茄子品种对茄二十八星瓢虫及其寄主蜂生长发育的影响

茄子不同品种对茄二十八星瓢虫及瓢虫标腹姬小蜂的影响结果表明,上海紫茄、呼杂34^#、托塔姆3^#、洋红茄4个品种中,取食上海紫茄的瓢虫发育历期明显短于取食其它3个品种的瓢虫。其幼虫－蛹历期比在托塔姆3^#上取食的瓢虫发育历期快5.69d。瓢虫柄腹姬小蜂在取食上海紫茄的瓢虫幼虫内发育出蜂数多、性比高,但寄生率稍低。而在托塔姆3^#上取食的幼虫内发育出蜂数少、羽化率低、蜂体小、但寄生率稍高。该蜂喜在3,4龄幼虫内寄生,在其上寄生蜂出蜂多、性比高、蜂的个体大。     

瓢虫柄腹姬小蜂对茄二十八星瓢虫功能反应的研究

研究了瓢虫柄腹姬小蜂功能反应。结果表明,在供试温度下,瓢虫柄腹姬小蜂对茄二十八星瓢虫的功能反应均符合Holling圆盘方程Ⅱ型,以25℃下的搜寻效率最高,其模型为Nα=1．94N／(1 0．39N),在茄枝叶、龙葵枝叶、酸酱枝叶和西红柿枝叶4种叶片上,以茄枝叶、龙葵枝叶上的搜寻效率最高,分别为1．85和1．94。瓢虫柄腹姬小蜂对不同密度的2、3、4龄幼虫的功能反应,以4龄的搜寻效率最高,其次为3龄,最低为2龄,实验中未发现瓢虫柄腹姬小蜂寄生1龄的幼虫。不同处理方法、不同药剂影响瓢虫柄腹姬小蜂对不同寄主密度的功能反应,其中阿维菌素组的搜寻效率与对照组没有显著性差异,苦皮藤索组的搜寻效率稍有降低,而敌敌畏、氯氰菊酯处理组的搜寻效率显著下降,处理时间相对延长。     

温度和寄主植物对瓢虫柄腹姬小蜂自身干扰反应的影响

研究了温度和寄主植物与寄生蜂密度对瓢虫柄腹姬小蜂PediobiusfoveolatusCrawford功能反应的影响。结果表明瓢虫柄腹姬小蜂对自身密度的干扰反应均符合Watt所提出的模型(A =aP-b)。在1 9～3 1℃5个温度下,以2 8℃下的干扰系数最小,其模型为A =4 0 4p-0 41。在4种寄主植物枝叶上,以酸酱枝叶上干扰系数最大,为0 . 5 0 ;而在西红柿枝叶、龙葵枝叶、茄枝叶上分别为0 . 2 8,0 .2 6,0 .2 4。可为合理地利用该蜂提供参考。     

不同放蜂比例及茄科蔬菜品种对瓢虫柄腹姬小蜂寄生率的影响

本文通过保护地放蜂试验,研究了不同的放蜂比例、不同茄科蔬菜植物以及同一作物的不同品系等因子对瓢虫柄腹姬小蜂Pediobius foveolatus Crawford寄生率的影响。结果发现:在不同的蜂虫比例下,随放蜂比例的增加,寄生蜂的寄生率在10 d内相应增加。当蜂虫比为1∶1时,寄生率高达97.63%,明显高于蜂虫比为1∶3和1∶5的寄生率(分别为62.58%和56.11%)。进一步研究发现,不同蔬菜、同一蔬菜的不同品系及同一植株的不同部位对寄生率也有影响。在茄子上,不同放蜂比条件下寄生蜂对害虫的寄生率均大于在西红柿上的寄生率,表明茄子作为寄主植物更适于寄生蜂的产卵寄生;而且香毛簇多的品系比香毛簇少的品系寄生率低。     

班氏跳小蜂对寄主龄期选择的研究

班氏跳小蜂Aenasiusbam bawalei Hayat是扶桑绵粉蚧Phenacoccus solenopsis Tinsley的优势种寄生蜂。本文研究了在限制选择和自由选择的条件下,扶桑绵粉蚧的2龄若虫、3龄若虫和雌成虫对该蜂的寄生率、发育历期、子代性比和个体大小的影响。结果表明:在两种选择条件下,班氏跳小蜂对扶桑绵粉蚧3龄若虫的寄生率显著高于对雌成虫和2龄若虫的寄生率,但寄生粉蚧雌成虫的子代雌雄性比显著高于寄生3龄若虫或2龄若虫的性比;在两种选择条件下,雌蜂在寄主三种虫龄(态)上的发育历期差异不显著,但是雄蜂在粉蚧雌成虫中的发育历期显著长于寄生2龄若虫或3龄若虫的发育历期;在两种选择条件下,寄生于粉蚧雌成虫的子代雌蜂和雄蜂的个体都是最大,其后足胫节长度显著长于寄生于2龄若虫或3龄若虫的子代胫节的长度。     

寄主大小对副珠蜡蚧阔柄跳小蜂产卵选择及繁殖的影响

为明确寄主体型大小对副珠蜡蚧阔柄跳小蜂产卵选择及繁殖的影响,在室内观察了副珠蜡蚧阔柄跳小蜂在不同大小的橡副珠蜡蚧上的产卵量、寄生率、发育历期及性比。结果表明:在选择性和非选择性的产卵试验条件下副珠蜡蚧阔柄跳小蜂对中型个体寄主(长4.0 mm,宽3.4 mm)的寄生率最高;小蜂的产卵量在选择性试验时,以大型寄主(长4.8 mm,宽4.0 mm)体内的最高(67.0粒),非选择性试验时,以中型寄主(长4.0 mm,宽3.4 mm)体内的最高(131.0粒),小型寄主(长3.2 mm,宽2.9 mm)体内产卵量最少(61.5粒);副珠蜡蚧阔柄跳小蜂后代出蜂数与寄主体型的大小呈显著正相关,雌性比则随寄主体型的增大而增减小,发育历期则受寄主体型的影响不明显。综上所述,副珠蜡蚧阔柄跳小蜂雌蜂能够根据寄主质量来调整产卵量及后代性比,以使后代适应度最大化。     

一种寄生梨茎蜂的重要天敌-梨茎蜂啮小蜂(膜翅目,姬小蜂科)新种记述

描述了寄生梨茎蜂Janus piri Okamoto et Muramatsu的一种重要天敌新种--梨茎蜂啮小蜂Tetrastichus janusi sp.nov.,该种属小蜂总科姬小蜂科啮小蜂属.新种群集外寄生于梨茎蜂幼虫,一般1头寄主上寄生4～14头个体,雌雄性比为2.6∶1.0.一年发生两代.在越冬代梨茎蜂幼虫中的寄生率达44.7%.新种在梨茎蜂的生物防治中具有良好的应用前景.这是啮小蜂亚科在国内外首次发现寄生于茎蜂科害虫.新种模式标本保存于中国林业科学研究院昆虫标本馆.     

几种因子对马尼拉侧沟茧蜂寄生效能的影响

马尼拉侧沟茧蜂Microplitis manilae是斜纹夜蛾Spodoptera litura的一种重要幼虫寄生蜂。本文以斜纹夜蛾2龄幼虫为寄主,在26±1℃、RH 65%±5%、L：D=12:12的人工气候箱内,研究生殖方式、雌蜂日龄、寄生时间段、雄蜂出现与否以及雄蜂密度等因子对其寄生效能的影响。结果表明：马尼拉侧沟茧蜂可营产雄孤雌生殖和两性生殖两种生殖方式,两种方式在亲代寄生率、子代羽化率和发育历期均无显著差异。随着雌蜂日龄的增加,其寄生率和子代性比显著降低,但子代发育历期随雌蜂日龄的增加而延长。马尼拉侧沟茧蜂在12:00-18:00时间段的寄生率、子代羽化率和性比最高,子代发育历期最短。当寄生蜂密度一定时,子代性比随着寄主密度的增加而显著增加;当寄主密度一定时,子代性比随着寄生蜂密度的增加而显著下降;雄蜂在场时,子代性比显著高于无雄蜂在场时。子代性比随着亲代雄蜂密度的增加而显著降低,但雄蜂密度对亲代寄生率,子代羽化率、发育历期无显著影响。     

斜纹夜蛾取食四种植物对马尼拉侧沟茧蜂发育和繁殖的影响

研究斜纹夜蛾Spodoptera litura幼虫取食4种植物后对马尼拉侧沟茧蜂Microplitis manilae生长发育和繁殖的影响,为利用该蜂开展斜纹夜蛾的生物防治提供理论依据。在人工气候箱内(26℃±1℃、RH 65%±5%、L∶D=12∶12)研究了斜纹夜蛾取食豇豆Vigna unguiculata、芋艿Colocasia esculenta、烟草Nicotiana tabacum和芥蓝Brassica alboglabra 4种植物对马尼拉侧沟茧蜂的生长发育和繁殖的影响。结果表明:马尼拉侧沟茧蜂寄生取食豇豆的夜蛾幼虫,其幼虫期最短,化蛹率、羽化率和累计存活率最高,性比最低,寿命最长;寄生取食烟草的夜蛾幼虫,其幼虫期最长,化蛹率、羽化率和累计存活率最低,蛹重最轻,蛹期最长;从取食芥蓝的斜纹夜蛾幼虫体内育出的雌蜂产卵量最高,但成蜂寿命最短;斜纹夜蛾取食4种植物对雌蜂个体大小无显著影响,但取食烟草的夜蛾幼虫体内育出的雄蜂个体最小。马尼拉侧沟茧蜂寄生取食不同植物的斜纹夜蛾幼虫,马尼拉侧沟茧蜂的发育和繁殖存在显著差异。     

菱斑巧瓢虫替代饲料的研究

瓢虫成虫饥饿24h后,通过室内对菱斑巧瓢虫Oenopia conglobata (Linnaeus)成虫饲喂24种人工饲料,研究菱斑巧瓢虫的取食行为;以桃蚜(MP)作对照,选择羊肝+蔗糖(SLS)、猪肝+蔗糖(PLS)、黄粉虫蛹+蔗糖(TMPS)3种饲料研究瓢虫产卵量;以白蛾周氏啮小蜂蛹(CCP)、SLS、PLS和MP对瓢虫成虫进行交叉饲喂试验,每周期7d,研究饥饿后恢复产卵时间和产卵量的差异;最后以CCP和MP饲喂瓢虫幼虫,观察其发育历期。结果表明:在羊肝、鸡心、菜蛾幼虫、鸡肝和黄粉虫蛹组中,无论是否添加蔗糖,瓢虫取食情况较好。瓢虫成虫饲喂SLS、TMPS、PLS及MP后,MP组的14d单雌产卵量为166.25粒、SLS组为18.15粒、PLS为9.65粒和TMPS组3.90粒,瓢虫恢复产卵的时间也有差异,MP组仅需要1d,而其它组需要3d至至5d。交叉饲喂试验发现,CCP组产卵量(40.67～46.87粒/雌)明显高于常用饲料-PLS组(4.53～7.13粒/雌),但与MP组(61.80～82.07粒/雌)仍有一定差距。利用CCP饲喂瓢虫幼虫,可以完成整个发育历期,但是存活率较低,1～4龄幼虫各龄期内存活率在63.64%～87.50%之间,并且发育历期(21.23d)明显长于饲喂MP组(15.71d)。     

RNAi介导的HvCDA1基因沉默影响茄二十八星瓢虫存活和发育

【目的】茄二十八星瓢虫Henosepilachna vigintioctopunctata是茄科(Solanaceae)植物上的重要害虫。昆虫体内几丁质脱乙酰酶1(chitin deacetylase 1, CDA1)催化N-乙酰氨基-D-葡萄糖胺脱去乙酰基,促使几丁质转化为壳聚糖,控制昆虫体内几丁质纤维有序堆积,并维持角质层结构的完整性。抑制虫体中CDA1基因的表达会抑制壳聚糖的合成,影响昆虫表皮结构的形成,使昆虫不能正常发育而亡。【方法】利用RT-qPCR方法测定HvCDA1基因在茄二十八星瓢虫不同发育阶段(卵、1-4龄幼虫和预蛹)和4龄幼虫不同组织(表皮、脂肪体、中肠和马氏管)中的表达模式。通过饲喂茄二十八星瓢虫1龄幼虫不同浓度dsHvCDA1溶液浸泡处理1 min的茄子叶片后及直接饲喂4龄幼虫不同浓度dsHvCDA1溶液,探究沉默茄二十八星瓢虫HvCDA1基因对其幼虫存活和发育以及HvCDA1基因表达量的影响。【结果】发育表达谱结果表明,HvCDA1在茄二十八星瓢虫的各发育阶段均有表达,但在1龄末和2龄末幼虫中的表达量最高。组织表达谱结果显示,在茄二十八星瓢虫4龄幼虫的表皮中H...     

Foraging success of parasitoid wasps on flowers: interplay of insect morphology, floral architecture and searching behavior

Intercropping with flowering herbaceous plants increases parasitoid survivorship, fecundity and retention and pest suppression in agroecosystems. Few studies, however, have examined the compatibility of parasitoid morphology and foraging ability with floral architecture. This study shows that floral architecture influences the selection of floral host resources used to provide nutrients to parasitoids in cropping systems. Parasitoid foraging performance was evaluated using real and artificial flowers which varied in degree of nectar accessibility for two eulophid parasitoids, Edovum puttleri Grissell and Pediobius foveolatus Crawford. Comparisons were made of searching performance on artificial flowers with nectars that were either scented (made from 1:1 honey-water solution) or scentless (made from 1 m sucrose solution) and differences in head widths were compared with corolla apertures. Our results showed a disparity in the ability of E. puttleri and P. foveolatus to gain access to nectar from particular types of floral architectures. E. puttleri fed efficiently only from flowers with exposed nectaries while P. foveolatus foraged efficiently from flowers having either exposed nectaries or nectaries partially obstructed by petals and stamens. Neither wasp species could forage on flowers with cup- or tube-shaped corollas because their heads are wider than the floral apertures. E. puttleri's foraging performance decreased as nectar inaccessibility increased in the artificial flowers, while P. foveolatus' foraging performance was uniform among the different artificial flowers. This indicates that E. puttleri has less propensity to search small openings for nectar than does P. foveolatus. The foraging success of both E. puttleri and P. foveolatus on artificial flowers was lower when 1 M sucrose solution was used as an artificial nectar rather than honey-water solution, indicating that the wasps were stimulated and attracted by the nectar odor. Our systematic evaluation of floral architecture with respect to parasitoid foraging ability has enabled us to predict which types of flowers would serve as suitable floral host plants for parasitoids in the field. That is, only flowers with nectaries that are completely exposed would function as suitable floral host plants for E. puttleri, while P. foveolatus could forage on flowers with either exposed or partially exposed nectaries. Examples of potentially suitable floral hosts suggested from our study include dill (Anethum graveolens L.) and fennel (Foeniculum vulgare L.) for both E. puttleri and P. foveolatus and coriander (Coriandrum sativa L.) for P. foveolatus.     

寄主植物对桃蛀螟生长发育及产卵选择行为的影响

为明确寄主植物对桃蛀螟生长发育及产卵选择行为的影响,利用实验种群生命表和二项产卵选择试验,研究了玉米、大豆、棉花和桃等4种寄主植物对桃蛀螟种群生长发育及产卵选择性的影响。结果表明:取食棉花的桃蛀螟幼虫存活率最低、幼虫历期最长,取食玉米的幼虫存活率最高、幼虫历期最短,取食桃和大豆的幼虫存活率和历期居于棉花处理组和玉米处理组之间;玉米处理组的桃蛀螟化蛹率、蛹重和蛹历期均为最高,棉花处理组为最低,大豆和桃处理组的这些参数均显著小于玉米处理组而大于棉花处理组;发育至成虫后,取食玉米的桃蛀螟羽化率显著高于其他3个处理组;取食桃的桃蛀螟成虫寿命(雌虫和雄虫)及个体发育历期均显著高于其他3种处理组;同时取食桃的桃蛀螟单雌产卵量最高,其次是玉米处理组,两者均显著高于大豆和棉花处理组。二项产卵选择试验结果显示,桃蛀螟雌蛾在棉花和玉米处理组、玉米和大豆处理组或棉花和大豆处理组间的落卵量差异不显著;但在包含桃的处理组中,桃蛀螟在棉花、玉米或大豆处理区的落卵量均显著高于桃处理区。上述结果表明,供试4种寄主植物中,桃蛀螟偏好在棉花、玉米和大豆上产卵,其中玉米对桃蛀螟的适合度相对较高,棉花对桃蛀螟的适合度相对较低。     

四种食料植物对斜纹夜蛾生长发育及营养指标的影响

在室内平均温度28.1℃,平均相对湿度84.0%的条件下研究了蓖麻、豇豆、番木瓜和香蕉等4种食料植物对斜纹夜蛾Prodenia litura(Fabricius)生长发育及营养效应的影响。结果表明:不同食料植物对斜纹夜蛾的幼虫发育历期、蛹重及营养效应等均有显著差异。幼虫发育历期以蓖麻组最短(9.93 d),香蕉组的最长(15.84 d);蛹重以蓖麻组最重(377.8 mg),香蕉组最轻(245.6 mg);幼虫存活率蓖麻组最高(98%),香蕉组最低(66.0%);斜纹夜蛾幼虫的相对取食量、近似消化率和相对生长率等以蓖麻组最高(分别为5.46,68.49,0.53),而以香蕉组最低(分别为0.86,16.30,0.26)。斜纹夜蛾嗜食蓖麻等,而不喜食香蕉。     

取食含不同植物源成分的饲料对香樟齿喙象幼虫生长发育及体内解毒酶活性的影响

【目的】明确取食含不同植物源成分的饲料对香樟齿喙象Pagiophloeus tsushimanus幼虫生长发育以及体内解毒酶活性的影响,以探究寄主植物对香樟齿喙象食性与抗性的作用。【方法】以3种樟科植物(香樟Cinnamomum camphora和浙江桂Cinnamomum chekiangensis和浙江楠Phoebe chekiangensis)枝条粉末为植物源成分,配制成半人工饲料。以半人工饲料进行室内饲养后,分别测定取食半人工饲料后香樟齿喙象幼虫的发育历期、体重、死亡率和化蛹率,以及饥饿12 h后取食含不同植物源成分的半人工饲料的4龄幼虫体内解毒酶(谷胱甘肽-S-转移酶、羧酸酯酶和乙酰胆碱酯酶)活性时序变化。【结果】香樟齿喙象幼虫的发育历期在取食含不同植物源成分的半人工饲料之间存在显著差异。取食含香樟成分的半人工饲料的幼虫发育历期最短(100.13 d),取食含浙江楠成分的半人工饲料的幼虫发育历期最长 (123.33 d);整个幼虫期的死亡率以取食含浙江桂成分的半人工饲料的幼虫最高(41.67%),以取食含香樟成分的半人工饲料的幼虫最低(10.00%);化蛹率以取食含香樟成分的半人工饲料的最高(87.32%);取食含香樟成分的半人工饲料的幼虫体重增长速率也明显高于取食含浙江桂或浙江楠成分的半人工饲料的幼虫。饥饿12 h后取食含不同植物源成分的半人工饲料的香樟齿喙象4龄幼虫体内GST和 AChE活性并无显著差异(P＞0.05);而取食含香樟成分的半人工饲料的幼虫CarE活性在60 h时大幅度上升。【结论】说明香樟齿喙象对天然寄主香樟具有较强的生理适应性,这可能与其专食性密切相关;同时,也表明香樟齿喙象可以通过调节自身生长发育和解毒代谢功能来适应不同寄主植物。     

Effects of host variety on blue willow beetle Phratora vulgatissima performance

Phratora vulgatissima adults exhibit feeding preferences among willow varieties, yet little is known of the effects of willow variety on larval and adult performance. The effects of host variety on adult fitness and fecundity as well as on larval mortality and development were studied under laboratory conditions for 35 willow varieties. The host variety significantly affected the number of days that adults survived and the rates of weight change. On average, males lost weight and females gained weight. The total number of eggs, eggs day¹, eggs clutch^?1 and the length of the oviposition period were also significantly affected by willow variety. Progeny from eggs laid by adults fed on the different willow varieties showed significant differences in days to pupation and pupal weight when subsequently reared on Salix × dasyclados or on the same variety as fed to the adults. However, there was no correlation between these parameters on S. × dasyclados and the variety fed to adults. The willow variety fed to larvae significantly affected larval mortality (four varieties caused 100% mortality), the shape of larval growth curves (as measured by predicted final weight and time to half the final weight), the number of days to pupation and pupal weight. There were significant positive correlations between previously determined adult P. vulgatissima feeding preferences of the 35 willow varieties and the following: number of eggs laid, length of the oviposition period, larval mortality and development and change in adult weight. There was a considerable degree of variation in these correlations and some varieties did not follow the general trend indicated by the size or sign of particular correlations, for example, having a high feeding preference ranking yet few eggs laid, low larval weight and longer time to pupation. The differences found between varieties for adult and larval performance in conjunction with previously established feeding preferences offer great potential for utilising plant resistance to P. vulgatissima as a means of strategic control. Despite the general correlation of feeding preference and performance parameters, the results found here suggest that it appears to be possible for plant breeders to circumvent this trend.     

茄子叶片绒毛与侧多食跗线螨抗性的关系

研究了27 个茄子品种叶片绒毛对侧多食跗线螨(Polyphagotarsonemus latus)的田间种群密度、叶片为害指数、种群增长倍数的影响.结果表明：不同品种茄子叶片绒毛密度和长度存在一定差异;同一品种叶片正面绒毛密度小于背面,正面绒毛长度大于背面;7个抗性较强品种叶片背面平均绒毛密度显著高于6个抗性较弱品种的平均绒毛密度.茄子叶片背面绒毛密度越高,螨的田间种群密度、叶片为害指数越低,茄子的抗性越强.     

棉铃虫在4个辣椒品种上的寄主适合度

在室内条件下,比较了棉铃虫幼虫对辣味程度依次下降的豫优鲜辣2号、豫艺绿冠、豫艺墨秀大椒和豫甜椒12号4个辣椒品种果实的嗜食性、食物转化率和利用率及种群增长情况。结果表明：（1）棉铃虫幼虫的取食选择性、对食物的近似消化率和利用率在4个辣椒品种之间存在明显差异。其中初孵、3龄和5龄幼虫对4个辣椒品种果实的选择性规律基本一致,在豫甜椒12号品种上幼虫出现的百分率和取食量比率均最大;随着辣椒品种辣味程度的降低,5龄幼虫在其上的取食时间和休息时间依次增加,活动时间则依次降低;取食4个辣椒品种的果实后,6龄幼虫的相对生长率、相对取食量和食物转化率差异不显著,但取食豫甜椒12号与豫优鲜辣2号和豫艺绿冠之间的近似消化率和食物利用率差异达显著水平。（2）室内271 ℃ 、70 %-80 % RH和16 L：8 D光周期条件下,棉铃虫在4个辣椒品种上均能完成其世代周期,随着辣椒品种辣味程度的增加,1龄幼虫和整个世代的发育历期依次延长,且在豫甜椒12号与豫优鲜辣2号之间差异达显著水平。其中在豫优鲜辣2号上棉铃虫的世代发育历期最长（27.86 d）,其次为豫艺绿冠（27.23 d）,再次为豫艺墨秀大椒（26.83 d）,在豫甜椒12号上的发育历期最短（25.85 d）;棉铃虫在4个辣椒品种上的世代存活率分别为豫优鲜辣2号为21.67%、豫艺绿冠为23.33%、豫艺墨秀大椒为23.33%、豫甜椒12号为35.00%;取食4个品种辣椒后,棉铃虫的蛹重差异不显著,其中雌蛹重分别为取食豫甜椒12号品种的为249.3 mg,取食豫艺墨秀大椒的为244.7 mg,取食豫艺绿冠的为243.4 mg,取食豫优鲜辣2号的雌蛹最轻,为209.4 mg。雄蛹重与雌蛹表现出的规律基本一致,但取食同一品种的雌蛹重均高于雄蛹重。（3）棉铃虫的种群净增殖率和内禀增长率在豫优鲜辣2号品种上最低,在豫甜椒12号品种上最高。以上结果表明,随着4个辣椒品种辣味程度的增加,棉铃虫在其上的寄主适合度则依次降低,其寄主适合度顺序为：豫甜椒12号＞豫艺墨秀大椒＞豫艺绿冠＞豫优鲜辣2号。     

Effects of transgenic Cry1A＋CpTI cotton and Cry1Ac toxin on the parasitoid, Campoketis chlorideae （Hymenoptera：Ichneumonidae）

Abstract The effect of transgenic double genes, Cry1A + CpTI cotton and Cry1Ac toxin on the parasitoid, Campoketis chlorideae Uchida of cotton bollworm, Helicoverpa armigera (Hübner), was investigated in the laboratory. Helicoverpa armigera larvae when in the first, second and third instar could not survive if fed on transgenic cotton leaves. Consequently, C. chlorideae larvae could not complete their development if parasitizing on such hosts. After H. armigera larvae were reared on transgenic or traditional cotton leaves for 12J48 hours, they were parasitized by C. chlorideae females. Parasitized larvae continued to feed on transgenic or traditional cotton for 12–48 h. The present results showed that the body weight of larvae of the parasitoids were significantly reduced when parasitized hosts fed on transgenic cotton leaves compared to those fed on traditional cotton. Duration of egg and larvae stage were significantly prolonged, pupal and adult weight of C. chloridae was decreased when the host larvae fed on transgenic cotton leaves longer than 48 h. The development duration of C. chlorideae pupae on the hosts fed on transgenic cotton leaves in each treatment was not significantly different from those of controls. The longevity of parasitoid females and males fed with a solution containing Cry1Ac toxin was not significantly different with that of the control.     

Functional response of Picromerus bidens: effects of host plant

Abstract:  The influence of three solanaceous plants (tomato, sweet pepper and eggplant) on the functional response of the predatory bug Picromerus bidens to densities of fourth-instar larvae of the beet armyworm Spodoptera exigua was assessed. Logistic regression indicated a type II functional response on all host plants. Over all prey densities, P. bidens killed significantly fewer fourth instars of S. exigua on tomato than on sweet pepper or eggplant (1.96 ± 0.17 vs. 4.37 ± 0.19 and 3.90 ± 0.15 larvae per predator per 24 h respectively). A higher theoretical maximum predation rate was estimated on sweet pepper (11.1 prey larvae per day) and eggplant (7.4) than on tomato (5.4). The mean number of prey killed per day by P. bidens females ranged from 0.78 at a density of one prey on tomato to 8.45 at a density of 24 prey on sweet pepper. The data indicated that the estimates of handling time ( T _h) and attack rate ( a ) were highly affected by host plant. Based on asymptotic 95% confidence intervals, a lower attack coefficient was found on tomato (0.02 h⁻¹) than on sweet pepper or eggplant (0.07 and 0.11 h⁻¹ respectively). On the other hand, handling times were significantly longer on tomato (4.42 h) and eggplant (3.23 h) than on sweet pepper (2.15 h). This laboratory study suggests that plant characteristics influence the ability of P. bidens to respond to changes in prey density.