圈养猞猁多雄交配雄性的成功繁殖

研究了笼养猞猁多雄交配的结果以及雄性的成功繁殖。雄兽与发情雌兽随机配对,其繁殖成功(所产生的后代数量)不取决于与雌兽的交配顺序、交配次数与持续时间、遗传关系或雄兽的行为特征,但似乎取决于精子质量,特别是取决于形态正常精子的百分率。繁殖成功的雄兽比其竞争对手具有更多的形态正常的精子,似乎更能成功地诱发交配雌兽的排卵。证实了4窝(占总窝数的20%)幼兽的双重父亲身份。在所有情形下, 2雄1雌的交配间隔为24h 。     

高龄大熊猫繁殖的饲养研究

通过营造冬暖、夏凉、通风良好的洞穴兽舍,改造饲料营养,采用先粗后精、少量勤添的饲喂方法,增加活动量,接受阳光照射,让雌、雄大熊猫有较多直接或间接接触的机会和增强其信息交流等技术管理措施,使高龄大熊猫“新星”雌兽20岁受配产仔,同时一胎产2仔,高龄大熊猫雄兽“新8号”25岁龄自然交配,并在25～27岁龄连年自然配种,使受配雌兽怀孕产仔,创下了圈养大熊猫雌、雄兽高龄繁殖的新记录。     

大熊猫父权认定的DNA指纹图分析

本文以大熊猫１４胎次,１９只幼子,２５只次雄兽个体的被毛、血液、精液、福尔马林固定的器官组织、粪和尿等为材料作了ＤＮＡ指纹检测。（１）同一大熊猫个体的被毛、血液、精液、固定组织及粪、尿检测,其ＤＮＡ指纹图完全一致。（２）大熊猫无论１雄配１雌,２雄配１雌、３雄配１雌,甚至４雄配１雌,受配雌兽所产任一子代个体的ＤＮＡ指纹图谱中,杂交谱带均分别来自父亲、母亲,以及父母双亲,没有新带出现,无误地认定了１９只幼子的真正父亲,排除了非父。（３）３只大熊猫雌兽的５个双胞胎,即１０只子代个体的ＤＮＡ指纹图谱,均具有个体特异性,表明为异卵双生,其中４个双生子为异卵异父双生,为大熊猫在一个发情期不一定同时排卵提供了佐证,亦为圈养雌兽发情高峰期用多只雄兽作多次配种或输精,能提高受孕产仔率提供了理论和应用依据。（４）ＤＮＡ指纹技术用于大熊猫的亲子鉴定,灵敏稳定,准确无误,为圈养大熊猫多雄配１雌,增加受配雌兽的受孕机会,提高产子率提供了鉴别手段,解除了多雄配１雌,其子代的父亲是谁的后顾之忧。（５）应用寡核苷酸探针ＬＺＦ－１作大熊猫亲子鉴定较ＪＨ１２．６探针更为适合     

野生小型兽繁殖的调查方法

在研究野生小型兽的繁殖中,详细比较雌雄两性在外形上的差别、性成熟时间、年产窝数、每窝仔数、繁殖期(交配、妊娠、哺乳)是很重要的。剖检雌兽卵巢、输卵管、子宫发育状况,以及雄兽睾丸体积和是否下降到阴囊,副睾大小及其是否有成熟精子,记录体重、体长、尾长、后足长和耳长等项,保留头骨作年龄鉴定,有了这些原始资料,经统计分析,才能对其繁殖强度作正确推断。作者依据多年的野外工作经验,初步总结如下。一、雌兽繁殖的研究方法(一)检查乳头和乳腺乳头小,隐藏毛中,难发现,挤压乳头基部时,没有乳汁外流,表示无哺乳;乳头大而显见,周围无毛或…     

雄性大熊猫配种期的性行为观察

本文通过对西安动物园大熊猫雄兽弯弯于１９８６－１９９１年与３只雌兽相继本交,爬跨３３次,交配２１次,产５胎,获６仔,育成６仔的性行为观察。获得雄兽在发情季节的爬跨与酱姿式,交配的时间与叫声,配种期的食量下降与活动量变化等资料。     

大熊猫父权认定的DNA指纹圈分析

本文以大熊猫１４胎次,１９只幼子,２５只次雄兽个体的被毛、血液、精液、福尔马楷固定的器官组织、粪和尿等为材料作了ＤＮＡ指纹检测,（１）同一大熊猫个体的被毛、血液、精液、固定组织及粪、尿检测,其ＤＮＡ指纹图完全一致。（２）大熊猫无论１雄配１雌,２雄配１雌,３雄配１雌,甚至４雄配１雌,受配雌兽产任一子代个体的ＮＤＡ指纹图谱中,杂交谱带均分别来自父亲、母亲,以及父母双亲,没有亲带出现,无误地认定了１９只     

种群密度调查——标志重捕法的模拟实验

种群密度是生物种群最基本的数量特征．标志重捕法是估算动物种群密度的常用方法．在野生动物保护、农林业害虫、害兽的监控与防治、渔业资源的评估、利用与保护上有重要应用。鉴于在中学现有条件下。对兽鸟鱼虫进行实际的标志重捕实验难以展开,在新课程教学实践中,我们反复研究了几种版本中标志重捕法的说明,设计并实施了如下标志重捕法的模拟实验,教学效果反馈很好。     

马来穿山甲的种群结构、繁殖力及仔兽出生记录

根据鳞甲、毛发、爪的磨损程度以及母幼行为关系和体重大小,对2011年6月查获的87头马来穿山甲(Manis javanica)种群结构进行了分析,幼年、亚成年、成年、老年组的比例和个体数分别为3.45%(3头)、25.29%(22头)、36.78%(32头)和34.48%(27头)。年龄结构呈倒金字塔型,属快速下降型种群。种群性比(♀︰♂)为1︰1.42(36︰51),雌性个体少。在各年龄组中,成年组雌性比例最小(28.13%)。每胎1仔,体重最小的孕兽只有1.95 kg,为亚成年个体。雌兽群体怀孕率为36.10%,成年雌兽的怀孕率最高(77.78%)。6只新生仔兽体重(143.3±6.67)g(120~170 g)、体长(14.7±0.29)cm(14.8~15.4 cm)、尾长(10.1±0.24)cm(9.5~11.2 cm)。该马来穿山甲种群结构的状况,可能预示野生种群已处于较为严重的不健康状态。     

山口红树林保护区圆尾蝎鲎种群动态

鲎是珍贵的海洋“活化石”生物。本研究于2014—2020年在广西北海山口红树林生态自然保护区开展圆尾蝎鲎(Carcinoscorpius rotundicauda)种群动态调查。总计观察到圆尾蝎鲎990只,种群数量呈现逐年下降趋势,其中第6个调查年相比第1个调查年下降94.60%,表明圆尾蝎鲎资源保护已势在必行;雄鲎占80.28%,雌鲎占17.50%。圆尾蝎鲎种群动态呈现显著季节规律性,种群数量与温度及北风和南风风向状态值(0和4)呈显著正相关,显示出滨海风向标生物特征。本研究揭示了圆尾蝎鲎种群动态及其影响因素,为保护区鲎资源保护提供参考依据。     

令人费解的角

500万年前曾发生过这样的事,在地中海的一个岩石小岛上,一群看起来既像鹿又像羚羊的动物正在吃草和灌木叶。但这群动物与鹿或羚羊又明显不同。它们的头骨顶部有五个角,嘴巴两边还伸出两个长獠牙。突然一只雄兽停止进食,警惕地抬起头,焦虑地嗅嗅空气、顿着足。雌兽和幼兽也都变得警觉起来,它们挤在一起,竖起耳朵。另一只雄兽——年青的竞争者从草丛中冲出来,向兽群的首领挑战。在这场显示力量的表演中,年长的雄兽转动身躯、侧着身子对着挑衅者,炫耀它的巨大。它左右摇摆着头,然后用角直着刺向对方。这个首领用摆着的姿势表明自已是兽群利益非凡的主宰和捍卫者。然后,这两只动物对抗性的朝     

Effects of Fertility Control on Behavior and Disease Transmission in Brushtail Possums

Abstract: Fertility control is currently under development for the control of brushtail possums (Trichosurus vulpecula), one of New Zealand's most serious vertebrate pests. Despite intensive research into various methods for achieving infertility, including immunocon-traception and disrupting endocrine control of reproduction, researchers know little about the potential effects of these methods on the behavior of wild possums. We assessed the effects of surgically imposed sterility, either to block fertilization (tubal ligation) or to disrupt endocrine control of fertility (gonadectomy), by using radiotelemetry on the movement patterns and site fidelity of wild brushtail possums. In addition, we assessed the effect of gonadectomy on the transmission rate of a commonly occurring, directly transmitted pathogen in possums, Leptospira interrogans serovar balcanica (hereafter L. balcanica), to determine the effect of any behavioral changes on possum contact rates. Both tubal ligation and gonadectomy of females did not appear to have any appreciable effect on behavior, with sterilized females having space-use patterns and fidelity to seasonal breeding ranges similar to those of fertile females. However, gonadectomy of male possums resulted in a significant reduction of 42% and 47% in the 95% and 70% isopleth seasonal breeding ranges, respectively. Furthermore, the transmission rate of L. balcanica in gonadectomized male and female possums was reduced by 88% and 63%, respectively, compared with that in fertile male and female possums. Overall, these results suggest that fertility control, either by blocking fertilization (e.g., immunocontraception) or by disrupting endocrine control of reproduction (e.g., gonadotropin-releasing hormone vaccines), is unlikely to have an impact on social organization and behavior of brushtail possums in ways that may compromise the efficacy of fertility control for reducing population density. However, the reduction in the transmission rate of L. balcanica indicates that fertility control that interferes with endocrine control of reproduction is likely to reduce the contact rate between possums. This could have implications for the control of other wildlife diseases requiring direct contact for transmission.     

Evolutionary assembly of island faunas reverses the classic island–mainland richness difference in Anolis lizards

Aim Islands are widely considered to be species depauperate relative to mainlands but, somewhat paradoxically, are also host to many striking adaptive radiations. Here, focusing on Anolis lizards, we investigate if cladogenetic processes can reconcile these observations by determining if in situ speciation can reduce, or even reverse, the classical island–mainland richness discrepancy. Location Caribbean islands and the Neotropical mainland. Methods We constructed range maps for 203 mainland anoles from museum records and evaluated whether geographical area could account for differences in species richness between island and mainland anole faunas. We compared the island species–area relationship with total mainland anole diversity and with the richness of island‐sized mainland areas. We evaluated the role of climate in the observed differences by using Bayesian model averaging to predict island richness based on the mainland climate–richness relationship. Lastly, we used a published phylogeny and stochastic mapping of ancestral states to determine if speciation rate was greater on islands, after accounting for differences in geographical area. Results Islands dominated by in situ speciation had, on average, significantly more species than similarly sized mainland regions, but islands where in situ speciation has not occurred were species depauperate relative to mainland areas. Results were similar at the scale of the entire mainland, although marginally non‐significant. These findings held even after accounting for climate. Speciation has not been faster on islands; instead, when extinction was assumed to be low, speciation rate varied consistently with geographical area. When extinction was high, there was some evidence that mainland speciation was faster than expected based on area. Main conclusions Our results indicate that evolutionary assembly of island faunas can reverse the general pattern of reduced species richness on islands relative to mainlands.     

Predicting the efficacy of virally-vectored immunocontraception for managing rabbits

Models were developed to examine the efficacy of immunocontraception as an alternative control method for pest rabbits. The models simulated the dynamics of rabbit populations structured by age and sex, and helped identify the benefits of an integrated pest management strategy that includes immunocontraception and lethal control. Virally vectored immunocontraception (VVIC) using a sterilising myxoma virus reduced the long-term density of rabbits. However, our models indicated that the efficacy of VVIC is much less than using lethal methods of management currently available (e.g. poison baiting). Nevertheless, in areas where lethal control cannot be used, a sterilising strain of myxoma may be a useful tool for rabbit management, but competition between sterilising and non-sterilising strains will reduce the overall efficacy of VVIC. Regardless of how effective poisoning is at reducing rabbit numbers, the benefits in terms of increased pasture availability and wool growth may not outweigh the costs incurred by a poisoning campaign. In our analysis the most cost-effective control remains natural epizootics of myxomatosis since they do not incur a cost to the landholder. There is likely to be some small additional benefit to releasing a sterilising strain of myxoma, and landholders may need to supplement this with baiting under some circumstances (e.g. above average breeding season or areas where myxomatosis occur infrequently).     

Characteristics and behaviour of brushtail possums initially moving into a depopulated area

Brushtail possums are controlled extensively in New Zealand because they are a livestock disease vector and have an impact on native biodiversity. Reinvasion of controlled areas and subsequent population recovery is a significant management problem but little attention has been paid to what influences the settlement of possums in depopulated areas. To address this gap we trapped possums out of an area of about 24?ha in native podocarp–hardwood forest and studied reinvasion and settlement in the central c. 14?ha over 22 months. Most new possums were young males, but adults were also trapped. Many of the new possums caught on the study site post-depopulation did not settle there, most likely because they continued to disperse, but some may have returned to their ranges nearby or were residents with a very low probability of capture. This finding highlights the need for better information about the origins and settlement of possums in depopulated areas to improve management of population recovery and long-term sustained control of possums.     

The island-mainland species turnover relationship

Many oceanic islands are notable for their high endemism, suggesting that islands may promote unique assembly processes. However, mainland assemblages sometimes harbour comparable levels of endemism, suggesting that island biotas may not be as unique as is often assumed. Here, we test the uniqueness of island biotic assembly by comparing the rate of species turnover among islands and the mainland, after accounting for distance decay and environmental gradients. We modelled species turnover as a function of geographical and environmental distance for mainland (M-M) communities of Anolis lizards and Terrarana frogs, two clades that have diversified extensively on Caribbean islands and the mainland Neotropics. We compared mainland-island (M-I) and island-island (I-I) species turnover with predictions of the M-M model. If island assembly is not unique, then the M-M model should successfully predict M-I and I-I turnover, given geographical and environmental distance. We found that M-I turnover and, to a lesser extent, I-I turnover were significantly higher than predicted for both clades. Thus, in the first quantitative comparison of mainland-island species turnover, we confirm the long-held but untested assumption that island assemblages accumulate biodiversity differently than their mainland counterparts.     

Responses of kukupa (

The kukupa or New Zealand pigeon (Hemiphaga novaeseelandiae) is gradually declining on the New Zealand mainland, due mostly to predation by introduced pest mammals including ship rats (Rattus rattus) and brushtail possums (Trichosurus vulpecula). We report on a co-operative project between Maori landowners, the Department of Conservation, and Manaaki Whenua–Landcare Research researchers to restore a Northland kukupa population and to examine kukupa nesting success in relation to pest abundance. Ship rats and possums were targeted by trapping and poisoning throughout Motatau Forest (350 ha) from 1997 to 1999; only possums were targeted in 2000. All 13 kukupa nests located before pest control started in late 1997 failed at the egg stage, but all seven nests located in 1998–99 successfully fledged young when trapping and tracking indices of possums and ship rats were less than 4%. After pest control, counts of kukupa and some other bird species increased at Motatau compared with counts in a nearby non-treatment block, suggesting numbers of adult kukupa can be increased in small forest areas by intensive pest control. This increase is due at least partly to increased nest success. Evidence from time-lapse video cameras, sign remaining at nests, and nest success rates under different pest control regimes suggest both ship rats and possums are important predators at kukupa nests.     

If hippopotamuses cannot swim,how did they colonize islands?

Owing to their aquatic lifestyle, hippopotamuses are normally believed to have reached islands by swimming. Yet, some studies suggest they cannot swim due to their relatively high density. If so, this raises the question of how hippopotamuses would have reached some islands. Their immigration into the British Isles, Sicily, Malta, Zanzibar and Mafia can be accounted for, because these islands sit on continental shelves and were often linked to the mainland during the Pleistocene glacio‐eustatic sea‐level falls. In contrast, their occurrence in Crete, Cyprus and Madagascar would be more difficult to explain. Available geological evidence does not seem to rule out that the latter islands might have been connected with the nearest mainland areas in very recent times. This study intends to consider possibilities about how hippopotamuses reached islands and to show that more effective collaboration is required among specialists involved with the study of insular evolution, colonization and speciation.     

Predicting community structure in snakes on Eastern Nearctic islands using ecological neutral theory and phylogenetic methods

Predicting species presence and richness on islands is important for understanding the origins of communities and how likely it is that species will disperse and resist extinction. The equilibrium theory of island biogeography (ETIB) and, as a simple model of sampling abundances, the unified neutral theory of biodiversity (UNTB), predict that in situations where mainland to island migration is high, species-abundance relationships explain the presence of taxa on islands. Thus, more abundant mainland species should have a higher probability of occurring on adjacent islands. In contrast to UNTB, if certain groups have traits that permit them to disperse to islands better than other taxa, then phylogeny may be more predictive of which taxa will occur on islands. Taking surveys of 54 island snake communities in the Eastern Nearctic along with mainland communities that have abundance data for each species, we use phylogenetic assembly methods and UNTB estimates to predict island communities. Species richness is predicted by island area, whereas turnover from the mainland to island communities is random with respect to phylogeny. Community structure appears to be ecologically neutral and abundance on the mainland is the best predictor of presence on islands. With regard to young and proximate islands, where allopatric or cladogenetic speciation is not a factor, we find that simple neutral models following UNTB and ETIB predict the structure of island communities.     

Island incidence and mainland population density: mammals from Mediterranean islands

Abstract. The reasons why some species are resistant to extinction or are better invaders of islands than others remain unexplained. In this study, we test the hypothesis that mammals living on the mainland at higher density than predicted by the density/body mass relationship have a much greater chance to colonize a small island successfully, and/or that they are less likely to become extinct when living on small islands. For this, we used data compiled on mammals from a number of Mediterranean islands. We show a nested pattern for mammals on western Mediterranean islands, which suggests that the distribution of mammals on these islands is not the result of a random process. Using two comparative methods, we show that mammal density on the mainland, corrected for body mass, is negatively correlated with island size. Mammals with a high density compared to the density/mass relationship are the best invaders and/or probably have less chance of going extinct on small islands when population size is small.     

Egg predation in forest bird communities on islands and mainland

Summary To examine if differences in egg predation rates could explain differences in bird community composition, egg predation was studied in two years on small islands in a South Swedish lake and on the nearby mainland using both natural and artificial nests.In plots with similar vegetation, the combined density of ground- and tree-nesting bird species did not differ between the islands and the mainland. Egg predation rates were similar on islands and the mainland for natural Turdus nests in two years, and for artificial Turdus and Phylloscopus nests. Unmarked and unvisited experimental nests suffered similar rate of egg predation as marked and visited nests. Egg predation rates were higher on natural nests when artificial nests were also put out, increasing the total nest density. Initial egg predation rates in artificial nests were also higher than later when nest density had decreased by 75%.The egg predators involved differed for artificial Phylloscopus nests between the islands and the mainland. Small mammals were apparently responsible for 29% of the predation on the mainland, but none on the islands. Artificial Turdus nests near crow nests suffered from a higher egg predation rate than nests further away from crow nests. Daily survival rates of Turdus nests increased from the laying to the incubation and further to the fledging state.Egg predation can not explain differences in bird community composition between islands and mainland in the present case.