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161.
天牛基因组DNA的提取方法   总被引:6,自引:0,他引:6  
通过试验探索出3种可以快速、简便地从天牛干标本、液浸标本和新鲜标本中提取DNA模板的方法。对所获得的基因组扩增分析表明,经过PCR之后的DNA能呈现明显的多态性,同种天牛用同一引物扩增幼虫和成虫所获得的结果相同,可以认为,RAPD技术可以应用于天牛成虫干标本及幼虫浸渍标本的鉴定及系统发育研究中,也证明了这3种方法用于提取不同保存时间、不同种天牛基因组的DNA是切实可行的。  相似文献   
162.
采用野外实验和室内实验相结合的方法,研究绢蒿荒漠草地中粪甲虫的介导对牛粪和马粪的分解状况及其对粪便下方土壤养分的影响.结果表明,有粪甲虫活动的粪便随着分解时间的延长酸性洗涤纤维(ADF)、中性洗涤纤维(NDF)、全碳、全氮和全磷降解率逐渐升高.有粪甲虫活动的粪便养分降解率均高于无粪甲虫活动的粪便,牛粪分解末期较无粪甲虫...  相似文献   
163.
应用北美小蠹信息素对中国一些小蠹的引诱研究(英文)   总被引:2,自引:1,他引:1  
应用南松大小蠹Dendroctonusfrontalis、西松大小蠹D.brevicomis,山松大小蠹D.pondrosae,云杉八齿小蠹Ipstypographas和I.sp的信息物,对华山松的小蠹和光臀八齿小蠹I.nitidus进行了三年的引诱试验。结果表明;云杉八齿小蠹信息素用于光臀八齿小蠹成虫诱集是成功的,可用于预测预报,也可配合防治处理;几种美洲的大小蠹信息素对华山松大小蠹D.armandi等多种小蠹的引诱只可用以进行分布预测及成虫发生期预测;对小蠹天敌也有一定引诱效果。  相似文献   
164.
Knowledge of the diversity and ecology of plant pathogenic fungi in cacao agroforests and surrounding natural ecosystems can inform the development of sustainable management strategies for new cacao disease outbreaks. This study investigated the occurrence of fungi related to the Ceratocystidaceae and their nitidulid beetle vectors in cacao agroforests in Cameroon, under diverse agroecological conditions. The fungi and their vectors were collected from artificially induced stem wounds on cacao and associated shade trees. Collections were also made from abandoned cacao pod husks and other tree wounds within and around plantations. Fungal isolates were identified using DNA sequence‐based phylogenies and morphological comparisons, and two representatives of each species were evaluated for pathogenicity on cacao. Five species of Ceratocystidaceae were recovered, including Huntiella chlamydoformis sp. nov., H. pycnanthi sp. nov. and H. moniliformis, as well as Thielaviopsis cerberus and T. ethacetica. The incidence of these fungi appeared to be influenced by the prevailing agroecological conditions. Nitidulid beetles in the genus Brachypeplus were found to be their most common insect associates on cacao. Both T. ethacetica and H. pycnanthi produced extensive lesions after inoculation on branches of mature cacao trees, while T. ethacetica also caused pod rot. Although their impact remains unknown, fungi in the Ceratocystidaceae and their nitidulid beetle vectors are common and probably contribute to the parasitic pressure in Cameroonian cacao agrosystems.  相似文献   
165.
Extensive ponderosa pine (Pinus ponderosa Dougl. ex Laws.) mortality associated with a widespread severe drought and increased bark beetle (Coleoptera: Curculionidae, Scolytinae) populations occurred in Arizona from 2001 to 2004. A complex of Ips beetles including: the Arizona fivespined ips, Ips lecontei Swaine, the pine engraver beetle, Ips pini (Say), Ips calligraphus (Germar), Ips latidens (LeConte), Ips knausi Swaine and Ips integer (Eichhoff) were the primary bark beetle species associated with ponderosa pine mortality. In this study we examine stand conditions and physiographic factors associated with bark beetle-caused tree mortality in ponderosa pine forests across five National Forests in Arizona. A total of 633 fixed-radius plots were established across five National Forests in Arizona: Apache-Sitgreaves, Coconino, Kaibab, Prescott, and Tonto. Prior to the bark beetle outbreak, plots with mortality had higher tree and stocking compared with plots without pine mortality. Logistic regression modeling found that probability of ponderosa pine mortality caused by bark beetles was positively correlated with tree density and inversely related with elevation and tree diameter. Given the large geographical extent of this study resulting logistic models to estimate the likelihood of bark beetle attack should have wide applicability across similar ponderosa pine forests across the Southwest. This is particularly true of a model driven by tree density and elevation constructed by combining all forests. Tree mortality resulted in significant reductions in basal area, tree density, stand density index, and mean tree diameter for ponderosa pine and for all species combined in these forests. Most of the observed pine mortality was in the 10–35 cm diameter class, which comprise much of the increase in tree density over the past century as a result of fire suppression and grazing practices. Ecological implications of tree mortality are discussed.  相似文献   
166.
The abundance and diversity of invertebrate communities (annelids and epigeic fauna) in three types of cultivated soils were studied. Soil biota communities in the three most widespread soil types in Estonia (Calcaric Regosols, Calcaric Cambisols and Stagnic Luvisols) are influenced by environmental conditions, the factors connected to soil texture including moisture, organic matter content and pH being the most essential, and by the intensity of agricultural practice. Potentially high biological activity and low intensity of agricultural human activity of Calcaric Regosols occurs in parameters of communities of organisms not sensitive to soil which dries off, i.e. epigeic fauna living on the soil surface and preferring dry and warm habitat; temporarily dried off soil is not a suitable habitat for Oligochaeta. Both groups of Oligochaeta (earthworms, enchytraeids) appear to prefer Calcaric Cambisols where soil moisture conditions are more stable. The abundance of invertebrate communities is the highest and the diversity is the lowest in Stagnic Luvisols. Some trends occurred in community characteristics along the soil surface following a hypothetical gradient; the number of carabids per trap and diversity of spiders decreased from the edge to the centre of the field. The results presented here on spatial variability in distribution of soil organisms are preliminary.  相似文献   
167.
Wounds on trees provide entrance for many members of the Ophiostomatales (Ascomycota), including economically damaging tree pathogens. Because very little is known regarding wound-associated fungi on hardwoods in Europe or their potential nitidulid beetle vectors (Coleoptera), the aim of this survey was to explore the diversity of these fungi in Poland. Wound samples associated with 26 tree species were collected from 18 stands in Poland. Fungi belonging to the Ophiostomatales were isolated and identified based on morphology and DNA sequence comparisons of five gene regions, combined with phylogenetic analyses. In total, 32 taxa were identified, including 20 known and 12 currently undescribed species. In addition, Grosmannia cainii, Ophiostoma cf. ponderosae, O. sparsiannulatum and Sporothrix aurorae were reported for the first time outside of the USA. The wound-associated members of the Ophiostomatales recovered from hardwoods showed high diversity and specificity. Among the species recovered, 16 belonged to Sporothrix, 11 represented Ophiostoma s. l., five could be assigned to Leptographium s. l., and one Graphilbum species was detected. Among the studied tree species, wounds on Quercus robur appeared to be the most vulnerable to infection by members of the Ophiostomatales. All the nitidulid beetle species were found in association with species assignable to Ophiostoma and Sporothrix. This study detected a significant association between the occurrence of species belonging to the Ophiostomatales and the health status of the wounded trees. Some of the isolated species were host specific although Ophiostoma quercus, the most frequently encountered species, had a broad host range.  相似文献   
168.
中国天牛名录厘定与汇总   总被引:1,自引:0,他引:1  
对中国天牛的中文名亚种不带种名、种名不带属名的问题进行了修订,统一了中国天牛的中文名,在原有2617种的基础上增加了891种,汇总的中国天牛名录已达3508种.  相似文献   
169.
  • 1. Biodiversity is probably at greater risk in freshwater systems than in other ecosystems. Although protected areas (PAs) play a vital role in the protection of biodiversity and are the mainstay of most conservation polices, the coverage of biodiversity by existing PA networks is often inadequate and few reserves are created that take into consideration freshwater biota.
  • 2. In this paper an attempt is made to address the performance of protected areas in the context of freshwater biodiversity conservation using data records for water beetles in a Mediterranean river basin.
  • 3. Although the present PAs in the study area cover a relatively high number of water beetle species, the distribution and extent of reserves is still inadequate or insufficient to protect freshwater biodiversity, especially species of conservation concern.
  • 4. Alternative area‐selection methods (hotspots and complementary) were more efficient than PAs for representing water beetles. Within these, complementarity was the most efficient approach, and was able to represent all species in a significantly lower area than the current PA network. On the other hand, the future Natura 2000 Network will result in a great increase in the total area of protected land as well as in the biodiversity represented.
  • 5. Unfortunately, the occurrence of a species within a protected area is not a guarantee of long‐term survival because the extent of PAs is often insufficient and disturbances occur outside park boundaries. Thus, whole‐catchment management and natural‐flow maintenance are indispensable strategies for freshwater biodiversity conservation.
Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   
170.
秦岭华山松小蠹生态位研究   总被引:23,自引:8,他引:23  
通过对秦岭林区海拔1600~2200m的中山地带华山松小蠹虫种类和生态位的研究,结果表明:在秦岭林区入侵危害寄主华山松的小蠹虫有19种,其中能构成竞争和共存的小蠹虫主要有11种。虽然,这11种小蠹虫具有各自不同的生态位宽度,且存在不同程度的生态位重叠,但各小蠹虫可依据其对寄主树木营养和空间需求的不同、种群密度的相互制约,以及入侵寄主树木时序的差异达到竞争的平衡和共存。秦岭华山松小蠹生态系统的建立,首先是由华山松大小蠹入侵健康华山松,并通过携带蓝变真菌入侵寄主树木,迅速克服寄主树木抗性系统,使寄主树木树势衰弱;其次松六齿小蠹、暗额星坑小蠹和松十二齿小蠹,作为秦岭华山松的主要次期性小蠹,迅速入侵衰弱的寄主华山松;最后其它次期性小蠹虫入侵寄主树木,利用寄主华山松剩余营养和空间。从而实现秦岭华山松立木小蠹生态系统的动态稳定。  相似文献   
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