益害虫比对沙巴拟刀角瓢虫与越南斧瓢虫捕食烟粉虱行为的影响

在实验室条件下研究了烟粉虱Bemisia tabaci Gennadius若虫不同密度、既定烟粉虱密度不同天敌数量两种条件下,沙巴拟刀角瓢虫Serangiella sababensis Sasaji和越南斧瓢虫Axinoscymnus apioides Kuznetsov & Ren的捕食行为.研究结果表明,但烟粉虱若虫密度从5增加到40头/cm2,沙巴拟刀角瓢虫和越南斧瓢虫搜寻猎物的时间,随着粉虱密度的增加而逐渐减少;取食猎物的时间,随着粉虱密度的增加而逐渐增加;对烟粉虱若虫的取食量也随密度的增加呈上升趋势.两种瓢虫相比,在既定猎物密度的情况下,刀角瓢虫搜寻、取食烟粉虱的时间要显著长于斧瓢虫所用的时间,但对烟粉虱的取食量明显低斧瓢虫的取食量.在固定粉虱数量的情况下,当瓢虫数量从1头增加到3头时,单头刀角瓢虫和斧瓢虫对烟粉虱的取食量逐渐减少,个体间的干扰作用逐渐显现.     

烟粉虱天敌沙巴拟刀角瓢虫与越南斧瓢虫的捕食行为比较

在实验室条件下研究了沙巴拟刀角瓢虫Serangiella sababensis Sasaji与越南斧瓢虫Axinoscymnus apioides Kuzne tsov and Ren对烟粉虱Bemisia tabaci(Genna dius)卵的捕食行为及各种行为的时间分配。2种瓢虫的捕食过程非常相似,大致可以分为搜寻、取食、清洁、静息、整翅和排泄6个部分。在整个捕食过程中,沙巴拟刀角瓢虫在饥饿状态下,其各行为所占的时间为爬行时间>取食时间>静息时间>清洁时间>猎物处置时间,而在非饥饿状态下,各行为所占的时间为爬行时间>静息时间>取食时间>清洁时间>猎物处置时间;对于越南斧瓢虫来讲,饥饿状态下各行为所占的时间比例为爬行时间>静息时间>取食时间>清洁时间>猎物处置时间,而在非饥饿状态,越南斧瓢虫用在取食方面的时间很少,仅长于处置猎物的时间。2种瓢虫相比,沙巴拟刀角瓢虫用在爬行和取食方面的时间要比越南斧瓢虫长,而用在静息和清洁方面的时间比越南斧瓢虫短。     

烟粉虱天敌日本刀角瓢虫的捕食行为

研究了日本刀角瓢虫雌成虫和幼虫捕食粉虱时的各种行为时间分配.结果表明,日本刀角瓢虫成虫的捕食行为可分为爬行、取食、清洁、静息、整翅和排泄6个部分.饥饿后的日本刀角瓢虫幼虫捕食烟粉虱卵时,幼虫各龄期间的取食和爬行时间无显著差异,对烟粉虱卵的处置时间随瓢虫幼虫虫龄的增大而缩短.日本刀角瓢虫雌成虫捕食烟粉虱卵时,饥饿后的雌成虫用于取食的时间显著长于非饥饿的雌成虫,而用于清洁、静息和爬行的时间显著短于非饥饿的雌成虫;饥饿后的瓢虫雌成虫对卵的处置时间显著长于非饥饿的雌成虫.饥饿后的日本刀角瓢虫雌成虫捕食烟粉虱若虫时,瓢虫雌成虫的取食时间随烟粉虱若虫虫龄的增大而增加,清洁和静息时间随烟粉虱若虫虫龄的增大而缩短,对若虫的处置时间随烟粉虱若虫虫龄的增大而增加.     

越南斧瓢虫对烟粉虱的捕食作用

【目的】烟粉虱Bemisia tabaci(Gennadius)是一种外来入侵性的重大农业害虫,越南斧瓢虫Axinoscymnus apioides Kuznetsov&Ren是其重要的捕食性天敌之一,本文系统研究了越南斧瓢虫对烟粉虱的捕食作用。【方法】在温度误差为±1℃,相对湿度为75%,光照周期为L︰D=14︰10条件下,测定瓢虫成虫对烟粉虱各虫态的功能反应和不同温度下对烟粉虱4龄若虫的功能反应以及测定瓢虫成虫取食烟粉虱4龄若虫个体间的干扰反应。【结果】结果表明,越南斧瓢虫对烟粉虱的功能反应呈HollingⅡ型,随着猎物龄期的增加,越南斧瓢虫成虫的寻找效率(a)逐渐降低,处置时间(Th)基本依次延长。温度对瓢虫的捕食效应影响显著,试验所设温度为15,20,25,30,35℃,越南斧瓢虫成虫的寻找效率(a)分别为0.3226,0.4496,0.5868,0.5788和0.6235,处置时间(Th)分别为0.2348,0.1451,0.1039,0.0904和0.0976,均与温度(T)则呈二次曲线关系。越南斧瓢虫对烟粉虱4龄若虫的捕食作用率(E)在捕食者密度较低(在1~5头)时,捕食作用率下降较快,而在捕食者>6时,其对捕食作用率的影响效果减小。寻找系数为0.0607,干扰系数为0.5569。【结论】随着猎物龄期的增加,越南斧瓢虫成虫的寻找效率降低,处置时间延长;越南斧瓢虫成虫对烟粉虱4龄若虫的寻找效率随着温度的升高而提高,而在更高的温度条件下,其寻找效率略有下降。瓢虫对烟粉虱的处置时间则随着温度的升高而不断缩短;越南斧瓢虫成虫自身密度对其捕食作用产生干扰反应,捕食作用率随着捕食者密度的增加而降低。     

沙巴拟刀角瓢虫生物学特性研究

探究以烟粉虱Bemisia tabaci Gennadius为食料,沙巴拟刀角瓢虫Serangiella sababensis Sasaji的生物学特性,为利用沙巴拟刀角瓢虫控制烟粉虱提供理论依据。本试验在实验室条件下观察取食烟粉虱的沙巴拟刀角瓢虫各虫态的形态特征、生活习性、不同虫态的发育历期、存活率和繁殖力,并计算沙巴拟刀角瓢虫生命表参数。结果表明,在26±1℃、L∶D=14∶10、相对湿度75%±10%的条件下,以烟粉虱卵和若虫为食的沙巴拟刀角瓢虫的世代历期分别为18.82 d和17.75 d,世代存活率分别为65.53%和75.00%,成虫寿命分别为106.65 d和105.58 d,每雌产卵量分别为286.20粒和366.67粒。以烟粉虱卵和若虫为食的沙巴拟刀角瓢虫的内禀增长率(rm)分别为0.0581和0.0780,净增殖率(R0)分别为107.0338和147.8748,平均世代历期(T)分别为80.3985和64.0385,周限增长率(λ)分别为1.0598和1.0811。研究发现,取食烟粉虱若虫的沙巴拟刀角瓢虫世代发育历期短于取食卵的世代发育历期,繁殖率也高于后者,烟粉虱若虫比烟粉虱卵更适宜作为沙巴拟刀角瓢虫规模化生产的食料。     

温度对沙巴拟刀角瓢虫生长发育和繁殖的影响

【目的】明确不同温度对沙巴拟刀角瓢虫Serangiellasababensis生长发育和繁殖的影响,为烟粉虱天敌的应用提供理论依据。【方法】在17、20、25、30和32℃的恒温条件下,测定沙巴拟刀角瓢虫的存活率和发育历期,计算出发育起点温度、有效积温和生命表参数。【结果】成虫前期存活率和产卵量在25℃时最高,分别为80.78%±6.42%和（284.00±59.71）粒。从卵发育至成虫的发育历期在17℃时最长（57.06±1.28）d,30℃时最短（13.85±0.12）d。成虫前期的发育起点温度和有效积温分别为（11.29±1.86）℃和（271.40±34.44）日·度。在25℃时,沙巴拟刀角瓢虫种群的净增殖力R0最高,内禀增长率rm在30℃最高。【结论】沙巴拟刀角瓢虫的最适温区为25-30℃,与烟粉虱Bemisia tabaci (Gennadius)的最适温区相近,可以在烟粉虱暴发的时期大量应用。     

引进天敌越南斧瓢虫的形态特征和生物学特性

引进天敌越南斧瓢虫Axinoscymnus apioides Kuznetsov & Ren原产于东南亚,是烟粉虱Bemisiatabaci(Gennadius)的重要捕食性天敌之一。文章详细描述越南斧瓢虫的形态特征,并研究其基本的生物学特性。越南斧瓢虫可取食烟粉虱的卵、若虫、伪蛹等各虫态,可有效地控制烟粉虱种群,具有很好的利用价值。在(26±1)℃条件下,越南斧瓢虫捕食烟粉虱的世代平均发育历期为20.33d,世代存活率为73.04%,雌成虫寿命为143.17d,平均单雌产卵量为284.33粒。越南斧瓢虫取食烟粉虱的内禀增长率(rm)为0.0457,净增殖率(R0)为103.4050,平均世代历期(T)为99.3626,周限增长率(λ)为1.0478。     

番茄褪绿病毒对刀角瓢虫捕食烟粉虱的影响

在实验室条件下研究了不同温度下刀角瓢虫Serangium japonicum对健康和感染番茄褪绿病毒(Tomato chlorosis virus,ToCV)番茄上的烟粉虱Bemisia tabaci的捕食效果.结果表明,无论在健康番茄还是感染ToCV番茄上,刀角瓢虫均可以取食烟粉虱的卵和若虫,对卵的捕食量最大,且对烟粉虱卵的功能反应都属于HollingⅡ型反应,方程式分别为NA=0.9650N/1+0.0007N和NA=0.9866N/1+0.0006N.温度可以影响功能反应的参数,在30℃时刀角瓢虫对健康番茄上的烟粉虱的控制作用最好,在35℃时刀角瓢虫对感染ToCV番茄上的烟粉虱控制效果最好.刀角瓢虫偏好感染ToCV的番茄植株,对健康番茄偏好性较弱.刀角瓢虫对感染ToCV番茄上的烟粉虱具有良好的捕食效果,可为烟粉虱的生物防治提供合理依据.     

中华草蛉、龟纹瓢虫和异色瓢虫对B型烟粉虱的捕食功能反应

室内研究了中华草蛉Chrysopa sinicaTjeder、龟纹瓢虫Propylaea japonica(Thunberg)和异色瓢虫Leis axyridis(Pallas)对B型烟粉虱Bemisiatabaci(Gennadius)若虫的捕食功能反应和寻找效应。结果表明,3种天敌成虫和幼虫的捕食量均随着猎物密度的增加而上升,当猎物增加到一定水平,捕食量趋向稳定,捕食功能反应曲线符合HollingⅡ型方程。异色瓢虫、中华草蛉和龟纹瓢虫成虫和幼虫对烟粉虱若虫的捕食量差异显著,理论最大日捕食量分别为417,263,156头和625,238,108头。3种天敌对烟粉虱若虫的寻找效应随着天敌密度的增加而下降,干扰作用逐渐增强,其寻找效应表现为龟纹瓢虫(0.5656)>异色瓢虫(0.4371)>中华草蛉(0.4029),对烟粉虱的控制能力表现为异色瓢虫>龟纹瓢虫>中华草蛉。     

烟粉虱捕食性天敌淡色斧瓢虫的形态特征及生活习性

对淡色斧瓢虫Axinoscymnuscadilobus的形态特征和生活习性进行了观察。在 ( 2 5± 1 7)℃条件下 ,以烟粉虱为食料 ,淡色斧瓢虫完成 1个世代平均历期为 49 5 9d ,成虫的平均寿命为 64 45d ,平均产卵量为 95 4粒 ;淡色斧瓢虫可捕食烟粉虱的卵、若虫、蛹及成虫 ,是烟粉虱的有效天敌 ,具有很好的保护利用价值。     

Prevalence of Wolbachia supergroups A and B in Bemisia tabaci (Hemiptera: Aleyrodidae) and some of its natural enemies

Wolbachia, a bacterial symbiont, is maternally transmitted in arthropods and nematodes. We report a systematic survey of Wolbachia taxonomy in the sweetpotato whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), and in some of its natural enemies. For the first time, Wolbachia infections in B. tabaci are correlated with various whitefly genetic groups, host plants, and natural enemies as well as with geographical regions. Polymerase chain reaction using 16S rDNA and fisZ genes revealed two Wolbachia supergroups, A and B, exist as single or double infections in B. tabaci as well as in some of its aphelinid parasitoids and predatory beetles. Approximately 89% of B. tabaci sampled were infected by Wolbachia, among which 34% were infected by A, 51% were infected by B, and 5% were infected by both A and B supergroups. These infection frequencies differed among B. tabaci genetic groups and locations. The invasive B. tabaci genetic group from the Middle East Asia Minor 1 (also referred as B biotype) and Mediterranean (also referred as Q biotype) was more likely to harbor A than B, whereas native genetic groups in AsiaI and AsiaII were more likely to harbor B than A. Although 60% of aphelinid parasitoids and 72% of coccinellid beetles also were infected by Wolbachia, they were more likely to host B than A. Furthermore, for the first time we report Wolbachia in B biotype from specimens collected outside of China. Construction of a phylogenetic tree clearly indicated that the Wolbachia sequences from different genetic groups of B. tabaci were not only similar to each other but also to sequences from beetles and parasitoids, which may provide evidence of coevolution and horizontal transmission of Wolbachia populations.     

Feeding preference of Macrolophus caliginosus (Heteroptera: Miridae) on Bemisia tabaci and Trialeurodes vaporariorum (Homoptera: Aleyrodidae)

A study of predation choices of Macrolophus caliginosus Wagner (Heteroptera: Miridae) late instars and adults, when offered various developmental stages (eggs and nymphs) of the recently established whitefly Bemisia tabaci (Gennadius) (Homoptera: Aleyrodidae), was made based on two preference indices. In addition, prey choices of late instars when presented with three ratios of Trialeurodes vaporariorum (Westwood) (Homoptera: Aleyrodidae) and B. tabaci at a similar developmental stage (eggs, young or late instars) were assessed. M. caliginosus preferred older nymphs of B. tabaci than any other stage. It also chose T. vaporariorum over B. tabaci, unless the latter consisted of > 75% of the available prey. These results suggested that M. caliginosus might interfere with parasitoids such as Encarsia, Eretmocerus, or Amitus spp. because all three species emerge from the host pupal case. Furthermore, in mixed infestations, M. caliginosus preference for T. vaporariorum might either negatively affect the control of B. tabaci, or, contrarily, enhance the predator population, before a B. tabaci outbreak occurs in the greenhouse.     

Ecdysteroids and juvenile hormones of whiteflies, important insect vectors for plant viruses

Ecdysteroids and juvenile hormones (JHs) regulate many physiological events throughout the insect life cycle, including molting, metamorphosis, ecdysis, diapause, reproduction, and behavior. Fluctuation of whitefly ecdysteroid levels and the identity of the whitefly molting hormone (20-hydroxyecdysone) have only been reported within the last few years. An ecdysteroid commitment peak that is associated with the reprogramming of tissues for a metamorphic molt in many holometabolous and some hemimetabolous insect species was not observed in last nymphal instars of either the sweet potato whitefly, Bemisia tabaci (Biotype B), or the greenhouse whitefly, Trialeurodes vaporariorum. Ecdysteroids reach peak levels 1-2 days prior to the initiation of the nymphal-adult metamorphic molt. Adult eye and wing differentiation which signal the onset of this molt begin earlier in 4th instar T. vaporariorum (Stages 4 and 5, respectively) than in B. tabaci (Stage 6), and the premolt peak is 3-4 times greater in B. tabaci ( approximately 400 fg/microg protein) than in T. vaporariorum ( approximately 120 fg/microg protein). The JH of B. tabaci nymphs and eggs was found to be JH III, supporting the view that JHs I and II are, with rare exception, only present in lepidopteran insects. In B. tabaci eggs, JH levels were approximately 10 times greater on day 2/3 (0.44 fg/egg or 0.54 ng/g) than on day 5 (0.04 fg/egg or 0.054 ng/g) post-oviposition. Approximately, 1.4 fg/2nd-3rd instar nymph (0.36 ng/g) was detected. It is probable that the relatively high level of JH in day 2/3 eggs is associated with the differentiation of various whitefly tissues during embryonic development.     

黄玛草蛉幼虫对草地贪夜蛾卵和低龄幼虫的捕食能力

【目的】明确本地优势天敌黄玛草蛉Mallada basalis对入侵我国的重大农业害虫草地贪夜蛾Spodoptera frugiperda卵及低龄幼虫的捕食能力和生防潜力。【方法】在实验室条件下采用功能反应模型评价了黄玛草蛉2和3龄幼虫对草地贪夜蛾卵及1和2龄幼虫的捕食能力。【结果】黄玛草蛉幼虫对草地贪夜蛾卵和低龄幼虫的捕食量均随猎物密度的升高而增加,最后趋于捕食饱和状态,而其捕食率随猎物密度的升高而逐步下降,对不同发育阶段的草地贪夜蛾均表现为Ⅱ型功能反应。黄玛草蛉2龄幼虫对草地贪夜蛾卵及1和2龄幼虫的瞬时攻击率a分别为0.150, 0.084和0.094,处理时间Th分别为0.282, 0.333和0.519 h,理论日最大捕食量T/Th分别为85106粒、72072头和46.242头;黄玛草蛉3龄幼虫对草地贪夜蛾卵及1和2龄幼虫的瞬时攻击率分别为2.018, 0.288和0.259,处理时间分别为0.102, 0.311和0.375 h,理论日最大捕食量分别为235294粒、77170头和64000头。【结论】黄玛草蛉2和3龄幼虫对草地贪夜蛾卵和低龄幼虫均具较强的捕食能力,其中黄玛草蛉3龄幼虫比2龄幼虫具有更强的捕食效率。     

Adult survival of Delphastus catalinae (Coleoptera: Coccinellidae), a predator of whiteflies (Hemiptera: Aleyrodidae), on diets of whiteflies, honeydew, and honey

Delphastus catalinae (Horn) is a coccinellid predator that is commercially sold for the management of whiteflies. A study was conducted to assay the effect of selected diets on the survival of adult D. catalinae. Treatments of water (as a control), 10% honey, honeydew, and whiteflies [Bemisia tabaci (Gennadius)] were provided to the beetles in laboratory assays. Newly emerged, unfed adult insects were used at the start of a survival experiment with trials lasting 50 d. Another survival experiment used mixed-aged adults from a greenhouse colony, and the trials lasted 21 d. Survival was poor on a diet of solely water; ~1% survived beyond a week at 26°C. Survival using the newly emerged insects was similar between those fed honeydew and honey diets, but those on the whitefly diet had the greatest survival (~60% on day 50). However, in the experiment with mixed-aged beetles, adults on honey, and whitefly diets performed the same over a 21-d experiment. Excluding those on the water diet, survival of beetles on the various diets ranged from ~50-80% after 21 d. In an open choice assay across 7 h, D. catalinae adults were found on the whitefly diet in a much greater incidence than on the other diets, and the number of beetles found on the whitefly diet increased over time. The data supports that when D. catalinae are employed in greenhouses or fields for whitefly management, during low prey populations, honeydew from the whitefly can help sustain the population of this predator. Moreover, a supplemental food such as a honey solution can help sustain the population of D. catalinae when the prey is decreased to low numbers. These results may help in the development of strategies to enhance the utility of predators for the management of whiteflies.     

小黑瓢虫与两种猎物作用系统研究:选择捕食作用

研究了小黑瓢虫与烟粉虱及红蜘蛛两种猎物作用系统中 ,小黑瓢虫雌成虫对两种猎物卵的选择捕食作用。结果表明 :当两种猎物共存时 ,小黑瓢虫雌成虫对烟粉虱卵在低密度下不表现喜好性 ,而在中等密度和高密度下表现正喜好性 ,对红蜘蛛卵在各密度下均不表现喜好性。对烟粉虱卵的转换效应会由于总猎物密度的不同而呈现不同的效应 ,即在低密度 (15 0粒 )时无转换行为 ,在中等密度 (30 0粒 )时有负转换行为 ,在高密度 (6 0 0粒 )时有正转换行为。而对红蜘蛛卵则在各总猎物密度下均呈现负转换效应。同时组建了两种猎物共存时 ,小黑瓢虫雌成虫对猎物的总捕食作用方程及对每一种猎物类型的捕食作用方程 ,分析了两种猎物共存时 ,小黑瓢虫雌成虫对各猎物寻找效应的变化情况。     

Efficacy of the entomopathogenic nematode, Steinernema feltiae, against sweetpotato whitefly Bemisia tabaci (Homoptera: Aleyrodidae) under laboratory and glasshouse conditions

The potential of using the entomopathogenic nematode Steinernema feltiae to control the sweetpotato whitefly Bemisia tabaci (Gennadius) has been established in previous laboratory studies. However, laboratory studies can overestimate the level of control achieved by biocontrol agents in the glasshouse. Glasshouse trials are therefore required to confirm laboratory results before full-scale commercial development is considered. Under both controlled laboratory and glasshouse conditions high mortality of second instar B. tabaci (>90% and >80%, respectively) was recorded after application of S. feltiae. The efficacy of the biocontrol agent at various application rates was also investigated, where halving the rate of S. feltiae application caused no significant reduction in B. tabaci mortality on tomato foliage. Steinernema feltiae has shown much potential for incorporation into integrated pest management strategies for the control of B. tabaci.     

烟粉虱成虫对黄瓜叶龄的喜好性及与后代发育适合度间的关系

在室内采用笼罩和发育测定方法,研究了烟粉虱成虫对黄瓜叶龄的喜好性及其与后代生长发育、存活之间的关系,同时调查了叶毛密度与成虫喜好性之间的相关关系。结果表明(1)烟粉虱成虫比较喜欢在黄瓜植株的中部叶片取食和产卵。(2)叶龄对烟粉虱的存活率没有显著影响,对烟粉虱的发育历期只在卵期和若虫四龄期表现出显著影响,对其他龄期或整个世代均没有显著影响。(3)叶毛密度随着叶龄的增大而顺次显著减小;在接虫初始阶段,烟粉虱成虫的叶片选择性与叶毛密度成显著负相关关系,但72h后具有中等叶毛密度的叶片上的成虫数量和着卵量均显著高于叶毛密度较大或较小的叶片。研究结果对培育抗烟粉虱的黄瓜品种和改进烟粉虱的防治措施具有一定指导意义。