Nitrogenous constituents in nest soils of harvester ants (messov ebeninus) and their influence on plant growth

Abstract

As a corollary of a detailed study on the ecology of the Harvester ants in soils of semi‐arid natural pastures, samples from a loessial Arid Brown soil were analyzed for the content of nitrogenous constituents (humic compounds, amino acids, nitrates, ammonia) as well as phenols and carbohydrates and the nutrient status of the soil.

While there was a significant increase in fulvic and humic acids in the ant nests, the simultaneous decrease in amino acids ‐ in relation to the surrounding soil ‐ indicates that the humic substances have been synthesized from amino acids and the abundantly present phenols and possibly carbohydrates.

The much higher concentration of nitrogen compounds in the ant mounds supports the idea that the soil mixing activity of the Harvester ants enhances microbiological processes and in turn the fertility of the mounds, as evident in the better growth of the pasture plants.     

内蒙古达赉湖西岸地区大鵟巢穴特征和巢址选择

2010年和2011年3月-6月,对内蒙古达赉湖国家级保护区达赉湖西岸地区大鵟(Buteo hemilasius)的巢穴结构和巢址选择因子进行了调查研究.采用野外观察和样方法定位了13个大鵟巢址,并对巢址样方的20个生态因子进行测量,运用主成分分析法对影响大鵟巢址选择的主要因子进行了分析.测量显示,大鵟巢穴的基本结构特征为:外径(94.7+4.2) cm;巢高度(46.1±2.7) cm;内径(24.8±1.5)cm;巢深(14.0±+0.9)cm.生境因子分析结果表明,达赉湖西岸地区大鵟的巢集中分布在湖岸或水塘附近的悬崖,营巢点坡度为15°-45°之间的阳坡或半阳坡;隐蔽度高于20％;草本密度大于5株/m2;植被均高大于30cm;巢距悬崖上部距离2-5m;距水源l00m以内;距居民点距离大于lkm;距草原道路的距离大于0.5km;而对于物种丰富度没有特殊要求.主成分分析显示,影响大鵟巢址选择的主要因子有3个,依次为:隐蔽性因子(主要包括巢址区域的植物特征和地形特征)、干扰因子和食物因子.各主成分中,相对系数绝对值最高的变量依次是:植被盖度、距居民点距离、巢的高度和距草原道路距离.     

Breeding density of the southern ground hornbill,Bucorvus leadbeateri,in the communal areas surrounding the Matobo National Park,Zimbabwe

The southern ground hornbill, Bucorvus leadbeateri, is on the IUCN Red List of Threatened Species as a ‘Vulnerable’ species with a decreasing population. Despite a myriad of threats, including loss of nesting sites, accidental poisoning and persecution, there has been no detailed study of the southern ground hornbill in Zimbabwe. We collected data on nest sites and usage for 42 nests over three breeding seasons in the communal areas surrounding the Matobo National Park. For the active nests in the breeding seasons of 2008/9 and 2009/10 the mean nearest neighbour distances were 4.41 km and 3.53 km, respectively. Most nests were found in granite crevices (67%) while the remainder were found in five different tree species. Most nests (90%) were in areas of subsistence crop farming, the remainder (10%) were found in forests and open savannas. The high breeding density of the southern ground hornbill in the communal areas surrounding the Matobo National Park in Zimbabwe could be attributed in part to traditional Ndebele culture which, for the most part, protects this species. Food also appears to be relatively abundant under communal farming conditions.     

南京裂爪螨丝膜数量消长及空间格局时序动态

林间调查分析结果表明：①南京裂爪螨丝膜数量消长与该螨种群一致，在年周期中有2个高峰期，分别是3月和9—11月，4—8月处于较底的水平；②丝膜数量与气温呈极显著相关(r＝-0．6187)；②一年中大多数时期南京裂爪螨丝膜呈聚集分布，仅5—8月呈均匀分布或接近于均匀分布，并具有明显的高度聚集分布—均匀分布—低度聚集分布—高度聚集分布周期；④丝膜的分布C值与气温及降雨量呈显著相关(r＝—0．5403，—0．4530)。     

稠李巢蛾丝巢和幼虫空间分布型的研究

稠李巢蛾是一种重要的食叶害虫，主要危害稠李、苹果、卫矛、樱桃等植物。Cassie指标、扩散系数、丛生指数和M*/M的计算结果表明：稠李巢蛾丝巢和幼虫的空间分布格局为聚集分布，聚集的基本单位为个体群；丝巢在树冠上的分布格局为聚集分布型，幼虫在丝巢中的分布格局为聚集分布型，聚集的程度不高，并有向随机分布变化的趋势。     

不同繁殖条件对虎皮鱼受精卵数量的影响

虎皮鱼是一种常见的小型鲤科观赏鱼,其繁殖条件与大多鲤科鱼类没有很大区别。一般条件下虎皮鱼受精卵的数量并不可观,满足不了市场的需求。对比不同繁殖条件下虎皮鱼产卵的数量,结果表明:鱼巢情况和放置顺序都会导致受精卵数量的明显差异,确定了放置鱼网和先放雌鱼相结合为最优条件,这对节约成本、指导生产实践和争取更大的经济效益有着十分重要的现实意义。     

模拟鸟巢式体育场对高羊茅草坪夏季生长的影响

通过模拟鸟巢式体育场环形结构来研究其对场内草坪草生长的影响,于2006年和2007年夏季分别测定了模拟鸟巢式体育场内外的温度差异及其对高羊茅Festuca arundinacea草坪的形态指标和生理指标的影响。结果表明：模拟鸟巢式体育场内的温度明显高于场外,夏季最高日气温场内比场外分别高出4.5和5.2 ℃,冠层温度分别高出6.2和5.8 ℃,10 cm处地温分别高出2.7和2.6 ℃。场内温度的增高严重影响了高羊茅的生长,场内草坪草的生长量和目测质量分别从7月20/21日和7月23/24日起均显著低于场外对照,目测质量在8月8/9日下降到可接受草坪质量(6.0)以下;场内草坪草叶片的叶绿素含量从7月28/29日起显著低于场外对照,但叶片的相对电导率则从8月6日起显著高于场外对照,叶片内的丙二醛含量则有一半左右的时间显著高于场外对照。表明由鸟巢式体育场环形结构所造成的逆境严重抑制了场内草坪草的生长。     

南美牛鹂宿主的反寄生防御行为(英文)

牛鹂(Molothrus属,拟鹂科)是一个单起源的类群,包括现存的5种寄生性繁殖鸟类。啸声牛鹂(M.rufoaxillaris)、巨牛鹂(M.oryzivorus)和紫辉牛鹂(M.bonariensis)主要分布在南美。其中,啸声牛鹂与紫辉牛鹂分别代表较古老和最近进化的两个支系,因此有着各自不同的与宿主协同进化的历史。本文研究了紫辉牛鹂的宿主莺鹪鹩(Troglodytes aedon)的拒卵行为,同时综述了以上3种牛鹂的不同宿主的反寄生防御行为。3种牛鹂的宿主均能识别和拒绝非模拟的寄生卵,其中巨牛鹂和紫辉牛鹂的大部分宿主用嘴叼卵,而啸声牛鹂的主要宿主栗翅牛鹂(Agelaioides badius)则用脚扔掉寄生卵。比紫辉牛鹂小的宿主,在遭遇寄生时则不扔卵,也不弃巢。有些宿主比另一些宿主种类对寄生的牛鹂更具有攻击行为。啸声牛鹂的宿主还能够识别非模拟的寄生雏鸟。我们的结果说明,尽管与牛鹂协同进化的历史不同,大部分牛鹂的宿主已经进化出不同类型的反寄生防御对策。     

Reproduction of Labeo umbratus (Pisces,Cyprinidae) in Wuras Dam,a shallow,turbid impoundments

Female Labeo umbratus reach sexual maturity at a larger size than males and dominate the population in fish over 450 mm in length. The gonads are large (up to 20% of total body mass) and they have a high fecundity which increases linearly with an increase in body mass. Successful spawning is dependent on suitable floods during the spawning season which extends from November to March or April. Spawning apparently occurred in the impoundment. All females did not spawn simultaneously and evidence suggests that individuals might spawn more than once during a particular season.     

红掌胶胞炭疽菌的分子检测

 胶胞炭疽菌是引起红掌炭疽病的病原菌。根据GenBank中炭疽属不同种的ITS序列差异,设计了胶胞炭疽菌的特异性引物E1/E2,由此建立的PCR检测体系可以从38个胶胞炭疽菌菌株中扩增得到329 bp的特异性条带,而扩增其它近似或相关菌株时没有相应的特异性条带。该检测体系对胶胞炭疽菌基因组DNA的扩增灵敏度达到10 pg。将引物E1/E2与ITS区通用引物进行套式PCR扩增后,检测灵敏度至少提高10 000倍。当土中胶胞炭疽菌分生孢子达到200个/g土时可检测出。进一步利用此检测体系对携带病原菌的灌溉水、发病组织进行检测,均能快速稳定地检测出病原菌。