Phenotypic plasticity in the reproductive traits of a parasitoid

Organisms show phenotypic plasticity - the capacity for a given genotype to express different phenotypes - in response to changes in the environment. Among the several factors that can cause phenotypic plasticity, nutritional constraints during development can affect the size of organisms and, consequently, affect most life-history traits, including reproductive traits. As their larvae are restricted by the amount of food contained in their host, parasitoids are a good model to study phenotypic plasticity related to size. The phenotypic plasticity of reproductive traits was investigated in the egg parasitoid Trichogramma euproctidis (Hymenoptera: Trichogrammatidae) by using host species of different sizes. Adult size, sperm storage organs (seminal vesicles and spermatheca), number of sperm stored and gamete size (sperm and oocyte) are all influenced by the host species; larger individuals have larger organs which contain more sperm, and both sperm and oocytes are correlated with adult size. However, while females become larger than males and mature larger oocytes in larger hosts, increase in sperm length stops after a given threshold.     

柞蚕卵繁殖赤眼蜂实验种群生命表的编制与分析

通过解剖柞蚕卵统计赤眼蜂幼期存活率与生殖力数据的方法,编制了松毛虫赤眼蜂在柞蚕卵上繁殖的实验种群生命表,松毛虫赤眼蜂在柞蚕卵上的单雌平均产卵量为86．15粒,赤眼蜂的卵、幼虫、蛹的各期存活率分别为1．00、0．9186、0．8895;羽化率为0．8668;种群趋势指数Ⅰ为54．48可见,大卵(柞蚕卵)繁蜂与小卵(如米蛾卵)繁蜂不同,大卵繁蜂时的幼期死亡率接近30％,是一个不可忽视的因素,文中还讨论了净生殖力R0、Ⅰ、内禀增长率rm3个重要生命表参数计算及其相互关系,认为R0和Ⅰ在生物学意义上相同,由Ⅰ值也可计算rm。     

Wolbachia在玉米螟赤眼蜂内的三重感染

Wolbachia是一类广泛存在于节肢动物体内的共生菌。玉米螟赤眼蜂Trichogramma ostriniae是我国玉米田间的优势赤眼蜂种, 据报道, 赤眼蜂种内有Wolbachia感染。本文利用Wolbachia的16s rDNA和wsp基因引物通过PCR方法对玉米螟赤眼蜂的野生种群进行了调查, 发现以wsp基因为鉴定依据, 检测的所有个体都感染了3种Wolbachia ［wOstGDAa (GenBank accession no. EU157103), wOstGDAb (GenBank accession no. EU157104) 和 wOstGDB (GenBank accession no. EU157105)］。本文首次报道了野生赤眼蜂种群内Wolbachia的三重感染率几乎为100%。根据本研究的结果, 可以推测当不同种赤眼蜂寄生同一寄主时, Wolbachia可能会在不同赤眼蜂种间进行横向传播。     

赤眼蜂防治小菜蛾适宜蜂种或品系的筛选(英文)

以控制小菜蛾为目的,在实验室对２９种赤眼蜂或品系进行了筛选。筛选评价根据５项指标：（１）能在小菜蛾卵上产卵的雌蜂比例,（２）每雌蜂寄生卵量,（３）子峰在每粒寄主上的存活率,（４）羽化率,和（５）子代性比。研究结果表明：有２３种赤眼蜂或品系能够寄生小菜蛾卵,但无论在种间还是品系间均存在很大差异。根据５项筛选指标综合评价,２９种中较好的为：前苏联的Ｔｒｉｃｈｏｇｒａｍｍａ ｔｒｊａｐｉｔｚｎｉ,美国的Ｔ．ｐｒｅｔｉｏｓｕｍ,法国的Ｔ．ｎａｇａｒｋａｔｔｉｉ,中国台湾的Ｔｒｉｃｈｏｇａｒａｍｍａｔｏｉｄｅａ ｂａｃｔｒａｅ,中国广东的Ｔ．ｃｈｉｌｏｎｉｓ和法国的一个种Ｔ．ｓｐ。其中美国的Ｔ．ｐｒｅｔｉｏｓｕｍ,中国台湾的Ｔｒｉｃｈｏｇａｒａｍｍａｔｏｉｄｅａ ｂａｃｔｒａｅ,中国广东的Ｔ．ｃｈｉｌｏｎｉｓ可以考虑作为大田防治小菜蛾的首选蜂种。田间筛选及大田验证试验正在进行之中。     

常规棉花粉和转Cru1Ac＋CpTI棉花粉对拟澳洲赤眼蜂繁殖和存活的影响

在室内评价了常规棉花粉和转Cry1Ac＋CpTI棉（Bt棉）花粉通过不同处理方式作为食物源对拟澳洲赤眼蜂Trichogramma confusum寿命、寄生卵数、子代羽化数和性比等繁殖和存活特征的影响。共设计7个饲喂处理,即不饲喂（UNFED）、水（w）、水＋常规棉花粉（W＋P）、水＋Bt棉花粉（W＋BtP）、10％蜂蜜水（H）、10％蜂蜜水＋常规棉花粉（H＋P）和10％蜂蜜水＋转Bt棉花粉（H＋BtP）。在提供或不提供米蛾Corcyra cephalonica 卵条件下,经W＋P或W＋BtP饲喂的雌蜂寿命与W或UNFED间无显著差异,但均显著短于H和H＋P或H＋BtP饲喂的雌蜂,而经H＋P或H＋BtP饲喂的雌蜂寿命又均显著长于经H饲喂的雌蜂（p〈0．05）。比较每雌寄生卵数和子代羽化数来看,各处理明显分为3类。即UNFED、W、W＋P和W＋BtP为最低,H为居中,H＋P和H＋BtP为最高。比较每雌子代性比来看,各处理也明显分为3类,即H、H＋P和H＋BtP为最低,W＋P和W＋BtP为居中,UNFED和W为最高。饲喂W＋P和W＋BtP的雌蜂寿命、寄生卵粒数、子代羽化数和性比分别与W＋BtP和H＋BtP饲喂间无显著差异（p〈0．05）。因而,棉花花粉需与蜂蜜组合才能成为拟澳洲赤眼蜂实现其最大存活和繁殖力的食物;Bt棉花粉对拟澳洲赤眼蜂无影响。     

甜菜夜蛾核型多角体病毒对拟澳洲赤眼蜂的影响：种群参数比较和PCR检测

用生命表方法和PCR检测研究了甜菜夜蛾核型多角体病毒（Spodopteraexiguamulticapsid nucleopolyhedrovirus, SeMNPV）对拟澳洲赤眼蜂Trichogramma confusum Viggiani的影响。结果表明,在25±1℃下,取食含SeMNPV蜂蜜和纯蜂蜜（对照）的两组赤眼蜂雌蜂的寿命、繁殖力、羽化率、产雌率均无显著差异;内禀增长率（r_m）分别为0.3524 和0.3418,周限增长率（λ）为1.42和1.41,非常接近;净繁殖率（RO）分别为 124.34和142.57,平均世代历期为13.6和14.5天, 种群倍增时间分别为1.96和2.03天。对5头取食含SeMNPV蜂蜜的雌蜂的子代的PCR 检测结果也均为阴性。因此,结论认为SeMNPV对拟澳洲赤眼蜂成蜂并无明显影响,体内携带病毒的亲代蜂并不能将病毒传给子代。     

Trichogramma ostriniae (Hymenoptera: Trichogrammatidae) response to relative humidity with and without host cues

Trichogramma ostriniae is a parasitoid wasp species that is used as a biological control for several lepidopteran agricultural pests. Our study examined the effects of relative humidity (RH) on the behaviour of female T. ostriniae. In Y-tube RH choice assays, wasps generally chose higher RH over lower RH but the latency time taken to make a choice displayed no clear patterns that could be ascribed to the magnitude of the RH difference between arms of the Y-tube. In trials conducted in glass arenas with fixed humidities, the conditional probabilities of transition from searching to interacting with the leaf disk, and from interacting with leaf disks to antennal egg drumming and oviposition, were not significantly different among the RH levels, nor were there differences in latency times. These findings suggest that the level of RH may influence habitat choice but have little effect on search efficacy.     

Is the parasitization capacity of Trichogramma cordubensis influenced by the age of the females?

We investigated the parasitization capacity of Trichogramma cordubensis Vargas & Cabello (Hymenoptera: Trichogrammatidae) females aged 24 h, 48 h, 72 h, 96 h, 120 h, and 144 h, using Ephestia kuehniella Zeller (Lepidoptera: Pyralidae) eggs as hosts. Wasps were held without hosts during the period of ageing, therefore being increasingly time-limited with respect to parasitization as they got older. The total number of parasitized hosts decreased as the age of the parasitoid increased. However, the proportion of lifetime parasitism carried out on the first day increased with wasp age, up to 120-h old females. These results show that the parasitization capacity of ageing T. cordubensis females changes as they become time-limited. The consequences of such changes for biological control programs are discussed.     

甜玉米地亚洲玉米螟为害的生态控制系统研究

利用自然种群生命表方法 ,研究了甜玉米品种抗虫性差异 ,斯氏线虫、玉米螟赤眼蜂对亚洲玉米螟种群系统的生态控制 ,根据不同卵量水平初步组建了第 5代亚洲玉米螟生态控制系统。结果得出 :亚洲玉米螟为害的生态控制系统由人工生态控制系统和自然控制系统两大部分组成 ,主要通过调控人工生态控制系统中的生态控制措施来达到生态控制目标。当甜玉米品种为穗甜 2号 ,卵密度为 18(块 / 10 0株 )时 ,不采取人为生态控制措施即可控制亚洲玉米螟的为害 ,即在人工生态控制系统内 ,利用穗甜 2号对亚洲玉米螟的抗性即可达到生态控制目标 ;当甜玉米品种为粤甜 1号 ,卵密度为 18或 35 (块 / 10 0株 )时 ,在人工生态控制系统内释放玉米螟赤眼蜂或撒施线虫颗粒剂均可达到生态控制目标 ;当甜玉米品种为粤甜 1号 ,卵密度为 6 2 (块 / 10 0株 )时 ,则要在人工生态控制系统内同时释放玉米螟赤眼蜂和撒施线虫颗粒剂 ,才能达到生态控制目标。通过生态控制系统的建立 ,为甜玉米的无公害化生产提供了一条切实可行的害虫控制途径     

短期高温对感染Wolbachia的松毛虫赤眼蜂发育和繁殖的影响

感染了沃尔巴克氏体Wolbachia的松毛虫赤眼蜂Trichogramma dendrolimi Matsumura营孤雌产雌生殖方式,但高温可能影响这一特性。为了模拟该赤眼蜂在田间遇到短期高温后的受影响情况,研究了柞蚕卵繁殖的Wolbachia感染了Wolbachia的松毛虫赤眼蜂孤雌产雌品系,于蛹中期和蛹后期经历6h32,35,38℃高温单次冲击处理,对当代羽化出蜂率、单卵出蜂数、单卵雌蜂率、寿命4个指标和处理子代羽化出蜂率、有效繁殖个体、单卵出蜂数、单卵雌蜂率4个指标的影响。结果表明,短期高温刺激会对孤雌产雌的松毛虫赤眼蜂产生不利影响,尤其是38℃高温不利影响明显,主要表现在羽化出蜂率和单卵出蜂数两指标明显降低;高温冲击对子代蜂各指标影响不明显。2代赤眼蜂均未有雄峰出现,表明短期高温冲击不能对Wolbachia调控其宿主生殖方式的作用产生影响。