Effects of host,temperature and relative humidity on competitive displacement of two invasive Bemisia tabaci biotypes [Q and B]

Abstract Bemisia tabaci shifted unexpectedly in China from a predominance of B biotype to Q biotype during 2005–2008. This observation stimulated an interest in investigating whether environmental factors, including host, temperature and relative humidity (RH) could possibly explain the observed shift in biotypes distribution. Results indicated that all three parameters examined influenced biotype survivability. The percentage of B biotype, when reared together on pepper plants with the Q biotype, decreased significantly from 66.7% in the founder population, to 13.6% and 3.7% in the first and second generations, respectively. When the B (founder at 66.7%) and Q (founder at 33.3%) biotypes were reared together on eggplant alone, or on pepper‐plus‐eggplant combination, the population size of the B biotype either remained constant, or increased somewhat in the first and second generations. On eggplant, the effects of RH and temperature on the competitiveness between the Q and B biotypes (3 pairs of Q and 6 pairs of B) were not significant.     

田间系统调查表明山东省农区烟粉虱优势种为Q隐种

【目的】为了揭示山东省农区烟粉虱 Bemisia tabaci 隐种的分布情况,对2013年7-8月份期间在该省不同农区采集的烟粉虱隐种组成进行了系统调查研究。【方法】在山东省15市22个地点作物上采集了69份烟粉虱样品,利用mtCOI基因PCR-RFLP方法进行了分子鉴定,并分析了烟粉虱Q隐种在不同寄主作物及地理区域内的分布状况。【结果】22个采集地点中,17个地点的采集样品全部为烟粉虱Q隐种;其他5个地点（潍坊、菏泽、泰安、淄博和临沂）的烟粉虱Q隐种所占比例均大于90%,B隐种比例较低（<10%）。烟粉虱Q隐种比例在5种寄主（茄子、辣椒、番茄、黄瓜和棉花）种群间以及在山东省东部丘陵、中部山地和西部平原地区间均没有显著差异。【结论】2013年田间调查发现烟粉虱Q隐种在山东各地已广泛取代B隐种成为该地区优势种群。     

B型烟粉虱与浙江非B型烟粉虱的竞争

为了了解近年来入侵中国的B型烟粉虱(Bemisiatabaci)取代本地非B型烟粉虱的潜能,在室内将一个B型与一个浙江非B型烟粉虱种群混合饲养在不同寄主植物上,跟踪观察混合种群中两个生物型个体数量相对比例的变化。结果表明,当两种生物型在棉花(Gossypiumhirsutum)上以相同初始数量共存竞争时,经过6代,非B型完全被B型替代;而在西葫芦(Cucurbitapepo)上以相同初始数量共存竞争时,只经过2代,非B型即完全被B型替代。在棉花上,即使以非B型占87%、B型占13%开始共存竞争,经过225d后,非B型也完全被B型替代。这说明B型烟粉虱具有在短期内竞争取代浙江非B型烟粉虱的能力。经分析,B型除了寄主范围比非B型的宽这一点对其竞争有利外,较强的内在竞争潜能也是其能成功入侵并替代本地非B型烟粉虱的一个重要原因。     

Parasitism,host feeding and immature development of Encarsia formosa reared from Trialeurodes vaporariorum and Bemisia tabaci on Trialeurodes ricini

Encarsia formosa Gahan (Hymenoptera: Aphelinidae), a thelytokous parasitoid, is an important biological control agent of whiteflies because of its outstanding reproduction and host‐feeding ability. In this study, we evaluated the parasitism, host feeding and developmental time of E. formosa populations reared on Trialeurodes vaporariorum (Westwood) (EFT) or on Bemisia tabaci (Gennadius) (EFB) when different nymphal instars of the castor whitefly, Trialeurodes ricini (Misra), were offered as hosts, with an aim to understand the preference of the parasitoid on nymphal instars of T. ricini. Experiments were conducted on castor bean plants at 26 ± 2°C, 50–60% RH and 16 : 8 (L : D) photoperiod. The results showed that E. formosa successfully oviposited and fed on all nymphal instars of T. ricini. However, numbers of the first instars fed on by the E. formosa populations reared on T. vaporariorum (EFT) and B. tabaci (EFB) were significantly greater (45.9 and 31.3, respectively) than those of the second (EFT: 30.4 and EFB: 15.8), the third (EFT: 22.4 and EFB: 13.2) and the fourth nymphal instars (EFT: 6.0 and EFB: 3.8). The number of T. ricini nymphs parasitized by E. formosa varied significantly among different instars, and the parasitism rates on the first instar (EFT: 15.2; EFB: 7.7) and fourth instar (EFT: 19.3; EFB: 4.9) were greater than those on the second and third instars. Encarsia formosa reared on T. vaporariorum had a significantly higher host feeding and ovipositing potential on T. ricini than EFB. When parasitizing the fourth instar nymphs, E. formosa completed development in a significantly shorter time (12.9 day) than when ovipositing in other instars (17.8–19.1 day). These results showed that EFT had a better host adaption than EFB. The information from this study should be useful for us to better understand the performance and nymphal preference of E. formosa from T. vaporariorum and B. tabaci when they parasitized and fed on T. ricini, and the interactions of parasitoids with different host whitefly species.     

寄主植物对B型烟粉虱选择行为和生物学参数的影响

通过培养皿内自由扩散观察和生物学观察,对黄瓜、茄子、辣椒、棉花和甘薯上B型烟粉虱的寄主选择性和生物学参数进行了研究.结果表明：B型烟粉虱成虫向寄主植物叶片自由扩散的初始阶段（2 h）,各寄主植物叶片上虫量的差异不大,在随后的4～48 h内黄瓜叶片上的虫量不断增加,茄子、棉花和甘薯叶片上的虫量相对稳定,而辣椒叶片上的虫量却不断下降,说明B型烟粉虱对黄瓜的选择性最强、对辣椒的选择性最弱,且饥饿和吡虫啉预处理均不影响B型烟粉虱的寄主选择性;取食不同寄主植物烟粉虱成虫的蜜露分泌量差异显著,从高到低依次为黄瓜、甘薯、棉花、茄子、辣椒;黄瓜、茄子、甘薯、棉花上烟粉虱成虫的寿命显著长于辣椒,其平均单雌产卵量(分别为224.33粒、182.33粒、191.73粒和172.60粒)也均显著高于辣椒(47.83粒);各寄主植物上烟粉虱卵的孵化率和发育历期差异均不显著;烟粉虱若虫在黄瓜、茄子、甘薯和棉花上的发育历期分别为10.60 d、11.96 d、11.11 d和13.20 d,死亡率分别为5.21%、27.78%、17.24%和37.11%,在辣椒上不能完成正常发育.     

Q型烟粉虱在中国的入侵生态过程及机制

外来种的入侵生态过程及机制是入侵生物学重要的研究内容, 相关领域的案例分析对入侵生物学学科构建具有重要的理论意义, 对于入侵生物的防控具有重要的实践价值。但迄今中国对外来种的入侵生态过程及机制案例分析较少。而近10年来中国学者对重大入侵昆虫Q型烟粉虱Bemisia tabaci的研究为这方面的分析提供了可能。基于上述因素, 本文以Q型烟粉虱为例, 追溯了Q型烟粉虱成功入侵中国的生态过程, 总结了该昆虫成功入侵的生态过程特征, 从种群遗传结构、 生态因子及人类活动等方面解析了该虫成功入侵的机制, 展望了Q型烟粉虱入侵生物学未来的研究方向。我们认为, Q型在中国的入侵生态过程具有传入隐蔽、 扩散快速、 危害严重等特点; Q型烟粉虱成功入侵中国涉及Q型烟粉虱种群遗传学基础、 生态因子及人类活动等多种因素, 其中杀虫剂在中国的大量使用对Q型取代B型的驱动作用可能是Q型烟粉虱在中国成功入侵的重要因素。     

寄主种类、距离和种群密度对烟粉虱扩散的影响

在笼罩条件下,分别以黄瓜、棉花、蕹菜为虫源寄主和诱集寄主,研究寄主植物、空间距离、虫源密度等因子对B型烟粉虱扩散的影响。结果发现,从虫源寄主上扩散的成虫量,与烟粉虱对诱集寄主和虫源寄主的嗜性差异程度有关,诱集寄主相对于虫源寄主的嗜性越强,扩散出来的成虫数量就越多,反之扩散的成虫数量就越少。成虫扩散量与诱集寄主的距离呈负相关,并且诱集寄主的嗜性越强,随着距离的增大,诱集量下降的速率越快。成虫扩散量与虫源种群密度呈正关,但非嗜好寄主上的虫口承载量相对较低,在虫口密度相对较高时,非嗜好寄主上烟粉虱向外扩散的相对量更大。烟粉虱的扩散量与寄主营养状况呈负相关,寄主营养胁迫时,非嗜好寄主上可以获得相对更高的诱集量。     

不同寄主植物对烟粉虱发育和繁殖的影响

研究了烟粉虱 B型 ( Bemisia tabaci Gennadius)在番茄、茄子、黄瓜和甘蓝上的发育、存活和繁殖情况。在 2 6± 1℃的条件下 ,烟粉虱从卵发育到成虫的存活率以在甘蓝上的最高 ,为 68.5 5 % ,黄瓜上的最低 ,为46.2 8% ;发育时间以在茄子上最短 ,为 1 7.5 d,黄瓜上最长 ,为 1 9.3d,差异显著 ;平均单雌产卵量以在甘蓝上最大 ,为 1 43粒 ,黄瓜上最小 ,为 98.2 5粒 ;成虫的寿命以在甘蓝上最长 ,平均为 2 5 .2 d,黄瓜上为 1 7.2 d;内禀增长率 rm以在茄子上的最大 ,为 0 .1 41 6,黄瓜上最小 ,为 0 .1 1 43。综合比较 4种不同寄主植物 ,茄子是烟粉虱种群生长发育和繁殖最适宜的寄主     

Differences in host selection and performance between B and Q putative species of Bemisia tabaci on three host plants

B and Q are two putative species of the Bemisia tabaci complex (Hemiptera: Aleyrodidae), and are among the most invasive and destructive pests of crops and horticultural plants worldwide. In China, Q predominates and is displacing B. Although researchers have proposed that the higher capacity of Q to utilize host plants plays an important role in its replacement of B, there are few relevant field surveys and experimental studies. The difference in host assessment between B and Q in multiple‐choice rather than in no‐choice situations may be essential to understanding the displacement. Here, we compared settling and oviposition preferences, and adult and nymph performance, for the putative species B and Q of the B. tabaci complex on three common host species: poinsettia [Euphorbia pulcherrima Wild. ex Klotsch (Euphorbiaceae)], cotton [Gossypium hirsutum L. (Malvaceae)], and cabbage [Brassica oleracea L. (Brassicaceae)]. Although the preferred hosts for settling and oviposition were the same as those that supported maximum fitness (adult longevity, fecundity, and nymph survivorship), these hosts differed between B and Q. When given a choice, B preferred to settle and oviposit on cabbage over poinsettia and cotton, whereas Q preferred to settle and oviposit on poinsettia and cotton over cabbage. In a no‐choice experiment, adult longevity, fecundity, and nymphal survival for B were greater on cabbage than on poinsettia and cotton, but the opposite was true for Q.     

不同寄主植物对B型烟粉虱发育适合度的影响

为探明寄主植物对B型烟粉虱Bemisia tabaci(Gennadius)种群发育适合度的影响,采用室内实验比较了B型烟粉虱在番茄、棉花、菜豆和辣椒上的生存曲线、发育进度和成虫性比等生物学指标。结果表明,B型烟粉虱种群在不同寄主植物上的生存曲线差异显著,由卵发育至成虫的存活率由高到低依次为:番茄=棉花>菜豆>辣椒。B型烟粉虱在辣椒、棉花、菜豆和番茄上50%成虫羽化期依次为25.5、23.0、22.8和22.5d,在辣椒上的发育进度显著慢于其他植物。在不同寄主植物上B型烟粉虱的雌成虫比例差异显著,由高到低依次为:辣椒(63.0%)>棉花(58.3%)>菜豆(52.0%)>番茄(49.7%)。在番茄上B型烟粉虱第二代的生存率显著高于第一代,发育速率较第一代加快,雌成虫比例(63.3%)也显著高于第一代(49.7%)。在棉花上,第一代和第二代间的生存曲线、发育进度和雌成虫比例则差异不显著。可见,不同寄主植物对B型烟粉虱的发育适合度不同,在番茄上的发育适合度则以第二代较第一代显著提高。此外,B型烟粉虱在不适寄主植物辣椒上的存活率较低,但后代雌成虫比例增加,推测B型烟粉虱可通过调整后代性比增加其在不适寄主植物上的种群。     

Bemisia tabaci in Iraq: Population structure,endosymbiont diversity and putative species

Whiteflies (Hemiptera: Aleyrodidae) are major pests of many crops worldwide. Bemisia tabaci is a cryptic species complex composed of more than 39 putative species. Understanding which putative species of B. tabaci are predominant in an area is vital for effective pest management since they may vary considerably with respect to insecticide resistance, host plant range and virus transmission. Here, for the first time, the genetic diversity, the symbiont diversity and population structure of B. tabaci in Iraq were studied. Fourteen populations were analysed using mitochondrial cytochrome C oxidase subunit 1 (mtCO1) sequencing and microsatellite genotyping. Symbiotic bacteria were identified using 16S rRNA and 23S rRNA sequencing. MtCO1 sequencing detected two putative species of B. tabaci. The predominant putative species in Iraq was Middle East-Asia Minor (MEAM) 1 subcladeB2. In addition, one individual was MEAM1-subcladeB. The second putative species was a single individual of MEAM2. The microsatellite data indicated low genetic diversity, with no biologically informative clustering. All MEAM1 individuals harboured one primary symbiont, Portiera aleyrodidarum, and most (96%) have two secondary symbionts: Hamiltonella sp. and Rickettsia sp. This study has identified the genetic diversity and population structure of B. tabaci in Iraq. Further investigation is needed to update the pest status of B. tabaci in this region. The current data, combined with investigations into the capacity of the various putative species to transmit plant viruses, especially tomato yellow leaf curl virus, will aid pest management and horticultural production.     

B型烟粉虱在甘蓝、西葫芦和辣椒上的刺吸取食行为

利用刺吸电波技术（EPG）记录了B型烟粉虱Bemisia tabaci在甘蓝Brassica oleracea L. var. caqitata、西葫芦Cucurbita pepo L.和辣椒Capsicum annuum L.上的刺吸取食波形。结果表明,3种寄主植物的适合度为甘蓝>西葫芦>辣椒。在所观察的25头烟粉虱中,到达甘蓝、西葫芦和辣椒韧皮部的个体数分别为24、19和15,其中持续吸食头数为22、10和1。在第一阶段（从刺吸开始到第一个E(pd)1出现）,烟粉虱在甘蓝、西葫芦和辣椒3种植物上非刺探时间所占比例分别为9.59%、23.55%和36.97%,三者差异显著; 在第二阶段（从第一个E(pd)1出现到第一次韧皮部持续吸食）,烟粉虱在甘蓝和西葫芦上所考察的4个指标无显著差异; 在第三阶段（从第一次韧皮部持续吸食至记录结束）,烟粉虱在甘蓝上第一次韧皮部持续吸食后的刺探次数（4.73）显著低于在西葫芦上的刺探次数（13.40）。在自由状态下,烟粉虱60 min内在甘蓝、西葫芦和辣椒上留存粉虱的百分比分别为100％、88％和28％,这进一步验证了上述依据EPG记录得到的结果。     

烟粉虱对不同寄主植物的选择性和适应性测试

为了明确在田间烟粉虱Bemisia tabaci(Gennadius)对不同寄主植物选择性和适应性,本实验在室内用Y型嗅觉仪测定了烟粉虱对13种寄主植物的选择性,随后对田间随机排列种植的这13种寄主植物依照测试结果由强到弱依次拔除(拔除次序为茄子、番茄、黄瓜、辣椒、棉花、茼麻、西葫芦、油菜、花菜、小青菜、莲花白、胡萝卜和苦瓜),每次拔除间隔时间为5 d,结果显示:田间第一次调查的结果与室内选择性测试结果一致;随着最适宜寄主的拔除,烟粉虱成虫数量在与其引诱力相近的一种或几种寄主上的略有增加,而其它植物上却没有大的变化,这表明随着最适宜寄主的拔除,烟粉虱成虫会重新分布,但趋向分布于引诱力相对较强的寄主植物;随着寄主植物的拔除,烟粉虱卵、若虫和蛹在引诱力较强的植株上均有所增加;但西葫芦拔除之后其余植株上烟粉虱卵、若虫和蛹的数量没有明显变化;小青菜拔除后,其余植株上烟粉虱卵、若虫和蛹的数量又有所增加。这表明随着最佳寄主的拔除,烟粉虱会趋向选择于引诱力相对较强的寄主植物产卵,当烟粉虱从嗜好性强的植物转移到嗜好性弱的植物时,产卵适应会滞后于取食适应。但整个实验过程中苦瓜上的烟粉虱上成虫、卵、若虫和蛹的数量均变化不大,苦瓜上的成虫应属偶然分布其上,烟粉虱成虫并不取食苦瓜,苦瓜对烟粉虱有趋避作用。本实验模拟田间种植模式,因此实验结果对田间种植具有指导意义。     

烟粉虱生物型的监测及其遗传结构研究

烟粉虱Bemisia tabaci(Gennadius)是一种重要的农业害虫并包括许多生物型,其中B型和Q型是入侵性较强的2种生物型。文章着重介绍近年来在烟粉虱生物型的监测及其遗传结构方面的研究进展。B型烟粉虱和Q型烟粉虱这2个生物型均已入侵我国,其中多数地区烟粉虱是B型烟粉虱,局部地区有Q型烟粉虱并呈现不断蔓延趋势。微卫星(SSR)分子标记分析结果表明我国B型烟粉虱的入侵来源具有多元化,而云南地区Q型烟粉虱来源比较单一。化学农药的使用能够影响室内种群的遗传结构,降低种群的遗传多样性。基于RAPD、ISSR分子标记的分析结果表明,Q型烟粉虱种群各项遗传多样性指数均比B型烟粉虱的高。今后加强烟粉虱入侵生物型的遗传结构及其种群动态关系等方面的研究,对于揭示烟粉虱的灾变机制及其控制具有重要的意义。     

寄主挥发物、叶色在B型烟粉虱寄主选择中的作用

在室温条件下,研究B型烟粉虱Bemisia tabaci(Gennadius)对不同寄主植物和颜色的行为趋性。笼罩实验的结果显示,烟粉虱雌虫对共存的5种寄主植物偏好存在显著差异,总体上表现为对番茄的趋性最强(35·0%),甘蓝次之(27·7%),烟草和棉花再次之,辣椒最低(7·1%);且随着时间的延长,烟粉虱数量在番茄上逐渐增加,在甘蓝上呈下降趋势,在烟草、棉花和辣椒上变动幅度不大,但数量总体上仍是番茄(48·8%)>甘蓝(18·4%)>烟草、棉花>辣椒(3·4%)。但烟粉虱在不同寄主植物上的产卵量则表现为:甘蓝>番茄>棉花、烟草>辣椒;其中甘蓝和番茄上卵量分别占总卵量的56·8%和28·2%;而烟草、棉花和辣椒上的卵量均不到总卵量的6·0%。"Y"型嗅觉仪进一步测定表明:寄主植物番茄和甘蓝气味对烟粉虱具有显著引诱作用,且表现为番茄>甘蓝,辣椒不具引诱作用;烟粉虱对3种植物(番茄、甘蓝、辣椒)的叶片颜色均有显著趋性,选择率在75%左右,但在三者之间的趋性差异不明显;烟粉虱雌虫对黄色和绿色均具有显著趋性,且对黄色的趋性显著大于对绿色的趋性,但对红色无趋性。综合分析表明,在对寄主定向和定位过程中,B型烟粉虱的视觉和嗅觉均起作用,但在对同种颜色(绿色)的寄主进行选择和定位的过程中,嗅觉起主要作用,而对不同种颜色(红、黄、绿)的选择和定位时,其视觉起决定作用。     

Comparison of performance on different host plants between the B biotype and a non-B biotype of Bemisia tabaci from Zhejiang, China

The capacity of the B biotype of the whitefly, Bemisia tabaci (Gennadius) (Homoptera: Aleyrodidae), to invade has often been linked to its presumably wider host range than the non‐B indigenous biotypes. However, there are few experimental studies of the relative performance of the B biotype and non‐B biotypes on different host‐plant species. Here, we compared the performance of the B biotype and an indigenous non‐B biotype (China‐ZHJ‐1) of B. tabaci from Zhejiang, China on five commonly cultivated host plants, each from a different family: cotton, tobacco, cabbage, squash, and kidney bean. We also examined the effect of rearing host plants on the performance of the B biotype. Overall, the performance of the B biotype on the five species of plants was much better than that of the indigenous non‐B population. On tobacco, cabbage, and kidney bean, no individuals of ZHJ‐1 completed development to adulthood, whereas the B biotype developed successfully from egg to adult on all three plants. On squash, the B biotype survived better, developed to adulthood earlier and had a higher fecundity than ZHJ‐1. The two biotypes performed more equally on cotton, but even on this plant the B biotype female adults lived nearly twice as long as that of ZHJ‐1 and may have realized a higher life‐time fecundity. The B biotype also showed a substantial capacity to acclimatize to alternative host plants for improved survival and reproduction, on both highly suitable and marginally suitable host plants. We conclude that the host range of the B biotype of B. tabaci may be much wider than those of some indigenous biotypes, and this advantage of the B biotype over the non‐B biotypes may assist in its invasion and displacement of some indigenous biotypes in the field.     

Performance of seedlings of the invasive alien tree Schinus molle L. under indigenous and alien host trees in semi-arid savanna

We assessed the importance of host trees in influencing invasion patterns of the alien tree Schinus molle L. ( Anacardiaceae ) in semi-arid savanna in South Africa. Recruitment of S. molle is dependent on trees in its invaded habitat, particularly Acacia tortilis Hayne. Another leguminous tree, the invasive alien mesquite ( Prosopis sp.), has become common in the area recently, but S. molle rarely recruits under canopies of this species. Understanding of the association between these species is needed to predict invasion dynamics in the region. We conducted experiments to test whether: (i) seedling survival of S. molle is better beneath A. tortilis than beneath mesquite canopies; (ii) growth rates of S. molle seedlings are higher beneath A. tortilis than beneath mesquite. Results showed that growth and survival of S. molle did not differ significantly beneath the native A. tortilis and the alien Prosopis species. This suggests that microsites provided by canopies of mesquite are as good for S. molle establishment as those provided by the native acacia. Other factors, such as the failure of propagules to arrive beneath mesquite trees, must be sought to explain the lack of recruitment beneath mesquite.     

烟粉虱体内营养物质对寄主植物多代诱导的响应

比较同一遗传背景的B型烟粉虱Bemisia tabaci Gennadius种群成虫在甘蓝、黄瓜和一品红上的适合度差异,测定3种寄主植物主要营养差异,并分析饲养不同时间后成虫体内的蛋白质、氨基酸和游离脂肪酸含量的多代变化规律。结果发现,B型烟粉虱成虫在黄瓜上的相对适合度最高,其次是甘蓝,在一品红上适合度最低,这可能与黄瓜叶片的总氮含量高和总糖含量低有关。饲养时间对烟粉虱体内主要营养物质含量没有显著影响,但寄主植物对烟粉虱成虫体内主要营养物质含量影响显著。在黄瓜上饲养烟粉虱成虫体内蛋白质含量都显著高于一品红和甘蓝上烟粉虱成虫的蛋白质含量,在黄瓜上饲养烟粉虱成虫总氨基酸含量都显著低于一品红和甘蓝上烟粉虱成虫的总氨基酸含量。相反,在3种寄主上饲养烟粉虱成虫游离脂肪酸含量都无显著差异。可见,寄主植物对B型烟粉虱体内主要营养物质组成影响显著,但饲养时间对B型烟粉虱体内主要营养物质组成影响较小。     

豇豆轻斑驳病毒CPMMV感染菜豆对B型烟粉虱寄主选择和生物学特性的影响

豇豆轻斑驳病毒（Cowpea mild mottle virus,CPMMV）的流行与其媒介昆虫烟粉虱Bemisia tabaci密切相关,但CPMMV感染寄主植物对B型烟粉虱寄主选择行为和生物学特性的影响尚不清楚。本研究探究了1）CPMMV感染菜豆Phaseolus vulgaris不同时间对B型烟粉虱寄主选择和产卵偏好性的影响;2）CPMMV感染菜豆对B型烟粉虱生物学特性的影响。结果发现：1）相较于健康菜豆,摩擦接种CPMMV后1周,B型烟粉虱却偏好在CPMMV感染的植株上停留和产卵;而摩擦接种后4周,B型烟粉虱却偏好在健康的植株上停留和产卵;2）无论是在摩擦接种后1周和4周的CPMMV感染植株上,B型烟粉虱在健康和CPMMV感染植株上的产卵量和存活率差异不明显。可见,CPMMV感染菜豆对于B型烟粉虱的寄主选择偏好性具有时间效应,而CPMMV感染菜豆对于B型烟粉虱的生物学特性没有显著影响。     

The Bemisia tabaci species complex: Additions from different parts of the world

Bemisia tabaci is one of the most threatening pests in many crops. We sequenced part of the mitochondrial cytochrome oxidase I gene from fifty whitefly populations collected in Indonesia, Thailand, India and China. Nineteen unique sequences (haplotypes) of the cytochrome oxidase I were identified in these populations. They were combined with sequences available in databases, resulting in a total of 407 haplotypes and analyzed together with nine outgroup accessions. A phylogenetic tree was calculated using the maximum likelihood method. The tree showed that all groups that were found in previous studies were also present in our study. Additionally, seven new groups were identified based on the new haplotypes. Most B. tabaci haplotypes grouped based on their geographical origin. Two groups were found to have a worldwide distribution. Our results indicate that our knowledge on the species complex around B. tabaci is still far from complete.