斑痣悬茧蜂寄主识别行为研究进展

斑痣悬茧蜂作为一种单寄生、容性寄生蜂,寄主范围广泛,可以寄生多种暴露取食的大型鳞翅目害虫的幼虫。斑痣悬茧蜂具有优秀的生防价值,在能有效控制蔬菜害虫基数的前提下,还具备环境友好、靶标专一、人畜安全等优点,是一种重要的生物防治资源。寄主识别行为是寄生蜂在对寄主做出寄生决策时的关键环节,了解寄生蜂的寄主识别行为对寄生蜂与其他病原物的协同应用、害虫优势种群的防控和寄生蜂的保护利用等方面均具有重要意义。本文针对影响斑痣悬茧蜂寄主识别的多个因素进行了综述,以期为斑痣悬茧蜂的生产化应用和对蔬菜害虫生防价值的提高等方面提供参考和理论支持,并对未来的研究方向进行展望。     

寄主龄期对马尼拉陡胸茧蜂繁殖力和寿命的影响

研究了甜菜夜蛾和斜纹夜蛾不同龄期对马尼拉陡胸茧蜂繁殖力、寿命的影响。结果表明,马尼拉陡胸茧蜂寄生甜菜夜蛾和斜纹夜蛾2龄幼虫时,繁殖力最高;当寄主虫龄大于2龄时,马尼拉陡胸茧蜂繁殖力随着虫龄的增大而降低。在寄生甜菜夜蛾和斜纹夜蛾的各个龄期中,马尼拉陡胸茧蜂的雌蜂寿命均长于雄蜂寿命。在寄生甜菜夜蛾和斜纹夜蛾2龄幼虫时,雌雄蜂寿命均最长;随着龄期的增长,雌雄蜂寿命逐渐缩短。     

角额壁蜂的寄生蜂及其防治

为了更有效地利用野生角额壁蜂资源为当地苹果梨进行授粉,对延边地区角额壁蜂的寄生蜂及其防治进行了研究.结果表明:延边地区角额壁蜂的寄生蜂有2种,一种是叉唇寡毛土蜂,寄生率为3.40%,而另一种为青蜂,寄生率为17.00%.对寄生蜂可采取人工防治,即在剥巢取茧时人工剔除寄生蜂茧,防效在40%左右,在果园放蜂时人工捕杀寄生蜂,防效达98%以上.     

斜纹夜蛾侧沟茧蜂研究现状及生防应用

对莲藕重要害虫斜纹夜蛾的幼虫寄生蜂——斜纹夜蛾侧沟茧蜂Microplitis prodeniae Rao and Kurian的形态学特征、生物学特性、发生规律及其在生物防治中的应用进行了概述,并就其今后的开发利用方向进行了简要阐述.     

果树害虫天敌讲座——寄生蜂

寄生蜂是目前生物防治中以虫治虫应用较广,效果显著的重要天敌。寄生蜂种类很多,已知有15000余种。寄生蜂可寄生于害虫的不同虫态。如卵、幼虫（若虫）和蛹。在寄主体内（个别种类在体外）取食其体液．被寄生的害虫皱缩死亡。蜂老熟后在虫尸内结茧化蛹羽化．或钻出害虫尸体外结茧。每种害虫都有一种或多种寄生蜂．有的种类寄生率很高。也有的蜂在被寄生过的虫体上再产卵寄生．能将先入的蜂吃掉。叫重寄生。大多数寄生蜂成虫以花粉或花蜜为食．有的小型蜂只喝露水。     

甜菜夜蛾为害习性及防治研究初报

通过对甜菜夜蛾的观察研究,认为此害虫具有明显的昼伏夜出和1～2龄群集为害习性,3龄以后幼虫抗药性较强。发生量以8月中旬至9月中旬为多。成虫有较强趋光性。可于9～10月进行光灯诱杀。用20％速灭杀丁乳油4000倍液、25％喹硫磷乳油500倍液或50％辛硫磷乳油亩用量100毫升等药剂于甜菜夜蛾的1～2龄幼虫期喷雾防治,能取得较好效果。用20％除虫脲1号80ppm加杀灭菊酯2000倍液防治甜菜夜蛾低龄幼虫,防效可达90％以上,药效保特10天以上,较好地发挥了两种药剂的灭虫特点;此外,还报道了侧沟茧蜂等3种寄生于甜菜夜蛾幼虫的寄生蜂。     

温度对粗脊蚜茧蜂基础生物学特性的影响

粗脊蚜茧蜂（Aphidius colemani）是棉蚜（Aphis gossypii）的一种寄生性天敌。为探究温度对粗脊蚜茧蜂基础生物学特性的影响,测定了15、20、25、30、35℃这5个温度下粗脊蚜茧蜂羽化率、成虫寿命、寄生率和产卵量。结果表明,在15℃时粗脊蚜茧蜂雌、雄蜂寿命均最长,并随着温度的升高而缩短,当温度为35℃时存活不超过1d。温度对粗脊蚜茧蜂的性比无显著影响。成虫羽化率和产卵量均在25℃时最高,分别为95.0%和186.4粒;寄生率在20℃时最高,为74.5%。成虫羽化率、寄生率和产卵量3个参数在20℃和25℃之间无显著差异,而在35℃时均为0。表明粗脊蚜茧蜂生长发育和繁殖的最适宜温度范围是20～25℃。本研究为粗脊蚜茧蜂的规模化扩繁及田间蚜虫生物防治提供了参考依据。     

唐山市白蛾周氏啮小蜂大规模繁殖技术研究

白蛾周氏啮小蜂(Chouioia cunea Yang)主要用于生物防治美国白蛾,现已在国内外多个地区得到应用,唐山市自2012年开始对其进行研究。本次试验研究了白蛾周氏啮小蜂在不同月份、温度、接蜂方法条件下的寄生率以及不同蜂种复壮方法获得蜂种的寄生率,结果表明:(1)不同月份白蛾周氏啮小蜂最适繁育温度不同,2、4月份为25℃,6、9月份为23℃。(2)三刀削茧法与茧内接蜂法于2、4月份适宜温度条件下培养寄生率差距不显著,而6、9月份寄生率前者明显高于后者,其抗高温作用优于后者。(3)白蛾周氏啮小蜂大规模繁育存在最适温度,高于或低于此温度,寄生率均会下降,高温条件下,腐烂率明显升高,低温条件下,未寄生率明显升高。(4)野外采集蜂种及变温处理孕蜂蛹均可达到理想的复壮效果。     

金纹细蛾天敌小茧蜂的生活习性及其应用技术

金纹细蛾（Lithocolletis ringoniella Mats.）是危害果树叶片的重要害虫之一。它以幼虫潜伏于叶片皮层内啃食叶肉进行危害,药物防治比较困难。金纹细蛾有多种寄生蜂天敌,其中小茧蜂就是很好的一种。笔者自2004年以来,对小茧蜂进行了多年的观察研究,发现它对金纹细蛾幼虫的寄生率高达46%,对抑制金纹细蛾的大发生起到了重要的作用,现将观察研究结果报道如下。     

夜蛾黑卵蜂(Telenomus remus Nixon)个体发育研究

夜蛾黑卵蜂（Telenomus remus Nixon）是多种夜蛾类害虫卵期重要寄生性天敌。在实验室温度（26±1）℃、相对湿度（70±10）%、光周期L：D为12h：12h条件下,以甜菜夜蛾卵为寄主,系统观察了夜蛾黑卵蜂个体发育过程中各虫态的形态特征及其发育历期。结果表明,夜蛾黑卵蜂的个体发育可分为卵、1龄幼虫、2龄幼虫、预蛹、蛹和成虫6个发育阶段。从卵发育到成虫约需10d,其中卵、1龄幼虫和2龄幼虫的发育历期分别为13h,59h和24h,预蛹期24h,蛹期5d。在实验室条件下,夜蛾黑卵蜂过寄生现象明显,但通常只有1头蜂能完成发育。夜蛾黑卵蜂成虫羽化时在寄主卵壳咬出1个羽化孔,雄蜂通常会比雌蜂早羽化约1d;雄蜂羽化后会守候在未羽化的雌蜂旁边,待雌蜂羽化,立刻与之交配。     

浙江省柑桔软蚧、褐软蚧寄生蜂种类及其对蚧虫制约作用的探讨

柑桔软蚧和褐软蚧两类蚧虫，在国外部分国家成为难以对付的害虫， 订是缺乏具有制约作用的寄生性天敌。目前在我国桔区为害并不严重，无须采取防治措施，这完全得益于寄生性天敌的自然控制作用。本文对浙江桔区这两类蚧虫的14种寄生蜂的发生、分布及其天然制约作用进行了深入研究，以跳小蜂科（Encyrtidae)的软蚧花翅跳小蜂、蜡蚧花翅跳小蜂、黑褐花翅跳小蜂、软蚧阔柄跳小蜂科的赖食软蚧蚜小蜂为优势种，寄生率高达80％－100％，在桔园只要在上述5种中任何一种寄生蜂存在，足以控制两类蚧虫为害。     

Antagonisten und Pr?datoren der Maulbeerschildlaus Pseudaulacaspis pentagona (Targioni-Tozzetti, 1886) (Homoptera: Diaspididae) in Baden-W��rttemberg

Antagonists of the white scale (Pseudaulacaspis pentagona, Targioni-Tozzetti, 1886) were determined from peaches and sweet cherries as host plant at the orchards of the Centre for Agriculture and Technology Augustenberg (LTZ) in 2009 and 2010 as well as from four other commercial red and black currant orchards in Baden-Wuerttemberg in 2010. The study focused mainly on the parasitoid species of P. pentagona as well as the rate of parasitism of white scale caused by these parasitoids using emergence traps with invested branch samples of the different host plants in the laboratory. Beside the parasitoids, possible predators of the white scale were observed in the field in 2010 at the orchard of the LTZ. The two parasitic wasp species Aphytis diaspidis and Encarsia berlesei (Howard, 1881 and 1906) were determined as parasitoids of the white scale, whereas A. diaspidis was dominant at most sites. Rate of parasitism caused by both species ranged from 1.9 to 23.0%. The Kidney-Spot Ladybird Beetle (Chilocorus renipustulatus, Scriba, 1790) could be observed as a predator of the white scale in the field.     

Land use and host community characteristics as predictors of disease risk

Land use has been implicated as a major causal factor in the recent surge of emerging and reemerging zoonotic diseases worldwide. Whirling disease, a parasitic infection caused by the myxozoan, Myxobolus cerebralis, has led to major declines in wild trout populations within the Intermountain West of the USA and is suspected to be exacerbated by land and stream management practices that create favorable habitat for the oligochaete host, Tubifex tubifex. Our objectives were to quantify relationships between whirling disease risk and (1) land use and (2) characteristics of the oligochaete host community within four major watersheds in western Montana. Risk was quantified by the severity and prevalence of infection in caged sentinel rainbow trout. A geographic information system (GIS) was used to model land use (e.g., agriculture, mines) within watersheds. Importance of predictor variables was assessed using regression tree and random forest analyses. A low proportion of riparian forest, high road density, high oligochaete density, and high Limnodrilus hoffmeisteri density were identified as important predictors of high risk. Although we did not examine the mechanisms underlying these correlations, a low proportion of riparian forest and a high road density likely increase stream sedimentation, thus, increasing habitat for oligochaetes. Although relationships identified are not necessarily causal, the ability to predict areas most at risk of M. cerebralis establishment and proliferation using broad scale predictors should serve as a useful management tool within Montana and elsewhere.     

印度实蝇姬小蜂寄生习性研究

【目的】探明印度实蝇姬小蜂Aceratoneuromyia indica(Silvestri)在广州地区阳桃园内的自然寄生情况及其寄生习性。【方法】以橘小实蝇和印度实蝇姬小蜂为研究对象,采集田间落果和采用室内饲养的方法研究了印度实蝇姬小蜂对橘小实蝇的自然寄生情况,并在室内研究了印度实蝇姬小蜂的寄生习性。【结果】田间调查表明,印度实蝇姬小蜂在广州阳桃园的田间寄生率可高达43.8%。印度实蝇姬小蜂对寄主具有选择性,能寄生于橘小实蝇的幼虫和蛹,但不能寄生黄粉虫卵、幼虫和蛹以及米蛾卵。从单只橘小实蝇蛹中羽化出的印度实蝇姬小蜂成虫数为16.4±4.2只;补充营养能显著增加印度实蝇姬小蜂成虫寿命;从繁殖印度实蝇姬小蜂后代的效果来看,不同营养物质对F1代的影响并不一致,室内饲养时,可用10%蔗糖和10%蜂蜜喂养印度实蝇姬小蜂成虫。【结论】印度实蝇姬小蜂是橘小实蝇幼虫和蛹期寄生蜂,可科学利用印度实蝇姬小蜂防治橘小实蝇。     

Broad-scale heterogeneity influences nest selection by Brown-headed Cowbirds

Increasing habitat heterogeneity is widely considered to improve conditions for biodiversity. Yet benefits for native species depend on scale and the effect of heterogeneity on key processes influencing survival and reproduction. We examined the relationship between habitat heterogeneity and brood parasitism at multiple scales in a region characterized by (1) relatively high cowbird abundance, (2) high abundance of our focal species, the grassland obligate Grasshopper Sparrow (Ammodramus savannarum), (3) variation in the structure and composition of grassland habitats, and (4) a gradient of woodland cover in the landscape matrix. Tree cover at broad scales was found to have the greatest impact on parasitism while factors at finer scales were relatively unimportant. We found that for every 1 % increase in tree cover within 1 km of Grasshopper Sparrow nests, the probability of parasitism decreases by 3 %. Parasitism reduced clutch sizes and the number of Grasshopper Sparrows fledged, but survival rates were similar between non-parasitized and parasitized nests. Furthermore, simple population projection models indicated that parasitism has the greatest impact at moderate survival levels and can inhibit the resiliency of this population. Our results support the hypothesis that cowbirds prefer forest hosts, which may reduce parasitism rates on grassland birds in heterogeneous landscapes. Collectively, our findings suggest that the effect of cowbird parasitism may be greater for Grasshopper Sparrows than was previously thought.     

Mistletoe infection in an urban forest in Mexico City

Urban forests are important lungs for urbanized environments; therefore, their study and conservation are needed. Compared with trees in natural areas, urban trees develop in more stressful conditions, which may make them more susceptible to infections by parasites such as mistletoes. Bosque de Tlalpan (BT) is an urban forest embedded in one of the largest cities of the world, Mexico City. The aim of this study was to assess which mistletoe species were present in BT, determine the intensity of the infestation, and distinguish which host species are more susceptible to mistletoe parasitism based on 20 randomly selected plots. We found that Cladocolea loniceroides was extensively distributed on the cultivated area of BT (17 plots), whereas a second species, Phoradendron brachystachyum, was found only on four plots. Seven tree species were susceptible to infection by C. loniceroides, whereas only one was susceptible to infection by P. brachystachyum. Fraxinus uhdei, the most abundant host, was the one with higher severities and larger sizes (tree height and crown length); the latter variables positively influence the severity of infection. Reforestation of the cultivated area with low diversity and exotic species appears to be a reason for the increased infestation. Therefore, we support the reforestation of urban areas with native species to provide benefits such as a lower incidence of parasitic infection and tree mortality.     

Habitat fragmentation and parasitism of a forest damselfly

We compared populations of a forest damselfly —Calopteryx maculata — in two kinds of landscapes. In fragmented landscapes, forested foraging patches were separated from streams (where oviposition and mating occur) by up to 500 m of pasture. In non-fragmented landscapes, there was continuous forest cover adjacent to streams. The prevalence and intensity of midgut infections of a gregarine parasite were significantly lower in the fragmented landscapes than in the non-fragmented landscapes. We have shown elsewhere that in the fragmented landscapes, damselflies move over greater areas to forage than in the non-fragmented landscapes. We postulate that these movements lower the rate of encounter between damselflies and oocysts, thus lowering the prevalence and intensity of infection. The differences suggest that actual habitat fragmentation events would alter the relationship between host and parasite, but that populations of both species would persist after fragmentation. Prevalence of parasitism is related to age but we found no residual effects of size on parasitism.     

Landscape factors and how they influence whitefly pests in cassava fields across East Africa

Context

African production landscapes are diverse, with multiple cassava cultivars grown in small patches amongst a diversity of other crops. Studies on how diverse smallholder landscapes impact herbivore pest outbreak risk have not been carried out in sub-Saharan Africa.

Objectives

Bemisia tabaci is a cryptic pest species complex that cause damage to cassava through feeding and vectoring plant-virus diseases and are known to reach very high densities in certain contexts. However, the factors driving this phenomenon are unclear.

Methods

Bemisia density data in cassava across a large number of sites representing a geographic gradient across Uganda, Tanzania and Malawi were collected. We tested whether in-field or landscape factors associated with land-use patterns underpinned Bemisia density variability and parasitism.

Results

We found the B. tabaci SSA1 species dominated our study sites, although other species were also common in some cassava fields. Factors associated with the surrounding landscape were unimportant for explaining variability in adult density, but the in-field variables of cassava age and cultivar were very important. The density of nymphs and the parasitism of nymphs was heavily influenced by a diversity of landscape factors surrounding the field, including the size of focal cassava field, and area of cassava in the landscape. However, unlike the trend from many other studies on drivers of natural enemy populations, this pattern was not solely related to the amount of non-crop vegetation, or the diversity of crops grown in the landscape.

Conclusions

Our findings provide management options to reduce whitefly abundance, including describing the characteristics of landscapes with high parasitism. The choice of cassava cultivar by the farmer is critical to reduce whitefly outbreak risk at the landscape-scale.

     

Oral administration of fasudil hydrochloride suppresses development of experimental autoimmune encephalomyelitis in mice

AIM:To explore the therapeutic effect of fasudil hydrochloride by the oral route on the development of experimental autoimmune encephalomyelitis (EAE) in mice and its possible mechanism. METHODS:The EAE model in female C57BL/6 mice was established by myelin oligodendrocyte glycoprotein 35-55 peptide(MOG35-55) immunization and the immunized mice were randomly divided into saline control group and fasudil intervention group, in which saline and fasudil were administered by the oral route once every day from post-immunization (PI) day 3 to day 27. Clinical score and body weight were recorded every other day. On PI day 28, the spinal cords were obtained for HE and myelin staining. The splenocytes were isolated and the expression of CD16/32, CD206 and interleukin (IL)-10 was analyzed by flow cytometry. The levels of IL-1β and tumor necrosis factor α (TNF-α) were detected by ELISA. RESULTS:Oral administration of fasudil delayed the onset of EAE, and attenuated the myelinoclasis of the model animals and the severity of EAE, accompanied by the phenotypic switch from M1 to M2 macrophages, the inhibition of the proinflammatory cytokine (IL-1β and TNF-α) production and the increase in IL-10 release. CONCLUSION: Oral administration of fasudil exhibits therapeutic effect on the development of EAE possibly through switching M1 macrophages to M2 phenotype and inhibiting inflammatory responses in mice.