蛇岛蝮蛇(Gloydius shedaoensis Zhao)种群分布格局对捕食率的影响

目的进一步了解蛇岛蝮蛇的种群动态,深入探讨全岛的种群密度和分布格局对捕食率的影响。方法结合蛇岛蝮蛇种群数量调查,对全岛所有区域的各种生境蝮蛇数量进行标记统计,每1～2天进行一个沟溪全面踏查,分别记录春秋两季不同区域、不同生境的蛇岛蝮蛇不同年龄组的分布数量和捕食状况,进行比较。结果2005～2006年蛇岛蝮蛇种群密度为0.0278条/m2,春秋两季是候鸟迁徙和捕食高峰时期,灌木林是蛇岛蝮蛇捕食栖息的主要场所,占全部种群的63.38%,其次是稀树草地27.04%,乔木林和裸地分别为5.86%、3.72%。蛇岛蝮蛇春季捕食持续时间短,捕食率10.92%,秋季捕食持续时间长,捕食率为8.61%。结论应密切关注候鸟迁徙的动态。     

《中国蛇岛》简介

《中国蛇岛》简介由大连自然博物馆李建立同志编著的《中国蛇岛》，已由辽宁科技出版社１９９５年６月出版，书中用中文和英文系统地介绍了蛇岛的自然概况，蛇岛蝗蛇的形态、分类、蛇岛生态、种群动态以及蛇岛蝮蛇的起源等问题，并配有彩色照片１７０幅，色彩恬静自然，集...     

蛇岛大自然的遗产

将中国渤海湾濒临辽宁省大连市旅顺口区的蛇岛视为一种特殊的自然遗产,一点也不过分。该岛面积虽只有0.73平方公里,但却是全世界特有种毒蛇“蛇岛蝮”的唯一栖息地。据近年估计,虽然岛上“蛇岛蝮”的数量尚有两万条左右,但它仍然是极度濒危的物种,原因就在于其分布地域的面积太小,禁不起任何风吹草动。生活在周围的渔民很早就知道蛇岛及岛上的毒蛇。早在1932年,日本国的学者曾将蛇岛上的毒蛇鉴定为“中介蝮”——一种广泛分布于亚洲北部的常见蝮蛇。此后,国内外大多数有关学者也沿袭这一分类观点。     

蛇岛蝮蛇生态的观察

蝮蛇(Agkistrodon halys)为我国分布最广的一种毒蛇,除青、藏、滇及两广外,各省区均有发现。这种蛇不仅数量多,毒性较强,常常伤害人畜,影响劳动力和战备,并且也是用途颇广的药材。因此,无论在其利用或蛇伤防治上,对它的生态都有研究的必要,但这方面的工作报道不多,而且全是关于蝮蛇的短尾亚种(A.h.brevicaudus)的。本文所观察的为蛇岛的蝮蛇,属于中介亚种(A.h.intermedius),分布在我国秦岭以北广大地区及东北三省。蛇岛位于渤海口,其上盛产     

蛇岛蝮蛇体内微量元素的分布特点

各种化学元素特别是金属元素在生命现象中的作用愈来愈引起人们的关注。但有关微量元素与蛇类生命活动的关系研究者甚少。为了进一步弄清蛇岛蝮蛇生命活动的规律及其与微量元素的关系，我们在以往工作基础上，就有关蛇岛蝮蛇体内微量元素及其分布规律，进行了比较全面系统的分析。     

影响蛇岛蝮蛇树栖分布相关因子的分析

目的了解影响蛇岛蝮蛇树栖分布的7个相关因子,探讨其间的关系。方法2006年10月12~15日,在蛇岛二沟南坡、北坡、西坡,测定不同年龄组蛇岛蝮蛇树栖环境的7个相关因子,进行比较分析。结果三种树栖环境中,老成体、成体、亚成体、幼体对因子的选择基本都有差异;不同年龄组的树栖高度与冠幅负相关不显著,与枝长(成体和亚成体中)负相关不显著,与其它正相关不显著;老成体和成体在林中和林缘,对树栖高度的选择差异显著,亚成体和幼体差异不显著;相同年龄组两两因子间线性关系明显。结论影响蛇岛蝮蛇树栖分布的因子具有一定的规律性。     

海底“蛇岛”

海底“蛇岛”钟吉富蛇岛。位于我国辽宁省大边市旅顺口西北２５里海面上,它是一个弹丸之地,那儿生活着数以万计的蝮蛇而闻名世界。位于离菲律宾宿务岛不远的巴霍海峡,有一座约１２米深的暗礁,居住着无数的海蛇,成了名符其实的海底“蛇岛”,却鲜为人所共知。全世界５...     

蛇岛蝮蛇消化道嗜银细胞的分布及形态学观察

应用Grimelius银染法对蛇岛蝮蛇Gloydius shedaoensis 消化道嗜银细胞的分布密度及形态进行研究.结果 表明,蛇岛蝮蛇的消化道中嗜银细胞分布广泛,见于其全长,主要分布于上皮细胞基部、上皮细胞之间、腺泡上皮细胞之间,也有少量位于固有膜内;胃贲门是嗜银细胞分布密度的高峰,胃体次之,食管分布密度最低;嗜银细胞形态多样,主要有锥体形、梭形、圆形和椭圆形,具有内、外分泌两种功能.     

蛇岛蝮蛇消化道5-羟色胺细胞的形态与分布

采用ABC(avidin-biotin-peroxidase complex)免疫组织化学方法,观察蛇岛蝮蛇(Gloydius shedaoensis)消化道内5-羟色胺(5-HT)免疫阳性内分泌细胞的分布及形态.结果显示,5-羟色胺细胞从食管到直肠各段均有分布.细胞分布密度呈波浪式,其中胃贲门部分布密度最高(7.15±2.38),直肠部次之(4.55±3.14),食管部最低(1.2±0.71).5-HT阳性细胞广泛分布于消化道上皮细胞之间、上皮基部、腺泡上皮细胞之间以及固有膜内.形态多样,呈圆形、锥体形、梭形等.分析认为蛇岛蝮蛇消化道5-HT细胞具有内、外分泌两种作用途径,并且其密度分布可能与其食性、生存环境有关.     

ON WEIGHTING AND CONGRUENCE

Abstract — A priori differential weighting of molecular characters is a common methodological practice in molecular phylogenetics and evolution. This has been a largely subjective exercise with few criteria for deciding which characters to down-weight and how much to do so. A priori differential weighting is conducted to remove heterogeneity from the data sets and to improve the congruence among the informative, and usually more conservative characters. Herein, we test whether congruence is improved with a priori differential weighting by using the incongruence length difference test on a linked genetic data set consisting of 14 mammalian taxa and the 13 protein coding genes of the mitochondrial genome. Weighting by omitting the third codon position did not improve congruence with respect to the equally weighted data, while weighting transversions did improve the congruence between the 13 protein coding genes. Nonetheless, the most parsimonious tree found from transversion weighting did not differ from one using all of the data equally weighted.     

STUDIES ON THE SYNERGISTIC EFFECT OF PIPERONYL BUTOXIDE AND ISOBUTYLUNDECYLENEAMIDE ON PYRETHRINS AND ALLETHRIN

Experiments are described to compare the toxicity of natural pyrethrins and allethrin, the completely synthetic homologue of cinerin I, and to show the effect of the two synergists, piperonyl butoxide and iaobutyl undecyleneamide (IN 930) on both these active ingredients, using a measured-drop technique with Mucca domestiur L. the housefly, and a residual-film technique with Cimex lectularius L. the bed bug. In the conditions of the experiment, pyrethrins were shown to be twice as toxic as allethrin to flies, and 5.5 times as toxic as allethrin to bugs. The two synergists were tested at several ratios to the two insecticides, ranging from 1 : 1 to 20 : 1. The results were plotted as series of log. concentration/probit regression linea. These were parallel for the bug tests; but in the fly tests, the slope of the line increased with a rise in the proportion of Synergist to insecticide. The estimated median lethal concentrations indicated, in all cases, that the toxicity increased with a rise in the ratio of synergist to insecticide, at least up to 20 : 1. However, the enhancement of toxicity was greatest for the smaller ratios and fell off as the ratio increased. Piperonyl butoxide was the more powerful synergist, increasing the potency of pyrethrins 5 times and allethrin 4 times to flies, and pyrethrins twice and allethrin 3 times to bugs, whereas IN 930 did not increase the potency of either ingredient more than twice to either test insect.
The addition of piperonyl butoxide to residual films of pyrethrins greatly prolonged their effectiveness; but an experiment designed to investigate the effect of the synergist on the stability of this insecticide showed that this action, if it exists, must be slight.     

再生稻褐飞虱为害损失测定和防治指标的研究

在福建,褐飞虱是再生稻的重要害虫,中进行了再生稻褐飞虱为害损失的测定,并对褐飞虱为害再生稻造成的产量损失结构进行了通径分析。根据虫量和产量损失的关系,结合现行稻谷价格,产量水平,防治费用等因素。确定允许为害损失率,同时建立了再生稻褐飞虱防治指标模型,按照防治指标模型,制定出不同产量水平的防治指标。