期刊文献+
共找到2篇文章
< 1 >
每页显示 20 50 100
黄鼠(Citellus dauricus Brandt)体外寄生的松江黄鼠蚤(Ceratophyllus tesquorum sungaris jordan)的季节消长调查 被引量:1
1
作者 柳支英 高钜镇 +1 位作者 吴厚永 蔡关元 《人民军医》 1960年第S2期33-40,共8页
(1)我们于1957(丰雨年份)和1958(亢旱年份)两年在×地区对松江黄鼠蚤进行了季节消长调查。(2)在整个活动季节内,黄鼠体松江蚤指数有二个高峰:一在春季四月,即黄鼠育幼分居之前;五月开始下降,六月最低,七月囘升,八、九月急剧增高,即... (1)我们于1957(丰雨年份)和1958(亢旱年份)两年在×地区对松江黄鼠蚤进行了季节消长调查。(2)在整个活动季节内,黄鼠体松江蚤指数有二个高峰:一在春季四月,即黄鼠育幼分居之前;五月开始下降,六月最低,七月囘升,八、九月急剧增高,即在黄鼠蟄眠前出现第二个高峰。(3)五、六月蚤指数剧降固与黄鼠增殖有关,但指数降低倍数较宿主增殖倍数为高,因此认为总蚤数的减少是实际存在的。这可能由于該时期温差大,蒸发量高,加速其死亡的结果。(4)虽然两年雨水量相差很大,但指数趋向基本一致;仅有的差别反映于第二高峰的程度有所不同,即在七、八月丰雨年份第二高峰远较第一高峰为高。但此点是否反映该地区的基本规律,尚须进一步作多年观察才能更好证明。(5)松江蚤是黄鼠的主要寄生蚤和鼠疫媒介,它不仅在鼠间鼠疫的发生和流行上起着重要作用,也是人们在野外直接感染鼠疫的主要媒介。结合秋季该蚤指数高、带菌也多的特点,在防疫措施上固不能在春夏季有所忽视,更应在秋季引起注意。 展开更多
关键词 黄鼠 寄生蚤 体外寄生 蚤指数 Ceratophyllus tesquorum sungaris jordan Citellus dauricus Brandt 松江 季节消长
下载PDF
New materials of the steppe mammoth, Mammuthus trogontherii, with discussion on the origin and evolutionary patterns of mammoths 被引量:5
2
作者 WEI GuangBiao HU SongMei +6 位作者 YU KeFu HOU YaMei LI Xin JIN ChangZhu WANG Yuan ZHAO JianXin WANG WenHua 《Science China Earth Sciences》 SCIE EI CAS 2010年第7期956-963,共8页
Recently found materials indicate that the steppe mammoth, Mammuthus trogontherii, survived in northern China into the late Pleistocene. East Asia is the key area of mammoth evolution after the initial radiation of ea... Recently found materials indicate that the steppe mammoth, Mammuthus trogontherii, survived in northern China into the late Pleistocene. East Asia is the key area of mammoth evolution after the initial radiation of early forms out of Africa and into Eurasia at the beginning of the late Pliocene (c. 3.5–3.0 Ma). M. rumanus, M. meridionalis, M. trogontherii, and M. primige- nius probably formed a continuous and transitional evolutionary lineage within the pan-Eurasian mammoth radiation in East Asia. Each speciation event of the Eurasian mammoths was followed by a rapid and large-scale dispersal event: out of East Asia. Allopatric speciation is the main speciation pattern of Mammuthus. The climatic vacillation was severe and frequent in East Asia from the early part of early Pleistocene (c. 2.6 Ma) onward, which probably brought about successive speciation in East Asia and the subsequent dispersal of the mammoths. 展开更多
关键词 Mammuthus trogontherii Mammuthus sungari MSE ALLOPATRIC SPECIATION out of EAST ASIA climate
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部