Effects of environmental factors on the species composition of aquatic insects in irrigation ponds

Although irrigation ponds contribute to the conservation of aquatic biodiversity, they have experienced declines in recent years. We therefore examined the relationships between various environmental factors and the community composition of aquatic insects, specifically insect predators, in irrigation ponds to gain knowledge that would aid in the conservation and restoration of biodiversity. We selected Odonata, Hemiptera and Coleoptera as target taxonomic groups and conducted censuses of these groups in 21 ponds in Shiga, central Japan. In total, we collected 30 and 10 species (or species groups) of Odonata and Hemiptera, respectively, and 17 species of Coleoptera. A partial canonical correspondence analysis revealed that the following four environmental factors significantly affected the species composition of aquatic insect communities: the number of emergent plant species, percent concrete revetment, presence of litter and peripheral length. Among these variables, the number of emergent plant species was the most potent factor, perhaps because emergent plants serve as sites for oviposition and emergence, and provide refugia for aquatic insects (odonate nymphs in particular). In contrast, some species specifically inhabited sites poor in emergent plants. This study shows that reductions in concrete revetments are necessary for the conservation of biodiversity. This would lead to increases in the number of aquatic plant species, which provide habitats and oviposition sites for many aquatic insects. Furthermore, to enrich the local biodiversity of aquatic insects, groups of irrigation ponds with different environments are needed.     

食用菌的代谢产物

本文概述了食用菌在新陈代谢过程中产生的代谢产物。这些物质主要包括抗生素、抗肿瘤活性物质、干扰素诱导物、降低胆固醇物质、特殊呈味物质、维生素及其它代谢产物等。     

一种六妹羊肚菌的新型柄腐病害

近年来,四川等地种植的六妹羊肚菌先后爆发柄腐病害,造成严重经济损失。本研究对该病害发生情况进行了调查,从四川、河南、甘肃、贵州4个省收集的12份六妹羊肚菌柄腐病子实体,分离纯化得到37株真菌和3株细菌。根据柯赫氏法则,对所有分离纯化得到的疑似病原菌进行了回接试验,最终确定GJB-3菌株为柄腐病的病原菌。经ITS、RPB2和EF1α序列分析,结合菌落形态和显微特征鉴定柄腐病的病原菌为Fusarium nematophilum。本研究为后期羊肚菌生产病害防控提供了有效的基础数据。     

The population of Odonata (dragonflies) in small tropical rivers with reference to asynchronous growth patterns

The odonate larval communities in three small rivers in Penang Island were studied. More species of dragonflies were found in the Botanical Garden and Titi Teras rivers (13 and 11 respectively) of relatively similar environmental parameters. Fewer (nine) dragonfly species were collected from the Youth Park River which has a lower dissolved oxygen (DO) and a higher biological oxygen demand (BOD), conductivity and turbidity. A mixture of sand, gravel and pebble substrate of Botanical Garden River with dense growth of submerged Hydrilla, grasses and Cladias (Araceae) provided suitable habitats for the dragonflies. The sandy substrate and relatively fast flowing water of Titi Teras River was highly preferred by gomphids. In the Youth Park River, the small community of dragonfly larvae was dominated by tolerant Pseudagrion rubriceps, P. microcephalum, Orthetrum chrysis and Crocothemis servilia. Based on the larval instar distribution of Ictinogomphus decoratus and O. chrysis, very asynchronous populations of these dragonflies occurred in each river. Young larvae were continuously introduced into the populations resulting in undulating growth rate curves. The growth rates of these two species were higher in the Titi Teras River when compared to those in other rivers. Density-dependent mortality, asynchronous cannibalism and fish predation could play important roles in regulating the larval dragonfly population in these rivers.     

Divergence in a transoceanic circumtropical dragonfly on a remote island

One terrestrial invertebrate that naturally spans the globe and travels vast distances is the dragonfly Pantala flavescens (Fabricius) (Odonata: Libellulidae). Recently, there has been a strong call to compare island with continental biota so as to meaningfully characterize island forms. This is done here. The variation and differences in morphology and behaviour of an African continental (Pietermaritzburg, South Africa) and a remote island population (Easter Island) of P. flavescens was investigated to determine whether the island population was panmictic with the migrant population, or whether it was a founder population. Several morphological characters were measured in both populations, and analysed using PCA, t-tests, coefficients of variation and Chi-square analyses. The continental and island populations were significantly different in body colour, head width and femur length. The island population had reduced hindwings, which were also more asymmetrical than the continental population, suggesting that the island individuals were possibly more genetically and environmentally stressed and had less genetic variation than the continental population. The island population was also more robust and flew lower to the ground than the continental population. There was no significant difference in body weight between the two populations because the migrant population had not begun to build up fat reserves for migration. Females were heavier than males in the continental population because they were carrying eggs. This was not the case in the island population because the individuals were not as mature. Colour was significantly different between the two populations, with island individuals having darker wings and abdomens, yet a lighter synthorax colouring than the continental population. Sexual dimorphism was marked in the abdomen and wing colour of the continental population, yet the island individuals showed more difference between the sexes in morphological characters than in colour. The fact that P. flavescens is the only species of dragonfly on Easter Island, and the great distance of the island from any mainland, suggests infrequent arrival of migrants arriving on the island, with resultant reduced genetic variation. The morphological and behavioural differences between the two populations suggests divergence is occurring.     

作物秸秆及其它废弃物栽培食用菌的农业生态效益研究

一、引言当前,世界上五大问题(环境、粮食、人口、资源和能源)日趋严重,在发展中国家解决饥饿、营养不良和贫困问题已成为人们关注的焦点。与此同时,人们也开始重视食用菌在利用农业有机废物转化为人类食物方面的积极     

In vitro ectomycorrhization of Tricholoma matsutake strains is differentially affected by soil type

The Japanese delicacy Tricholoma matsutake has been conducted in vitro ectomycorrhizal syntheses for more than 20 y. The development of its ectomycorrhizal structures varies among experimental systems. Here, we examined the effects of soil-fungus interactions on the early stage of in vitro T. matsutake ectomycorrhization. Axenic Pinus densiflora seedlings were transplanted into autoclaved natural inorganic soil, inoculated with the cultured mycelium of T. matsutake, and incubated for 90 d in vitro. Both soil type and fungal strain significantly affected host plant growth; host plant growth and mycorrhization levels significantly differed among soil type/fungal strain combinations. Therefore, the selection of T. matsutake strains for optimal mycorrhization must take into account such fungal and soil properties.     

Current issues involved with the identification and nutritional value of wood grubs consumed by Australian Aborigines

The so called witchetty grub is a publicized food source for Australian Aborigines. Despite heavy use, the identities and number of species consumed is still not known because of the lack of identified voucher specimens. Taxonomy based on adults makes identification of larval forms difficult. Dwelling in the root, trunks, and stems of woody plants, grubs are a reliable and highly valued food source that may be in decline. Much information on edible insects may already be lost in parts of Australia heavily settled by Europeans. However, there are many parts of Australia where information on edible insects is still strong and needs to be recorded accurately for long‐term use. Recent identification of “witchetty grubs” from the witchetty bush at Barrow Creek has revealed that those there, based on their DNA, are not Endoxyla leucomochla. As grubs are collected and eaten before they mature and scientific taxonomy is based on adults, there are many unanswered questions on the grub identification and biology, host plants, and plant and grub distributions.     

Trace metals in edible marine molluscs and crustaceans from Lebanon

Samples of the edible tissue of cephalopod molluscs (cuttlefish, squid, octopus) and crustaceans (lobster, shrimp) collected off the coast of Lebanon were found to concentrate similar levels of cadmium, copper, nickel, and chromium. Lead and zinc were highest in the cephalopods and iron was highest in the crustaceans.The molluscs collected from Beirut had higher levels of many metals than those taken from the other locations. The Beirut octopus had higher lead, cadmium, copper, iron, and chromium. Lead, cadmium, and copper were also highest in the Beirut cuttlefish while iron and zinc were elevated. The crustaceans from Beirut showed no strong tendency to concentrate higher metal levels, except for the Beirut lobster which had higher copper than the other samples.In the cuttlefish, the analysis of bone showed generally higher cadmium, zinc, nickel, and chromium but lower copper and iron than the muscle. However, at Beirut, the bone samples had much higher iron. Levels of most metals in the exoskeletons of the lobster and shrimp were quite similar to those in the muscle tissue with the exception of iron in the lobster which was highest in the exoskeleton, and zinc in both crustaceans, which was more highly concentrated in the muscle.     

基于F2群体的香菇遗传图谱构建及其在QTL定位中的应用

以171个F2双核体菌株为作图群体,通过相互配对的2个单核体的基因型推断双核体基因型,构建了第一张基于双核体群体的香菇遗传图谱。该图谱包含分布于15个连锁群的459个标记,覆盖长度为989.7cM,平均标记间隔为2.2cM。此外,以此双核体群体作为表型分离群体,定位了6个与香菇双核体菌丝生长速度相关的QTLs,位于5个连锁群上。采用全同胞单核体随机交配策略,易于构建相对大的双核体群体,用于连锁图构建和QTL定位。研究表明,在食用菌连锁图谱构建及QTL定位研究中,利用F2群体,可能为提高遗传作图效率,解决作图群体与表型分离群体间不一致问题提供新的途径。