三种阔叶草坪草对斜纹夜蛾生长发育及营养利用的作用

为了探讨斜纹夜蛾Spodoptera litura对草坪的为害,提供综合治理该虫的理论依据,室内利用白三叶草Trifolium repens、红三叶草T. pratense和马蹄金Dichondra repens 3种阔叶草坪草,分别饲喂斜纹夜蛾幼虫;应用编制实验种群生命表的方法,分析斜纹夜蛾种群生长发育的趋势;同时研究该幼虫对3种草坪草的趋性及营养利用。结果表明：斜纹夜蛾幼虫的趋性表现为白三叶草＞红三叶草＞马蹄金。该虫在3种草坪草上都能够完成生活史;2种三叶草饲喂的该虫幼虫存活率、化蛹率、成蛾率显著高于马蹄金,幼虫期和蛹期则显著短于马蹄金;3种草坪草饲喂的该虫产卵期和平均产卵量相互之间差异不显著,而马蹄金饲喂的产卵前期和雌成虫寿命则显著短于2种三叶草。3种草坪草饲喂的该虫净生长率（Ro）、世代平均周期（T）、内禀生长率（r_m）、周限生长率（λ）、种群加倍时间（DT）及种群增长参数（I）都有差异,其中2种三叶草的各种群增长参数较接近。对5龄幼虫取食3种阔叶草坪草的营养指标测定结果显示：取食马蹄金的相对生长率显著高于取食红三叶草的;取食马蹄金的相对取食量和近似消化率显著高于取食三叶草的;取食马蹄金的食物利用率和食物转化率显著低于取食三叶草的;2种三叶草间无显著差异。综合分析认为,斜纹夜蛾最喜食三叶草,最容易在三叶草草坪上猖獗为害。     

染料标记对斜纹夜蛾生长发育及成虫飞行能力的影响

以斜纹夜蛾Spodoptera litura为研究对象,将染料添加到半人工饲料中饲喂幼虫,评价其对该虫生长发育和成虫飞行能力的影响,以期为开展该虫的田间诱集和扩散行为研究提供标记方法。结果表明,添加不同浓度苏丹红7B、苏丹蓝Ⅱ和龙胆紫的半人工饲料饲养斜纹夜蛾幼虫,含0.006%苏丹红7B的半人工饲料幼虫存活率高,成虫标记效果好。进一步研究显示,取食含0.006%苏丹红7B半人工饲料的斜纹夜蛾幼虫发育历期、蛹重以及成虫寿命、体长、翅展及飞行能力等与对照相比均无显著差异。含0.006%苏丹红7B半人工饲料饲料对斜纹夜蛾的生物学无显著影响,标记效果显著,操作简单,适合于大规模标记斜纹夜蛾成虫。     

模拟降雨对草地贪夜蛾卵和幼虫的影响

为探究降雨对草地贪夜蛾Spodoptera frugiperda种群的影响,本研究通过室外模拟降雨研究了雨水冲刷对草地贪夜蛾卵和幼虫的影响。结果表明：在4种不同降雨强度0 mm/h（对照）、10.2 mm/h（中雨）、26.5 mm/h（暴雨）、42.8 mm/h（大暴雨）处理下,卵块的掉落率随着降雨强度的增加而增加;在暴雨、大暴雨条件下卵块的孵化率分别为75.14%、43.58%,显著低于对照和中雨;对比有无鳞毛层覆盖的卵块之间的掉落率和孵化率,二者在各个降雨强度之间差异不显著;对比玉米叶片不同位置卵块的掉落率和孵化率,在中雨降雨强度影响下,二者差异不显著,而在暴雨、大暴雨条件下,玉米叶片背面卵块的掉落率低于正面,孵化率高于正面。此外,在相同的降雨强度下,草地贪夜蛾幼虫（2龄、3龄、4龄、5龄）的掉落率随着龄期的增加而降低;当降雨强度增加时,3龄幼虫的掉落率增加。结果表明降雨,特别是暴雨和大暴雨,对草地贪夜蛾的卵和幼虫均有不利影响,为预测草地贪夜蛾种群提供一定依据。     

Distribution and metabolism of exogenous ecdysteroids in the egyptian cotton leafworm Spodoptera littoralis (lepidoptera: noctuidae)

After ingestion of various amounts of either [³H]ecdysone or [³H]20-hydroxyecdysone (0.8 ng to 10 μg) by sixth instar larvae of the Egyptian cotton leafworm Spodoptera littoralis, apolar metabolites are rapidly detected in the gut and frass. Hydrolysis of the apolar products with Helix hydrolases releases solely [³H]ecdysone or [³H]20-hydroxyecdysone, respectively. This, coupled with the formation of chemical derivatives (acetonide and acetate) which cochromatograph with authentic reference compounds on hptlc and hplc demonstrates that these apolar metabolites consist of ecdysone or 20-hydroxyecdysone esterified at C-22 with common long-chain fatty acids. The major fatty acids have been identified by RP-hplc and their contribution to the mixture determined. In contrast, [³H]ecdysone injected into the haemolymph of S. littoralis is metabolized to yield 20-hydroxyecdysone, ecdysonoic acid, and 20-hydroxyecdysonoic acid. Thus, two different pathways exist for the metabolism of ecdysteroids in this species. In addition to an essentially polar pathway operating on injected and endogenous ecdysteroids, exogenous ecdysteroids entering the gut of S. littoralis are detoxified, yielding apolar ecdysteroid 22-fatty acyl esters which are rapidly excreted. The significance of these results in relation to the effects of ingested ecdysteroids on S. littoralis is discussed. Arch. Insect Biochem. Physiol. 34:329–346, 1997. © 1997 Wiley-Liss, Inc.     

Regulation of sex pheromone biosynthesis in two noctuid species,S. littoralis and M. brassicae,may involve both PBAN and the ventral nerve cord

In order to understand better the mechanism of regulation of pheromone production in moth species, we performed ELISA analyses to detect and follow pheromone biosynthesis activating neuropeptide-like immunoreactivity (PBAN-IR) in different tissues of the two noctuidae species, Spodoptera littoralis and Mamestra brassicae. Male S. littoralis and both male and female M. brassicae brain-subesophageal ganglion (Br-SEG), corpora cardiaca-corpora allata complex, and terminal abdominal ganglion extracts showed the presence of PBAN-IR during both the photophase and the scotophase. However, PBAN-IR was found only in scotophase in female hemolymph. Analysis of extracts of Br-SEG, terminal abdominal ganglion, and hemolymph after HPLC fractionation showed that the most immunoreactive fraction in all the extracts exhibited the same retention time as Hez-PBAN, suggesting that similar PBAN-like material is present in all these tissues. In vivo studies demonstrated that severing the ventral nerve cord in M. brassicae anterior to the terminal abdominal ganglion impaired normal sex pheromone production by third-scotophase females, as was previously shown in S. littoralis. Additionally, PBAN-IR levels were lower in hemolymph samples obtained at the peak of pheromone production in both S. littoralis and M. brassicae females that had the ventral nerve cord severed compared with sham operated animals. These results, along with earlier reported data, indicate that control of pheromone production in both species may involve both PBAN (or PBAN-like peptides) and the ventral nerve cord and support the hypothesis that a neural input from the ventral nerve cord triggers the release of the pheromonotropic peptide(s) into the hemolymph, which then acts directly on the pheromone gland to stimulate pheromone biosynthesis. Arch. Insect Biochem. Physiol. 37:295–304, 1998. © 1998 Wiley-Liss, Inc.

1 We thank Germán Lázaro for insect rearing.

     

Induction of cuticular melanization in Spodoptera littoralis larvae by PBAN/MRCH: Development of a quantitative bioassay and structure function analysis

PBAN (also termed melanization and reddish coloration hormone, MRCH) is a cerebral factor known to regulate sex pheromone biosynthesis and cuticular melanization in moths. In the present study we developed a quantitative method (based on computerized image analysis of cuticles) to determine the effect of Helicoverpa zea PBAN (Hez-PBAN) on cuticular melanization and to study the structure-activity relationship of the neuropeptide in Spodoptera littoralis larvae. The results indicate that Hez-PBAN stimulates cuticular melanization in an interspecific manner, and that the minimal dose evoking formation of melanins is between 3–10 pmol/larva. Higher doses of Hez-PBAN did not stimulate melanization any further. Examination of the structure-activity relationship of Hez-PBAN revealed that the first eight N-terminal amino acids are not essential for the melanotropic activity and that the activity resides in the C-terminal region. Within this region the C-terminal amide was found to play a very important role. © 1996 Wiley-Liss, Inc.     

警惕南方黏虫传入我国

原产于美洲热带的南方黏虫Spodoptera eridania(Stoll)是一种多食性的农业害虫。2016年南方黏虫入侵到非洲4个国家,对木薯和番茄等作物造成了严重危害,目前在我国尚未发现该害虫及相关报道。本文综述了南方黏虫的形态特征、地理分布、生物学特性以及防治措施,为我国今后南方黏虫的检测、监测和防治工作提供参考。从适生性度看,南方黏虫的寄主植物在我国广泛分布;我国也存在气候环境与该虫生存条件相似的地区,且寄主植物所在区域的气候条件同样适于南方黏虫的生长发育。伴随着国际贸易和其自身强大的迁飞能力,南方黏虫具有入侵我国的可能性。因此,有必要对其入侵我国的威胁提出预警,加强边境口岸检疫是防范该虫入侵的主要手段。     

斜纹夜蛾发生期预测预报的探讨——有效积温预测法

根据斜纹夜蛾发育起点温度和有效积温,探讨了斜纹夜蛾发生期预测方法。结果表明,田间斜纹夜蛾发生高峰期与预测的日期基本吻合。     

海洋微生物杀虫活性筛选方法比较

采用活体昆虫浸渍法和细胞毒性测定法对海洋微生物发酵液进行了杀虫活性比较,从294株供试菌株中,共筛选出7株活性较好的菌株;对Lv7-1、02AB8 a、T31和BBY-9四株菌株,在不同时间的生物量、发酵液pH值与细胞毒活性等方面的关系进行了研究。