柑橘蓟马种类和种群季节动态

2010年1～12月对建水县柑橘蓟马种类及种群季节动态进行了系统调查。结果表明,危害柑橘的蓟马有11种,西花蓟马(Frankliniella occidentalis)、花蓟马(F.intonsa)、茶黄硬蓟马(Scirtothrips dorsalis)、黄胸蓟马(Thrips hawaiiensis)、八节黄蓟马(T.flavidulus)、棕榈蓟马(T.palmi)、杜鹃蓟马(T.andrewsi)、端大蓟马(Megalurothrips distalis)、普通大蓟马(M.usitatus)、褐三鬃蓟马(Lefroyothrips lefroyi)、华简管蓟马(Haplothrips chinensis)。不同柑橘品种上蓟马种类稍有不同,其中普通大蓟马(M.usitatus)仅在脐橙采集到,而花蓟马仅在椪柑上采集到。西花蓟马(F.occidentalis)是脐橙和椪柑的共有优势种种类,采集量分别占46.28%和48.46%,主要危害的种类还有黄胸蓟马(T.hawaiiensis)、杜鹃蓟马(T.andrewsi)和棕榈蓟马(T.palmi)。在椪柑发现一种捕食性蓟马长角蓟马属(Franklinothrips sp.)。文中提供了上述12种蓟马成虫的分类检索表。柑橘蓟马雌雄虫均有发生,而且雌虫明显多于雄虫,脐橙和椪柑各蓟马种类的雌雄虫数量变动情况不同。种群数量季节动态调查结果显示,脐橙蓟马数量明显多于椪柑的蓟马数量,蓟马种群出现两次高峰期,3～4月花期和幼果期及9～10月秋梢抽发期。

大仓鼠种群季节动态的模拟模型

本文提出了一个描述大仓鼠种群增长的计算机模型,其主要结构为:其中,x_1为幼鼠,x_2为产仔雌鼠,x_3为产仔后雌鼠,x_4为越冬雌鼠。R_(i,j)为相对转移率,这里R_(12),R_(32)分别由成熟历期,生殖时滞所决定,R_(23)=1_3R_(42)决定了越冬雌鼠首次产仔的分布。d_i为相对死亡率。MF为雌性占总体的比例。L为胎仔数。BRC为繁殖钟。Δt为推进步长。采用Boxcar法模拟各发育过程。 通过对模型中各参数的估计,对1986年河北饶阳县的大仓鼠种群的实际铗捕数据进行了拟合分析,结果表明,模型能够较好地描述大仓鼠种群繁殖与增长特性。此外,对模型中各参数的重要性都作了检验,发现成熟历期,性比和胎仔数对种群繁殖与数量增长影响较大。

青海湖裸鲤寄生湟鱼棘头虫的种群季节动态研究(英文)

以在青海湖收集的寄生于青海湖裸鲤的湟鱼棘头虫（Ｅｃｈｉｎｏｒｈｙｎｃｈｕｓ ｇｙｍｎｏｃｙｐｒｉｉ）４个季节的样本研究湟鱼棘头虫种群的季节动态．结果表明：种群的平均丰度，感染强度和感染率都没有明显季节变化．这与湟鱼棘头虫温度依赖性死亡、中间宿主的季节数量动态、宿主食性的季节改变有关．湟鱼棘头虫种群在宿主种群的分布在各季度中都是聚集性的．这与宿主食性的分化及第一中间宿主（钩虾）的分布不均匀性有关．雄虫体长小于１１ ｍｍ，雌虫在５．０与２４．３ｍｍ之间．湟鱼棘头虫感染青海湖裸鲤（Ｇｙｍｎｏｃｙｐｒｉｓ ｐｒｚｅｗａｌｓｋｉｉ ｐｒｚｅｗａｌｓｋｉｉ）主要发生在夏天和秋天．成熟和交配则主要发生在冬天和春天．湟鱼棘头虫在春夏秋冬的性比（雌／雄）分别为１、５５，１．５５，１．９７和２．２４。

SEASONAL PERFORMANCE AFFECTING POPULATION DYNAMICS OF CITRUS RED MITE, PANONYCHUS CITRI (MCGREGOR) (ACARI: TETRANYCHIDAE), ON PEAR

The population of the citrus red mite, Panonychus citri (McGregor), does not increase on pear from spring to mid summer but thereafter increases abruptly. To elucidate this phenomenon, we compared the performance of the mites on pear leaves with that on citrus leaves, at different time throughout the pear growing season. No significant difference was detected between the oviposition rate on pear and that on citrus throughout the season. However, the survival rate of ovipositing females that had fed on pear and the hatch rate of eggs laid by those females were significantly lower than those for females that had fed on citrus, until August. However, no significant difference was observed thereafter. The results showed that the decline of the population of citrus red mite before autumn is due to the high mortality of adult females that had fed on pear leaves and the low hatch rate of the eggs produced by those females.