我国入侵害虫西部喙缘蝽的溯源分析

本文对我国外来入侵物种西部喙缘蝽Leptoglossus occidentalis Heidemann, 1910进行了溯源分析,依据对国内种群的观察和标本简要描述了其形态特征和生活习性。通过野外采集国内种群标本,提取扩增COI基因序列,结合原产地和国外其他入侵种群的公共序列,构建西部喙缘蝽COI基因数据集,以中国入境口岸对木材的检疫情况为参考,分析西部喙缘蝽的入侵来源。全世界目前已知10种单倍型,中国存在4种。山东青岛种群有H＿8、H＿9和H＿10三种单倍型,其中H＿8与韩国共享,H＿9和H＿10为中国特有单倍型,青岛种群可能部分来自韩国;山东烟台两个采集点的种群都属于H＿2,可能来自北美东部,与青岛种群的入侵来源不同。以上分析表明,我国西部喙缘蝽种群可能来源于多次独立入侵事件,同时在国内发生了小范围的扩散迁移。本研究首次对我国入侵害虫西部喙缘蝽做了溯源分析,为更好地制定规制措施,开展检疫防治工作提供了科学依据。     

气候变化下新入侵种——西部喙缘蝽在中国的潜在分布区预测

西部喙缘蝽Leptoglossus occidentalis Heidemann是一种为害针叶树的全球性害虫。中国于2021年首次在威海和青岛发现该成虫,是一种新入侵物种。为明确西部喙缘蝽在中国的潜在分布情况,揭示未来气候变化下西部喙缘蝽的分布动态,本研究以其在全球的824个有效分布记录和筛选出的12个环境变量为基础,用最大熵模型和地理信息系统软件,对其在第6次国际耦合模式比较计划（The 6th Coupled Model Intercomparison Project,CMIP6）不同的共享社会经济路径（Shared socioeconomic pathways,SSP）下,预测当前和2021-2040 年、2041-2060年、2061-2080年、2081-2100年时期空间分布格局的动态变化。最大熵模型评估ROC曲线结果显示,西部喙缘蝽的训练值和测试值分别为0.943和0.944,表明模型预测结果极好,可信度极高。在当前气候条件下,西部喙缘蝽在中国的潜在分布区总面积为1.95 × 106 km2,共计有21个省份或地区有其适生区;在未来气候条件下,西部喙缘蝽潜在分布区面积大多数时候比当前气候条件下的面积略小,且呈现先下降后上升再下降的波浪式趋势,在低强迫情景（SSP1-2.6）和高强迫情景下（SSP5-8.5）的变化趋势一致,均在2061-2080 年出现一个峰值。西部喙缘蝽危害大、扩散快,在中国具有较大的潜在分布面积,本研究可为该虫的入侵和扩散提出预警,并为虫害的管理和综合防治提供科学依据。     

Mountain pine beetle host-range expansion threatens the boreal forest

The current epidemic of the mountain pine beetle (MPB), an indigenous pest of western North American pine, has resulted in significant losses of lodgepole pine. The leading edge has reached Alberta where forest composition shifts from lodgepole to jack pine through a hybrid zone. The susceptibility of jack pine to MPB is a major concern, but there has been no evidence of host-range expansion, in part due to the difficulty in distinguishing the parentals and their hybrids. We tested the utility of a panel of microsatellite loci optimized for both species to classify lodgepole pine, jack pine and their hybrids using simulated data. We were able to accurately classify simulated individuals, and hence applied these markers to identify the ancestry of attacked trees. Here we show for the first time successful MPB attack in natural jack pine stands at the leading edge of the epidemic. This once unsuitable habitat is now a novel environment for MPB to exploit, a potential risk which could be exacerbated by further climate change. The consequences of host-range expansion for the vast boreal ecosystem could be significant.     

Evaluating resistance of some rootstocks to grape phylloxera with in vitro and excised root testing systems

Summary The life table of a local strain of grape phylloxera was determined to evaluate the resistance of the most commonly used rootstocks: Rul40, R99, and 3309C, and one local variety ‘Helwani’. The study was carried out by applying both in vitro dual culture and small root pieces testing systems. The results showed that there was a great variation in percentage mortality of immature stages, number of eggs laid, adult fertility, oviposition period, and developmental time between all tested rootstocks and the local variety, regardless of the applied testing systems. Based on the population prediction, Helwani would be a suitable host as it would be susceptible to the destructive insects in the field and the rootstocks would be resistant. However, Rul 40 rootstock was more susceptible than R99 and 3309C rootstocks.     

Interpreting recruitment limitation in forests

Studies of tree recruitment are many, but they provide few general insights into the role of recruitment limitation for population dynamics. That role depends on the vital rates (transitions) from seed production to sapling stages and on overall population growth. To determine the state of our understanding of recruitment limitation we examined how well we can estimate parameters corresponding to these vital rates. Our two-part analysis consists of (1) a survey of published literature to determine the spatial and temporal scale of sampling that is basis for parameter estimates, and (2) an analysis of extensive data sets to evaluate sampling intensity found in the literature. We find that published studies focus on fine spatial scales, emphasizing large numbers of small samples within a single stand, and tend not to sample multiple stands or variability across landscapes. Where multiple stands are sampled, sampling is often inconsistent. Sampling of seed rain, seed banks, and seedlings typically span <1 yr and rarely last 5 yr. Most studies of seeding establishment and growth consider effects of a single variable and a single life history stage. By examining how parameter estimates are affected by the spatial and temporal extent of sampling we find that few published studies are sufficiently extensive to capture the variability in recruitment stages. Early recruitment stages are especially variable and require samples across multiple years and multiple stands. Ironically, the longest duration data sets are used to estimate mortality rates, which are less variable (in time) than are early life history stages. Because variables that affect recruitment rates interact, studies of these interactions are needed to assess their full impacts. We conclude that greater attention to spatially extensive and longer duration sampling for early life history stages is needed to assess the role of recruitment limitation in forests.     

Glycosides from Pinus contorta needles

The β-d-glucopyranosides of zingerone, rheosmin acetoxydihydro-p-coumaryl alcohol, chavicol, benzoic acid and 2(or 4)-hydroxy-4(or 2)- methoxyprop-1-ene were isolated from the water soluble fraction of Pinus contorta needles, in addition to a dilignol-l-rhannopyranoside.     

Influence of broadleaf trees on soil chemical properties: A retrospective study in the Sub-Boreal Spruce Zone,British Columbia,Canada

A retrospective study examined the influence of broadleaf trees, principally paper birch (Betula papyrifera Marsh.), on soil properties under mixedwoods with lodgepole pine (Pinus contorta var. latifolia Dougl. ex Loud.) in the Sub-Boreal Spruce zone of central British Columbia, Canada. After 23 years, approximately 50% of the forest floor mass typical of mature forests in this zone had already accumulated on an initially denuded surface, but this new forest floor was poor in woody components. Correlation analysis found no relationship between the degree of broadleaf occupancy and total forest floor accumulation, but a significant qualitative influence on chemical properties of the non-woody forest floor components: higher pH, total N, available P, extractable Ca, Mg, and K, and lower C:N ratios. No such relationships existed for the surface (0–20 cm depth) mineral soils.     

高温对西花蓟马卵巢发育及卵黄蛋白含量的影响

【目的】为探明短时高温热激后西花蓟马 Frankliniella occidentalis (Pergande)生殖力和卵巢发育的相互关系。【方法】选择1龄、2龄若虫,预蛹,蛹和1日龄成虫,采用不同高温（41和45℃）短时（2 h）处理,观察卵巢发育及卵黄蛋白相对含量的变化。【结果】高温热激主要抑制了西花蓟马生殖器官和胚胎的正常发育,导致卵巢管数量减少,卵巢管和胚胎发育畸形;电泳结合不同的染色方法证明西花蓟马的卵黄蛋白为一种磷酸化、糖基化的脂蛋白,由3个亚基组成,分子量分别为116,70和47 kDa。除热激蛹期外,热激其他龄期的若虫对其当代成虫卵黄蛋白合成都起到抑制作用,且45℃热激1龄或2龄若虫后,其对卵黄蛋白相对含量的影响持续到了F₁代。【结论】温度对雌虫生殖力的影响是由于其对生殖器官发育和卵黄蛋白合成的影响引起的。本研究为西花蓟马的卵黄蛋白和卵黄发生的进一步研究奠定了基础。     

Spatial Distribution of Mountain Pine Beetle Outbreaks in Relation to Climate and Stand Characteristics:A Dendroecological Analysis

Principal components analysis, followed by K-means cluster analysis, was used to detect variations in the timingand magnitude of Pinus contorfa Dougl. ex Loud. growth releases attributed to mountain pine beetle outbreaks in31 stands of central British Columbia. Four major growth release patterns were identified from 1970 to 2000.Variations in the timing of growth releases among clustered stands corresponded well to aerial survey dataindicating the timing of beetle outbreaks in the study area. Redundancy analysis was used to determine howvariations in the timing and magnitude of growth releases attributed to beetle outbreaks changed with variationsin climate or stand conditions over the study area. The first RDA axis, which accounted for 39% of the variations ingrowth patterns among stands, was significantly (P<0.05) correlated with gradients in the percentage of pine instands killed by mountain pine beetle, summer aridity, variation in summer precipitation, distance from initialinfestation site, average pine age, and maximum August temperatures. The second RDA axis explained 6% of thevariations and was significantly correlated with gradients in the beetle climate suitability index, extreme coldmonth temperatures, and site index. Comparisons of growth release patterns with aerial survey data and redun-dancy analyses indicated that dendrochronological techniques are useful for identifying mountain pine beetleoutbreaks in central British Columbia, particularly among stands that had a density high enough to produce agrowth release signal. Provided future studies account for interannual weather fluctuations, identification ofgrowth increases due to stand thinning caused by beetle outbreaks will be useful for reconstructing the history ofbeetle outbreaks over much longer time periods.