展壮大的多重因素,提出种群保护与栖息地保护并重、强化疫病监测等保护对策,为麋鹿及其它大型陆生濒危哺乳动物突破种群发展瓶颈提供借鉴。     

Effects of season on the secretion of LH and testosterone in intact and castrated red deer stags (Cervus elaphus).

At 2--4 monthly intervals during the year blood samples were collected every 15 min for 6 h from 2 intact and 3 castrated red deer stags to study the relationship between season and the secretion of LH and testosterone. In the intact stags plasma LH and testosterone concentrations changed during the year; the LH levels were maximal in August during the phase of testicular redevelopment, while the testosterone levels were maximal from September to November coinciding with the time of peak testicular activity and the mating season. The castrated stags had higher plasma levels of LH than the intact stags at all times of the year, and there was no clear seasonal cycle in LH levels in these animals.