The spread of the western flower thrips Frankliniella occidentalis (Pergande)

Abstract 1 Since the late 1970s, the western flower thrips has spread from its original distribution in western North America to become a major worldwide crop pest. 2 A wide range of data sources have been used to map the original distribution in the U.S.A. and Canada, and the progress of the spread in the U.S.A., Canada, Europe, northern Africa and Australia. 3 The possible reasons for the start of the spread are discussed. The most likely reason is that intensive insecticide use in horticulture in the 1970s and 1980s selected an insecticide resistant strain or strains. These then established in glasshouses across North America and spread from there to Europe, Asia, Africa and Australia. 4 The international spread of the western flower thrips occurred predominantly by the movement of horticultural material, such as cuttings, seedlings and potted plants. Within Europe, an outward spread from the original outbreak in the Netherlands is discernible. The speed of spread was 229 ± 20 km/year. 5 The spread has not been restricted to glasshouses. The western flower thrips has established outdoors in areas with milder winters; for example, across the southern U.S.A., southern Europe and Australia. It also overwinters in some regions with colder winters. 6 Polyphagous phytophagous thrips have many factors predisposing them to become worldwide crop pests, particularly in glasshouses. Some other species that might spread in a similar way to the western flower thrips are listed.     

紫茎泽兰叶片水浸液对蚕豆的化感效应

外来入侵植物可以通过淋溶、自然挥发、根系分泌和植株凋落物分解等途径向周围环境释放化感物质,抑制伴生植物的生长、发育。该研究以不同浓度紫茎泽兰(Eupatorium adenophorum)叶片水浸液处理蚕豆(Vicia faba)种子,研究紫茎泽兰叶片水浸液对蚕豆根尖细胞微核、染色体畸变、细胞凋亡、蚕豆幼苗叶片叶绿素和N含量、光合生理特性、生物量的影响。结果表明:(1)紫茎泽兰叶片水浸液处理显著抑制蚕豆根尖的伸长和细胞的有丝分裂,并诱导蚕豆根尖细胞染色体畸变和细胞微核的产生,有丝分裂指数随着叶片水浸液浓度增加而减小,根尖细胞微核率随叶片水浸液浓度增加而增大,高浓度叶片水浸液处理对蚕豆根尖细胞的凋亡及坏死有明显影响。(2)紫茎泽兰叶片水浸液处理引起蚕豆幼苗叶片的叶绿素和N含量显著降低,并导致蚕豆幼苗最大净光合速率和生物量的显著下降。总之,紫茎泽兰叶片水浸液可能引起蚕豆根尖的氧化损伤和抑制根尖的伸长,且叶片水浸液的抑制作用呈现一定的剂量效应。紫茎泽兰叶片水浸液对蚕豆根尖的损伤和抑制作用可能影响了植株对氮素的吸收,进而对蚕豆幼苗光合生理表现以及生物量积累产生显著负面效应。     

Predation of zebra mussels by round gobies, Neogobius melanostomus

Preliminary gut analysis of a recent Great Lakes invader, the round goby, Neogobius melanostomus (7.0–8.4 cm), collected from the Detroit River, showed that they ate zebra mussels (58%), snails (6%), and other invertebrates (36%), including aquatic insects (Hexagenia), softshelled crayfish, and zooplankton. Because zebra mussels, Dreissena polymorpha, predominated as prey, we investigated the ability of round gobies to consume different size classes of zebra mussels. In laboratory experiments, we examined feeding preferences of three size classes of round gobies (5.5–6.9 cm; 7.0–8.4 cm; 8.5–10.3 cm standard length) on four different size classes of zebra mussels (6.0–9.9 mm, 10.0–12.9 mm, 13.0–15.9 mm, 16.0–18.9 mm). All sizes of round gobies ate zebra mussels < 10.0 mm. Only the largest size class of round gobies ate larger zebra mussels (10.0–12.9 mm) when all prey sizes were presented. The association between the total mass of zebra mussels available and the amount consumed by round gobies increased positively up to about 6.5 g of available mussels and then levelled off. Round gobies consumed an average of 1.0 g of mussels in 24 h. There was a significant positive relationship between gape size and standard length of round gobies. Although larger round gobies (over the size range of fish in our study) are able to consume larger zebra mussels, small mussels were preferred. Our findings suggest that the preference of small zebra mussels by round gobies has the potential to alter the size structure of zebra mussel populations. This revised version was published online in July 2006 with corrections to the Cover Date.     

Exotic snakes in São Paulo City, southeastern Brazil: why xenophobia?

Introduced exotic species cause environmental changes and threat public health in target sites. Illegal trade has enhanced this problem. To first report these risks in Brazil, exotic snakes found in São Paulo City (SPC) (23°32 S, 46°38 W), southeastern Brazil, and sent to Instituto Butantan between 1995 and 2000, were listed and characterized by their biological attributes. Seventy-six individuals of sixteen alien species were collected. Euriecians snakes, mainly booids, were predominant. Using multivariate techniques, their ecological niches were compared to those of 26 native species, as a way to point out the resource's availability. To evaluate the potential of successful implantation, two species absent in SPC and considered as problem snakes are included in these analyses: the brown treesnake Boiga irregularis and the habu Trimeresurus flavoviridis. There were niche similarities between these pest snakes, exotic booids and native viperids largely due to the similarities in the chosen prey (mammals), diel activity (nocturnal), color pattern (variegated) and body size (medium to large). To avoid predictable undesirable effects of implanted pest snakes, traffic control and punishment should be improved, as well as parallel environmental education programs.     

住院患者多重耐药菌感染临床研究

目的 探讨住院患者多重耐药菌感染情况与病原学特点,为临床制定医院感染控制措施提供参考依据.方法 对住院患者中的多重耐药菌感染及病原特点情况进行统计分析.结果 住院患者多重耐药菌感染发生率为3.5％,主要为革兰阴性菌(71.5％),多重耐药菌居前7位的依次是大肠埃希菌、肺炎克雷伯菌、鲍曼不动杆菌、铜绿假单胞菌、凝固酶阴性葡萄球菌、肠球菌属、金黄色葡萄球菌等.多重耐药菌感染的患者主要来自于重症监护室、神经外科、呼吸内科等.多重耐药菌对选用的抗生素均有较高的耐药性.结论 多重耐药菌耐药率普遍较高,临床医师应重视病原学检查及药敏监测,合理选择使用抗菌药物.     

Introduction of the African Catfish Clarias gariepinus (BURCHELL, 1822) into Southern Brazil

We record here the introduction of the African catfish Clarias gariepinus into the Guaraguaçu River basin in Paraná State, Brazil, an area with an extremely rich endemic fish fauna, including many catfishes. C. gariepinus was introduced as escapees from ponds built for recreational angling. These catfishes are very large and hard predators, thus posing serious potential for impact on the native fish fauna. The impact of C. gariepinus needs study with emphasis on finding means for controlling its spread.