三种瓢虫集团内捕食卵对初龄幼虫生长发育的影响

种内和种间捕食卵现象常见于对食蚜瓢虫的研究报道中。源自亚洲、入侵北美和欧洲的异色瓢虫(Harmonia axyridis)由于卵含有生物碱而被认为可能是威胁本土瓢虫生存的原因,但该推测只有在明确异色瓢虫在原产地是否对本土瓢虫具有类似负面影响后,才能确证。通过饲喂实验,旨在明确异色瓢虫在原产地是否对本土七星瓢虫(Coccinella septempunctata)和龟纹瓢虫(Propylea japonica)具有食卵负面作用,为揭示异色瓢虫入侵机理提供依据。实验中用蚜虫(对照)和3种瓢虫卵对瓢虫初孵1龄幼虫进行饲喂处理,观察幼虫生长发育指标。对瓢虫初龄幼虫存活表现的分析结果表明:(1)龟纹瓢虫初孵幼虫取食同种卵和七星瓢虫卵后存活至2龄的比率均高于取食异色瓢虫卵的近7倍;(2)七星瓢虫幼虫取食异色瓢虫卵未存活到2龄,但取食其他瓢虫卵和蚜虫后85%以上个体存活至2龄;(3)异色瓢虫初孵幼虫取食同种和其他2种瓢虫卵后有90%以上存活至2龄。龟纹瓢虫和七星瓢虫1龄幼虫取食异种卵比同种卵后的发育历期显著延长,但异色瓢虫并未表现出差异。龟纹瓢虫和异色瓢虫1龄幼虫取食同种和异种卵后的体增重相同,但七星瓢虫取食龟纹瓢虫卵后体增重比取食同种卵减小。研究结果说明,异色瓢虫卵对七星瓢虫和龟纹瓢虫初孵幼虫的生存具有负面影响,反之不然。所以,取食异色瓢虫卵本身并非是导致北美和欧洲本土瓢虫数量减少的原因。     

异色瓢虫酪氨酸羟化酶基因不同发育历期表达及RNAi抑制黑化效果分析

酪氨酸代谢在昆虫黑色素形成中具有重要的调控作用。本研究为探讨酪氨酸代谢调控异色瓢虫黑色素代谢平衡及其发育的影响,先检测异色瓢虫不同发育阶段酪氨酸羟化酶(Tyrosine hydroxylase,TH)基因表达情况,采用RNAi技术对4龄幼虫注射dsTH RNA抑制酪氨酸羟化酶mRNA表达,探索其在蛹期和成虫羽化阶段黑色素形成中的潜在功能。研究结果表明,TH基因在4龄幼虫体内的表达量最高,而在预蛹阶段和羽化后第2天开始表达量显著性下降。其次,dsTH RNA注射后能够显著降低TH本基因的表达,且异色瓢虫4龄幼虫发育缩短,与注射dsGFP RNA组相比较,提前化蛹。最后,dsTH RNA注射后异色瓢虫蛹的重量略有增加,且发育出现异常,即蛹的颜色变化不加深,与对照组相比较,无黑色斑点出现。这些结果表明成虫是在蛹期开始形成黑色素的,及酪氨酸羟化酶能够通过调控酪氨酸代谢途径而影响异色瓢虫化蛹阶段的发育和表皮颜色的变化。相关研究结果有助于丰富酪氨酸代谢调控异色瓢虫表型的内容,为将来保护异色瓢虫,并将其用于害虫生物防治提供理论基础。     

转Cry1Ac/1Ab基因棉花对异色瓢虫生长发育及其捕食功能的影响

【目的】为探究转Cry1Ac/1Ab基因棉花对异色瓢虫生长发育及其捕食功能的影响。【方法】以转Cry1Ac/1Ab基因棉与其亲本常规棉为实验材料,利用取食不同棉花品种叶片的棉铃虫饲喂异色瓢虫幼虫。【结果】与常规亲本棉相比,取食饲喂转基因棉花叶片的初孵棉铃虫幼虫的异色瓢虫幼虫从1龄发育至化蛹期时间延长0.77 d,但差异不显著;除1龄幼虫体重增加(0.0773 mg)外,其余各龄期幼虫体重均有所下降,但差异均不显著;异色瓢虫1、2、3、4龄幼虫对初孵棉铃虫捕食量均随棉铃虫密度的增加而增加,捕食功能反应均符合HollingⅡ圆盘方程。【结论】转Cry1Ac/1Ab基因棉花对异色瓢虫生长发育无显著影响,饲喂取食转Cry1Ac/1Ab基因棉花的棉铃虫对异色瓢虫捕食功能无显著差异。     

吡虫啉对异色瓢虫种群控害功能的影响

【目的】杀虫剂对天敌的非致死效应是杀虫剂安全性评估的重要内容。【方法】本研究以吡虫啉亚致死浓度处理的大豆蚜Aphis glycines饲喂异色瓢虫Harmonia axyridis,测定了异色瓢虫的发育历期、存活率、蛹重和捕食功能反应。【结果】异色瓢虫G0代不论从哪个龄期开始饲喂毒蚜,LC25(W)处理各龄期其发育均显著延长,且未成熟期(1龄至成虫)显著延长,蛹重和存活率显著降低;异色瓢虫G0代从1龄、3龄和4龄开始饲喂毒蚜,显著延长G1代的3龄龄期,显著缩短G1代的4龄龄期;G0代从4龄开始饲喂毒蚜,显著延长G1代1-3龄的发育历期;G0代不论从哪个龄期开始饲喂毒蚜,G1代蛹重都显著降低,G1代幼虫存活率无显著的变化;异色瓢虫对LC25处理的2龄、3龄和4龄幼虫的最大捕食量显著降低,其余组无显著变化。【结论】吡虫啉亚致死浓度对异色瓢虫G0代和G1代的生长发育均产生影响,且影响异色瓢虫的捕食能力,从而影响异色瓢虫种群的控害功能,这种杀虫剂对非靶标天敌昆虫的非致死效应需要在杀虫剂的安全性评估中予以考虑。     

异色瓢虫对豆蚜的捕食功能反应

试验开展了异色瓢虫Harmonia axyridis Pallas对豆蚜Aphis craccivora Koch的捕食功能反应研究。结果表明,异色瓢虫各虫态的功能反应类型均属于HollingⅡ型。随着豆蚜数量的上升,异色瓢虫对豆蚜的捕食增加量逐渐减小直至趋于稳定。异色瓢虫各龄幼虫、成虫对豆蚜的寻找效应均随豆蚜数量的增加而减小。异色瓢虫4龄幼虫的a/Th值最大,为2255.67,捕食功能最强,其后为成虫、3龄、2 龄、1龄幼虫。     

异色瓢虫幼虫对卵的种内自残和种间捕食

自残现象的发生在异色瓢虫Harmonia axyridis中很是常见,为明确自残行为对其存活和生长发育的影响,在非选择性条件下我们对异色瓢虫幼虫对非姊妹卵的种内自残和对七星瓢虫Coccinella septempunctata卵的种间捕食进行了研究。结果表明,异色瓢虫取食同种卵和异种卵均可完成生长发育,与取食蚜虫相比：①其从卵到成虫及蛹期的发育历期明显缩短（P<0.05）,其中1龄幼虫发育历期缩短非常明显（P<0.01）;②自然条件下高死亡率的1龄幼虫的存活率明显提高（P<0.05）;③2-4龄幼虫、蛹和成虫的体重变轻（P<0.05）,且体长在4龄幼虫间也表现出显著差异（P<0.05）。这表明异色瓢虫种内自残和种间捕食对其在食物恶劣条件下延续种群至关重要,但对种群的繁衍却不是最理想的途径。     

异色瓢虫非同胞间食卵自相残杀对成虫生殖力的影响

【目的】食卵自相残杀现象常见于瓢虫中,业已明确取食同胞卵对于初孵瓢虫至关重要,但取食非同胞卵的营养价值是否高于蚜虫仍存争议。本研究旨在明确异色瓢虫Harmonia axyridis在幼虫期除取食蚜虫外兼捕食非同胞卵是否影响其雌成虫的生殖表现。【方法】在异色瓢虫幼虫期设置3个饲喂处理,即仅饲喂禾谷缢管蚜Rhopalosiphum padi(对照)、除饲喂蚜虫外还分别给各龄幼虫饲喂少量非同胞卵(分散食卵)以及除饲喂蚜虫外仅给高龄幼虫饲喂较多非同胞卵(集中食卵)等,观察雌成虫体型大小、产卵前期、连续10 d的逐日产卵量和卵孵化率等形态和生殖特性。【结果】饲喂处理对瓢虫雌成虫体型大小无显著影响,对照、分散食卵和集中食卵3种饲喂处理下的雌成虫身体体积分别为92.30,89.73和93.98 mm~3;饲喂处理对雌成虫产卵前期也无显著影响,3种饲喂处理下雌成虫产卵前期分别为7.50,7.74和7.70 d;但饲喂处理对雌虫生殖力具有显著影响,分散食卵处理与对照无显著差异,羽化后10 d分散食卵和对照下累计产卵量分别为185和205粒,但集中食卵(88粒)比对照或分散食卵的产卵量显著降低;饲喂处理对卵孵化率无显著影响,对照、分散食卵和集中食卵3种饲喂处理下的卵孵化率分别为63.10%,72.58%和66.61%。【结论】结果说明,异色瓢虫各龄幼虫偶尔取食非同胞卵不影响其成虫的生长发育和生殖,但高龄幼虫捕食较多非同胞卵可降低其雌成虫的生殖力。     

球孢白僵菌对桃蚜及其两种捕食性天敌的影响

从自然感病的温室桃蚜上分离到一株球孢白僵菌Bb21,测定了该菌株对桃蚜的致病性及其对两种捕食性天敌的影响.结果表明:Bb21菌株对桃蚜的致病力强,LD5o为97孢子·mm-2,95％置信区间为45～191孢子·mm-2;对草蛉2龄幼虫有较弱的致病性,LD50为1089孢子·mm-2,是桃蚜的11.2倍;对异色瓢虫致病性极小,高浓度处理(5×108孢子·mL-1)的平均感染率仅为l3％.该菌株低浓度处理对两种捕食性天敌的发育历期和生殖力均无显著影响,但高浓度处理(5×108孢子·mL-1)使异色瓢虫的幼虫期平均缩短1.4d,羽化率降低33％,产卵量减少14％,使普通草蛉的幼虫期平均缩短0.7d,羽化率降低24％,产卵量减少11％.该菌株对桃蚜的半致死剂量远低于对两种捕食性天敌的半致死剂量,并且在防治桃蚜使用浓度下对两种捕食性天敌成虫羽化率和繁殖力的影响极小,可作为温室桃蚜的生物控制因子在有害生物综合治理中应用.     

环境颜色对异色瓢虫生长发育及繁殖能力的影响

在室内利用不同颜色的饲养容器,对异色瓢虫Harmonia axyridis (Pallas) 生长发育、体长体重变化及繁殖能力进行了比较研究。结果显示：不同环境颜色条件对异色瓢虫幼虫各龄历期均有显著影响; 尽管蛹期受不同颜色影响显著,但其总胚后发育期在各处理间差异不显著。异色瓢虫1龄和2龄幼虫体长增量在不同颜色处理间无显著差异,但3龄幼虫在红色条件下体长增量显著小于其余各处理。不同环境颜色条件下异色瓢虫各虫期体重增量均有显著差异,而4龄幼虫体重增量在各处理中均显著大于其余各虫期,并占总胚后发育期体重增量的50%以上。异色瓢虫成虫的交配持续时间在各处理间无显著差异,但其产卵前期在黄色及绿色条件下显著小于其余各处理。其首堆产卵量在各处理间无显著差异,但在红色及自然光下的48 h累计产卵量均显著小于其余处理。     

茄子品种对茄二十八星瓢虫及其寄生蜂生长发育的影响

茄子不同品种对茄二十八星瓢虫及瓢虫柄腹姬小蜂的影响结果表明 ,上海紫茄、呼杂 3 4# 、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     

不同水平亮氨酸对繁殖期意大利蜜蜂蜂群群势及工蜂发育的影响

【目的】评价日粮中不同水平亮氨酸对繁殖期意大利蜜蜂Apis mellifera ligustica蜂群群势及工蜂发育的影响。【方法】选取重庆荣昌本地繁殖期意大利蜜蜂21群,随机分为7组,分别饲喂添加0,15.30,17.50,26.25,35.00,43.75和52.5 g/kg亮氨酸的试验日粮,每12 d测定各组蜂群群势、封盖子量、蜂群取食量和营造王台情况,24 d后测定蜂群采集行为、工蜂初生重、工蜂虫体蛋白质含量及工蜂寿命。【结果】当亮氨酸添加水平为43.75和52.50 g/kg时能够显著提高繁殖期意大利蜜蜂的蜂群群势、封盖子量、蜂群取食量及采集行为(P0.05)。与空白对照组相比,基础日粮组及各亮氨酸添加组的新出房蜂和6日龄幼虫体蛋白质含量较高(P0.05);各亮氨酸添加组的工蜂初生重显著高于空白组(P0.05);不同亮氨酸添加水平对意大利蜜蜂工蜂寿命影响较小。此外,亮氨酸添加水平26.25,35.00和43.75 g/kg能够在饲喂0-24 d时促进蜂群营造自然王台,刺激蜂群分蜂。【结论】配方日粮中43.75和52.5 g/kg的亮氨酸能够显著促进繁殖期意大利蜜蜂蜂群发展,其中43.75 g/kg的亮氨酸饲喂量还能刺激蜂群营造自然王台,激发蜂群分蜂。     

苯醚威作用于印鼠客蚤的组织学研究

【目的】通过研究苯醚威对印鼠客蚤 Xenopsylla cheopis (Rothschild,1903)的早 3 龄幼虫和未吸血新羽化成虫的组织学变化,探讨其灭蚤机理,为鼠疫媒介蚤种的防治提供基础资料。【方法】以微量点滴法将苯醚威施药于印鼠客蚤早3龄幼虫和未吸血新羽化成虫,采用组织学、显微摄影及统计学方法观察组织变化。【结果】经苯醚威作用后,印鼠客蚤的早 3 龄幼虫的表皮增厚、卵巢芽生殖细胞萎缩、睾丸芽精原细胞间质减少;未吸血新羽化成虫的睾丸塞消失快、唾液腺细胞破坏严重、中肠上皮细胞萎缩。【结论】(1)苯醚威通过干扰印鼠客蚤幼虫的变态,引起幼虫表皮、生殖芽异常改变,不能发育为成虫而死亡;(2)苯醚威可加速印鼠客蚤新羽化雄性成虫的睾丸塞吸收;(3)苯醚威可破坏印鼠客蚤新羽化成虫的唾液腺细胞,并引起中肠上皮细胞萎缩。     

Effect of buprofezin on survival of immature stages of Harmonia axyridis, Stethorus punctum picipes (Coleoptera: Coccinellidae), Orius tristicolor (Hemiptera: Anthocoridae), and Geocoris spp. (Hemiptera: Geocoridae)

The effect of buprofezin, a chitin synthesis inhibitor, on development and survival of immature stages of Harmonia axyridis (Pallas), Stethortus punctum picipes Casey, Orius tristicolor (White), Geocoris pallens St?l, and Geocoris punctipes (Say), was examined in a series of laboratory bioassays. Very few H. axyridis larvae (3.1%) treated with buprofezin reached adulthood, although 65% of treated pupae emerged successfully. Buprofezin caused no mortality to eggs of S. punctum picipes but 71.1% of treated early instar larvae failed to complete development. Eighty percent of treated late instars and 92.3% of pupae produced viable adults. Early instar nymphs of O. tristicolor were unaffected by buprofezin, whereas 47.7 and 85% of G. punctipes and G. pallens nymphs, respectively, failed to complete development. Treated eggs of G. pallens hatched successfully. The use of buprofezin in integrated pest management in Washington state wine grapes is discussed.     

Effects of a juvenoid, DPE-28, on biology and behaviour of Culex quinquefasciatus, the human filariasis vector

Studies on the effect of a juvenoid, DPE-28 (2,4-dinitrophenyl-2',6'-di-tertiarybutyl phenyl ether) on biology and behaviour of Cx. quinquefasciatus showed that the developmental duration, sex ratio, mating success and blood feeding were considerably affected by the exposure of larvae and pupae to the compound. Exposure of fourth instar larvae to 0.007 (EI90) and 0.0019 (EI50) ppm of DPE-28 prolonged the duration of pupation by 58.6 and 52.4 hr and delayed the adult emergence by 35.4 and 17.7 hr in males and 36.8 and 21.1 hr in females respectively. Exposure of freshly ecdysed pupae to 10 and 5 ppm delayed the adult emergence with respect to the control by 54.3 and 32.4 hr in males and 55.2 and 33.2 hr in females respectively. The sex ratio of the adults emerged from treated larvae and pupae was also affected. The female mosquitoes that survived from the exposed fourth instar larvae and pupae exhibited a low blood engorgement ratio. This depression in blood feeding was more pronounced in adults emerged from treated pupae than that of treated fourth instar larvae. A significant proportion of adults emerged from treated larvae and pupae were able to feed only partially. Mating success of the treated populations declined considerably when crosses were made between the males and females emerged from treated fourth instar larvae and pupae. The adults emerged from treated larvae and pupae showed a significant reduction in the oviposition.     

Neural inhibition of the corpus allatum in the last larval instar differs from that in adults in the blood-feeding insect, Rhodnius prolixus

An active corpus allatum (CA) in the blood feeding insect, Rhodnius prolixus, releases a substance that inhibits metamorphosis in larvae, and activates egg production in adults. In adults, transecting the nervus corporis cardiacum II's (NCCII), which are attached posteriorly to each protocerebral lobe, greatly increases egg production indicating that the adult CA is activated and receives neural inhibition from cells associated with the NCCII [Chiang, Arch. Insect. Biochem. Physiol. 39:126-131 (1998)]. In the present study, the NCCII's in fifth instar larvae were transected immediately before or after feeding to determine if these nerves normally inhibit CA activity in the last larval instar. Approximately 20 to 25 days following ingestion of a blood meal, L5's with transected NCCII's emerged as fully-formed adults with no larval characteristics. Examination of the brain in these recently emerged adults revealed that the NCCII's were absent. Since fifth instar larvae with transected NCCII's emerged with no juvenile characteristics, cutting the NCCII's did not activate the CA, indicating that the mechanism for inhibition of the CA differs in the last larval instar and adult animals.     

无翅桃蚜对龟纹瓢虫的视觉和嗅觉识别反应

为探明桃蚜Myzus persicae是否可以识别来自其捕食性天敌的嗅觉和视觉信息,本研究采用桃蚜和龟纹瓢虫Propylaea japonica这一猎物-捕食者系统,在室内测定了无翅桃蚜对龟纹瓢虫成虫体色和挥发物的识别反应。选择反应试验结果表明,无翅桃蚜既能通过视觉信息识别瓢虫的存在,也能通过嗅觉信息识别瓢虫的存在,说明桃蚜对龟纹瓢虫体色和气味信息的识别存在一定的冗余现象。剂量反应试验结果表明,龟纹瓢虫粗提物的剂量与其对桃蚜的驱避率呈现良好的线性关系,识别反应剂量的临界值在0.3~0.6个瓢虫当量之间,1.2~1.5个瓢虫当量的粗提物的驱避作用与20头活体龟纹瓢虫的驱避作用相当。结论认为,桃蚜可以识别龟纹瓢虫的存在,并对其作出一定的躲避反应,从而降低被捕食的风险。     

Vulnerability of larvae of two species of aphidophagous ladybirds, Adalia bipunctata Linnaeus and Harmonia axyridis Pallas, to cannibalism and intraguild predation

Vulnerability of larvae of two species of aphidophagous ladybirds, Adalia bipunctata Linnaeus and Harmonia axyridis Pallas, to cannibalism and intraguild predation was assessed in the laboratory. In the first experiment, a first instar of one of the two above species was kept with a fourth instar of the other species in a Petri dish. The number of times each first instar larva was encountered by the fourth instar larva and the fate of the first instar was determined over a period of 10 min. The fourth instar larvae captured and killed all the first instar larvae of their own species at the first encounter. However, when presented with fourth instar larvae of the other species the first instar larvae of A. bipunctata and H. axyridis were encountered 6.4 ± 1.3 ( n  = 10) and 19.4 ± 2.1 ( n  = 10), respectively. In this experiment no first instar larvae of H. axyridis , whereas all those of A. bipunctata , were killed.     

Laboratory Effects of Ingestion of Azadirachtin by Two Pests ( Ceratitis capitata and Spodoptera exigua ) and Three Natural Enemies ( Chrysoperla carnea , Opius concolor and Podisus maculiventris )

The effects of azadirachtin on two pests: neonate larvae and newly emerged adults of Ceratitis capitata (Wiedemann) and last instar larvae of Spodoptera exigua (Hubner); and three natural enemies: newly emerged adults of Opius concolor Szepligeti, second instar larvae of Chrysoperla carnea (Stephens), and fifth instar nymphs of Podisus maculiventris (Say) were studied in laboratory. Adult insects were exposed to a non-oil formulation of azadirachtin (Align, emulsifiable concentrate, 3.2% azadirachtin, Sipcam Inagra, Spain) via their drinking water and immature instars were reared in the presence of the insecticide-treated diet. The natural enemies were exposed to at least the maximum field recommended concentration of the insecticide (0.15% v/v). Azadirachtin was highly toxic to neonate larvae of C. capitata and prevented adult emergence at a concentration of 1 mg a.i. l -1 . When adults were fed the insecticide at the maximum recommended concentration, their survival was not affected but egg laying was totally inhibited. Last instar S. exigua larvae were also very susceptible (LC 50 = 7.7 mg a.i. l -1 ) and at a concentration of 10 mg a.i. l -1 fecundity of surviving adults, and egg fertility, were reduced by 72 and 85%, respectively. Effects on O. concolor were large, and significant reductions in longevity, percentage of attacked hosts, and progeny size per female, were recorded. The predator P. maculiventris was much less sensitive to azadirachtin, but slight reductions in survival of emerged adults and of reproductive parameters occurred. The insecticide had no significant effect on C. carnea larvae fed with treated Sitotroga cerealella (Oliver) eggs, probably because of its inability to penetrate inside the egg.     

Growth and induction in food consumption of Helicoverpa armigera Hbn. (Lep., Noctuidae) larvae on chickpea, soybean, and maize diets

Laboratory studies were conducted to determine the effect of different artificial diets made of powdered seed materials of chickpea ( Cicer arietinum ), soybean ( Glycine max ), and maize ( Zea mays ) on the growth, consumption, and feeding preferences of Helicoverpa armigera larvae. Food consumption and growth of ultimate instar gram pod borer larvae were minimal on maize diet. The nutritive value of the soybean diet was higher, but the consumption rate of larvae was highest on chickpea diet compared with the other test diets. The growth of larvae was statistically equal on chickpea and soybean diets, in spite of differences in the consumption rate of these diets and their nutritive value. There appears to be a direct correlation between the quantity of the diets consumed and their nutritive value for growth of the larvae on chickpea and soybean diets. The lower nutritive value of chickpea diet is correlated with its higher intake by the larvae. Similarly, the lower consumption rate of larvae on soybean diet is correlated with its higher nutritive value. The diet on which the larvae were fed during earlier instars did not induce any feeding preference for that particular diet in the ultimate larval instar. The larvae consumed similar quantities of each of the three diets in their ultimate instar, irrespective of having fed on any of these diets during any preceding instars. However, induction in the quantitative consumption of food by the larvae was evident. The higher or lower consumption rate of diet by the larvae in the ultimate instar was influenced by their food during earlier instars. Hence the food consumption rate of larvae in the last instar appears to be set while feeding on a diet in the preceding instars.