斜纺猫蛛对茶尺蠖幼虫捕食作用的初步研究

在室温条件下测定了斜纺猫蛛亚成蛛及成蛛对茶尺蠖１～２龄幼虫的日捕食量及功能反应,捕食者自身密度效应和温度对功能反应的影响,斜纹猫蛛亚成蛛及成蛛对茶尺蠖幼虫的功能反应均呈ＨｏｌｌｉｎｇⅡ型反应,模拟模型分别为Ｎａ＝０．９１９５Ｎｔ／（１＋０．００４７０３Ｎｔ）和Ｎａ＝０．９２２６８Ｎｔ／（１＋０．００５０８１Ｎｔ）自身密度反应模型分别为Ｅ＝０．５４１９Ｐ＾－０．６０５２和Ｅ＝０．５１３９Ｐ＾－０．５     

中阈尺蠖的生物学及其防治

中阈尺蠖Ｐｈａｎｅｒｏｔｈｙｒｉｓ ｓｉｎｅａｒｉａ （Ｇｕｅｎｅｅ）是近年来在闽北出现的一种为害青钱柳的重要害虫。１年发生５代,以蛹在林冠下浅土层越冬。幼虫共６龄,末２龄（５￣６龄）为暴食期。此虫发生气温、海拔及坡向关系密切。在虫害较生的林地,可结合秋冬垦复清除越冬蛹,８０％敌敌畏乳油１０００￣１２００倍或２０％氰戊菊酯乳油５０００￣６０００倍喷射３￣４龄幼虫;于越冬代和第１代老熟幼虫初下地时,     

茶尺蠖人工饲料的研究

本报道饲养茶尺蠖(Ectropis obliqua hypulina Wehrli)的5种人工饲料及其饲养方法．5种人工饲料均可用于大规模饲养一代幼虫．其中62号配方可用于续代饲养,在实验室内饲养5代的结果表明。效果良好．在饲料成分的加工．配制及饲养方法等方面．较前人有相当大的改进,因而叶因子用量减少,幼虫历期缩短．用人工饲料饲养的幼虫历期为13-20天。基本接近以茶叶饲养的对照(11—18天)．实验结果还表明饲料含水量．饲养方法．饲养密度和添加饲料的次数不同,对茶尺蠖的生长发育有明显的影响．初龄幼虫用平面培养基倒置饲养和高龄幼虫用片状饲料正置饲养为最佳方法．     

饲料类型对茶尺蠖幼虫肠道细菌多样性及幼虫存活率的影响

【目的】茶尺蠖是茶园中的重要害虫。研究茶尺蠖寄主食物-肠道菌群-茶尺蠖生长发育三者之间的关系对于茶尺蠖的防治具有重要的理论指导价值。【方法】分析不添加茶叶因子的纯人工饲料和茶树鲜叶对茶尺蠖幼虫的存活影响;用高通量测序技术分析不同饲料饲喂的茶尺蠖幼虫的肠道菌群异同。【结果】取食人工饲料的幼虫死亡率远远高于取食茶树鲜叶的幼虫;取食人工饲料的幼虫肠道细菌多样性和丰富度高于取食茶树鲜叶的幼虫;茶尺蠖幼虫肠道中存在很多促进宿主生长的细菌。【结论】饲料类型影响茶尺蠖幼虫的存活;饲料类型影响茶尺蠖幼虫肠道菌群结构。     

春尺蠖生物学特性研究

【目的】为新疆北疆地区春尺蠖Apocheima cinerarius预测预报工作提供理论依据。【方法】本文在林间对春尺蠖的各虫态进行详细调查,记述了各虫态的形态特征、生活史、性比、行为与习性。【结果】春尺蠖蛹主要集中分布在树盘基部30~60 cm、土壤深度为20~30 cm范围的土层中,成虫羽化后,次日19:00—23:00或第3天下午4:00—6:00交尾,其交配行为是多次交配型。雌虫比雄虫羽化稍早,雌虫平均寿命为16~18 d,雄虫平均寿命为8~13 d。翌日黄昏开始产卵,卵期最长34 d,最短26 d,雌虫每天平均产卵块数最高达5.1块/头、平均卵粒数为363.1粒/头,最低为1块/头、平均卵粒数为86粒/头,平均孵化率为86%。1、2龄幼虫食叶量较低,3龄开始暴增,5龄最高,平均每日食叶量可达443 mm2/头。【结论】春尺蠖成虫按翅面斑纹和颜色,可分三种类型:深色型、常见型、浅色型。幼虫的头壳与虫龄呈显著直线正相关。幼虫1~2龄期间,死亡率较高,高达60.37%;4~5龄幼虫,死亡率较低,且食叶量占总食叶量的85.81%。所以应选择在3龄幼虫高峰期之前进行防治。雌雄比为1︰0.7068,可预测下一代种群数量呈上升趋势。     

猫眼尺蠖在三种女贞属植物上的实验种群两性生命表

【目的】猫眼尺蠖Problepsis superans是一种鳞翅目尺蛾科食叶害虫, 有报道称它只危害园林植物小叶女贞Ligustrum quihoui Carr., 关于其他寄主及其寄主对其生命特征的影响很少研究。开展本研究有助于了解小叶女贞及其可能寄主金叶女贞Ligustrum×vicaryi Hort.和女贞Ligustrum lucidum Ait.对猫眼尺蠖生长发育和繁殖的影响。【方法】在室内25±1℃, 相对湿度为75%±5%, 光周期为16L∶8D条件下, 组建了猫眼尺蠖在这3种植物上的实验种群年龄-龄期两性生命表。【结果】金叶女贞、小叶女贞和女贞对猫眼尺蠖幼虫历期、产卵量有明显影响, 对卵期、蛹期、产卵前期（指雌虫羽化至开始产卵）、雄虫存活时间等无显著影响。猫眼尺蠖取食金叶女贞幼虫历期（21.33 d）显著短于取食小叶女贞（23.46 d）和女贞(27.28 d), 产卵量（529.1粒/雌）显著高于在小叶女贞（442.5粒/雌）和女贞（339.7粒/雌）上。猫眼尺蠖在金叶女贞和小叶女贞上的内禀增长率(r)、周限增长率(λ)、净增殖率(R₀)无显著差异, 但两者都显著大于在女贞上。猫眼尺蠖在3种植物上的平均世代周期(T)差异显著, 它们从小到大为: 金叶女贞、小叶女贞、女贞, 在3种植物上总繁殖率(GRR)没有显著差异。【结论】金叶女贞和小叶女贞相比女贞提供了猫眼尺蠖较好质量的食物, 金叶女贞和女贞具备作为猫眼尺蠖的寄主或临时寄主的可能。     

沈阳地区国槐尺蠖发生规律研究

通过室内饲养和田间观察,对国槐尺蠖Semiothisa cinerearia Bremer et Grey各虫态(成虫、卵、幼虫、蛹)特征进行了详细的描述。对国槐尺蠖的行为习性、生活史以及田间种群消长规律进行了深入的研究。研究结果表明,国槐尺蠖在沈阳一年发生3代,无世代重叠,以蛹在树下松软土壤中越冬。国槐尺蠖幼虫共有7龄,1～4龄取食量小,5龄以后食量大增,进入暴食期,取食量占全幼虫期的80%～90%,而且随着虫龄的增长,其存活率增加。国槐尺蠖幼虫发生期为5月到9月,6月上旬、中旬至7月下旬为幼虫为害盛期,9月以后种群呈递减趋势,老熟幼虫开始入土化蛹越冬。     

菊花叶片作为茶尺蠖饲料并用于其核型多角体病毒增殖的研究

本报道了以菊花叶片饲养茶尺蠖获得成功的试验结果．经连续三代饲养表明：以菊花叶片为饲料。幼虫取食量、蛹期、蛹重、成虫寿命、产卵置、种群特征参数与以茶树叶片为饲料的相比均无显性差异,但其幼虫历期延长1-2天．用它作饲料,饲养茶尺蠖增殖其核型多角体病毒,产量也不受显影响．故可用于茶尺蠖的大量饲养及其病毒的增殖．     

油桐尺蠖血球细胞系的建立及其对多角体病毒敏感性的测定

建立了稳定生长的油桐尺蠖幼虫血球细胞系,称为WIV-BS-02细胞系,原代培养始于1981年4月,至今已传至第83代,细胞系的群体倍增时间为48～72小时,形状有圆形和梭形两种,具有鳞翅目昆虫的典型染鱼体。比较了6种培养液和3种培养温度对细胞生长的影响,观察了同源油桐尺蠖核型多角体病毒感染后,光学显微镜下的细胞病理变化及电镜下病毒的形态发生,测定了细胞培养物对油桐尺蠖的体外培养细胞和幼虫的感染性。     

有效积温法预测茶尺蠖防治适期的研究

利用22年历史气象资料和有效积温法,由茶尺蠖幼虫期或成虫发生高峰期预测下一代防治适期,并进行验证。1993年在室内外经5代39次预测验证,总符合率达96．6％。由幼虫期预测可使预报提前20～35天。     

Effects of the ecdysteroid agonists RH 5849 an RH 5992, alone and in combination with a juvenile hormone analogue, pyriproxyfen, on larvae ofSpodoptera exigua

Biological activity assays with RH 5849 and RH 5992 indicated that both compounds affected growth and development of last-instar larvae ofSpodoptera exigua (Hübner) (Lepidoptera: Noctuidae) in a dose-dependent manner. Within the first 24 h after treatment by continuously offering leaves dipped in a water solution of ≥50 mg/l RH 5849 and ≥0.5 mg/l RH 5992, symptoms of a prematurely induced larval moult and head capsule apolysis were visible. Intoxicated larvae died shortly afterwards, showing signs of unsuccessful ecdysis. LC₅₀-values of RH 5849 and RH 5992 for fifth-instarS. exigua larvae were 110 and 2.5 mg/l, respectively. Pyriproxyfen alone affected the larval stage and disturbed normal metamorphosis. One supernumerary larval instar occurred occasionally. LC₅₀-value for pyriproxyfen was 1.7 mg/l. Larvae simultaneously treated with RH 5849 or RH 5992 and pyriproxyfen, continued to grow until they attained a size and weight about 2–3 times that of the controls. This growth was accompanied by at least one and sometimes two supernumerary moults. Concerning thein vivo imaginal wing disc growth and development, only in larvae treated with 10 and 50 mg/l RH 5849 or 0.5 mg/l RH 5992, tracheole migration was observed earlier than in the controls. When applying 300 mg/l RH 5849 or 3–7 mg/l RH 5992, the discs remained small and no signs of tracheole migration were observed. In larvae simultaneously treated with RH 5849 or RH 5992 and pyriproxyfen, tracheole migration was not prematurely induced and a pupal cuticle was produced in the discs of larvae, undergoing a supernumerary moult. No clear signs of evagination were observed.     

The ecdysoid RH5849 induces yolk polypeptide synthesis in male flies

Summary

RH5849 is a benzoyl hydrazine analog which has been reported to mimic several effects of the arthropod steroid hormone ecdysone to which it is chemically totally unrelated. In adult Diptera, ecdysone is the hormone that triggers vitellogenin synthesis. We report here that RH5849, upon oral ingestion, is able to induce vitellogenin synthesis in male Drosophila, Neobellieria, Phormia and Lucilia. This contrasts to data in the literature which showed that RH5849 could not mimic the pupariation-inducing effect of ecdysone in last instar fly larvae. RH5849 neither exerts a juvenile hormone mimicking effect nor behaves as an anti-juvenile hormone in both the Colorado potato beetle and Galleria.     

Regulation of cytochrome P-450 dependent steroid hydroxylase activity in Manduca sexta: effects of the ecdysone agonist RH 5849 on ecdysone 20-monooxygenase activity

The non-steroidal ecdysone agonist RH 5849 (1,2-dibenzoyl-1-tert-butylhydrazine) was found to inhibit in a dose-response and apparently competitive fashion the cytochrome P-450 dependent ecdysone 20-monooxygenase activity in the midgut of wandering stage last instar larvae of the tobacco hornworn, Manduca sexta. More effectively on a per molar basis than the naturally occurring molting hormones ecdysone and 20-hydroxyecdysone, RH 5849 was also found to elicit the dramatic 50-fold increase in midgut steroid hydroxylase activity (which normally occurs with the onset of the wandering stage) when injected into competent head or thoracic ligated pre-wandering last instar larvae. These data support and extend the potential usefulness of RH 5849 as a pharmacological probe for further investigating the actions of ecdysteroids and their role(s) in the regulation of ecdysteroid monooxygenases.     

Endocrine background of how 20-hydroxyecdysone agonist, RH 5849, influences diurnal pattern of pupation in shape Spodoptera littoralis

Under laboratory conditions (L16:D8, 24°C, r.h. 80%), applying of an ecdysone agonist, RH 5849, (1,2-dibenzoyl-1-tert-butylhydrazine) onto final instar larvae of Spodoptera littoralis (Boisd.), Noctuidae, Lepidoptera, delayed or advanced the time of pupation depending on the time of treatment. This response was dose-dependent. In addition, non-lethal doses of RH 5849, ranging from 0.05 to 10 µg/larva were used. Following treatment of S. littoralis larvae with 5 µg RH 5849 the endogenous ecdysteroid level was increased or decreased depending on the time of application. Based on the results presented, we suggest that potential users of non-steroidal ecdysone agonists should consider the proper circadian timing of application in the field.     

Induction of supernumerary larval moulting in the tobacco hornworm Manduca sexta: interaction of bisacylhydrazine ecdysteroid agonists with endogenous Juvenile Hormone

Abstract When given in a critical dietary dose range, the insecticidal bisacylhydrazine ecdysteroid agonists RH‐5849 or tebufenozide (RH‐5992) cause fifth stage Manduca sexta (L.) larvae to moult to a supernumerary sixth‐stage giant larva. The effect is dependent on exposure to the chemicals immediately after the previous ecdysis. Previous removal of the corpora allata does not interfere with the induction of premature moulting by RH‐5849 but completely prevents the formation of supernumerary larvae. The juvenilizing effect is therefore due to the interaction of the moult‐promoting effect of the ecdysteroid agonists with the high titre of endogenous Juvenile Hormone that is present just after ecdysis to the fifth stage in this insect. The ecdysteroid agonists themselves appear to have no intrinsic Juvenile Hormone‐agonist properties. Sixth‐stage larvae resulting from exposure to critical dietary concentrations of RH‐5849 are morphologically completely larval in character. When transferred to diet without the ecdysteroid agonist, they feed normally and gain weight, growing much larger than control fifth stage insects. At the end of the supernumerary stage, they cease to feed, wander in the usual way, and form a normal pupal cuticle but then die as pharate pupae without shedding the sixth‐stage larval cuticle.     

On the action of RH 5849, a nonsteroidal ecdysteroid agonist, on a cell line from Chironomus tentans.

RH 5849 competes with ³H-ponasterone A for ecdysteroid binding sites in Chironomus tentans cells with an about fourfold lower relative affinity as compared to 20-OH-ecydsone. It does not interfere with glucocorticoid and estrogen binding sites in vertebrates. It is also not recognized by an ecdysteroid antibody. RH 5849 exerts typical morphological and physiological effects ascribed to the action of 20-OH-ecdysone on C. tentans cells, namely an increase in acetylcholinesterase activity and an inhibition of chitin synthesis.     

The effects of ingested ecdysteroid agonists (20-hydroxyecdysone, RH5849 and RH5992) and an ecdysteroid antagonist (cucurbitacin B) on larval development of two polyphagous lepidopterans (Acherontia atropos and Lacanobia oleracea)

Larvae of two polyphagous lepidopteran species, Lacanobia oleracea (Tomato moth) and Acherontia atropos (Death's head hawkmoth), have been treated with representatives of three classes of compounds which are known to interact with the ligand binding site of insect steroid hormone receptors: a steroidal ecdysteroid (20-hydroxyecdysone; 20E; agonist), two non-steroidal dibenzoylhydrazines (RH5849 and RH5992; agonists) and the triterpenoid cucurbitacin B (cucB; antagonist). Both species are unaffected by dietary 20E at concentrations up to 400 ppm. L. oleracea metabolises ingested [³H]20E to a mixture of C-22 fatty acyl esters, while A. atropos excretes [³H]20E unmetabolised. Both species are susceptible to the dibenzoylhydrazines when these are incorporated into the diet, with RH5992 proving lethal at 1 ppm and RH5849 proving lethal at 10 ppm. Thus, the metabolic/excretion mechanisms which are so effective against ingested 20E do not recognise the non-steroidal agonists. The two species showed varying degrees of tolerance to cucB; L. oleracea was unaffected by 400 ppm in the diet, while A. atropos showed effects at 400 ppm, but not at 40 ppm. Feeding cucB in conjunction with 20E or injecting cucB when the ecdysteroid titre was low or rising also had no effect in L. oleracea. It is suggested that tolerance to the two classes of natural products (ecdysteroids and cucurbitacins) is associated with the occurrence of these compounds in some of the host plants of these species; evidence is presented for the presence of phytoecdysteroids in the host plants.     

Establishment and characterization of two human cell lines with amplified dihydrofolate reductase genes

Two SV40-transformed human cell lines, GM637, derived from a normal human subject, and GM5849, derived from a patient with ataxia-telangiectasia (A-T), were grown in increasing concentrations of the cytotoxic agent methotrexate (MTX). The GM637 line was naturally more resistant to methotrexate than was GM5849 and, over a 5-month period, became resistant even to very high concentrations (up to 100 microM). The GM5849 line became resistant to 500 nM methotrexate during the same period. However, dot blot and Southern blot analyses showed that both cell lines had amplified their dihydrofolate reductase (dhfr) genes to about the same extent, approx. 50-fold. Using the GM5849 line with amplified dhfr, we attempted to determine if interruption of DNA synthesis by hydroxyurea would cause DNA to be replicated twice within a single cell cycle, as has been reported for Chinese hamster ovary cells. No evidence for such a phenomenon was obtained.     

Effect of an ecdysone agonist,RH-5849, on wandering behaviour in Spodoptera littoralis

1. Wandering behaviour of the fall armyworm, Spodoptera littoralis has been examined using a video-digitizing computer system. 2. Ecdysteroid titers prior to and during wandering have been determined using an enzyme immunoassay. 3. RH 5849, an agonist of 20-hydroxyecdysone (20E) applied at various times before wandering to last instar larvae of S. littoralis caused a delay in the onset of wandering, varying from 0.5 to 4.5 hr. This delay was dose dependent. 4. We suggest that wandering in S. littoralis may be induced by a decrease in ecdysteroid titers.     

Environmental and physiological factors for diapause induction and termination in the aphid parasitoid,Aphidius ervi (Hymenoptera: Aphidiidae)

In the aphid parasitoid Aphidius ervi Haliday, the incidence of diapause around the critical photoperiod was dependent on temperature. At a photoperiod of 12 h light:12 h dark, a significantly higher proportion of diapausing individuals was found at 12 degrees C than at 15 degrees C. The second larval stage of the parasitoid was most sensitive to photoperiod and localised-illumination experiments showed that the parasitoid responded independently of the aphid host. The sex ratio of the population which emerged after rearing in short-days and/or after diapause was male biased. Topical application of the juvenile hormone-mimic, pyriproxyfen, before or during diapause delayed emergence of Aphidius ervi but did not induce diapause or influence its termination. The ecdysteroid mimic RH 5849 induced diapause in a few treated individuals but did not affect diapause termination.