Distribution of ichthyoplankton in the eastern Peter the Great Bay,Sea of Japan,in June and July of 2007

Comparison of the results of ichthyoplankton surveys conducted at 97 stations in the eastern part of the Peter the Great Bay of the Sea of Japan, in June–July 2007 with the similar research data of the 1950s shows that at present, as was the case 50 years ago, flatfish eggs belonging mainly to the yellowfin sole Limanda aspera and brown sole Pleuronectes herzensteini prevail in the local ichthyoplankton (up to 86%). The highest concentrations of these species’ eggs were recorded in the Vostok Bay and Strelok Bay. The spawning activity of flatfish in 2007 is found to be lower than in the mid 1900s, but the significance of the eastern part of the Peter the Great Bay for flatfish reproduction remains large. The importance of long-term monitoring in this area, which is being subjected to steadily growing anthropogenic impacts, is also proven.     

小蓬草精油对两种蚊虫的毒杀活性和成分分析

【目的】明确小蓬草Conyza canadensis ( L.) Cronq.精油的杀虫潜力及其活性成分。【方法】通过浸虫法和密闭熏蒸法测试了小蓬草精油对白纹伊蚊Aedes albopictus和致倦库蚊Culex pipiens quinquefasciatus幼虫及成蚊的毒杀活性, 并利用气相色谱 质谱联用仪（GC-MS）对精油的挥发性成分进行了定性分析。【结果】 小蓬草精油对白纹伊蚊1-4龄期幼虫及蛹的24 h LC50值分别为25.01, 45.88, 56.94, 64.60和346.23 μg/mL; 对致倦库蚊幼虫1-4龄期幼虫及蛹的24 h LC₅₀值分别为9.16, 8.65, 32.12, 43.68和197.83 μg/mL。在剂量分别为48, 64, 80, 96, 112和128 μg/cm3时, 小蓬草精油对白纹伊蚊成蚊的KT₅₀值分别为28.81, 22.31, 20.38, 17.05, 13.92和9.74 min; 对致倦库蚊的KT50值分别为34.90, 32.97, 23.97, 19.60, 15.20和10.34 min。 24 h熏蒸对白纹伊蚊和致倦库蚊成蚊的LC50值分别是75.46和99.19 μg/cm³。小蓬草精油的GC MS定性分析共分离鉴定出31种化合物, 其中单萜类物质6种, 倍半萜烯类物质17种, 含氧萜烯类6种。【结论】结果表明小蓬草精油对这两种蚊虫的毒杀活性较高, 具有深开发潜力。     

Winter spatial distribution of fish larvae assemblages relative to the hydrography of the waters surrounding Taiwan

The aim of this study was to investigate the species composition and distribution of fish larvae in relation to hydrographic conditions in the waters surrounding Taiwan Island (TI) in February 2003. In total, 242 kinds of fish larvae belonging to 127 genera and 75 families were recognized. Among these, 109 taxa were identified to the family or genus level, others to the species level. The 12 predominant types, which constituted 71% of the total fish larvae, were Engraulis japonica, Scomber sp., Diaphus spp., Benthosema pterotum, Carangoides ferdau, Embolichthys mitsukurii, Maurolicus sp., unidentified Myctophidae, Gonostoma gracile, Trichiurus lepturus, unidentified Gobiidae, and Myctophum asperum. The distribution of fish larvae showed a clear association with water masses around TI, with higher abundances and lower species richness northwest of TI where the China Coastal Current prevails, and lower abundances and higher species diversity east of TI where the Kuroshio Current dominates. Cluster analysis distinguished three station groups and four species groups, and the distribution patterns of fish larvae also corresponded to hydrographic conditions. The total abundances of fish larvae and eight of the 12 predominant taxa showed significant and positive correlations with zooplankton abundance, which suggests that food source might be a key factor determining the abundance and distribution of fish larvae during the winter.     

登革Ⅱ型病毒在白纹伊蚊体内分布的研究

利用蚊虫连续石蜡切片免疫组织化学技术,对登革Ⅱ型病毒(DEN-2)感染白纹伊蚊Aedes albopictus后的散播时间、程度及组织器官的感染顺序进行监测,以了解DEN-2在媒介白纹伊蚊体内的分布规律。结果表明：大剂量感染登革Ⅱ型病毒后,在蚊虫消化道的主要部位以及大多数组织器官包括神经及内分泌系统在内,如涎腺、脑、神经节等亦检测到病毒抗原。登革Ⅱ型病毒一旦感染并逸出中肠会迅速侵染其它组织。从各组织感染率的高低推断,病毒逸出中肠后通过血淋巴传播到其它组织的顺序通常为：前肠、涎腺、咽部神经节、脑及食管下神经节、后肠及复眼的小眼等。     

Differential lipid reserves influence host-seeking behaviour in the mosquitoes Aedes cantans and Aedes punctor

ipid reserves of bait-caught female Ae.cantans and Ae.punctor mosquitoes (Diptera: Culicidae) were significantly higher than in teneral females. Female Ae.cantans given access to 10% w/v sucrose solution post-emergence showed an ability to synthesize lipid and, after 192 h, they were willing to take a bloodmeal from a human volunteer. At this point, mean lipid reserves were not significantly different from mean lipid reserves of bait-caught females. Prior to 192 h, females would not take a bloodmeal and lipid reserves were significantly lower than in bait-caught females. Female Ae.punctor given access to 10% w/v sucrose solution post-emergence also showed an ability to synthesize lipid. Females of this species were willing to feed from a human host after only 48 h, at which point lipid content was not significantly different from that in bait-caught females. The level of lipid reserves in females coming to bait differs significantly between species: Ae.cantans has lipid reserves approximately double those of Ae.punctor . In addition, Ae.punctor is able to synthesize lipid to a level comparable with that found in bait-caught females after only 24 h, whilst it takes 192 h for Ae.cantans females to synthesize the amount of lipid found in host-seeking females, when allowed free access to sugar. Physiological differences in lipid synthesis and the level of lipid reserves required may therefore explain the differences observed between the species in the time taken to initiate host seeking.     

Anti-mosquito antibodies decrease the reproductive capacity of Aedes aegypti

Aedes aegypti (L.) fed on rabbits immunized with mosquito antigens showed a reduction in fecundity in the first oviposition and decreased viability of the progeny. Feeding behaviour of mosquitoes was not affected and no significant mortality was observed due to the presence of anti-mosquito antibodies in the bloodmeal. Antibodies were detected in the oocytes of mosquitoes 48 h after the bloodmeal. The role of specific antibodies in influencing fecundity is discussed.     

Establishment of an in vitro sciarid fly larvae assay to study plant resistance

Mechanisms underlying natural plant resistance to herbivorous invertebrates are still poorly understood in comparison with bacterial or fungal interactions. One reason is the difficulty in reliably and reproducibly assessing the effects under controlled conditions. This article describes a newly developed in vitro biological assay system that enables the interactions between sciarid larvae and plants, whose roots they feed on, to be studied under highly controlled conditions. The bioassay eliminates the problems created by the often variable environmental factors by providing an aseptic arena where experimental plants can be germinated and grown on agar within a Petri dish. Sciarid fly eggs are then collected, sterilised and added to the Petri dish. The system allows the eggs to hatch and the larvae to feed on the plant roots. A range of developmental parameters can then be recorded over time which can then be correlated with the experimental plant type. This assay system also allows a simultaneous comparison or 'choice chamber' between two (or more) different genotypes. The assay should greatly help to facilitate the identification of new components involved in insect resistance mediated pathway via the characterisation of mutant plants.     

Entomological surveillance,spatial distribution,and diversity of Culicidae (Diptera) immatures in a rural area of the Atlantic Forest biome,State of São Paulo,Brazil

Because of the high adaptive capacity of mosquitoes, studies that focus on transitional environments become very important, such as those in rural areas, which are considered as bridges between wild diseases and human populations of urban areas. In this study, a survey of the existing species of mosquitoes was performed in an Atlantic Forest area of the city of Santa Bárbara d'Oeste, São Paulo state, Brazil, using traps for immatures and analyzing the frequency and distribution of these insects over the sampling months. Five mosquito species were found: Aedes albopictus (the most frequent species), Aedes aegypti, Aedes fluviatilis, Culex quinquefasciatus, and Toxorhynchites theobaldi. The 4,524 eggs collected in ovitraps showed the presence of the tribe Aedini. Aedes aegypti and Ae. albopictus were identified after larval hatching in the laboratory, with different spatial distributions: the first of which coincides with the area of greatest diversity calculated using the Simpson index, while the second does not. The association of ecological analysis of spatial diversity with simple methods of data collection enables the identification of possible epidemiological risk situations and is a strategy that may be implemented to monitor ecological processes resulting from the interaction among different species of mosquitoes.