不同地理区域桔小实蝇解毒酶系活性及其与抗药性水平关系

昆虫体内的解毒酶活性是反映其抗药性水平的主要生理指标，本文比较了桔小实蝇Bactrocera dorsalis的几种解毒酶活性和抗药性水平关系。测定了9个地理品系和相对敏感品系的桔小实蝇成虫的三种解毒酶，即多功能氧化酶(Mixed function oxidase, MFO)、羧酸酯酶（Carboxylesterase, CarE）和谷胱甘肽Ｓ-转移酶(Glutathione S-transferase, GST)的活性,利用药膜法测定其对敌百虫(Trichlorphon)、高效氯氰菊酯(β-cypermethrin)和阿维菌素(Avermectin)的抗性水平，比较了各地理品系的桔小实蝇这些酶活性和对不同杀虫剂的抗性水平的关系，并作通径分析。结果表明：广东广州地区桔小实蝇体内的MFO-O-脱甲基活性最高，为相对敏感品系酶活性的1.4782倍；而广东茂名地区品系酶活性最低，只有0.8649倍。广东惠州地区桔小实蝇体内CarE活性最高，为相对敏感品系酶活性1.8147倍；而广西南宁地区的桔小实蝇体内酶活性最低，为敏感品系的0.9636倍。广东茂名地区桔小实蝇GST活性最高，是相对敏感品系2.2557倍；而广东广州地区桔小实蝇GST活性最低，只有相对敏感品系的1.1622倍。抗性水平表明：各地理品系对敌百虫的抗性水平为相对敏感品系的2.1552倍至100.2271倍之间，对高效氯氰菊酯的抗性水平在1.0065到26.0026倍之间，对阿维菌素的抗性水平在2.3353倍至29.0688倍之间。相关性分析表明：桔小实蝇体内的GST活性和对敌百虫抗性水平的相关系数为0.41，存在显著性正相关；CarE活性与桔小实蝇对高效氯氰菊酯抗性水平存在极显著正相关，相关系数为0.50。通径分析结果表明：GST活性对敌百虫的抗药性水平的直接通径系数为0.4414，对敌百虫的抗性上升起到正向作用；MFO-O-脱甲基活性、CarE活性和GST活性对高效氯氰菊酯抗性水平的直接通径系数分别为0.3311，0.4946和0.1775，均起到正向作用；GST活性与阿维菌素的抗性水平的直接通径系数很小，为0.0668。结果显示了桔小实蝇的解毒酶与抗药性水平关系密切，在抗性发展中起到了促进作用。     

Concurrently burrowing host fly larvae reciprocally enhance pupation depth to minimise parasitism risk

1. Variation in parasitism risk among hosts is a key factor influencing host–parasitoid interactions; however, within-patch variation (as opposed to between-patch variation) in parasitism risk has hardly been studied. This study investigated the mechanisms of within-patch variation in parasitism risk in the oriental fruit fly, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae). 2. Bactrocera dorsalis pupates underground. Previous studies have shown that pupae at greater depths have a reduced risk of parasitism by a pupal parasitoid Dirhinus giffardii (Silvestri) (Hymenoptera: Chalcididae). When a pupa near the ground surface is parasitised, the victim may decrease the risk of parasitism risk for pupae located at deeper depths. It was hypothesised that larvae will pupate at greater depths when they perceive the presence of conspecifics because of the benefit of pupating deeper than other individuals. 3. In a series of laboratory experiments, the effects of three factors on pupation depth were examined, including: (i) the density of larvae during development; (ii) the density of concurrently burrowing larvae; and (iii) the presence of pre-existing pupae in the pupation substrate. Only the density of concurrently burrowing larvae influenced pupation depth, which suggests that when a burrowing larva perceives the presence of other burrowing larvae, it aims to burrow deeper than them. 4. This study shows not only that parasitism risk is variable among pupae within a patch, but also that it is density-dependent. A commonly made assumption (i.e. the absence of within-patch variability in parasitism risk) needs to be re-evaluated in a wide range of host–parasitoid systems.     

Isolation and characterization of microsatellite loci in the avocado thrips Scirtothrips perseae (Thysanoptera: Thripidae)

The recent invasion of California by avocado thrips, Scirtothrips perseae, has had a serious economic impact on the Californian avocado industry. Here we report the isolation and characterization of six microsatellite loci for S. perseae, four of which were highly polymorphic (number of observed alleles ranged from three to 13 and expected heterozygosity from 0.31 to 0.87). These markers will be used to investigate the invasion history and route of entry into California of S. perseae. Three of the six loci successfully amplified in other Scirtothrips and Neohydatothrips species.     

The effect of prey species and environmental complexity on the functional response of Franklinothrips orizabensis: a test of the fractal foraging model

Abstract. 1. The hypothesis proposed by the fractal foraging model, that prey procurement by predators declines as habitat complexity increases, was tested. To evaluate this hypothesis, the effect of two prey species, second-instar larvae of Scirtothrips perseae Nakahara and Heliothrips haemorrhoidalis (Bouché) (both Thysanoptera: Thripidae), and environmental complexity on the functional response of the predatory thrips Franklinothrips orizabensis Johansen (Thysanoptera: Aeolothripidae) was examined.
2. The Koch curve, a well-studied fractal, was used to generate the shapes of experimental arenas to test the effect of environmental complexity on the functional response of F. orizabensis. Complexity was defined in terms of the number of acute vertices in which prey thrips could seek refuge and the length of the perimeter that had to be searched by the predator. Four shapes were tested: a circle (zero acute vertices, circumference = 186.61 mm), equilateral triangle (three acute vertices, perimeter = 240 mm), star (six acute vertices, perimeter = 277.13 mm), and snowflake (18 acute vertices, perimeter = 333.65 mm). All shapes were scaled so that the area of each arena was 2771 mm².
3.  Franklinothrips orizabensis exhibited a Type II functional response for both prey species and all four experimental arenas tested. Significantly fewer S. perseae larvae were killed in the most complex arena (i.e. the snowflake) when prey densities exceeded 16. For H. haemorrhoidalis , significant differences in mortality were observed only when prey densities equalled four. These results demonstrated that the fractal foraging model was supported when certain prey densities coincided with particular levels of environmental complexity.
4. Subtle changes in environmental complexity and different prey species of varying density can affect prey–predator interactions significantly.     

香茅精油对桔小实蝇产卵驱避作用及其化学成份分析

研究了香茅Cymbopogon nardus精油对桔小实蝇Bactrocera dorsalis (Hendel)的产卵驱避作用及其化学成分。结果表明,香茅精油对桔小实蝇产卵具有一定的驱避作用,不同浓度香茅精油处理芒果上的产卵量均显著低于对照,且随着香茅精油浓度的提高其产卵量逐渐减少,当浓度为10000μg/mL时,产卵驱避率为70.06%。采用气相色谱—质谱联用(GC-MS)技术分析了香茅精油的化学成份,结果发现该精油挥发物中含量较高的是3-蒈烯,香茅醛,香叶醇,香茅醇,柠檬烯。     

Screening of T7 phage displayed Bactrocera dorsalis (Hendel) antenna cDNA library against chemosensory protein

Recent studies have shown that chemosensory proteins (CSPs) were involved in diverse life activities such as insect feeding, development, mating, immune regulation, as well as other important circadian rhythms, etc. To screen the proteins involved in the BdorCSP-related physiological activity, a cDNA library of the Bactrocera dorsalis (Hendel) antenna expressed on the surface of T7 phage was screened against BdorCSP. After four rounds of screening, ELISA-positive samples of selected phages were sequenced and identified as protein disulfide isomerase (PDI), trypsin-like serine protease (Ser), TakeOut (TO), and a new protein by GenBank blast, respectively. Real-time quantitative PCR results showed that the expression levels of Ser, TO, and the new protein were the highest in antenna, sharing similar expression pattern with BdorCSP. These results reveal that these proteins might be involved in the BdorCSP-related physiological or metabolic activities. This work paves a new way for exploring the function of CSPs.     

prima蛋白与马拉硫磷混合后点喷对橘小实蝇防治效果的研究

应用prima蛋白加农药马拉硫磷对橘小实蝇进行防治,每8d点喷一次,共喷5次。试验结果表明：prima蛋白与马拉硫磷混合后点喷对橘小实蝇的诱杀效果显著,保果率达到64．71％左右,卡方检验的结果为P=0．027〈0．05,表明点喷prima蛋白与马拉硫磷的混合溶液对柚子的保果效果显著。     

橘小实蝇雌雄成虫生殖系统中可培养细菌的分离鉴定

本研究分离鉴定了来自赣南脐橙基地橘小实蝇Bactrocera dorsalis (Hendel)雌性和雄性成虫生殖系统中的可培养细菌.采用LB培养基分离纯化和菌株16S rRNA基因序列分析相结合的方法,从饲养10 d的橘小实蝇雌雄成虫生殖系统,获得15株具有不同表观特征的细菌,分属变形菌门Proteobacteria、拟杆菌门Bacteroidetes、放线菌门Actinobacteria和厚壁菌门Firmicutes.橘小实蝇雌雄成虫生殖系统共同拥有4个相同属,分别是不动杆菌属Acinetobacter、苍白杆菌属Ochrobactrum、金黄杆菌属Chryseobacterium和芽孢杆菌属Bacillus.雌性成虫特有无色杆菌属Achromobacter、剑菌属Ensifer、鞘脂杆菌属Sphingobacterium、微杆菌属Microbacterium和细球菌属Micrococcus;雄性成虫特有假单胞菌属Pseudomonas和拟杆菌属Bacteroides.其中,不动杆菌属菌株数量最多,分别占雌、雄成虫生殖系统菌株数量的35.00％和31.58％,为橘小实蝇生殖系统可培养的优势细菌属.橘小实蝇雌性和雄性成虫生殖系统的内生细菌存在差异,为研究橘小实蝇性别与内生细菌的协同进化提供信息,也为分析内生细菌在橘小实蝇生殖系统中的功能奠定基础.     

不同生境中橘小实蝇种群动态及密度的差异

为揭示不同生境条件对橘小实蝇种群动态及密度的影响,通过设置橘小实蝇诱捕器,对2008-2009年福州地区不同生境条件下的橘小实蝇种群动态进行了监测。结果表明：（1）各寄主的转色成熟期是该果园橘小实蝇发生的高峰期。（2）在瓜果的成熟期,果园内橘小实蝇的种群数量要高于果园周边丛林的种群数量;成熟期过后,果园内部的种群数量小于果园周边丛林。（3）山谷生境橘小实蝇种群数量明显高于山脊生境,沿河生境则要明显高于非沿河生境。（4）城区的橘小实蝇的发生期早于乡村,且发生量要大于乡村。