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Males of Nippostrongylus brasiliensis, an intestinal parasite of rodents, were maintained in an environment permeated with pheromone produced by females of the species. After the males were removed from that environment, their subsequent ability to orient to a gradient of the pheromone emanating from living females was greatly reduced for periods up to 2 hours. This phenomenon might serve as the basis for a new, selective antihelminthic technique in which the premating communication between males and females is disrupted. 相似文献
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Pfennig KS 《Science (New York, N.Y.)》2007,318(5852):965-967
Mating with another species (hybridization) is often maladaptive. Consequently, females typically avoid heterospecifics as mates. Contrary to these expectations, female spadefoot toads were more likely to choose heterospecific males when exposed to environmental conditions that favor hybridization. Indeed, those females with phenotypic characteristics for which hybridization is most favorable were most likely to switch from choosing conspecifics to heterospecifics. Moreover, environmentally dependent mate choice has evolved only in populations and species that risk engaging in, and can potentially benefit from, hybridization. Thus, when the benefits of mate choice vary, females may radically alter their mate selection in response to their own phenotype and their environment, even to the point of choosing males of other species. 相似文献
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汤玉清 《福建农林大学学报(自然科学版)》1985,(1)
<正> 棒小蜂(Signiphoridae)是小蜂总科(Chalcidoidea)中一个甚小的科,仅含7个属:Thysanus Walker、Clytina Erdos、Neosigniphora Rust、Kerchiella Rosanov、Signiphora Ashmead、Chartocerus Motschulsky和Rojanouilla Subba Rao,其中Chartocerus属又分为三亚属:Chartocerus S.Str.、Xana Kurdjumov和SigniphorinaNikolskaja(Rojanov,1965;De Santis,1968;Subba Rao,1974)。该科绝大多数的种类为介壳虫、粉虱、木虱和蝇蛹的寄生蜂,常为重寄生。 相似文献
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盐碱土中可培养中度嗜盐菌的研究 总被引：1，自引：1，他引：0
为了调查大庆盐碱地的中度嗜盐菌资源,采集重度盐碱化的土壤样本进行嗜盐微生物的分离纯化,获得45株中度嗜盐细菌。形态学特征显示,40%菌落呈黄色,其余为乳白色;细胞为直线或弯曲的杆状,G+和G-细菌比例为19:26。进一步的生理生化特征分析筛选出8株进行16S rDNA基因序列的测定及系统发育分析。结果表明,它们分别属于Bacillus(3株),Halomonas(2株)和Alkalibacillus(3株)属的菌株。菌株15-2应为现有种Bacillus agaradhaerens,X10-1(或X10-7)可能为Bacillus属潜在的新种,15-7(或X10-2)可能为Halomonas潜在的新种,有待于进一步的验证。研究虽然仅获得了有限的中度嗜盐菌资源,但却丰富了我们对大庆盐碱土中可培养中度嗜盐菌多样性的认识,为今后合理开发和利用大庆地区的嗜盐微生物资源提供了素材和参考。 相似文献
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The distribution of male and female plants was examined in five dioecious, wind-pollinated species representing five plant families and two classes (gymnosperms and angiosperms). The arid to semiarid habitats occupied by these species in northern Utah were stratified for sampling into two categories: chronically xeric and seasonally moist. The results show that for all species, males are more abundant on xeric microsites, while females are over represented on the moister parts of each local environment. Differential distribution of the sexes along a soil moisture gradient is a strategy that maximizes seed set of females and pollen dispersal of males; it also tends to minimize intraspecific competition between the sexes. 相似文献
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本文记述中国短索蚜小蜂属Archenomus,Howard的13种,含2种中国新记录和4种新种,提出中国短索蚜小蜂属分种检索表.新种的模式标本分藏福建农学院生物防治研究所和植物保护系. 相似文献
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A fusiform, spirally coiled and pleated, free-living, heavily placate echinoderm with an expansible test has been discovered in the Lower Cambrian Olenellus zone of California. It is characterized by 10 "interambulacral" areas, a single principal endothecal ambulacrum with a short branch, and oral and apical regions at opposite poles. A new class, the Helicoplacoidea is proposed for the new genus Helicoplacus, with two new species, H. gilberti (type species) and H. curtisi. 相似文献
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溴氰菊酯对微小牛蜱未吸血幼蜱的半致死浓度（ＬＣ５０）为０．３６×１０－６，对未吸血成蜱的半致死量（ＬＤ５０）为４．６８７μｇ／虫，对饱血雌蜱的ＬＤ５０为６．８６８μｇ／虫；而敌百虫对未吸血幼蜱的ＬＣ５０为１７５×１０－４，对未吸血成蜱和饱血雌蜱的ＬＤ５０分别为１１１６和５２６６μｇ／虫．可见，溴氰菊酯对微小牛蜱未吸血幼蜱、未吸血成蜱及饱血雌蜱的杀蜱效果分别为敌百虫的４８６、２３８和７６７倍．现场杀蜱试验，采用５％溴氰菊酯水和剂１２．５×１０－４时．杀蜱率达９２％，３０×１０－６时达１００％杀蜱效果，对牛无副作用。 相似文献
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对生长在福州地区的高榕进行长期追踪观察,发现高榕榕果内仅生活着Eupristina altissima和Eupristina sp.榕小蜂,前者为高榕的传粉小蜂,后者无传粉行为,两者雌蜂之间在体色、触角、花粉袋和花粉刷等部位存在细微的差异,而两者雄蜂之间无形态差异。通过克隆福建地区5个样地的高榕榕果内收集到的E. altissima和Eupristina sp.榕小蜂,以及细叶榕的传粉小蜂Eupristina verticillata(外群)的Cytb及COI基因,并进行碱基组成及遗传距离分析,用邻接法构建系统发育树,分析两榕小蜂群体之间的遗传进化关系,结果显示:(1)榕小蜂COI及Cytb序列碱基组成中A+T的含量(Cytb序列中A+T=75.3%,COI序列中A+T=75.5%)显著高于G+C,符合膜翅目昆虫线粒体基因碱基组成特征。(2)对两群体小蜂进行遗传距离分析显示,Cytb序列中E. altissima和Eupristina sp. 群体内各样本之间的平均遗传距离分别为0.0092和0.0030,而E. altissima与Eupristina sp. 群体间的平均距离为0.1588;COI序列中E. altissima 与Eupristina sp. 群体内各样本之间的平均遗传距离分别为0.0065和0.0205,而二者群体间的平均遗传距离为0.1043,表明两者群体间的遗传距离明显大于各自群体内各样本间的遗传距离。统计GenBank中下载的6个属34种榕小蜂Cytb序列的种间遗传距离为0.0811-0.1723,6个属28种榕小蜂COI序列的种间遗传距离为0.0939-0.1986。由此认为E. altissima和Eupristina sp.之间的遗传距离差异已经达到了种间水平,即E. altissima与Eupristina sp.为两个不同的种。(3)在形态上,两种小蜂的雌蜂之间有微小差异,而二者雄蜂之间无差异,但Cytb与COI序列分析结果一致表明:E. altissima与Eupristina sp.雄蜂之间,以及二者雌蜂之间的遗传距离均差异显著,表明形态变异滞后于基因变异。雌蜂在表型上进化快于雄蜂,可能是由于雌蜂羽化后从榕果出飞,受到外界环境因素的影响较大,且两种雌蜂在传粉功能上存在差异,故二者之间的形态差异较大,而雄蜂寿命短,又终生生活在黑暗封闭、环境变化相对恒定的榕果内,两种雄蜂在行为上不存在差异,故二者表型变异较为缓慢。E. altissima和Eupristina sp.小蜂对宿主的专一性不强,在榕-蜂协同进化过程中,可能发生过宿主转移事件。 相似文献
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为了研究新疆硝尔库勒盐湖中的放线菌多样性,以微生物抗高渗透压的生理机制为指导,结合盐湖高盐、寡营养的特点,设计了含有在嗜盐微生物细胞中起渗透调节作用的多种碳源和氮源的分离培养基,以TP培养基、GW1培养基和F6培养基为对照,对新疆硝尔库勒湖沉积物样品进行分离。结果表明,海藻糖-肌酸培养基(B3)分离效果最好,能分离到10个属16个不同种的放线菌;海藻糖-天冬氨酸培养基(B1)和海藻糖-谷氨酸培养基(B2)分离效果次之,均能分离到5个属7个不同种的放线菌,并有2个潜在的放线菌新物种被发现(菌株编号为41376、41293)。这说明以渗透调节物作为碳源和氮源是高盐环境放线菌分离比较理想的选择,为以后高盐环境微生物的分离培养提供了理论指导。 相似文献
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Two species of Drosophila that differ in their ecology and mating systems have been compared with respect to male contribution to the somatic tissues and developing oocytes of females. In the species Drosophila mojavensis females remate daily, exhibit a copulatory plug, and have been shown to obtain a contribution from the male ejaculate. In contrast, Drosophila melanogaster males do not contribute to females. Female Drosophila melanogaster do not remate as frequently as Drosophila mojavensis females nor is a copulatory plug formed. 相似文献
13.
长春市一新外来入侵物种--白蜡虫的生物学特性与种群控制研究 总被引：2，自引：1，他引：2
首次报道了白蜡虫在长春市的分布。经观察,白蜡虫在长春市1年发生1代,以受精雌虫在水蜡树枝上越冬。4月中旬雌虫开始活动,5月上旬至5月下旬为卵期,6月上旬卵开始孵化。初孵若虫经1周后在水蜡树叶片上固定取食。2龄若虫在枝条上为害,至8月下旬羽化成虫。雌虫经交尾后越冬。对2龄若虫进行化学防治试验表明,以体积分数为3%顺式氯氰菊酯1:3 000~7 000倍液和40%毒死蜱1:800~1 000倍液进行喷雾防治,防治效果均可达到99%。 相似文献
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小食心虫族隶属于鳞翅目卷蛾科,世界广布。其中很多种类为农、林、果树害虫,有着很重要的经济意义。依据南开大学多年收藏和天津自然博物馆昆虫研究室近2年采集的标本,共记述北方七省市小食心虫族10属34种,初步分析区系组成,并对地区环境和多样性保护问题提出新的看法。 相似文献
15.
本文记述了来于西藏高寒山区田鼠大肠内首尾寄生线虫属一新种,定名为西藏首尾线虫。本新种在同属中异于原有种的特征在于:a.泄殖孔前缺纵行肛前栉;b.泄殖孔前缘仅2对乳突,呈上下重叠、左右对称的排序;c.交合刺长于有记载虫种的1倍以上(0.19～0.21:0.005:0.089);d.雌虫体长(14.26～14.35)长于C.andrejevi雌虫体长(8.22～9.55)。 相似文献
16.
Mundinger PC 《Science (New York, N.Y.)》1970,168(3930):480-482
American goldfinch females recognize individual males by their individually distinctive flight calls. Goldfinches and other cardueline finch species are also capable of learning new flight calls by imitation during pair and flock formation. Vocal imitation can occur between members of different species as well as between members of the same species. Learning of new flight calls differs in several respects from typical passerine song learning. 相似文献
17.
Lloyd JE 《Science (New York, N.Y.)》1980,210(4470):669-671
Photuris males emit flashed signals matching those of unrelated sympatric forms (Photinus and Pyractomena species). Some have only one flash pattern matching that of another species, others mimic at least two species, as well as emitting "their own" species-specific pattern. They tend to restrict the mimicking signals, but not their own, to the habitats, seasons, and daily periods of the mimicked species. Since Photuris females prey on males of other firefly species by mimicking their females' flashes, the Photuris males may be using their mimicry to locate and seduce their own hunting females. This mimicry is without known parallel in other animal communicative systems. It explains why the genus Photuris has been a frustrating mystery to taxonomists, who have long used flash patterns to distinguish sibling species in other genera. 相似文献
18.
Pleszczynska WK 《Science (New York, N.Y.)》1978,201(4359):935-937
Field experiments on breeding populations of lark buntings (Calamospiza melanocorys) in South Dakota support the hypothesis that polygyny is promoted by a high variance in quality among male territories. Among these birds protection of the nest site from solar radiation is the major indicator of quality: nestling survival was significantly correlated with nest-site cover, and experimental increase of shading resulted in higher reproductive success. Males with superior territories attracted two mates, whereas those with poor territories failed to attract any. Secondary females had fledging success at least equal to that of contemporaneous monogamous pairs. On the sole basis of a shading score for each territory, the mating status of males (polygynous, monogamous, or bachelor) was predicted accurately in new areas of Colorado and North Dakota before females arrived. 相似文献
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系统研究了分布于中国、印度和尼泊尔的直翅目蚱科尖顶蚱属Teredorus昆虫种类共计22种,其中有2个新种,即太白尖顶蚱Teredorus taibeiensis sp.nov.和短背尖顶蚱Teredorus brachinota sp.nov.,并有1个新组合,即格尖顶蚱Teredorus graveli(Gunther,1939)com.nov.,同时提供了尖顶蚱属昆虫的分种检索表和分布地区。模式标本保存于陕西师范大学动物研究所昆虫标本室。 相似文献
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Beukeboom LW Kamping A Louter M Pijnacker LP Katju V Ferree PM Werren JH 《Science (New York, N.Y.)》2007,315(5809):206
The insect order of Hymenoptera (ants, bees, sawflies, and wasps) consists almost entirely of haplodiploid species. Under haplodiploidy, males develop from unfertilized eggs and are haploid, whereas females develop from fertilized eggs and are diploid. Although diploid males commonly occur, haploid females have never been reported. In analyzing the phenomenon of gynandromorphism in the parasitoid wasp Nasonia vitripennis, we found a line that generates complete phenotypic females from unfertilized eggs. These females have ovaries, can lay eggs, and are haploid, as shown by cytological and flow cytometric analyses. The data show that diploidy is not necessary for female development. 相似文献