粘虫及其寄生性天敌—管侧沟茧蜂饲养方法

系统介绍了粘虫Mythimna separata (Walker)室内饲养的设备、步骤、技术要点、人工饲料配方及环境要求,并以粘虫为中间寄主,实现了粘虫低龄幼虫寄生性天敌管侧沟茧蜂Microplitis tuberculifer (Wesmael) 的室内大量繁殖,为进一步利用该蜂防治甜菜夜蛾、粘虫等田间害虫打下了良好的基础。     

Suitability of some farmscaping plants as nectar sources for the parasitoid wasp, Microplitis croceipes (Hymenoptera: Braconidae): Effects on longevity and body nutrients

In support of an ongoing study to evaluate potential farmscaping plants for utilization in organic vegetable production systems, we examined the effects of the nectar of three flowering plant species, sweet alyssum (Lobularia maritima), buckwheat (Fagopyrum sagittatum), and licorice mint (Agastache foeniculum), on the lifespan and body nutrient levels of the wasp, Microplitis croceipes (Cresson) (Hymenoptera: Braconidae), a key parasitoid of some caterpillar pests of vegetable crops in the USA. The greatest longevity (～16 days) was recorded for honey-fed wasps (positive control). Buckwheat significantly increased the lifespan of female and male wasps by at least two-fold relative to wasps provided water only (longevity = 3–4 days). Licorice mint significantly increased female longevity and numerically increased male longevity. Sweet alyssum slightly increased longevity of both sexes but this was not significantly different from the water only control. Females had a significantly longer longevity than males on all the diet treatments. The greatest carbohydrate nutrient levels (sugar content and glycogen) were recorded in honey-fed wasps followed by wasps fed buckwheat, whereas very little nutrients were detected in wasps provided sweet alyssum, licorice mint or water only. However, female wasps were observed to attempt to feed on all three flowering plant species. Thus, the low nutrient levels detected in wasps provided sweet alyssum or licorice mint may be because the nectars were not accessible or were of poor quality. Further studies will evaluate the effects of the promising farmscaping plants on the beneficial and pest insect communities in the field.     

Disruption effect of Microplitis bicoloratus polydnavirus EGF-like protein, MbCRP, on actin cytoskeleton in lepidopteran insect hemocytes

Microplitis bicoloratus is a braconid endoparasitic wasp associated with the polydnavirus named Microplitis bicoloratus bracovirus （MbBV）. Parasitism of Spodoptera litura larvae leads to an impaired cellular immune response and to the disappearance of the 42 kDa actin in host hemocytes. In this work, we investigated if the absence of actin in blood cells was related to MbBV infection. An MbBV gene similar to egf-like genes identified in another bracovirus was partially cloned and named Mbcrp1. The full-length gene, named Mbcrp, is transcribed throughout the course of parasitism in host hemocytes and the 30 kDa MbCRP protein was detected in hemocytes 6-7 d post-parasitization. The Mbcrp1 gene contains the cysteine-rich trypsin inhibitor-like （TIL） domain coding sequence and the expression of recombinant MbCRP1 inhibited the expression of the 42 kDa actin in Hi5 cells. The 34.1 kDa MbCRPl-green fluorescent protein fusion protein locate specifically in the cytoplasm. These results suggest that expression of MbCRP in lepidopteran insect cells is related to the disruption of the actin cytoskeleton.     

马尼拉陡胸茧蜂对甜菜夜蛾的控害潜能

为评价幼虫寄生蜂马尼拉陡胸茧蜂对甜菜夜蛾的控害潜能,编制了寄主和寄生蜂的实验种群生命表,测定了马尼拉陡胸茧蜂对甜菜夜蛾幼虫的寄生功能反应。结果表明:甜菜夜蛾年龄特征生命表参数为:净生殖力(种群趋势指数)R0(I)=122.0172,内禀增长率rm=0.1522,世代平均历期T=40.8556(d),周限增长率λ=1.1644;马尼拉陡胸茧蜂寄生甜菜夜蛾幼虫的生殖力表参数为:R0(I)=20.2479,rm=0.3045,T=9.8788,λ=1.3559。马尼拉陡胸茧蜂对甜菜夜蛾幼虫的捕食功能反应符合HollingⅡ型模型,a=0.8952,Th=0.0205,Namax=48.78(头)。通过生命表参数比较和功能反应模型分析,可见马尼拉陡胸茧蜂对甜菜夜蛾幼虫的寄生能力强,繁殖速率高,对甜菜夜蛾种群有较强的控制能力;从世代平均历期T的比较可知,在甜菜夜蛾繁殖1代的时间内,马尼拉陡胸茧蜂可以繁殖4个世代,在时间上天敌对害虫的发生是"超前的"而不是"跟随的"。因此在放蜂技术上应采取相应的对策,才能充分发挥天敌的控害潜能。     

复配杀虫剂BtA对棉铃虫的杀虫效果及对天敌中红侧沟茧蜂蛹和成虫的触杀毒性(英文)

为了科学施药, 合理保护和利用天敌对棉铃虫Helicoverpa armigera进行综合防治, 本研究在室内测定和比较了复配杀虫剂BtA和7种常用杀虫剂（阿维菌素、 Bt、 β-氯氰菊酯、辛硫磷、定虫隆、氰戊菊酯和丁硫克百威）对棉铃虫的杀虫效果及对其天敌中红侧沟茧蜂Microplitis mediator蛹和雌成虫的触杀毒性。采用浸叶法测定杀虫剂在室内72 h内对棉铃虫3龄幼虫的杀虫效果, 结果表明： 与其他杀虫剂相比, BtA对棉铃虫幼虫具有更高的毒性和致死效应 (LC₅₀=0.7364 mg/mL)。将棉铃虫3龄幼虫接到用浓度4 mg/mL上述杀虫剂分别处理过的大白菜上24, 48和72 h, 发现其死亡率之间存在显著差异（P≤0.05）。但在72 h后, BtA和其他杀虫剂对棉铃虫幼虫的杀虫效果之间并无显著差异(P>0.05)。BtA施药后, 随着时间的延长, 棉铃虫幼虫的死亡率也在增加。另外, 通过杀虫剂对寄生蜂中红侧沟茧蜂蛹和雌成虫的触杀毒性的生物测定发现： 与β-氯氰菊酯、 氰戊菊酯和丁硫克百威相比, BtA对中红侧沟茧蜂蛹和雌成虫的毒性较低, 对其蛹和雌成虫致死率分别仅为13.82%和7.33%。本研究证明BtA对鳞翅目害虫具有中等毒性, 而对寄生蜂中红侧沟茧蜂则具有较低毒性。     

The effects of host age and superparasitism by the parasitoid, Microplitis rufiventris on the cellular and humoral immune response of Spodoptera littoralis larvae

To study the dynamics of stage-dependent immune responses in Spodoptera littoralis (Boisd.) larvae (Lepidoptera: Noctuidae), single and superparasitism experiments were carried out using the parasitoid Microplitis rufiventris Kok. (Braconidae: Hymenoptera). Compared to younger (preferred) host larvae, the older (non-preferred) host larvae displayed a vigorous humoral response that often damaged and destroyed the single wasp egg or larva. Superparasitism and host age altered both the cellular and humoral immune responses. Younger host larvae showed a stronger encapsulation response compared to older host larvae. Moreover encapsulation rates in younger hosts (e.g., second instar) decreased with increasing numbers of parasitoid eggs deposited/larvae. In older larvae, the encapsulation rate was low in fourth, less in fifth and absent in sixth instar hosts. Conversely, the order and magnitude of the cellular immune response in S. littoralis hosts were highest in second instar larvae with the first instar larvae being a little lower. The immune response steadily decreased from the third through to the fifth instar and was least obvious in the sixth instar. In contrast, the general humoral immune response was most pronounced in sixth instar larvae and diminished towards younger stages. The results suggest that both cellular and humoral responses are stage-dependent. Wasp offspring in younger superparasitized host larvae fought for host supremacy with only one wasp surviving, while supernumerary wasp larvae generally survived in older superparasitized larvae, but were unable to complete development. Older instars seem to have a method for immobilizing/killing wasp larvae that is not operating in the younger instars.     

中红侧沟茧蜂对烟草挥发物的触角电生理及行为反应

中红侧沟茧峰 Microplitis mediator是棉铃虫 H elicoverpa armigera的主要内寄生蜂 ,是优良的蜂种 ,在生物防治上具有广阔的应用前景。但迄今 ,有关中红侧沟茧蜂的化学生态的研究甚少。利用触角电位技术 ,测定了中红侧沟茧蜂对烟草叶片粗提物和烟草中 10种挥发物的触角电生理反应 ,并测定了中红侧沟茧蜂的触角电位反应随日龄的变化。以嗅觉仪测定了中红侧沟茧蜂对烟草粗提物、烟草中 4种挥发物的行为反应。结果表明中红侧沟茧蜂利用烟草释放的气味向烟草定向 ,进而找到其寄主——棉铃虫 ,也佐证了烟草同样是棉铃虫的重要寄主植物的论点。雌蜂对脂肪族化合物反应最强 ,对芳香族化合物和糠醛 (杂环化合物 )的反应居中 ,对萜类化合物反应较弱或者不反应。表明烟草挥发性物质在中红侧沟茧蜂寻找寄主的过程中起着重要的作用 ,但挥发物各组分的作用存在着差异。雌性中红侧沟茧蜂对顺 - 3-己烯醇的触角电位反应随日龄的增加而变化。 1日龄的雌蜂的反应较弱 ,2日龄、3日龄的雌蜂反应较强 ,4日龄、5日龄的雌蜂的反应又减弱。这与该蜂产卵习性相符 :羽化当天的雌蜂产卵较少 ,羽化 2～ 3d之后的雌蜂产卵量较大     

中红侧沟茧蜂多分DNA病毒基本特征研究

本文首次报道中红侧沟茧蜂 (Microplitismediator)雌蜂卵巢中存在多分DNA病毒 (MicroplitismediatorPlolyd navirus,MmPDV) ,初步研究了MmPDV形态和基本生理生化特征。利用蔗糖密度梯度超速离心分离纯化了MmPDV粒子 ,电镜负染显示PDV粒子分三段 ,带有一明显的尾部结构 ,大小约为 130× 35nm ;SDS PAGE电泳条带较多 ,至少可以分辨出 2 6个电泳条带 ,表明病毒粒子衣壳蛋白复杂 ;琼脂糖凝胶电泳显示MmPDV基因组至少由大小不同、丰度不等的 14个DNA分子组成 ,用 6种内切酶 (EcoRI,HindIII,BssHII,PstI,BamHI,BglI)酶切MmPDV基因组后 ,估算出MmPDV基因组大小约为 10 8kb。用雌蜂输卵管萼液注射小地老虎幼虫 ,注射后的小地老虎体重和龄期发育动态表明 ,MmPDV具有抑制寄主生长发育的生理功能     

寄主利它素对稻螟赤眼蜂寄生行为的影响

对稻螟赤眼蜂Trichogrammajaponicum(Ashmead)在寄主定位过程中所利用的寄主利它素的存在部位、作用方式及其应用效果作了初步研究。生测结果表明 :寄主利它素存在于三化螟Tryporyzaincertu las(Walker)卵块盖毛和成虫鳞片中 ,其中以盖毛中利它素含量最高 ,雌蛾鳞片次之 ,雄蛾鳞片含量最少。结果还表明盖毛在卵块上的完整性对稻螟赤眼蜂的寄主搜索行为有明显影响。室内应用效果表明利它素可以使稻螟赤眼蜂对寄主卵寄生率提高 1 0 %以上。     

Influence of Precocene II on the estimated changes within the haemocyte population of parasitized spodoptera littoralis larvae by microplitis rufiventris

Series of experiments were undertaken to investigate whether application of Precocene II (PII) to parasitized S. littoralis larvae can influence their THCs and DHCs. PII was applied in single dose treatments (70μg/5 μl/dose). Haemolymph samples were taken at daily intervals from day 3 to day 8 post‐treatments. Two distinct alterations were noted; first, PII‐treatments caused significant decrease in THCs. Once the parasitoid larvae emerge from either treated or untreated hosts, a sharp decline in THCs was observed. The second effect was changes in DHCs of S. littoralis larvae. In controls, haemocyte types could be arranged in descending order due to their relative occurrence into plasmatocytes (PLs), prohaemocytes (PRs), spherule cells (SPs), granular cells (GRs) and oenocytoids (OEs). This order changed in treated hosts to PLs, GRs, PRs, SPs and OEs, i.e., GRs that were less prevalent in the haemolymph of control larvae increased significantly in PII‐treated hosts. In the latters, sharp rise in GRs levels followed parasitoid emergence. OEs cells were scarce in both treated and untreated hosts. No significant difference was observed between the overall means of PLs in both types of host larvae. But GRs‐PRs was markedly altered in treated larvae.