无机化学学科发展回顾与展望

对化学学科发展过程中的巨大成就进行了回顾,对无机化学方面的发展前景进行展望。     

食用昆虫的研究与应用进展

对食用昆虫的研究与应用进行综述,介绍了世界各地对食用昆虫的利用概况,分析了食用昆虫的营养价值,以及昆虫在有机废弃物生物转化方面、作为人类食品和作为动物饲料代替鱼粉方面的应用情况、产业化研究现状及存在问题,最后对食用昆虫的研究开发前景进行了展望.     

关于高中生物教学几点探讨

本文对高中生物教学进行了思考,笔者对多年的教学实践进行了分析总结,从教育理念、教育方法、教育模式等方面进行了研究。     

森林生态系统研究中几个重要方面的进展

本文对森林生态系统研究中几个重要方面的进展进行了综述,包括森林细根生物量与生产力、调落物、粗死木质残体和森林降水化学等。对今后这些方面研究中的重点内容与趋势进行了评述。     

独立学院大学英语教学改革探究——以南昌大学共青学院为例

本文对独立学院大学英语教学进行了现状分析,以南昌大学共青学院为例阐述了独立学院在学生生源等方面存在的问题,以而介绍了独立学院就分层引导的教学方法和转变教学模式等方面进行一系列的教学改革。     

农产品质量安全预警研究现状分析

分析了国内外在农产品质量安全预警方面的实践,并从环节、手段等方面对国内外农产品质量安全预警的研究进展进行了综述。     

NaCl对光合作用影响的研究进展

对NaCl对光合作用影响的几个重要方面的研究进展进行了综述,包括NaCl对光合作用的影响途径,气孔效应与非气孔效应,NaCl对光能吸收与转换、光合电子传递、光合磺素同化的影响及盐与其他胁迫因子对PSⅡ活性的协同影响等,对今后这些方面研究中的重点内容与趋势进行了评述。     

物种灭绝机制

对灭绝类型、灭绝率、灭绝特点等物种灭绝的基本概念进行了阐述,从灭绝与进化,灭绝与系统发育历程之间的关系等方面探讨了灭绝的内在机制,并从生物学、物理学及人类影响三方面对物种灭绝的外在机制进行了系统的说明。     

森林生态系统研究中几个重要方面的进展

本文对森林生态系统研究中几个重要方面的进展进行了综述,包括森林细根生物量与生产力、调落物、粗死木质残体和森林降水化学等。对今后这些方面研究中的重点内容与趋势进行了评述。     

对高中生物纸笔测验改革的思考

讨论了高中生物新课程改革背景下,教学评价方式之一的纸笔测验的改革问题。通过对纸笔测验在检测学生知识性目标达成方面的改革、在能力考核方面如何强化、在情感态度与价值观考核方面的尝试进行了深刻的思考,并对纸笔测验的形式变革、结果处理方面提出了一些看法。     

Genes, gene flow and adaptation of Diabrotica virgifera virgifera

1  Diabrotica virgifera virgifera has emerged as a major pest of cultivated maize, due to a combination of its high capacity to inflict economic damage, adaptability to pest management techniques and invasiveness.
2 This review presents a survey of the current state of knowledge about the genetics of D.   v.   virgifera . In addition, the tools and resources currently available to Diabrotica geneticists are identified, as are areas where knowledge is lacking and research should be prioritized.
3 A substantial amount of information has been published concerning the molecular phylogenetic relationships of D.   v.   virgifera to other chrysomelids.
4 There is a growing literature focused on the population genetics and evolution of the species. Several adaptations to anthropogenic selection pressure have been studied, with resistance to synthetic insecticides providing some particularly well-characterized examples.
5 A notable deficiency is a lack of studies directed toward the formal genetics of D.   v.   virgifera .     

Western corn rootworm (Diabrotica virgifera virgifera LeConte) population dynamics

1 The western corn rootworm Diabrotica virgifera virgifera LeConte is a major insect pest of field maize, Zea mays L. Larvae can cause substantial injury by feeding on maize roots. Larval feeding may destroy individual roots or root nodes, and reduce plant growth, stability, and yield. Costs associated with managing corn rootworms in continuous maize are annually one of the largest expenditures for insect management in the United States Corn Belt.
2 Even though D. virgifera virgifera has been studied intensively for over 50 years, there is renewed interest in the biology, ecology, and genetics of this species because of its ability to rapidly adapt to management tactics, and its aggressive invasive nature.
3 This article provides a comprehensive review of D. virgifera virgifera population dynamics, specifically: diapause, larval and adult development, seasonality, spatial and temporal dynamics at local and landscape scales, invasiveness in North America and Europe, and non-trophic interactions with other arthropods.
4 Gaps in current knowledge are identified and discussed especially within the context of challenges that scientists in North America and Europe are currently facing regarding pest dynamics and the need to develop appropriate management strategies for each geographic area.     

Selection of entomopathogenic fungi for the control of the western corn rootworm Diabrotica virgifera virgifera

Abstract:  The western corn rootworm Diabrotica virgifera virgifera Le Conte (Col., Chrysomelidae), a serious pest of maize, has been recently introduced into Europe. Several approaches for its control are presently under investigation including microbial agents. During a field survey in Hungary in 2005, naturally occurring entomopathogenic fungi were found to attack this pest. These novel isolates together with standard isolates were tested for virulence against D. v. virgifera larvae and adults. Twenty strains of Metarhizium anisopliae , Beauveria bassiana and Beauveria brongniartii were used in bioassays in the laboratory. Larvae and adults were dipped into a spore suspension with a concentration of 1 × 10⁷ conidia (con.)/ml. They were kept for 14 days at 22°C (±2°C) and 70% relative humidity. The number of infected larvae and adults were counted and infection rates were calculated. Adults were significantly more susceptible to entomopathogenic fungi than larvae. The most virulent isolate infected about 47% of larvae ( M. anisopliae Ma2277), whereas the infection rate in adults was up to 97% ( M. anisopliae Ma2275). Isolates of M. anisopliae caused significantly higher mortalities than isolates of B. brongniartii and B. bassiana . Most of the adult beetles were killed within 12 days. Isolates from D. v. virgifera were more virulent than those from other hosts.     

Population density of Diabrotica virgifera virgifera LeConte beetles in Serbian first year and continuous maize fields

A 5‐year field survey examined western corn rootworm (WCR) (Diabrotica virgifera virgifera LeConte) beetle density in Serbia from 2002 to 2006. First‐, second‐, third‐, fourth‐ and fifth‐year maize fields were sampled; they represented 64.61%, 21.66%, 9.45%, 3.53% and 0.75% of all sampled fields respectively. Results showed that the mean WCR beetle population density from 794 maize fields differed depending on cropping history. Minimum mean WCR/trap/day was 0.0 in the first‐year maize fields in 2002 and 2006. Maximum mean WCR/trap/day was registered in the fourth‐year and the fifth‐year maize fields (27.8 and 21.2 respectively). Mean population density of WCR adults increased with the number of years of continuous maize from 1.17, 4.61, 6.41, 10.30 up to 13.53 WCR/trap/day for first‐fifth‐year maize fields respectively. Mean WCR/trap/day ± SE exceeded the economic population threshold of >6 WCR/trap/day in third‐year continuous maize fields. Out of 794 maize fields, 697 (87.78%) registered a mean population density below the <6 beetles/trap/day threshold. In only 97 fields was WCR population density >6 beetles/trap/day, a finding that predicts a risk of economic damage to a subsequent maize planting. These data are representative of the Serbian situation from 2002 to 2006; they indicate that WCR are well dispersed across commercial maize fields in Serbia. These results provide new insight into the current low WCR population densities in maize fields managed by crop rotation, a finding that can help in creating long‐term management strategy.     

Miscanthus,a host for larvae of a European population of Diabrotica v. virgifera

The EU policies for decreasing reliance on fossil fuels and reducing greenhouse gas emissions present challenging targets for bioenergy production. Field trials in Europe of Miscanthus×giganteus (Poales: Poaceae) over the past 20 years have shown that this plant is suitable for the production of biomass but the economic models promoting its use for this purpose often assume that controlling its pests will cost little or nothing. Laboratory experiments were conducted to determine whether this plant is suitable for the development of larvae of the western corn rootworm (WCR), Diabrotica virgifera virgifera (Coleoptera: Chrysomelidae), which is an important pest of maize. Larvae of WCR, originating from a Central and South Eastern European population, can develop on Miscanthus.     

Assessment of establishment and persistence of entomopathogenic nematodes for biological control of western corn rootworm

Abstract:  The use of entomopathogenic nematodes (EPN) is potentially one ecological approach to control the invasive alien western corn rootworm ( Diabrotica virgifera virgifera LeConte, Col., Chrysomelidae) in Europe. This study investigated the establishment and the short- and long-term persistence of Heterorhabditis bacteriophora Poinar (Rhabditida: Heterorhabditidae), Heterorhabditis megidis Poinar, Jackson and Klein (Rh., Heterorhabditidae) and Steinernema feltiae Filipjev (Rh., Steinernematidae) in three maize fields in southern Hungary, using the insect-baiting technique. All three EPN species equally established and persisted in maize fields. The timing of application (April or June) did not influence the establishment of EPN species. EPNs persisted for 2–5 months, i.e. they survived up to and throughout D. v. virgifera larval occurrence in the soil. Results demonstrate that D. v. virgifera larvae can potentially be controlled by EPNs during the same year of EPN application but no long-term control effect is expected under intensive maize cultivation practices.     

Influence of corn planting date on the life stage development and phenology of Diabrotica virgifera virgifera

Under field conditions in eastern South Dakota, USA three different planting dates of corn and three times of egg infestation were used to imposed synchronous and asynchronous timing of corn growth and Diabrotica virgifera virgifera LeConte egg hatch and subsequent development. Median occurrence of each of the three larval stages and of the adult stage for each of the infestation-planting treatments was determined by relating occurrence to thermal units and to days after infestation. No significant differences were found among the treatments for median occurrence of each life stage when the thermal unit approach was used. However, significant differences were found among treatments for median occurrence when the day after infestation approach was used. Consistent parameters are needed for prediction of the occurrence of life stages of this insect. Despite the various imposed conditions, this study indicates that the least variable method of predicting life stage occurrence and adult emergence of D. v. virgifera was the use of thermal unit accumulations (base 11°C).

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Résumé Dans les conditions de l'est du Sud Dakota (USA), 3 dates de semailles de maïs et 3 dates de contamination avec des ufs de D. virgifera virgifera LeConte ont servi à imposer ou à empêcher la synchronisation des éclosions des ufs et par conséquent des développements ultérieurs. Les dates médianes d'apparition de chacun des 3 stades larvaires et des imagos ont été déterminées en relation avec les unités de température et le nombre de jours depuis la contamination. Aucune différence significative entre les dates médianes d'apparition n'a été mise en évidence par utilisation des unités de température; par contre, ces différences deviennent significatives lorsque l'on utilise le nombre de jours depuis la contamination. Des paramètres fiables sont nécessaires pour prédire la présence des différentes stades de cet insecte. En dépit des différentes conditions imposées pour cette étude, la méthode la moins capricieuse pour prédire l'apparition d'un stade larvaire et l'émergence des adultes est la somme de températures avec une base de 11°C.

     

Immunological assessment of an insecticide resistance-associated esterase in the Western corn rootworm

In previous investigations, we have determined that organophosphate resistance in the western corn rootworm, Diabrotica virgifera virgifera, is at least partially attributed to a group of non-specific carboxylesterases referred to as group II. Antiserum raised against a purified 66-kDa group II esterase is specific for the denatured enzyme. This antiserum reacts similarly with both beetle homogenates from resistant and susceptible populations, although there is much higher signal intensity in immunoblots of resistant relative to susceptible beetles. These results suggest that overproduction of group II esterases is the underlying basis of esterase-mediated resistance in D. v. virgifera by demonstrating that (1) group II esterases are immunologically indistinguishable between the resistant and susceptible populations, and (2) the intensity differences are due to increased group II esterase proteins in the resistant population. The diagnostic potential of immunological-based assays was tested with a traditional diagnostic concentration bioassay and a biochemical-based native PAGE assay. Significant correlations were observed among all three diagnostic assays (regression coefficients ranging from 0.95 to 0.96). These results demonstrate the importance of the 66-kDa protein as a resistance-associated biochemical marker, thus emphasizing the potential for 66-kDa protein-targeted immunoassays in resistance monitoring programs.     

Reproductive Biology of Celatoria compressa (Diptera: Tachinidae), a Parasitoid of Diabrotica virgifera virgifera (Coleoptera: Chrysomelidae)

The tachinid Celatoria compressa, a parasitoid of adult Diabrotica species in North America has been studied as a candidate classical biological control agent for the western corn rootworm, Diabrotica virgifera virgifera, in Europe. Prior to its potential importation, a thorough understanding of the parasitoid's reproductive biology is essential, and is an important component in the evaluation of a species as a biological control agent. In this study it has been clarified that C. compressa belongs to a group of a few tachinid species characterised by having eggs that contain fully developed larvae which are laid directly into the host. After mating, the egg load of females increased steadily from day 1 to a maximum egg load on day 4. Thereafter eggs containing fully developed first instar larvae reached a maximum of 31 in 69 eggs. At the first day of larviposition, females laid on average only five eggs into multiple hosts, which is in contrast to the availability of 18 eggs containing fully developed first instars in the uterus per female at that time. During a mean female's larviposition period of 23 days, a total of 33 first instars were larviposited into the hosts, which is only half of the female's egg load. Lifetime fecundity of C. compressa was significantly correlated with longevity. However no relationship was found between body size and either lifetime fecundity or longevity. In this study, an inverse host density-dependent pattern of percent parasitism was shown for C. compressa under 24-h fixed-time laboratory conditions, reflecting a Holling type II response. The number of host parasitized per C. compressa female reached an upper limit of 10 hosts with an increasing host density, which can be explained by the long host handling time of C. compressa.     

Relationship between phenotypic traits and selected fitness components of Diabrotica virgifera virgifera

Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae) is one of the most important and best-studied maize pests, yet little information is available regarding the basic relationships among its phenotypic traits, particularly those that reflect the overall fitness of this successful invader in Europe and North America. Such information is critical for studies on the invasiveness, behavioural ecology, and management of this pest. Phenotypic traits that change over the lifetime of the beetle were investigated (e.g., fresh body weight) as they can indicate changes in adult physiology or fitness of D. v. virgifera . Phenotypic traits that remain stable over the beetle's lifetime were also investigated (e.g., pronotum width, head capsule width, hind tibia length), as they most likely allow detection of genetic differences between populations. Furthermore, phenotypic traits were investigated that may best predict fecundity (e.g., fresh body weight, elytra width) and life span (e.g., elytra length), as these two factors influence the population growth of this highly invasive species. Finally, regression equations are provided for the age-specific oviposition and survival of the long-living D. v. virgifera adults, which may allow researchers to reduce the duration of their bioassays without losing information.