关键词： 树鼩   实验动物   灵长   结构形态   进化程度  

摘要： 一种被国际公认的高级实验动物树鼩,在我校动物实验中心饲育成功,并用于中德合作课题研究。树鼩(Twpaia belangeris,Tree shrew)国际通称为村仙(Twpaia Glis)。

关键词： 乙型肝炎病毒   乙肝疫苗   树鼩  

摘要： 接种乙肝疫苗的10只树鼩,9只血清出现抗-HBs。注射含HBV的人血清后,其中只有1只血清出现短暂的HBsAg,保护率为88.88％;其血清抗-HBc始终阴性。未接种乙肝疫苗的10只对照树鼩注射HBV人血清后,5只血清HBsAg阳性;8只抗-HBc阳性。接种疫苗组HBV感染率显著低于对照组(p<0.01)。实验前所有树鼩血清HBsAg、抗-HBs及抗-HBc均阴性。实验结果表明:1)乙肝疫苗能阻断树鼩感染HBV,进一步确证树鼩能感染HBV,是用于研究HBV的有用的动物模型;2)树鼩可能代替黑猩猩进行乙肝疫苗安全性和免疫保护效果鉴定之用。

关键词： 麻风杆菌   树Qu   动物模型  

摘要： 树鼩(Tupaia Belangeri)是云南的一种野生动物,属哺乳动物,体温近于人类者(38℃左右)。寿命5～10年。因而我们选择此动物进行麻风杆菌动物模型的实验。从1983年开始,在5年中,进行多种方式和多次的重复足垫的接种,证实麻风杆菌已能在此动物中生长繁殖,其细菌量可达2.7×10~9,多于小白鼠足垫中者。足垫的组织病理变化也符合麻风的表现。所以我们认为根据以上实验结果,证实树鼩是麻风杆菌又一个新的模型。

关键词： Seasonal population abundance   Soil surface-inhabiting arthropods   Abiotic environmental variables   Tropical semi-arid savanna  

摘要： Seasonality of relative population abundance in different groups of soil-surface arthropods was investigated monthly by pit-fall traps during a 2-year period in the grassland and tree-planted areas of a tropical semi-arid savanna at Warangal (south India). Densities of most groups were lowest during summer and highest during the rainy season. They were less abundant during winter. Arthropods were recorded in higher numbers in tree-planted compared to grassland areas. Certain arthropods that were found only during part of the year were recorded for a longer period in tree-planted area. Formicidae Monomorium indicum Forel, Crematogaster sp. and Pachycondyla? tesserinoda (Emery), and Coleoptera, Pachycera sp. reached maximum densities in the rainy season and minimum numbers during winter and summer in the grassland area. However, these species had lower densities during the rainy season and reached maximum densities during winter and summer in the tree-planted area. The seasonal abundance of arthropods showed significant linear correlations with different abiotic environmental variables such as rainfall, soil moisture, organic matter, soil and air temperatures, soil pH, relative humidity at the soil surface, and potassium and phosporus of surface soil. Soil moisture and rainfall were generally the strongest correlates with densities, particularly in the grassland area.

关键词： Platanus   Entomofauna   Pests   Phyllonorycter platani  

摘要： Fifty-four insect and four mite species are included in a list of the entomofauna of plane [Platanus] trees in Isreal. Only two species are monophagous: Phyllonorycter platani (Stgr.) (Lepidoptera: Gracillariidaed) and Edwardsiana iranicola Zachv, (Heteroptera: Cicadellidae). Four species are noxious: P. platani, the main insect pest of the plane trees in Israel;Zeuzera pyrina L. (Lepidoptera: Cossidae);Kalotermes flavicollis F. (Isoptera: Kalotermitidae);and E. iranicola. Of much lesser importance are Targionia vitis Sign. (homoptera: Diaspididae), Heliothrips haemorrhoidalis Bche. and Retithrips syriacus May. (Thysanoptera: Thripidae). About half of the listed species are natural enemies and many are parasites of P. platani. Details are given on the noxious species, together with recommendations for prevention and control.

关键词： 三维   动物体表   线性八叉树   表示法  

关键词： Tannic acid   Nutritional ecology   Malacosoma disstria   Orgyia leucostigma   Toxin  

摘要： Feeding efficiencies of ultimate instar larvae of two polyphagous tree-feeding Lepidoptera, Malacosoma disstria (Lasiocampidae) and Orgyia leucostigma (Lpiparidae), were measured on artificial diets containing from 0% to 8% tannic acid. Relative growth rate (RGR) of O. leucostigma was not affected by up to 8% tannic acid, suggesting that O. leucostigma has evolved an effective conteradaptation to hydrolyzable tannins. In contrast, as little as 0.5% tannic acid caused a significant reduction in RGR of M. disstria, due both to reduced efficiency of conversion of digested food (ECD) and reduced relative consumption rate (RCR), and caused a significant increase in mortality during the pupal stage. Moreover, when reared from hatching on tannin-containing diets, no M. disstria larvae survived past the fourth instar. Although tannins are commonly referred to as "digestibility-reducing substances", tannic acid did not reduce the ability of M. disstria or O. leucostigma larvae to digest either the whole diet or nitrogen contained in the diet. For M. disstria, tannic acid acts as a toxin and a feeding deterrent, but not as a digestibility-reducing substance. Growing evidence that tannins commonly act as toxins warrants a reassessment of their role in anti-herbivore chemistry.

关键词： Forest dynamics   Trees bark   Thermal properties   Arthropod fauna   Africa  

摘要： The thermal properties of 26 Africian tree species in two different ecosystems were studied using thermocouples. In a subtropical moist forest were three bark types of trees: species with thin and smooth bark types with low values of insulation across the bark;species with a more structured bark type and medium insulation values;and species with deep-fissured or scaly bark types and high insulation values. Only these trees are able to survive openings in the subtropical forest and stand alone on edges of forest gaps. In the savanna all tree species showed adaptations in the structure of their bark in different forms: many tree species shade their trunks. Some have low bark insulation and these are known to be sensitive to fires. Some tree species show high bark insulation and do not shade their trunks. Tree species with white bark avoid overheating of their surface by reflection of the radiation. The arthropod community living exclusively on the bark was investigated for the first time on South African trees, on ten tree species. In the two different ecosystems this habitat is occupied by different arthropod groups. In the subtropical forest Acari, Araneae, Opiliones, Isopoda, Myriopoda, Blattodea, Psocoptera, Heteroptera, Coleoptera, Formicidae, and Nematocera (Diptera) are the main arthropod groups living exclusively on the bark of trees. In the savanna Pseudoscorpiones, Araneae, Collembola, Blattodea, Psocoptera, Coleoptera, Neuroptera, Termites, Formicidae, Hymenoptera and Brachycera (Diptera) are the main arthropod groups living exclusively on the bark of trees. Within one ecosystem on one bark type the dominant species are similar;richly structured bark types have a richer fauna. In the forest, bark arthropod diversity is related to the bark structure of the constituent trees, and the arthropod communities on the bark would reflect changes in the structure of the forest. Forests comprising tree species with different bark types would have a richer total bark a

关键词： Disturbance   Dung   Grazing   Mesquite   Prosopis glandulosa   Rio Grande Plains   Succession   Texas  

摘要： The relationship between domestic cattle and vegetation change in a savanna woodland was evaluated with respect to dung deposition and the dispersal and establishment of mesquite (Prosopis glandulosa var. glandulosa, Mimosaceae), a cosmopolitan woody invader of grasslands in the southwestern USA. Dung deposited in autumn disintegrated rapidly, leaving patches of bare ground ranging from 50 to 900 cm2. Herbaceous cover on gaps created by dung deposition recovered to levels comparable to neighboring vegetation by the end of the following growing season. Vegetation colonizing gaps consisted primarily of grasses not found in the surrounding vegetation. Dung deposition increased species diveristy and spatial heterogeneity of the herbaceous vegetation and contributed to the development of a fine-grain mosaic of small patches of varying successional age-states. The role of cattle in facilitating the ingress and establishment of mesquite has broader implications with regard to the conversion of grasslands to woodlands. On the site with cattle, mesquite seedlings were found in 75% of dung pats surveyed in September (mean = 4.2 seedlings per pat;maximum = 50). Although seedling survival in dug (79%) was only 16% greater than that of mesquite emerging from seeds experimentally sown away from dung, no seedlings were found on areas without cattle. Mean (.+-. SE) density of mesquite seedlings ranged from 12 .+-. 2 to 15 .+-. 2 m-2 on the site with cattle. Seed densities away from parent plants averaged 10.7 m-2 and 0.0 m-2 on areas with and without cattle, respectively. Seed densities beneath adult plants were comparable between sites. The high density of seedlings on areas with cattle, in contrast to absence of seedlings on the area without cattle, suggests rates of invasion of grasslands by mesquite would have increased substantially in North America following the settlement and introduction of domestic ungulates. Prior to the introduction of livestock, poor seed dissemination

关键词： African savanna   Spiders   Small-mammal burrows  

摘要： In the Nylsvley Nature Reserve, in the South African savanna, the spider community in 320 abandoned mammal burrows was investigated. Three species, Agelena ocellata (Agelenidae), Euprosthenops proximus (Pisauridae) and Smeringopus pallidus (Pholcidae), coexisted in the burrows. The number of individuals and the number of species inhabiting the burrows increased with burrow size. Gerbil burrows were apparently too small to provide space for more than one individual of any of the three species. Only the burrows of springhares, warthogs, and antbears contained more than one spider. When artificial burrows were provided a rapid increase in settlement resulted. Competition for space therefore seems to be the determining factor influencing the population size. A relatively low number of prey items (136, in 119 webs) were found in agelenid webs only. Kleptoparasitic ants were observed stealing prey items from the webs.