虫生真菌在准格尔旗沙棘木蠹蛾上的流行

为了了解沙棘木蠹蛾Holcocerus hippophaecolus幼虫的虫生真菌的物种多样性和流行情况,对内蒙古准格尔旗某沙棘林中的虫生真菌进行了调查,采集到11个虫生真菌标本。经实验室显微观察鉴定,其中1个为雷州被毛孢Hirsutella leizhouensis侵染,1个为一种被毛孢Hirsutella sp.侵染,9个为球孢白僵菌Beauveria bassiana侵染;分离纯化得到7株球孢白僵菌菌株。     

玉米大斑病菌对广州地区甜玉米的致病性观测

通过对桂甜和华珍两个甜玉米品种的玉米大斑病病斑扩展速率及病情指数的研究结果表明,不同品种对玉米大斑病菌的抗性存在明显的差异;病斑的产孢特性显示,病斑首次产孢量显著高于再次产孢量。通过比较不同温度下的菌丝生长量,分析出广州地区玉米大斑病菌的主要构成属于高温型。     

Evidence that moxidectin is a greater risk factor than ivermectin in the development of resistance to macrocyclic lactones by Ostertagia spp in sheep in south eastern Australia

AIM: To determine associations between resistance of Ostertagia (= Teladorsagia) spp to macrocyclic lactone (ML) anthelmintics and history of use of anthelmintics, by type, on commercial sheep farms in temperate regions of southern South Australia and Victoria, Australia.

METHODS: Faecal egg count reduction tests (FECRTs) were conducted during a 2.5-year period (from August 2001 to January 2004) and records of the type of anthelmintic used in the 5 years preceding the FECRTs were collected from commercial sheep farms (n=103) in southern South Australia and Victoria, and data analysed retrospectively. ML resistance was defined as <95% reduction of Ostertagia spp 10–14 days after treatment with ivermectin (IVM), orally, at half the manufacturer's recommended dose rate. Use of anthelmintics in the preceding 5 and 10 years on each property was classified according to the nett number of years each of the following classes of drug had been used: IVM oral liquid (IVO), IVM controlled-release capsules (CRCs), abamectin (ABA), moxidectin (MOX) or a non-ML an- thelmintic. The prevalence of ML resistance, by property, was analysed for associations with prior use of anthelmintics.

RESULTS: Resistance by Ostertagia spp to ML anthelmintics was evident on 51/103 (49.5%) properties. The prevalence of resistance was lowest (23%) on properties on which MOX had not been used, and was significantly higher (64–77%) on properties on which MOX had been used for ≥2 of the preceding 5 years (p<0.001). In contrast, the prevalence of resistance was highest (70–74%) on the properties on which IVM, or IVM and/ or ABA, had not been used in the previous 5 years (on which the use of MOX was predominant), and was markedly lower (20– 42%) on properties that had used IVM or IVM and/or ABA for at least one of the preceding 5 years. Prevalence of resistance was higher for properties on which the only ML anthelmintic used was MOX (19/29=66%) than for those on which the only ML used was IVO (2/19=11%; p<0.001). Properties on which the only ML used was MOX were 2.72 times more likely to have resistance than properties on which the only ML used was IVO (95% confidence interval (CI) = 1.01–5.08).

CONCLUSION: Use of MOX for ≥2 of the preceding 5 years was associated with a higher prevalence of resistance to ML by Ostertagia spp on sheep farms in south eastern Australia than the use of IVO.     

浅析伊图里河林业局森林资源消长趋势

文章通过对伊图里河林业局1994年、2005年两次二类调查数据的分析,详细阐述了森林资源消长变化总趋势,在此基础上对伊图里河林业局森林资源现状及其特点进行了分析,提出了对森林资源管理利用的建议。     

An approach for regional threat assessment under IUCN Red List criteria that is robust to uncertainty: The Fiordland bottlenose dolphins are critically endangered

Numerous globally abundant species are exposed to human impacts that threaten the viability of regional populations. Assessing and characterising the risks faced by these populations can have significant implications for biodiversity conservation, given the ecological importance of many such species. To address these risks, the IUCN is starting to conduct assessments of regional populations in addition to species-level assessments of conservation status. Here, we demonstrate a threat assessment process that is robust to uncertainty, applying the IUCN criteria to a regional population of bottlenose dolphins in Fiordland, New Zealand. We compiled available population-specific information to assess the population under the five Red List criteria. We estimated there were 205 Fiordland bottlenose dolphins (CV = 3.5%), using current estimates of abundance for two sub-populations and stochastic modelling of an earlier estimate for the third sub-population. Population trajectory and extinction risk were assessed using stochastic age-structured Leslie matrix population models. The majority of model runs met the criteria for classification as critically endangered (C1: 67.6% of runs) given the number of mature individuals (123; CV = 6.7%) and the predicted rate of population decline (average decline: 31.4% over one generation). The evidence of isolation of the population confirms this was an appropriate regional classification. This approach provided an assessment that was robust to uncertainty.     

Response of weed emergence to rate of Vicia villosa Roth and Secale cereale L. residue

Vicia villosa Roth (hairy vetch) or Secale cereale L. (rye) residue at 2 to 4 times the natural field rate reduced seedling emergence of a wide variety of weed species. However, the natural rate of residue was insufficient for control of most weed species. The form of the response of weed emergence to increasing rates of residue varied among species: emergence of some species showed a monotonic decline in response to increasing rates of residue whereas emergence of others increased at low rates before declining at higher rates. In addition to reducing number of seedlings, high rates of residue delayed the date of emergence. Seed size was generally not a good indicator of a species' ability to emerge through residue, although one very large seeded weed, Abutilon theophrasti. was especially insensitive to residue. V. villosa and 5. cereale did not differ greatly in their effect on weeds early in the growing season, but V. villosa decomposed more rapidly and allowed greater emergence later in the season. Effet de résidus de Vicia villosa Roth et de Secale cereale L. sur la levée des mauvaises herbes Des résidus de Vicia villosa Roth (Vesce velue) et de Secale cereale L. (seigle) à 2–4 fois la quan-tité normale réduisaient la levée d'un large spectre de mauvaises herbes. Cependant la quantité normale de résidus était insuffisante pour lutter contre la plupart d'entre elles. La réponse de la levée des mauvaises herbes à des quantités crois-santes de rVsidus différait selon les espèces. Pour certaines, la levée subissait un déclin monotone; pour d'autres, elle augmentait en présence de faible quantités de reésidus puis décroissait pour des quantités plus importantes. Ces dernières réduisaient la levée et la retardaient également. La taille des graines n'était généralement pas un bon indicateur de la capacité des espèces à lever au travers des résidus, bien qu'une trèAs grosse grains, Abutilon theophrasti Medic., était particu-lièrement insensible aux résidus. V. villosa et 5. cereale ne différaient pas beaucoup dans leur effet sur les mauvaises herbes en début de saison, mais V. villosa se décomposait plus rapidement et permettait des levees plus importantes en fin de saison. Wirkung von Emterückständen von Vicia villosa Roth und Secale cereale L. aufdie Keimung von Unkräutern Durch 2- bis 4 fache Ernteräckstände der Be-haarten Wicke (Vicia villosa) und des Roggens (Secale cereale) wurde die Keimung einer großen Zahl von Unkrautarten herabgesetzt. Normale Ernterückstandsmengen behinderten jedoch die Keimung nur unzureichen. Die Art und Weise der Reaktion der Keimung auf höhere Riick-stände war von Art zu Art verschieden: Die Keimung einiger Arten nahm mit zunehmender Menge an Ernterückständen gleichmäßig ab, während sie bei anderen bei niedrigen Mengen anstieg, urn dann bei höheren Mengen abzunehmen. Zusätzlich zur Verringerung der Keimpflanzendichte wurde bei hohen Rück-standsmengen die Keimung verzögert. Die Samengröße war im allgemeinen kein guter Indikator für die Fähigkeit einer Art, durch das Rückstandsmaterial zu keimen, obwohl eine Art mit großen Samen, Abutilon theophrasti, gegenüber diesen Rückständen besonders unempfindlich war. Die Rückstände der beiden Kulturpflanzen zeigten zu Beginn der Vegetationsperiode keine großen Wirkungsunterschiede, aber die Rückstände von Vicia villosa zerfielen schneller und ließen später eine stärkere Keimung zu.     

Spatial scale invariance of southern Australian forest fires mirrors the scaling behaviour of fire-driving weather events

Power law frequency-size distributions of forest fires have been observed in a range of environments. The scaling behaviour of fires, and more generally of landscape patterns related to recurring disturbance and recovery, have previously been explained in the frameworks of self-organized criticality (SOC) and highly optimized tolerance (HOT). In these frameworks the scaling behaviour of the fires is the global structure that either emerges spontaneously from locally operating processes (SOC) or is the product of a tuning process aimed at optimizing the trade-offs between system yield and tolerance to risks (HOT). Here, we argue that the dominant role of self-organized or optimised fuel patterns in constraining unplanned-fire sizes, implicit in the SOC and HOT frameworks, fails to recognise the strong exogenous controls of fire spread (i.e. by weather, terrain, and suppression) observed in many fire-prone landscapes. Using data from southern Australia we demonstrate that forest fire areas and the magnitudes of corresponding weather events have distributions with closely matching scaling exponents. We conclude that the spatial scale invariance of forest fires may also be a mapping of the meteorological forcing pattern. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Glycaemic index, glycaemic load and risk of endometrial cancer: a prospective cohort study

OBJECTIVE: High-glycaemic-load diets may increase endometrial cancer risk by increasing circulating insulin levels and, as a consequence, circulating oestrogen levels. Given the paucity of epidemiological data regarding the relationship between dietary glycaemic index and glycaemic load and endometrial cancer risk, we sought to examine these associations using data from a prospective cohort study. DESIGN, SETTING AND SUBJECTS: We examined the association between dietary glycaemic load and endometrial cancer risk in a cohort of 49,613 Canadian women aged between 40 and 59 years at baseline who completed self-administered food-frequency questionnaires between 1982 and 1985. Linkages to national mortality and cancer databases yielded data on deaths and cancer incidence, with follow-up ending between 1998 and 2000. RESULTS: During a mean of 16.4 years of follow-up, we observed 426 incident cases of endometrial cancer. Hazard ratios for the highest versus the lowest quartile level of overall glycaemic index and glycaemic load were 1.47 (95% confidence interval (CI) = 0.90-2.41; P for trend = 0.14) and 1.36 (95% CI = 1.01-1.84; P for trend = 0.21), respectively. No association was observed between total carbohydrate or total sugar consumption and endometrial cancer risk. Among obese women (body mass index >30 kg m(-2)) the hazard ratio for the highest versus the lowest quartile level of glycaemic load was 1.88 (95% CI = 1.08-3.29; P for trend = 0.54) and there was a 55% increased risk for the highest versus the lowest quartile level of glycaemic load among premenopausal women. There was also evidence to support a positive association between glycaemic load and endometrial cancer risk among postmenopausal women who had used hormone replacement therapy. CONCLUSIONS: Our data suggest that diets with high glycaemic index or high glycaemic load may be associated with endometrial cancer risk overall, and particularly among obese women, premenopausal women and postmenopausal women who use hormone replacement therapy.     

Evaluating light trap efficiency by application of mesh to prevent inter- and intra-specific in situ predation on fish larvae and juveniles

Amongst passive collecting gear types, light traps have been used extensively to sample the larvae and juveniles of fish in both marine and freshwater environments, and especially so in structurally complex habitats. Although a number of modifications have been proposed to increase efficiency, no account has hitherto been made of the possible loss of trapped larvae and juveniles as a result of within-trap predation by piscivorous fish. To address this issue, we evaluated the efficiency of modified light traps by the addition of mesh (3 mm knot-to-knot wrapped around the entrance chambers), by combining results from a long-term monitoring study with those from a designed field experiment. Abundance of larvae and juveniles collected during the monitoring program was higher in the years following mesh application (hence, beyond monthly variation), and this was supported by the experiment. Based on the latter, light/mesh traps consistently caught only larvae/juveniles, hence excluding adults; whereas the opposite was true of the light/no-mesh trap combination. Also, mesh/no-light traps did not capture any fish, unlike no-mesh/no-light traps, which sampled only adults. Our findings suggest that in situ predation on larvae and juveniles within light traps should not be overlooked. The occurrence of piscivorous and cannibalistic behaviour in Hypseleotris spp. is also discussed.     

Precambrian sponges with cellular structures

Sponge remains have been identified in the Early Vendian Doushantuo phosphate deposit in central Guizhou (South China), which has an age of approximately 580 million years ago. Their skeletons consist of siliceous, monaxonal spicules. All are referred to as the Porifera, class Demospongiae. Preserved soft tissues include the epidermis, porocytes, amoebocytes, sclerocytes, and spongocoel. Among thousands of metazoan embryos is a parenchymella-type of sponge larvae having a shoe-shaped morphology and dense peripheral flagella. The presence of possible amphiblastula larva suggests that the calcareous sponges may have an extended history in the Late Precambrian. The fauna indicates that animals lived 40 to 50 million years before the Cambrian Explosion.