The Complete Mitochondrial Genome of the Beet Webworm,Spoladea recurvalis (Lepidoptera: Crambidae) and Its Phylogenetic Implications

The complete mitochondrial genome (mitogenome) of the beet webworm, Spoladea recurvalis has been sequenced. The circular genome is 15,273 bp in size, encoding 13 protein-coding genes (PCGs), two rRNA genes, and 22 tRNA genes and containing a control region with gene order and orientation identical to that of other ditrysian lepidopteran mitogenomes. The nucleotide composition of the mitogenome shows a high A+T content of 80.9%, and the AT skewness is slightly negative (-0.023). All PCGs start with the typical ATN codons, except for COX1, which may start with the CGA codon. Nine of 13 PCGs have the common stop codon TAA; however, COX1, COX2 and ND5 utilize the T nucleotide and ND4 utilizes TA nucleotides as incomplete termination codons. All tRNAs genes are folded into the typical cloverleaf structure of mitochondrial tRNAs, except for the tRNA^Ser(AGY) gene, in which the DHU arm fails to form a stable stem-loop structure. A total of 157 bp intergenic spacers are scattered in 17 regions. The overlapping sequences are 42 bp in total and found in eight different locations. The 329 bp AT-rich region is comprised of non-repetitive sequences, including the motif ATAG, which is followed by a 14 bp poly-T stretch, a (AT₁₁ microsatellite-like repeat, which is adjacent to the motif ATTTA, and a 9 bp poly-A, which is immediately upstream from the tRNA^Met gene. Phylogenetic analysis, based on 13 PCGs and 13 PCGs+2 rRNAs using Bayesian inference and Maximum likelihood methods, show that the classification position of Pyraloidea is inconsistent with the traditional classification. Hesperioidea is placed within the Papilionoidea rather than as a sister group to it. The Pyraloidea is placed within the Macrolepidoptera with other superfamilies instead of the Papilionoidea.     

Effects of Entomopathogenic fungi and Bacillus thuringiensis‐based biopesticides on Spoladea recurvalis (Lepidoptera: Crambidae)

Spoladea recurvalis (Fabricius) is one of the most devastating pests of amaranths causing severe yield losses of 60%–100% to the crop. Unfortunately use of chemical pesticides is the most common control strategy that vegetable farmers rely on to control the pest. However, it is not effective and harmful to environmental and human health. Aiming to provide more environmentally friendly alternatives, this study evaluated the effects of various entomopathogenic fungal isolates and commercial based Bacillus thuringiensis Subsp. kurstaki product Halt^®, on the pest. Twenty‐four entomopathogenic fungal (EPF) isolates from three genera (14 Metarhizium anisopliae, 9 Beauveria bassiana and 1 lsaria fumosorosea) were screened in the laboratory to assess their pathogenicity against second instar larvae of S. recurvalis. Only M. anisopliae ICIPE 30 reached a moderate threshold, causing 58.3% larval mortality. All the 11 isolates (8 M. anisopliae, 2 B. bassiana and 1 l. fumosorosea) tested against adult S. recurvalis were pathogenic, with M. anisopliae ICIPE 30 and B. bassiana ICIPE 725 causing the highest mortality of 92% and 83%, respectively. Metarhizium anisopliae ICIPE 30 had the shortest LT₅₀ value of 4.8 days. Bacillus thuringiensis Subsp. kurstaki product Halt^® caused <50% mortality on S. recurvalis larvae. A consecutive application of M. anisopliae ICIPE 30 and Bt did not cause a significant increase in larval mortality compared to separate applications of both products. Results of this study suggest that M. anisopliae ICIPE 30 was the most potent candidate and could be used in an autodissemination approach for management of adult S. recurvalis.     

Molecular detection of Cotesia vestalis (Hymenoptera: Braconidae) in the beet webworm Loxostege sticticalis L. (Lepidoptera: Crambidae)

Genomic DNA samples from larvae of the beet webworm Loxostege sticticalis collected in the south‐western Russia were used to amplify mitochondrial cytochrome oxidase unit I (COI) gene. In a small proportion of samples, the sequenced product showed considerable heterogeneity due to admixture of a minor sequence. A preliminary BLAST analysis of a 100‐bp‐long fragment of this minor sequence showed its maximal similarity to the COI gene region of Cotesia, a genus of braconid larval endoparasitoids of Lepidoptera. An additional primer was designed to specifically amplify ca 300 bp of the COI gene region from Braconidae. As many as seven of 25 samples were positive by PCR. Sequencing of the amplified products in all these samples showed nucleotide sequence identity to the COI region of Cotesia vestalis (Cotesia plutellae) and the presence of two molecular haplotypes among individual parasitoid samples.     

On the temperature tolerance of diapausing prepupae of the beet webworm Loxostege sticticalis L. (Lepidoptera,Pyraloidea: Crambidae)

The beet webworm, Loxostege sticticalis L. is a very dangerous polyphagous insect pest. The beet webworm overwinters at the pronymphal stage. In some individuals, the diapause can last from the first generation to the next spring. The influence of 30-days-long exposure at temperatures of +5, +10, +15, +20, and +25°C on survival and subsequent reactivation of diapausing pronymphs of L. sticticalis has been investigated in laboratory conditions. The beet webworm was shown to be very thermotolerant: although the temperature of +5°C, as expected, was optimal for reactivation, the other thermal regimes did not cause a significant decrease in survival and in the proportion of individuals reactivated before the end of the experiment (in 120 days). These data suggest that the southern boundary of the geographical range of L. sticticalis is determined not by high winter temperatures, but rather by some other factors (possibly, by high summer temperatures).     

草地螟滞育幼虫的蛋白和核酸含量变化

为了阐明草地螟Loxostege sticticalis 滞育的分子调控基础, 本研究应用Trizol法、 DNA和蛋白质定量试剂盒、 SDS-PAGE电泳技术分别对进入滞育1, 2, 3和4个月、 解除滞育以及非滞育草地螟老熟幼虫中的核酸含量、 总蛋白含量和组分的变化进行了测定。结果表明： 滞育不同月份幼虫的总RNA含量显著低于非滞育幼虫的总RNA含量（P＜0.05）; 解除滞育幼虫的总RNA含量显著高于滞育2, 3和4个月的幼虫, 但仍显著低于非滞育的对照组。滞育不同月份、 非滞育以及解除滞育幼虫的总DNA含量没有显著差异（P＞0.05）。RNA/DNA比值随滞育的开始而显著下降, 随着滞育的结束而显著上升。滞育不同月份的幼虫总蛋白含量显著高于非滞育幼虫的总蛋白含量（P<0.05）, 但解除滞育与非滞育幼虫的总蛋白含量无显著差异。利用SDS-PAGE电泳分析发现滞育幼虫体内存在滞育关联蛋白, 蛋白条带在24 kDa左右, 但非滞育和已经解除滞育的幼虫则没有该蛋白条带。这些结果表明, 总RNA含量的降低、 RNA/DNA比值下降、 总蛋白含量的升高, 以及24 kDa蛋白的存在是草地螟幼虫滞育的主要生理特征。     

Efficacy of commercial formulations of entomopathogenic nematodes against tropical sod webworm,Herpetogramma phaeopteralis (Lepidoptera: Crambidae)

Large quantities of insecticides are used on warm season turfgrasses to combat pest infestations. To investigate the potential for microbial control, we screened commercially available entomopathogenic nematode products against Herpetogramma phaeopteralis Guenée, an economically injurious pest in the south‐eastern United States and Caribbean islands. All tested products, based on Steinernema carpocapsae, S. feltiae, Heterorhabditis bacteriophora, H. megidis and H. indica, were pathogenic to H. phaeopteralis larvae in the laboratory, but S. carpocapsae caused the highest mortality. Amongst nematode species, median lethal concentration (LC₅₀) was not different for three different larval sizes (based on 95% CL) with the exception of H. indica, which had higher LC₅₀ for small larvae. The number of infective juvenile stages (IJs) produced per White trap was significantly greater from larvae infected by H. bacteriophora and least for those infected by H. indica. A proprietary formulation of S. carpocapsae ‘Millenium^®’ was chosen for further greenhouse experiments. Overall, the neonicotinoid insecticide clothianidin provided the best control, but greenhouse experiments also revealed that the label rate of Millenium (10⁶ IJ/l at 2500 l/ha) reduced webworm populations by 83–93% and was as effective as clothianidin against larger‐size larvae. Our data suggest that commercial formulations of S. carpocapsae can be a good option for H. phaeopteralis biocontrol, but further field studies are warranted to confirm effectiveness under different environmental scenarios.     

Optimization and field evaluation of the sex pheromone of Trichophysetis cretacea (Lepidoptera,Crambidae) for pest monitoring

Field studies using the synthetic sex pheromone of Trichophysetis cretacea, a trinary blend of (Z)‐11‐hexadecenyl acetate (Z11‐16:OAc), (Z)‐11‐hexadecenal (Z11‐16:Ald) and (Z)‐11‐hexadecenol (Z11‐16:OH), were performed in Sichuan to determine operational parameters for detection and control, such as dispenser type, blend ratio, dosage, and trap type, height and density. Of three pheromone dispensers tested, grey halo‐butyl isoprene elastomeric septa were significantly more effective than polyvinyl chloride capillary tubing or silicone rubber septa. The ratio of the three components in the blend significantly affected moth catch. In the halo‐butyl isoprene septa, the most effective ratio was 5 : 2 : 1 Z11‐16:OAc:Z11‐16:Ald:Z11‐16:OH. Sticky wing traps caught significantly more moths than water, noctuid moth or cone funnel traps. The most effective height at which wing traps were hung was 20 cm above the jasmine plants. Optimum trap density was 45 traps per hectare. Addition of volatile jasmine compounds did not increase the attractiveness of the sex pheromone. A dosage of 50 μg Z11‐16:OAc per lure was most effective in the autumn weather conditions of Quanwei. These data provide sufficient information to develop effective protocols for using the T. cretacea pheromone to detect and monitor this pest in the jasmine fields.     

基于高通量测序的阿尔泰蝠蛾(鳞翅目:蝙蝠蛾科)幼虫转录组分析

本研究采用Illumina HiSeq TM 2500测序平台对阿尔泰蝠蛾Hepialus altaicola Wang幼虫进行转录组测序及生物信息学分析.经序列拼接后共获得100133个Unigenes,总长度86319112 bp,平均长度862 bp,N50长度1628 bp.将Unigenes与NR、COG/KOG、Pfam、Swiss-Prot、GO、KEGG数据库比对,共获得38198条Unigenes,其中Nr数据库注释的Unigenes最多,为32381条,占32.34％.通过GO功能分类,共有13216个Unigenes在GO数据库中细胞组分、分子功能和生物学过程等3大类57个分支中找到注释;KEGG通路分析,共有15058条Unigenes被注释,归属于305条代谢通路.CDS预测发现54002条序列可被编码,占全部基因的53.93％.基因注释进一步获得311个与冷适应相关的代谢调节基因,并用FPKM值对基因表达量进行评估.本研究获得的转录组信息及分析结果,为进一步研究阿尔泰蝠蛾的基因功能及低温生态适应性奠定分子基础.     

Molecular characterization and phylogenetic analysis of three odorant binding protein gene transcripts in Dendrolimus species (Lepidoptera: Lasiocampidae)

Pine caterpillar moths, Dendrolimus spp. (Lepidoptera: Lasiocampidae), are serious economic pest of pines. Previously, phylogenetic analyses of Dendrolimus using different methods yielded inconsistent results. The chemosensory systems of insects may play fundamental roles in promoting speciation. Odorant‐binding proteins (OBPs) participate in the first step of odor detection. Studying the evolution of OBPs in closely related species may help us to identify their role in speciation. We identified three OBPs – one pheromone‐binding protein and two general odorant‐binding proteins – from male antennae of four Dendrolimus species, D. superans (Butler), D. punctatus (Walker), D. kikuchii Matsumura, and D. houi Lajonquiere, the olfactory recognition systems of which had not been previously investigated. We analyzed their molecular characteristics and compared their sequences to those of OBPs in D. tabulaeformis Tsai et Liu. Ka/Ks ratio analyses among the five Dendrolimus species indicate that PBP1 genes experienced more evolutionary pressure than the GOBPs. Phylogenetic relationships of PBP1 and GOBP1 both indicated that D. houi was the basal species, then branched D. kikuchii, while D. tabulaeformis, D. punctatus, and D. superans evolved more recently. These relationships are consistent with the changes in sex pheromone components of these five species. Dendrolimus tabulaeformis and D. punctatus are closely related sister species. However, the distances among GOBP2 sequences in the five Dendrolimus were very short, and the relationships of D. houi and D. kikuchii could not be resolved. Integrating our results with those of previous studies, we hypothesized that D. kikuchii, D. punctatus and D. superans evolved from the basal ancestor because of sex pheromone mutations and environmental pressure.     

Diapause termination, post-diapause development and reproduction in the beet webworm, Loxostege sticticalis (Lepidoptera: Pyralidae)

Effects of photoperiod and cold exposure on diapause termination, post-diapause development and reproduction in Loxostege sticticalis were examined. Larvae were reared at diapause inducing condition (22 °C, L:D 12:12) consistently or transferred to long day photoperiod (L:D 16:8) and darkness (L:D 0:24) respectively, after entering into diapause. Diapause was terminated in approximately 40% of the larvae after 36 days, and no significant differences were observed between photoperiods, suggesting larval diapause was terminated spontaneously without being induced by photoperiods. Cold exposure significantly hastened diapause termination. The diapause termination incidence increased significantly with peaks of 98% at both 5 °C and 0 °C exposure for 30 days, as compared to 42% in controls not exposed to cold, while the mortality and number of days required for diapause termination decreased dramatically. The optimal low temperature exposure periods under 5 °C or 0 °C were 20 days and 30 days, showing a higher termination incidence and shorter time for diapause termination. This suggests that the low temperatures in winter play an important role in diapause termination under natural conditions. The threshold temperatures for post-diapause development in prepupae and pupae were 9.13 °C and 10.60 °C respectively, with corresponding accumulations of 125 and 200 degree-days. Adults that experienced larval diapause significantly delayed their first oviposition, oviposition period was prolonged, and the lifetime number of eggs laid was decreased, however both males and females have significantly longer longevity. The field validation of diapause termination, the degree-days model, and the relationship between diapause and migration in L. sticticalis were also discussed.     

Effects of larval density on flight potential of the beet webworm, Loxostege sticticalis (Lepidoptera: Pyralidae)

Tethered-flight techniques were used to investigate the flight potential of 1-d-old adult beet webworm, Loxostege sticticalis L. (Lepidoptera: Pyralidae), reared at densities of1, 10, 20, 30, and 40 larvae per 650-ml jar. Larval density had a significant effect on the flight potential, including total flight duration, distance, average velocity, and longest flight duration. Adults reared at a density of 10 larvae per jar, and those reared in isolation displayed the greatest and poorest flight capacity,respectively, relative to the other density treatments. Larval density also significantly affected length of the preoviposition period. Females with longer preoviposition period usually showed greater flight potential, and preoviposition period was positively correlated with flight potential. Body weight, water content, and triglyceride content of the moths were significantly affected by larval density, whereas glycogen content was not. Triglyceride content of adults reared at the different larval densities corresponded to the observed differences inflight potential, whereas water content and body weight were not related to their flight potential. These results suggest that larval density exerts a significant influence on preoviposition period and triglyceride content, which in turn influence flight potential of adult L. sticticalis.     

桃蛀螟性信息素结合蛋白CpunPBP3的表达模式及性信息素结合特性

[目的]本研究旨在对桃蛀螟Conogethes punctiferalis性信息素结合蛋白CpunPBP3进行鉴定和定性分析,完善对桃蛀螟性信息素感受机制的理解.[方法]扩增、分析桃蛀螟CpunPBP3的cDNA序列,并与其他草螟科昆虫的同源蛋白氨基酸序列进行比较.利用qRT-PCR测定桃蛀螟不同日龄雄成虫触角中Cpu...     

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。     

The range of the beet webworm Loxostege sticticalis L. (Lepidoptera,Pyraloidea: Crambidae) in the former USSR territory and its subdivision by the number of generations per season

The distribution limits of the beet webworm, Loxostege sticticalis L., with its sustainable development in one, two, three, or four successive generations per season in the former USSR territory were mapped for the first time using routine GIS procedures. The expected number of generations was determined based on the sum of daydegrees (above a threshold of 12°C), critical day length value (14 h), and Selyaninov’s hydrothermal index (> 0.3). The compiled map was in good agreement with that prepared for China (Luo Li-zhi and Li Guang-bo, 1993).     

草地贪夜蛾的性信息素通讯研究进展

草地贪夜蛾Spodoptera frugiperda原产于美洲,具有长距离迁飞特性。该虫于1988年入侵欧洲,2016年入侵非洲,并引起巨大的粮食损失,2018年入侵亚洲,2019年从缅甸传入中国,并在短时间扩散至全国10多个省。草地贪夜蛾依赖性信息素通讯,实现雌雄间识别、交配和繁衍,为了深入研究草地贪夜蛾的性信息素通讯及其机制并开发更高效的预测预报和防治技术,本文综述了草地贪夜蛾性信息素通讯的研究现状。1967年首次报道草地贪夜蛾性信息素为顺9-十四乙酸酯,随后发现有不同的鉴定结果,1986年确认其性信息素由顺9-十四乙酸酯和顺7-十二乙酸酯两个组分组成,其比例为96.6∶3.4时表现出最强的引诱活性。除此而外,对不同地理种群的研究发现,草地贪夜蛾雌蛾的信息素腺体提取物还存在顺9-十二乙酸酯、顺11-十六乙酸酯和反7-十二乙酸酯,田间实验表明这些物质在性信息素通讯中也可发挥作用。根据分子标记和喜食寄主,草地贪夜蛾可分为玉米品系和水稻品系。两个品系在外部形态上无法区分,性信息素组分也相同,但在组分比例上存在一定的差异。两个品系间存在一定程度的生殖隔离,但室内可以正交和反交并产生可育的F1代,F1代的性信息素比例与母本的比较相似。关于草地贪夜蛾雄性对性信息素的感受机制方面研究较少,仅见有感器形态的鉴定和对性信息素组分的触角电位反应研究的报道。根据目前草地贪夜蛾在我国的发生情况及其性信息素通讯机制的研究现状,我们建议尽快开展以下研究：(1)鉴定草地贪夜蛾我国入侵种群的雌性性信息素,尽快用于其种群动态监测及防治;(2)研究草地贪夜蛾雄性对性信息素的嗅觉编码机制;(3)研究草地贪夜蛾两个品系的行为隔离程度及其演化结局。     

幼虫密度对草地螟生长发育及繁殖的影响

为了明确幼虫密度对草地螟Loxostege sticticalis种群增长的影响, 对室内条件下（温度22±1℃, RH 70%±5%, 光周期16L∶ 8D）不同幼虫密度[1, 10, 20, 30和40头/瓶（650 mL）］饲养的草地螟生长发育及繁殖进行了研究。结果表明: 幼虫密度对草地螟幼虫体色、 发育历期和存活率, 以及蛹重和成虫生殖等有显著影响。随着幼虫密度的增加, 幼虫体色黑化程度呈增强趋势, 幼虫密度大于10头/瓶时的体色黑化值均显著大于幼虫密度为1头/瓶时的体色黑化值（P<0.05）。20头/瓶的幼虫和蛹历期最短, 且随幼虫密度的增加而显著延长（P<0.05）。幼虫存活率以10头/瓶最高, 其他幼虫密度的幼虫存活率显著较低（P<0.05）。蛹重以1头/瓶的最重, 并随幼虫密度增加而显著下降（P<0.05）。成虫产卵量和交配率分别以1和20头/瓶的幼虫密度最高, 幼虫密度升高则产卵量、 交配率逐渐降低。成虫产卵历期随着幼虫密度的增加逐渐缩短。雌、 雄蛾寿命分别以10和20头/瓶幼虫密度时最长, 幼虫密度过高时雌雄蛾寿命又显著缩短（P<0.05）。生命表分析表明, 幼虫密度对草地螟种群增长指数有显著影响, 以10头/瓶幼虫密度的种群增长指数最高, 幼虫密度过高或过低时种群增长指数下降。据此认为, 幼虫密度是影响草地螟种群增长的重要因子之一。     

Transcriptome analysis of sugar beet root maggot (Tetanops myopaeformis) genes modulated by the Beta vulgaris host

Sugar beet root maggot (SBRM, Tetanops myopaeformis von Röder) is a major but poorly understood insect pest of sugar beet (Beta vulgaris L.). The molecular mechanisms underlying plant defense responses are well documented, however, little information is available about complementary mechanisms for insect adaptive responses to overcome host resistance. To date, no studies have been published on SBRM gene expression profiling. Suppressive subtractive hybridization (SSH) generated more than 300 SBRM ESTs differentially expressed in the interaction of the pest with a moderately resistant (F1016) and a susceptible (F1010) sugar beet line. Blast2GO v. 3.2 search indicated that over 40% of the differentially expressed genes had known functions, primarily driven by fruit fly D. melanogaster genes. Expression patterns of 18 selected EST clones were confirmed by RT‐PCR analysis. Gene Ontology (GO) analysis predicted a dominance of metabolic and catalytic genes involved in the interaction of SBRM with its host. SBRM genes functioning during development, regulation, cellular process, signaling and under stress conditions were annotated. SBRM genes that were common or unique in response to resistant or susceptible interactions with the host were identified and their possible roles in insect responses to the host are discussed.     

标记回收法确认我国北方地区草地螟的迁飞

为了证实草地螟Loxostege sticticalis L.（鳞翅目： 螟蛾科）由我国华北越冬区向东北迁飞危害的假说并提供直接的证据, 采用网捕成虫喷雾染料标记释放回收的方法,于2009年越冬代草地螟成虫盛发期间（6月1-4日）分别在内蒙古武川县（41.07°N, 111.42°E）和察右中旗（41.13°N, 112.58°E）的6个标放点共标记当地越冬代草地螟成虫约181万头并自然释放。标记释放后, 在东北、 西北和华北11个草地螟常发省（市、 区）组织各级监测预警部门利用虫情测报灯、 捕虫网和性诱剂诱捕器等多种器械进行回收, 先后于2009年6月7-29日在内蒙古科右中旗、 乌兰浩特、 扎兰屯分别回收到由察右中旗标记释放的成虫9头, 在辽宁省北票市回收到由武川县标记释放的成虫1头。标记释放点至回收点直线距离为725~1 117 km。这是迄今为止世界上确认的草地螟最远迁飞距离。这些证据不仅证实了我国越冬代草地螟成虫能从华北迁往东北危害, 而且为进一步了解草地螟的种群动态规律, 改善草地螟的预测预报技术提供了重要的科学依据。