人工巢箱繁殖鸟类主要巢捕食者及其影响因素

巢捕食是影响鸟类繁殖成功率的一个重要因素,也是鸟类繁殖生态研究中的一项重要内容。确定鸟类的主要巢捕食者及影响巢捕食的因素对于了解鸟类繁殖成功率、种群增长率及种群数量等具有重要意义。2009—2012年,对辽宁仙人洞国家级自然保护区人工巢箱中繁殖的杂色山雀(Parus varius)、沼泽山雀(P.palustris)、大山雀(P.major)和白眉姬鹟(Ficedula zanthopygia)四种鸟类的巢捕食率及影响巢捕食的因素进行了研究。研究共记录到238个繁殖巢(杂色山雀74巢、沼泽山雀21巢、大山雀118巢、白眉姬鹟25巢),其中35巢被捕食,捕食率为14.7%,雏鸟期被捕食占91.4%。巢捕食率在4种鸟类之间无差异(x~2=0.429,df=3,P=0.934)。以锦蛇(Elaphe spp.)为代表的蛇类是该地区小型森林洞巣鸟类繁殖期主要捕食者,占总捕食率的94.3%。对影响巢捕食的22个相关因子进行二元逻辑斯蒂回归分析发现,坡度、地面裸露率、草本盖度对巢捕食具有显著性影响;出雏时间、坡位、距碎石块距离对巢捕食的影响接近显著水平;而巢高、树粗、巢箱年龄、窝卵数、距路距离等对巢捕食无显著影响。因此,处于坡度较陡,坡位较高,草本覆盖率较高,地面裸露率较低,距碎石块距离较近,且出雏时间较晚的巢更容易被捕食。     

杂色山雀的反盗食贮食策略

盗食现象在贮食动物中非常普遍,种内竞争者或种间竞争者的盗食是贮藏食物丢失的主要原因之一,同时也是贮食动物贮食行为不断进化的重要选择压力,开展反盗食贮食策略的研究有助于阐释贮食行为进化的原因和对贮食鸟类的保护。杂色山雀(Parus varius)秋季有明显的贮食行为,贮食方式为分散贮食。通过人为投食的方法,以投食点为中心,根据贮食点距投食点距离远近设定了被盗高风险区、被盗中风险区和被盗低风险区,研究杂色山雀个体在无潜在盗食者和有潜在盗食者的情况下,在上述3个风险区贮食比例的变化,探讨杂色山雀个体基于自身以及周围环境条件,在权衡取食及贮藏过程中时间及能量的花费和收益后,其反盗食贮食策略的选择。40只杂色山雀个体贮食策略的统计结果表明,不论潜在盗食者出现与否,杂色山雀个体贮食的总体趋势大致相同,即主要将食物贮藏在中风险区,而高风险区和低风险区贮食比例较低;比较种间和种内潜在盗食者出现的情况下与无潜在盗食者时,杂色山雀个体在各贮食风险区的贮食策略:种间及种内潜在盗食者的出现,都会引起被盗高风险区贮食比例降低(种间潜在盗食者:F=3.174,P0.05;种内潜在盗食者:F=90.475,P0.05),低风险区贮食比例上升(种间潜在盗食者:F=220.440,P0.05;种内潜在盗食者:F=15.651,P0.05);但种间潜在盗食者出现时,杂色山雀个体在被盗中风险区的贮食比例降低(F=143.749,P0.05),而种内潜在盗食者出现时,杂色山雀个体在被盗中风险区贮食比例不变(F=0.776,P0.05),即杂色山雀个体对种间潜在盗食者的出现更加敏感,防范盗食的投入更大。此外,分别比较无潜在盗食者、有种间潜在盗食者和有种内潜在盗食者存在的情况下,雌雄杂色山雀个体在各贮食风险区的反盗食贮食策略,发现其结果也明显不同。无潜在盗食者和种内潜在盗食者出现时,雄性杂色山雀为预防灾难性盗食发生而付出的努力较雌性个体高(无潜在盗食者:高风险区t=4.962,df=16.546,P0.05;中风险区t=﹣0.890,df=29.255,P0.05;低风险区t=﹣2.166,df=30,P0.05。有种内潜在盗食者:高风险区t=﹣0.152,df=29,P0.05;中风险区t=2.352,df=19.568,P0.05;低风险区t=﹣2.287,df=19.563,P0.05);种间潜在盗食者出现时,雌雄杂色山雀反盗食贮食策略趋于一致(高风险区t=1.361,df=29,P0.05;中风险区t=﹣0.194,df=21.529,P0.05;低风险区t=﹣1.599,df=29,P0.05)。     

人工巢箱条件下两种山雀鸟类的同域共存机制

种间竞争会导致鸟类对自身的生存策略进行多方面调整,将多种因素结合起来分析不同鸟类的同域共存机制具有十分重要的意义.2009-2011年的3-7月,在辽宁省东部山区以悬挂人工巢箱的方法招引杂色山雀(Parus varius)和大山雀(Parus major),通过比较这两种鸟类在繁殖时间、繁殖参数和巢址选择上的差异,分析其繁殖期的栖息地选择及繁殖对策,探讨这两种鸟类同域共存的机制.结果表明,生态位的部分分离是大山雀和杂色山雀能够长期共存的基础.两者都是在繁殖期到来立即开始繁殖,均出现两次繁殖高峰,采用消减窝卵数的对策来适应环境质量的下降.对繁殖参数的分析表明,两种鸟类的繁殖对策都为k-选择,但大山雀略偏向r端,大山雀倾向高窝卵数、低繁殖成功率的繁殖策略;杂色山雀倾向低窝卵数、高繁殖成功率的繁殖策略.两种鸟类都选择在林龄较长的森林中筑巢,但是大山雀较注重巢址的安全性能,巢距地面较高,周围乔木密集;杂色山雀较为注重植被类型的选择,巢址多选择在植被多样、灌木生长茂盛的针阔混交林中,推测可能与杂色山雀的食物构成有关.     

不同性别杂色山雀血浆活性氧和超 氧化物歧化酶与繁殖成效的关系

氧化应激是指活性氧等氧化剂的产生大于抗氧化防御系统清除能力时的不平衡状态,是个体应对内外环境刺激的适应性生理机制,是衡量个体身体状况的综合性生理指标。为探究氧化应激对鸟类繁殖的预测作用,本研究测量了育雏前期(雏鸟6～8日龄)杂色山雀(Sittiparus varius)亲鸟血浆氧化应激分子活性氧和超氧化物歧化酶含量,通过巢箱监测获得了杂色山雀的繁殖参数,采用偏最小二乘回归法分析杂色山雀氧化应激对其雏鸟出飞率和繁殖成功率的预测作用。结果显示,雌性杂色山雀亲鸟血浆活性氧浓度与雏鸟出飞率(n=13,P 0.05)、繁殖成功率(n=13,P 0.01)均呈显著负相关关系,即血浆活性氧水平越低的雌性杂色山雀,其繁殖巢雏鸟出飞率和繁殖成功率越高;雌性杂色山雀亲鸟血浆超氧化物歧化酶浓度与雏鸟出飞率(n=13,P0.05)、繁殖成功率(n=13,P 0.05)无显著相关关系。本研究中这两项血浆氧化应激标记物与杂色山雀雄性亲鸟繁殖成效间均无显著的相关关系。该结果表明,杂色山雀雌性亲鸟活性氧水平对其繁殖成效具有显著的预测作用。     

不同纬度洞巢鸟类对人工巢箱的利用及差异

迄今对洞巢鸟类生活史特征的纬度变异（特别是热带洞巢鸟类的繁殖）了解还十分有限。我们于2018年3至8月,分别在海南吊罗山（热带）、河南董寨（亚热带）和河北塞罕坝（温带）的林缘地带,悬挂相同规格的人工巢箱招引洞巢鸟类繁殖,用以比较不同地理区域的洞巢鸟类对人工巢箱的利用情况及其孵化成效和繁殖成功率。野外共悬挂577个木制巢箱,3个研究地的利用率在海南吊罗山为最低（32.6%）,河南董寨最高（92.0%）。3个地点均有大山雀（Parus cinereus）入住（占总巢数的84.3%）,其孵化成效和繁殖成功率在3个地点不存在显著差异（P > 0.05）。但在河北塞罕坝,大山雀的孵化成效（75.7%）和繁殖成功率（65.7%）显著低于同域繁殖的褐头山雀（Poecile montanus）（97.7% 和97.7%）和煤山雀（Periparus ater）（93.5%和90.3%）（P < 0.05）。研究表明,3个地理区域利用巢箱繁殖的洞巢鸟的种类、数量以及对巢箱的利用率均存在差异,但对于广布种大山雀来说,地理位置的差异并不影响其孵化成效和繁殖成功率。     

繁殖期杂色山雀应激水平的皮质酮浓度 与繁殖投入的关系

皮质酮是鸟类重要的糖皮质激素,在其适应环境变化及压力应激反应中起重要的调节作用。非应激状态时,鸟类血浆皮质酮浓度处于基线水平,当鸟类面对应激刺激时,血浆皮质酮浓度迅速升高,应激水平的皮质酮对鸟类个体生存至关重要。然而,目前繁殖季鸟类血浆应激水平的皮质酮浓度变化及其与繁殖投入关系的研究结果存在种间差异,仍需在不同的物种中进行实验研究。本研究分析了繁殖季杂色山雀（Sittiparus varius）血浆应激水平的皮质酮浓度在繁殖阶段的变化,及育雏期亲鸟血浆应激水平的皮质酮浓度与繁殖参数和亲鸟育雏投入的关系。结果显示,与求偶期相比,育雏期杂色山雀亲鸟血浆应激水平的皮质酮浓度极显著升高（P < 0.001）,雌性与雄性亲鸟之间无显著性差异（P > 0.05）;雌性与雄性亲鸟血浆应激水平的皮质酮浓度与繁殖参数、亲鸟递食投入、巢防卫行为均无显著相关性（P > 0.05）。     

吉林珲春2002～2005年鸟类环志监测报告

2002～2005年在吉林省珲春市马川子乡依力南沟开展了鸟类环志研究工作。这里为长白山低山丘陵区,是候鸟经长白山脉、乌苏里江迁徙途中重要的停歇地和食物补给站。4年共环志鸟类126种63386只,其中春季103种9761只,秋季113种53625只,隶属13目37科。春季以黄喉鸦（Emberiza elegans）为迁徙鸟类的优势种,环志2467只,占春季环志数量的25．3％;秋季以黄喉鸦、红胁蓝尾鸲（Tarsiger cyanurus）、黄眉柳莺（Phylloscopus inornatus）、大山雀（Parus major）、白眉鸦（E.tristrami）、极北柳莺（P.borealis）等6种为迁徙鸟类的优势种,累计33586只,占秋季环志数量的62．6％;通过环志研究发现,被认为是留鸟的大山雀、银喉长尾山雀（Aeghhalos caudatus）、沼泽山雀（P.palustris）、长尾雀（Uragus sibiricus）具有定期的迁徙行为。     

人工巢箱中大山雀和褐头山雀的繁殖比较

2009年3-7月,在北京小龙门森林公园悬挂人工巢箱,对大山雀(Parus major)和褐头山雀(P.montanus;)的繁殖进行比较研究.野外共悬挂100个巢箱,其中19巢(19.0%)被大山雀、11巢(11.0%)被褐头山雀进驻,总利用率为30.0%.同域繁殖的大山雀和褐头山雀在窝卵数、孵化期上有极显著差异(P＜0.01),其中大山雀的窝卵数(8.21枚±0.25枚,n=19)极显著大于褐头山雀(6.18枚±0.23枚,n=11),而褐头山雀的孵化期(14.22d±0.44d,n=10)极显著长于大山雀(13.17 d±O.83 d,n=12).两者在卵重、卵大小、出雏数、雏鸟出飞数上无显著差异(P＞0.05).大山雀的繁殖成功率(27.0%)和营巢成效(63.2%)均显著低于褐头山雀(54.5%和100%)(P＜0.01).表明大山雀可能采取高产卵数、低存活率的繁殖对策,而褐头山雀的繁殖策略则可能为低产卵数、高存活率.     

山地次生林冬季鸟类集群的初步研究

通过山地次生林两冬季鸟类集群的研究表明,集群的鸟类主要是由大山雀、沼泽山雀和普通Ｓｈｉ组成;每群个体数为７．４１－１０．６３只;据群的行为（单种群、多种集群和单独个体）分析,大多数种类是单独个体活动,冬季鸟类集群大小和组成有空间的变化。气候因子影响群的形成和行为。     

北京西山地区大山雀与其它鸟类种群种间联结分析

引入2*2列联表联结指数法,用固定样带法月连续全天定位调查数据,以森林鸟类广布种山雀科大山雀(Parus major)为目标种,研究了北京西山地区该种与留鸟、夏候鸟、冬候鸟、旅鸟的种间联结关系,结合前人关于营巢行为、取食行为、生态位等方面成果分析了产生联结的原因,首次确立了鸟类群落种间联结的研究方法。结果表明： （1）用固定样带法月连续全天定位调查,引入2*2列联表以日尺度的定性数据检验与测定联结度,与月尺度的联结频率结合起来,分析鸟类群落的种间联结是可行的;鸟类群落的种间联结具有时间与空间尺度的双重属性,鸟类群落的种间联结度不仅是鸟类群落时空结构与格局的表征,同时,反映了鸟类群落的动态性,而且,鸟类群落的种间联结对栖息的植物群落具有依赖性与关联性。 （2）日尺度上,选择χ2统计量、PCC与PC指数相结合进行种间联结检验、测度,能充分反映鸟类群落的种间联结特征,但由于鸟类的居留、繁殖、迁移等季节动态性特征,种间联结度存有不确定性。 （3）月尺度上,鸟类总体种间联结8月份为显著负联结,其余各月为显著正联结;根据PCC联结度的月联结频率,可将鸟类划分为正联结组、正负联结均较弱组、负联结组;大山雀与留鸟、夏候鸟、冬候鸟、旅鸟等不同居留型的联结关系,随着种数的减少,显著联结种对、联结度、联结复杂程度呈递减趋势。大山雀与留鸟的联结：与鸦科鸟类呈明显正联结,与同科鸟类呈正负均等的弱联结并趋于负联结,与体型较大的雉、啄木鸟、乌鸦等鸟类呈负联结。大山雀与夏候鸟的联结：与杜鹃科四声杜鹃呈正联结,与同科的黄腹山雀、鹟科的白眉姬正负联结均较弱,与莺科的黄腰柳莺、鸫科的北红尾鸲等呈负联结。大山雀与冬候鸟的联结：与岩鹨科棕眉山岩鹨的正负联结均较弱,与鸫科的斑鸫、鹀科多种鸟类呈明显的负联结。大山雀与旅鸟的联结：与莺科鸟类由正负联结均较弱到明显的负联结。     

A Unique Protease Cleavage Site Predicted in the Spike Protein of the Novel Pneumonia Coronavirus (2019-nCoV) Potentially Related to Viral Transmissibility

正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases     

Curcuminoids as inhibitors of thioredoxin reductase: A receptor based pharmacophore study with distance mapping of the active site

Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.     

Comparative morphology of the carpel in the Liliaceae: Hewardieae, Petrosavieae, and Tricyrteae

The young pistils in the melanthioid tribes, Hewardieae, Petrosavieae and Tricyrteae, are uniformly tricarpellate and syncarpous. They lack raphide idioblasts. All are multiovulate, with bitegmic ovules. The Petrosavieae are marked by the presence of septal glands and incomplete syncarpy. Tepals and stamens adhere to the ovary in the Hewardieae and the Petrosavieae but not in the Tricyrteae. Two vascular bundles occur in the stamens of the Hewartlieae and Tricyrtis latifolia. Ventral bundles in the upper part of the ovary of the Hewardieae are continuous with compound septal bundles and placental bundles in the lower part. Putative ventral bundles occur in the alternate position in the Tricyrteae and putative placental bundles in the opposite. position in the Petrosavieae. The dichtomously branched stigma in each carpel of the Tricyrteae is supplied by a bifurcated dorsal bundle.     

Enterovirus 71 3C proteolytically processes the histone H3 N-terminal tail during infection

Highlights
1. The N-terminal tail of histone H3 is specifically cleaved during EV71 infection.
2. Viral protease 3C is identified as a protease responsible for proteolytically processing the N-terminal H3 tail.
3. Our finding reveals a new epigenetic regulatory mechanism for Enterovirus 71 in virus-host interactions.     

Detection of EBV and HHV6 in the Brain Tissue of Patients with Rasmussen’s Encephalitis

Rasmussen’s encephalitis (RE) is a rare pediatric neurological disorder, and the exact etiology is not clear. Viral infection may be involved in the pathogenesis of RE, but conflicting results have reported. In this study, we evaluated the expression of both Epstein-Barr virus (EBV) and human herpes virus (HHV) 6 antigens in brain sections from 30 patients with RE and 16 control individuals by immunohistochemistry. In the RE group, EBV and HHV6 antigens were detected in 56.7% (17/30) and 50% (15/30) of individuals, respectively. In contrast, no detectable EBV and HHV6 antigen expression was found in brain tissues of the control group. The co-expression of EBV and HHV6 was detected in 20.0% (6/30) of individuals. In particular, a 4-year-old boy had a typical clinical course, including a medical history of viral encephalitis, intractable epilepsy, and hemispheric atrophy. The co-expression of EBV and HHV6 was detected in neurons and astrocytes in the brain tissue, accompanied by a high frequency of CD8⁺ T cells. Our results suggest that EBV and HHV6 infection and the activation of CD8⁺ T cells are involved in the pathogenesis of RE.     

Perinatal Vertical Transmission of Chikungunya Virus in Ruili,a Town on the Border between China and Myanmar

正Dear Editor,Chikungunya virus (CHIKV), an arbovirus in the family of Togaviridae, genus Alphavirus, is transmitted by the A.aegyptii or A. albopictus mosquito, and causes disease in humans characterized by fever, rash, and arthralgia (Silva and Dermody 2017; Suhrbier 2019). It was first reported in 1953 in Tanzania, and caused only a few outbreaks and sporadic cases in Africa and Asia in last century. However, in the epidemic in 2004, CHIKV acquired mutations that conferred enhanced transmission by the A. albopictus mosquito(Schuffenecker et al. 2006). Since then, it has successively caused outbreaks in Africa, the Indian Ocean, South East Asia, the South America, and Europe (Zeller et al. 2016).     

Development of a Novel Reverse Transcription Loop-Mediated Isothermal Amplification Method for Rapid Detection of SARS-CoV-2

In conclusion, the novel visual RT-LAMP assay is a simple, rapid, and sensitive approach for detection of SARS-CoV-2, and it is ready for application in primary care and community hospitals or health care centers, and even patients' own houses in response to the current SARS-CoV-2 epidemic because the assay does not require sophisticated equipment and skilled personnel. Furthermore, it is also ready to be used in fields for screening samples from wild animals and environments to facilitate the identification of potential intermediate hosts that mediate the cross-species transmission of SARS-CoV-2 from bats to humans.