Ostrinia spp. in Japan: their host plants and sex pheromones

To contribute to the understanding of the genus Ostrinia (Lepidoptera; Pyralidae) in Japan, we collected larvae of Ostrinia spp. from known host plants and plants not recorded as hosts, and we examined the morphology and sex pheromones of the adults obtained. Consequently, the host plant ranges of the 7 Ostrinia spp. in Japan were clarified, and the sex pheromones of the 5 species O. scapulalis, O. zealis, O. zaguliaevi, O. palustralis and O. latipennis were identified in addition to that of the Asian corn borer O. furnacalis. The phylogenetic relationships of Japanese Ostrinia spp., with reference to the European corn borer O. nubilalis, are discussed based on these findings and results of molecular phylogenetic analyses.     

Clonal diversity and polyphyletic origins of hybrid and spontaneous parthenogenetic Campeloma (Gastropoda: Viviparidae) from the south-eastern United States

Some theories for the maintenance of sexual reproduction indicate that parthenogens may persist if there is high clonal diversity and high dispersal rates. Using allozymic variation, we report on the origin, clonal diversity and population structure of hybrid and spontaneous parthenogens from south-eastern United States populations of the freshwater snail Campeloma. Independent origins of triploid hybrid parthenogens in the Florida panhandle occurred by hybridization between an Atlantic coastal species (C. limum or C. floridense) and the Florida sexual species (C. geniculum). Allozyme genotypic diversity is similar between these hybrid parthenogens and sexuals. Diploid spontaneous parthenogens originated multiple times from nonlocal C.limum sexual populations in Atlantic coastal rivers, and levels of genotypic diversity are significantly higher in sexual C. limum. How parthenogens originate, the degree of clonal diversity, and their subsequent dispersal influence whether basic assumptions of evolution-of-sex models are met.     

Dominance hierarchy and reproductive conflicts among subordinates in a monogynous queenless ant

In insect societies lacking morphologically specialized breedersand helpers, reproduction is often restricted to behaviorallydominant individuals. Such societies occur in about 100 speciesof ants that have secondarily lost the queen caste. All females,who are morphologically workers, can potentially mate and layeggs but only a few do so, and we demonstrate in Dinoponeraquadriceps that this is regulated by a dominance hierarchy.Six types of agonistic interactions allowed the ranking of 5-10workers in the hierarchy (n = 15 colonies). In particular, alphaand beta had characteristic behavioral profiles and were easily recognized.Only alpha mated, and workers ranking beta to delta sometimes producedunfertilized, male-destined eggs. Natural replacements (n = 19)and experimental removals (n = 15) of alpha demonstrated that betawas the individual most likely to replace alpha, although gammaand more rarely delta sometimes did, and we discuss the conflictthat occurs among high-ranking individuals over who should replacealpha. After such replacements, the new alpha behaved more aggressivelythan the overthrown alpha. Newly emerged workers tended to reachhigh ranks and displaced older high-ranking individuals downthe hierarchy. Low-ranking subordinates often prevented high-rankingindividuals from replacing alpha by biting and holding theirappendages (worker policing), which is consistent with the patternof relatedness associated with monogyny and monandry in D. quadriceps. Weinvestigated the relative importance of chemical communicationand dominance interactions to regulate reproduction. Alpha,beta, and sterile workers have different signatures of cuticularhydrocarbons, and these may provide honest information whichunderpins worker policing by low-ranking individuals.     

Laboratory and field experiments towards the development of an attract and kill strategy for the control of the codling moth, Cydia pomonella

A viscous formulation based on castor oil containing the pyrethroid insecticide cyfluthrin and E8, E10-dodecadienol, the main component of the codling moth sex pheromone, (Cydia pomonellaL.: Tortricidae, Olethreutinae) was developed. The insecticidal performance of the formulation was evaluated in the laboratory using a tarsal-contact bioassay. The pheromone dosage required to attract male moths to the formulation was determined in behavioural tests performed in a wind tunnel. The efficacy of formulations applied to seedlings of the host plant was further investigated in glasshouse experiments conducted with male moths in small wire-gauze cages. The laboratory tests resulted in a formulation for preliminary field trials containing 4% cyfluthrin and 0.1% pheromone. During the 1995 growing season, experiments were conducted in apple orchards at three locations in Germany. The formulation was first applied to the bark of apple trees (Malus domestica) in mid May and then again in late July. A good level of control, comparable with a spray treatment using the insect growth regulator Alsystin was achieved. The potential of the attract and kill strategy, combining selective attraction of a pest species with the efficacy associated with a pyrethroid insecticide treatment, as a means of controlling the codling moth in commercial apple growing, is discussed.     

烟实夜蛾性信息素合成激活肽基因的分子克隆

根据家蚕Bombyx mori和玉米夜蛾Helicoverpa zea的性信息素合成激活肽基因序列,设计若干套引物, 以烟实夜蛾Heliothis assulta基因组DNA为模板进行PCR扩增, 得到0.63 kb的特异性DNA片段。该片段克隆进适当载体,序列测定和同源比较, 查明烟实夜蛾的基因组中存在性信息素合成激活肽基因。烟实夜蛾的性信息素合成激活肽由33个氨基酸组成, C末端是FXPRL结构,是目前发现的第4种昆虫性信息素合成激活肽。在该神经肽第14和第15个氨基酸之间, 插入一个0.42 kb的内含子。 进一步的分析证明了烟实夜蛾的性信息素合成激活肽基因在潜成虫期的食道下神经节中表达。     

两种性信息素诱捕器对棉铃虫雄蛾的诱捕效果比较

1995年在山东和安徽棉区4个地点比较研究了性信息素笼罩诱捕器和水盆诱捕器对棉铃虫雄蛾的诱捕效果。试验结果表明,4地点笼罩诱蛾量分别是水盆诱蛾量的2.8、3.5、2.5和2.0倍,平均2.7倍。两种诱捕器诱蛾量倍数的变异系数分别为22.9%、31.5%、50.7%和51.2%。可见笼罩诱捕器比水盆诱捕器对棉铃虫雄虫具有更高的诱捕效率。考虑到笼罩诱捕器高效、稳定及简便,建议在我国尽快用其取代水盆进行棉铃虫成虫的标准化监测。     

斜纹夜蛾性信息素通讯系统

采用单雌腺体微量分析技术,对斜纹夜蛾(中国种群)雌蛾腺体的组份进行鉴定,并研究了各组份的个体差异及释放规律,测试了雄蛾对各组份及其混合物的触角电位反应。雌蛾腺体内含有4个组份：Z9, E11-14∶Ac(A)、Z9, E12-14∶Ac(B)、Z9-14∶Ac© 和E11-14∶Ac(D),其比例为100∶27∶20∶27。     

甜菜夜蛾交配行为和能力

在(27±1)℃,光周期L14∶D10的条件下对甜菜夜蛾I>Spodoptera exigua的交配行为及能力进行了研究。结果表明：成虫在羽化当晚即可进行交配,交配率以羽化后头三个晚上的较高(>82%),但从第4天起则显著下降。成虫一天中的交配时间出现于23:30～05:30之间,交配高峰出现在01:30～02:30和03:00～04:00 之间, 其中以第1高峰的发生频率较高。成虫交配持续时间从22～191 min不等,但以30～60 min的为多(40.8%, n=97), 60～90 min的次之(19.4%),超过180 min的较少(10.2 %)。另外,交配持续时间与蛾龄紧密相关。蛾龄越大,交配持续的时间越长,且差异显著。雄蛾一生的交配能力由1～11次不等,但受性比的影响显著：在性比为1∶1的条件下,雄蛾平均交配次数仅为3.0 次,而在2♀∶1♂至5♀∶1♂时,则增加到5.1～6.0 次。雌蛾交配比例及次数受性比的影响也很大：没有交配的雌蛾比例从1∶1时的8.3%增加到5♀∶1♂时的32%,仅交配一次的比例从16.7%增加到38.7%,而交配≥5 次的比例则从 25%下降到0。最后,对这些结果在甜菜夜蛾防治中应用的可能性进行了讨论。     

性信息素大面积诱捕法防治东北越冬代水稻二化螟

2002年和2003年,在吉林省柳河县绿色大米生产基地,开展了应用性信息素诱捕法防治越冬代水稻二化螟Chilo suppressalis的试验。与对照区相比,2002年和2003年两年诱捕区诱蛾量分别下降84.54%和83.75%,雌虫交配率分别下降54.10%和47.67%; 同时,诱杀区二化螟卵孵化率下降25.50%,卵块密度也显著降低。2002年二化螟雌雄性比由对照区的1.14上升为诱捕区的3.96,而 2003年由1.12上升到3.84;诱杀区二化螟幼虫为害率,无论是枯鞘、枯心,还是白穗,也较之对照区显著下降,造成稻谷产量损失也明显降低。通过上述一系列评价指标表明性信息素诱捕法能有效控制东北越冬代水稻二化螟,可为东北绿色大米的可持续生产提供技术支持。     

Bt毒素对棉铃虫雄蛾感受雌蛾性信息素EAG反应的影响

用含Bt毒素的人工饲料饲养棉铃虫Helicoverpa armigera 3龄幼虫至成虫(死亡率为40%～50%),采用触角电位 (electroantennogram, EAG) 技术,测定了雄蛾对雌蛾性信息素2种组分顺9-十六碳烯醛(Z9-16:Ald)、顺11-十六碳烯醛(Z11-16:Ald)及其混合物(Z11-16:Ald∶Z9-16:Ald=97∶3)的EAG反应。结果表明,Bt毒素对雄蛾感受性信息素单一组分和混合物的EAG反应均具促进作用;且随信息素剂量的增加,这种促进作用也随之增强。这一结果对于评价和实施延缓棉铃虫对Bt棉抗性的“庇护所"策略,具有一定的参考意义。