入侵红火蚁生物学特性的研究

入侵红火蚁是一种杂食性害虫,它的生物学特性主要表现在它的社会性、多型性、群居地栖性、好攻击性、受惊转移和堆尸习性等,大多从卵发育为成虫需要22-38d,每个族群中有单个蚁后或多个蚁后,蚁后寿命最长可达7a,一般每天可产卵1500-5000粒,1个蚁巢可有成蚁5～50万只,盛夏和寒冬整个族群均向蚁巢下部转移,有翅繁殖蚁可四季产生,多在春末夏初飞出蚁巢在空中交配,落地后雌蚁脱翅成为蚁后,并产卵繁殖建立新的族群,主要靠人为传播和自然扩散来扩展入侵地。     

楝属川楝素含量与生物活性的关系

本文报道用高速液相色谱测定了川楝素含量的各地楝树样品水提物及几种川楝素产品对菜青虫的生物活性,讨论了川楝素含量与生物活性的关系。叶、果样品中虽不含或仅含少量川楝素,但对试虫仍表现出一定的活性。皮中含有较丰富的川楝素,其含量与拒食活性呈正相关,但与毒效作用不相关。四川样品川楝素含量及生物活性均很高而值得重视。川楝素粗产品相对于纯川楝素而言对试虫具更高的生物活性。这种川楝素含量与活性的非线性关系说明样品中其它成份也具活性或与川楝素有着协同作用。通过测定、分析和讨论,指出用川楝素粗产品防治菜青虫是一经济、有效,可行的措施。文中应用了评判援效型杀虫剂的新方法,供讨论和参考。     

主成分分析法在昆虫目级阶元分类上的应用

根据昆虫图象,对半翅目、鳞翅目、鞘翅目的28种昆虫提取的形状参数、叶状性、球状性等7项数学形态特征进行了主成分分析,利用主成分分析法所得出的结果与传统分类方法相比较,结果表明:半翅目中除黑哎猎蝽独立外,基本上归属于鞘翅目中,鳞翅目中除棉铃虫独立外,其他昆虫种类仍在一类。这说明主成分分析的分类结果与传统分类有较大的相似性,同时也揭示了传统的分类结果可能存在不足,利用数学形态特征和先进的数学方法对昆虫分类进行研究具有重要的意义。     

昆虫保幼激素及其类似物的应用研究进展

介绍了昆虫保幼激素及其类似物应用于杀虫剂和昆虫生长调节剂的研究情况,并展望了昆虫保幼激素及其类似物的应用前景。     

The paradox of keystone species persecuted as pests: A call for the conservation of abundant small mammals in their native range

Small mammals, such as European rabbits (Oryctolagus cuniculus), plateau pikas (Ochotona curzoniae) and prairie dogs (Cynomys spp.), traditionally have been perceived as pests and targeted for control within their native ranges, where they perform essential ecosystem roles and are considered keystone species. These species can reach high densities, and have been subjected to eradication campaigns because of their putative negative impact on natural habitats and agriculture and their competition with livestock for forage. Eradication programmes have been a main factor causing sharp declines of these species in their natural ranges. Paradoxically, they are keystone species where they are abundant enough to be perceived as pests. The term “pest” is usually a social perception that is rarely supported by scientific data, whereas there is considerable scientific evidence of the key ecological roles played by these species. We call for the conservation of these species and present a conceptual model regarding the management of their populations. Where they occur at high numbers, and hence their effects on biodiversity are still of crucial importance, the persecution of these species should be avoided and their natural habitats preserved. In areas with high conservation value, but where these species occur at low densities, management efforts should aim to increase their density. In areas of high commercial value, managers ideally should consider changing prioritization of the area to high conservation value by purchasing the land or obtaining conservation easements. In situations with high commercial value and demonstrable low conservation concern, small mammals could be reduced humanely.     

稻鸭共作技术对水稻及其病虫害的影响

稻鸭共作技术,源于中国传统农业的精华——稻田养鸭,完善于日本,发展于亚洲。稻鸭共作是具有良好的生态效应、农牧混合的生态型农业技术。本文就稻鸭共作技术的优点及其对水稻、病虫害的影响作一综述。     

植物生长调节剂在害虫生物防治中的应用

植物生长调节剂是一类调节和控制植物生长发育及各种生理活动的有机化合物,同时它能诱导植物产生一些次生物质对害虫产生生长抑制、防御和驱避等作用。概述植物生长调节剂的种类和作用特点,并对其在害虫生物防治中的应用进行介绍。     

日光温室西红柿病虫害防治对策

简析了日光温室生态系统西红柿生育特点和病虫害发生特点,并提出“改善环境、健身栽培、综合预防、合理用药”防治策略。     

Consequences of the spatial configuration of resources for the distribution and dynamics of the endangered Parnassius apollo butterfly

Based on several years of data from two populations of the endangered Apollo butterfly (Parnassius apollo, L. 1758), we study how the amount and spatial location of patches of larval (host-plant) and adult (nectar plant) resources affects the distribution of females and their larval offspring in the following year. In the coastal population (nectar-plant and host-plant patches spatially segregated), females moved frequently between patches to aggregate on larger host-plant patches close to nectar-plant patches. In the archipelago population (where nectar-plants and host-plants co-occur), the abundance of females increased with higher proximity to other host-plant patches and with more nectar-plants on the patch. Next year’s larval abundance correlated with the abundance of females in the previous season in both populations. A model of the population dynamics in the two populations in relation to the spatial configuration of nectar and host-plant patches showed that the spatial configuration of larval and adult resources had population-dynamical consequences. In many organisms, different life-history stages use different resources. Incorporation of information on the location and abundance of adult resources can provide additional insight for the suitability of a particular landscape in harbouring a population.     

Analysis based on RAPD and ISSR Markers Reveals Closer Similarities among <Emphasis Type="Italic">Citrullus</Emphasis> and <Emphasis Type="Italic"> Cucumis</Emphasis> Species than with <Emphasis Type="Italic">Praecitrullus fistulosus</Emphasis> (Stocks) Pangalo

A cucurbit species named Praecitrullus fistulosus (Stocks) Pangalo, which thrives in India, is considered to be a distant relative of watermelon. Recent experiments indicated that it has mild resistance to whiteflies (Bemisia tabaci). However, our attempts to cross various US plant introductions (PIs) of P. fistulosus with watermelon or other Citrullus PIs have not been successful. Thus, to determine genetic relatedness among those species, phylogenetic analysis [based on simple sequence repeat (SSR)–anchored (also termed ISSR), and randomly amplified polymorphic DNA (RAPD) markers] was conducted among PIs of P. fistulosus, Citrullus lanatus var. lanatus (watermelon), C. lanatus var. citroides and the wild Citrullus colocynthis. Phylogenetic relationships were also examined with Cucumis melo (melon), Cucumis sativus (cucumber), and wild Cucumis species including C. africanus, C. metuliferus, C. anguria, C. meeusei, and C. zeyheri. Wide genetic distance exists between Citrullus and Cucumis groups (8% genetic similarity). Phylogenetic relationships among Citrullus species and subspecies are closer (25–55% genetic similarity) as compared with those among most Cucumis species (14–68% genetic similarity). P. fistulosus appeared to be distant from both Cucumis and Citrullus species (genetic similarity between P. fistulosus and Cucumis or Citrullus groups is less than 3%). Although wide genetic differences and reproductive barriers exist among cucurbit species examined in this study, they are still considered as potential germplasm source for enhancing watermelon and melon crops using traditional breeding and biotechnology procedures.