Effect of Swiss needle cast on Douglas-fir stem ethanol and monoterpene concentrations, oleoresin flow, and host selection by the Douglas-fir beetle

Douglas-fir growing on the western slopes of the Oregon Coast Range are experiencing an unprecedented outbreak of Swiss needle cast (SNC) caused by the fungus Phaeocryptopus gaeumannii. SNC can produce substantial physiological stress in host trees by reducing needle gas exchange and enhancing premature needle abscission, resulting in slower growth. Based on the frequent link between stressed trees and insect activity, we explored the potential influence of SNC on Douglas-fir beetle, Dendroctonus pseudotsugae, activity and some tree physiological parameters that may influence beetle attraction (i.e., constitutive ethanol and monoterpene contents of woody tissues) and host susceptibility (i.e., wound-induced resin flow). Woody tissue ethanol concentrations, wound-induced resin flow, and beetle attraction were all reduced as SNC severity increased. Although trees affected by SNC attracted fewer beetles, the number of attacks did not decline, the attacks were more likely to penetrate to sapwood depth, and the galleries were longer than in healthier trees, most likely due to a weakened oleoresin defense. However, there have been no current reports of increased Douglas-fir beetle activity on SNC stressed trees, and no rapid increases in beetle population numbers, or outbreaks associated with these diseased forests. SNC stressed trees may remain free from attacks because pioneering beetles have difficulty recognizing them as being stressed with low ethanol concentrations. Furthermore, beetle populations may not be increasing since stressed trees appear unsuitable for reproduction, as no eggs, larvae, or adult beetles were observed in excavated galleries on any attacked trees. However, if large volumes of host materials became available as a result of some catastrophic event (e.g. wildfire or wind-throw), and the beetles can reproduce successfully enough to increase population densities then the potential for a devastating outbreak of Douglas-fir beetle in SNC stressed trees might be exacerbated because they have compromised oleoresin defense systems, and may be killed with fewer beetle attacks.     

Annual variation of pathogen occurrence and pathogen prevalence in<Emphasis Type="Italic"> Ips typographus</Emphasis> (Coleoptera,Scolytidae) from the BOKU University Forest Demonstration Centre

Four different pathogen species (Gregarina typographi, Chytridiopsis typographi, Unikaryon montanum and Menzbieria chalcographi) were found in adult Ips typographus from the Forest Demonstration Centre, BOKU University in the course of a 7-year period of investigation (1995–2001). Annual variations were found in both the spectrum and prevalence of pathogen species. Variations were found in the number of infected male and female beetles as well as the infections of beetles with different dates of emergence.     

Resistance of picea abies to ips typographus: tree response to monthly inoculations with ophiostoma polonicum,a beetle transmitted blue‐stain fungus

Fifty pole stage trees were inoculated with O. polonicum at monthly intervals between May and September. Most infection, measured as the area of sapwood blue‐stained, occurred in July and least in May and September. The difference between July, August and September might be explained by the effect of temperature on fungal growth, but in May and June the trees had a higher resistance than expected. Tree resistance was correlated with resinosis. Tree variables not correlated with resistance were DBH, annual ring width, periodic growth, vigor index, or phloem carbohydrate concentration.     

白僵菌防治甘蔗金龟子试验

试验结果表明，白僵菌与3．6％广谱型杀虫双颗粒剂混合施用，能有效控制金龟子幼虫对蔗根的危害，相对防效迭75％～85％，显著或极显著优于单独使用白僵菌或农药处理。     

How we improved a landscape study of species richness of beetles in woodland key habitats, and how model output can be improved

In an earlier study (Franc et al., 2007), local species richness of saproxylic oak beetles (including red-listed beetles) in forests was predicted mainly by the landscape (area of woodland key habitat within 1 km of plots). Such results are important for conservation work, but need to be backed up well, for reliable advice. We tested a two-stage method that improved our earlier models and our advice for conservation planning. We studied temperate mixed forest, rich in oaks Quercus robur/Quercus petraea, in a large landscape in Sweden. Franc et al. (2007) analysed 21 forests. Here we selected the significant explanatory variables (predictors) and other biologically relevant predictors, used the earlier 21 forests and sampled 11 new forests such that we expanded the range on the axes of the predictors. We collected in total 320 species of saproxylic oak beetles (23,137 individuals) of which 65 and 38 were red-listed (IUCN criteria, Swedish list 2000 and 2005, respectively). We partly confirmed our original results, but the results also changed in important ways: local species richness is now predicted by a combination of local, landscape and regional factors. Moreover, a local variable (dead wood) was the main predictor of saproxylic oak beetles (all species included), while for red-listed saproxylic oak beetles the landscape (woodland key habitat within 1 km of plots) was the main predictor, of local species richness. Thus, species richness of red-listed saproxylic oak beetles seems to depend mainly on landscapes factors, while total species richness of saproxylic oak beetles seems to depend more on local stand factors. We conclude that a two-stage research design can be useful in landscape and conservation studies, especially for species-rich taxa that require large samples per site.     

应用信息化合物防治小蠹虫的研究进展

小蠹虫是世界上重要的森林害虫,常造成森林大面积死亡.小蠹虫多存在于高中山区且其生活隐蔽,利用传统的防治方法很难达到较好的效果.近年来利用化学信息物质防治小蠹虫成为国内外研究的热点.本文简要概述了化学信息物质,特别是寄主次生性物质和小蠹虫信息素对小蠹虫寄主选择行为的影响,以及国内外应用化学信息物质防治小蠹虫的进展.     

辽宁白石砬子自然保护区小蠹区系的研究

通过调查,在白石砬子自然保护区共采到小蠹28种,隶属4亚科14属,欧洲-西伯利亚区系种类占绝大多数.东北四眼小蠹(Polygraphus sachalinensis Eggers)、中穴星坑小蠹(Pityogenes chalcographus Linnaeus)、六齿小蠹(Ips acuminatus Gyllenhal)为优势种.小蠹虫在保护区内主要为害衰弱木、濒死木、枯萎木及风倒雪压木等,少数种类也为害健康树木,如黄须球小蠹(Sphaerotrypes coimbatorensis Stegbbing)、纵坑切梢小蠹(Tomicuspiniperda L.).不同海拔高度及不同林分类型小蠹种类及为害也有明显差异.及时清除,集中处理保护区内的风倒木,是控制虫源、减轻为害的重要措施.     

Selecting areas to protect the biodiversity of aquatic ecosystems in a semiarid Mediterranean region using water beetles

• 1. In this work, carried out in the province of Murcia, a representative semi‐arid area of the Iberian Peninsula, water beetles were used as indicators to identify the aquatic ecosystems with the highest interest for conservation. For that purpose, an iterative algorithm of complementarity based on the richness of aquatic Coleoptera was applied. ‘Complementarity’ refers to the degree to which an area, or set of areas, contributes otherwise unrepresented attributes to a set of areas. This principle was used to maximize the number of species represented within a given number of areas.
• 2. Only the species subsets whose taxonomic status, presence and distribution in the study area are well known were used. In total, 146 species were included, of which 12 are Iberian endemics and 32 are rare species (found only in one grid cell in the study area).
• 3. The highest correlation was generally shown by species richness with endemic, rare and vulnerable species richness. Thus, basing conservation strategies on species richness appears to be an effective protocol.
• 4. To preserve the highest degree of biodiversity in the aquatic ecosystems of the study area, the following need to be protected: (a) headwater streams in the north west of the province; (b) the uppermost reaches of the Segura River; (c) hypersaline and coastal ramblas; (d) rock pools and coastal ponds.
• 5. The present network of Protected Natural Spaces in the study area does not include many of the aquatic ecosystems shown to have the highest biodiversity of beetles. However, the future European ‘Natura 2000’ network will protect the 10 grid cells of highest aquatic biodiverstity, or at least part of them.

Copyright © 2004 John Wiley & Sons, Ltd.     

阿拉山口口岸进境木材截获小蠹虫鉴定与分析

对阿拉山口出入境检验检疫局从进境木材中截获的11种小蠹虫的寄主、分布、危害及主要形态鉴定特征等进行了描述,并分析了其经济及检疫重要性,为国内同类口岸进境木材检疫鉴定提供了参考。     

内蒙古武川县农田退耕还草对粪金龟子群落的影响

2006年5-9月,诱捕法采集粪金龟子,以农田为对照,选择内蒙古武川县不同农田退耕管理方式为研究样地,分析了农田退耕后采取不同管理方式对粪金龟子群落的影响,以为农田退耕还草管理措施生态效应的评价和完善提供依据。共捕获粪金龟子21671头,隶属于3科5属25种。优势种为直蜉金龟(Aphodius rectus)和蜉金龟属(Aphodius sp.7),占总捕获量的比例分别为59.34%和11.71%。几种退耕管理方式都导致粪金龟子群落物种丰富度、生物量和多度提高,且具有显著的季节特征。Pearson相关分析表明,粪金龟子群落的物种丰富度、生物量和种数以及不同功能群和主要种的个体数与退耕年限、平均草高和植物群落盖度的变化存在显著正相关关系(P<0.01或P<0.05)。由于长期农业耕作以及缺少大型食草动物和较大面积放牧草地,研究地区的粪金龟子群落组成以功能群Ⅱ和Ⅲ为主,功能群Ⅰ的多度和物种丰度较低。可以认为,在研究地区以农田景观为主要基质的区域,采取多样化的农田退耕管理方式,提高了生境的空间异质性,在减少人为耕作活动对粪金龟子影响的基础上,对粪金龟子物种丰度和多度的维持起到了促进作用。农田退耕、保留适当面积放牧草地或适当数量大型放牧家畜将有利于功能群Ⅰ物种丰度和多度的提高,有益于粪金龟子群落物种多样性和整体生态功能的维持。