Intrinsic competition between two European egg parasitoids of the brown marmorated stink bug

Following the accidental introduction and spread of the invasive polyphagous agricultural pest Halyomorpha halys (Stål) (Hemiptera: Pentatomidae), the two European egg parasitoids Anastatus bifasciatus (Geoffroy) (Hymenoptera: Eupelmidae) and Ooencyrtus telenomicida (Vassiliev) (Hymenoptera: Encyrtidae) have been investigated for inundative biological control. Since the competititve outcome between the two generalist parasitoids is difficult to predict, intrinsic competition was investigated with a time-course development study. Both species readily oviposited in H. halys eggs containing eggs and early instar larvae of the competitor, but oviposition decreased when eggs contained late instar larvae and pupae. Ooencyrtus telenomicida offspring emergence from multiparasitized eggs was significantly lower than that from rearing controls, independent of the order of parasitization. Anastatus bifasciatus offspring emergence was not influenced by the presence of O. telenomicida when it parasitized as the first species, but emergence was decreased after oviposition in eggs containing O. telenomicida larvae and pupae. There was no indication that O. telenomicida can act as a facultative hyperparasitoid of A. bifasciatus. These results suggest that A. bifasciatus is the superior intrinsic competitor and no or minor negative implications for A. bifasciatus are expected if released in combination with O. telenomicida.     

双条杉天牛的生物学特性

双条杉天牛Semanotus bifasciatus(Motschulsky)是危害我国重要绿化树种侧柏的重要害虫。通过室内饲养观察及野外调查相结合的方法,观察分析双条杉天牛的各虫态历期、生活习性和发生规律,并得到出蜇率与温湿度的相关性,及在不同的温度条件下,该虫对颜色有不同的趋性,但总体而言,对绿色有较强的趋性,对无害防治具参考价值。     

双条杉天牛幼虫龄数的划分(鞘翅目:天牛科)

双条杉天牛 Semanotus bifasciatus Motschulsky 是危害我国侧柏 Platycladus orientalis 和圆柏 Sabina chinensis 的重要钻蛀性害虫,其幼虫龄数及最佳分龄指标的确定是进一步研究其生物学特性、发生规律的基础.本研究通过室内木段饲养法获取不同发育阶段的双条杉天牛幼虫,分别测量幼虫的前胸背板宽、头壳宽和上颚宽3项形态指标.采用频次分析法确定幼虫龄数,运用Crosby生长法则和线性回归进行验证分析.结果表明:双条杉天牛幼虫有5龄,其前胸背板宽符合Dyar氏法则和Crosby生长法则并呈现明显的线性回归关系,可作为幼虫龄数划分的重要指标.1～5龄幼虫前胸背板宽分别为0.574±0.012 mm、1.162±0.013 mm、1.738±0.027 mm、2.760±0.011 mm 和3.492±0.015 mm.前胸背板宽(Y1)和幼虫龄数(X)的最佳线性回归方程为lgY1 = 0.185X-0.340(r =0.9647).本研究明确了双条杉天牛幼虫龄数及最佳分龄指标,为深入研究该虫各生长发育阶段的生物生态学特性提供了参考.     

Reproductive strategy of the sugi bark borer,Semanotus japonicus (Coleoptera: Cerambycidae) on Japanese cedar,Cryptomeria japonica

The inner bark of Japanese cedar,Cryptomeria japonica D. Don., is the main food of the sugi bark borer,Semanotus japonicus Lacordaire, but may also be involved in resistance to attack by the borer. I used newly hatched larvae to inoculate cedar logs that had been cut 2-weeks to 12-months earlier, and undamaged living cedar trees. On living trees, all larvae were killed by resin flow from the traumatic resin canals between the outer- and inner bark or between the inner bark and cambium. In logs that were cut more than 4 months prior to inoculation, larvae were unable to complete development. In logs cut 2 weeks prior to inoculation, almost all larvae were able to reach the adult stage but they were smaller in size than adults from living trees damaged by this borer. These results suggest that poor nutrient conditions in the inner bark of logs affected development and survival of the borer. Because of its nutritional advantage, living cedars provide a better environment for the sugi bark borer. However, all larvae are killed by resin flow, suggesting that this insect is “in between” being primary and secondary with respect to living trees, or a “weak” primary insect. The sugi bark borer seems to develop early in the season so that early instar larvae encounter reduced amounts of resin flow and so that late-instar larvae feed mostly in summer when nutrient levels in the inner bark are at their highest.     

药剂喷施饵木防治双条杉天牛成虫的试验

2007年3月在室内进行药效筛选试验,结果表明,阿维·毒、毒死蜱、高效氯氟氰菊酯3种药剂喷施侧柏饵木均能杀死双条杉天牛成虫,毒死蜱作用最快,5d完全死亡率达到94.7%。2008年3月选用高效氯氰菊酯、阿维菌素·毒死蜱、丙溴磷进行了野外试验,结果表明,3种不同药剂防治效果差异显著,同种药剂不同浓度之间防治效果差异不显著,高效氯氰菊酯2000倍液效果最好。喷施高效氯氰菊酯、阿维菌素·毒死蜱不影响饵木的诱集效果。丙溴磷对饵木引诱效果产生影响,其机制机值得得进一步探讨。     

利用中华甲虫蒲螨防治双条杉天牛幼虫研究

双条杉天牛Semanotus bifasciatus(Motschulsky)是危害柏树类树木的主要蛀干害虫之一,主要以幼虫蛀干危害树木。1～4龄幼虫主要危害韧皮部,4龄后幼虫则开始进入到木质部危害,并且用虫粪堵塞蛀道与外界的联络通道,造成小型天敌进入困难。本文通过利用中华甲虫蒲螨Pyemotes zhonghuajia(YuandZhang)防治双条杉天牛1～2和3～4龄幼虫研究试验,比较了天敌中华甲虫蒲螨不同释放量对双条杉天牛的防治效果。结果表明,当中华甲虫蒲螨释放量为1管/木段时,对1～2龄幼虫防治较好,达83.0%;当中华甲虫蒲螨释放量为2管/木段时,对3～4龄幼虫防治也有较好的防治效果,防治效果高达87.7%;但从防治经济高效的角度出发,最合理高效的投放量为1管蒲螨/木段,防治1～2龄幼虫可行性最高。通过中华甲虫蒲螨对双条杉天牛幼虫的寄生结果比较得知,其对寄生体长为1～2cm的双条杉天牛幼虫有明显的趋向性。     

中华甲虫蒲螨寄生双条杉天牛幼虫血淋巴变化

为了解中华甲虫蒲螨Pyemotes zhonghuajia Yu and Zhang对双条杉天牛Semanotus bifasciatus(Motschulsky)的致死过程,将已发育成熟的中华甲虫蒲螨膨腹体移入放有双条杉天牛2龄幼虫的玻璃指形管中,在蒲螨的一个生活史60h内,观察其取食行为,并在移入后每隔12h用考马斯亮蓝法分别测定天牛幼虫和蒲螨血淋巴中总蛋白质含量。结果显示,蒲螨蛋白含量总体呈现上升的趋势,在36～48h上升幅度最大,达61.78%;而天牛幼虫血淋巴总蛋白质含量则呈总体下降趋势,与对照相比,在36～48h之间下降最为明显;蒲螨总蛋白质含量在24h后处理组与对照组差异均为极显著,天牛幼虫总蛋白质含量在48h后处理组与对照组差异显著,这表明蒲螨在24h已搜寻到寄主开始取食,且取食效果明显,而天牛幼虫在48h后表现为麻痹致死,36～48h蒲螨取食对天牛致死起关键作用。12h时处理组的双条杉天牛幼虫总蛋白质含量比对照组略高,推测是由于幼虫对外寄生物蒲螨具有一定的免疫防御反应。     

侧柏树干的超临界CO_2萃取物组分分析及双条杉天牛的EAG反应

利用超临界CO2萃取法和索氏提取法分别提取侧柏Platycladus orientalis(L.)的韧皮部和木质部挥发物,经GC/MS分析其成分,结果表明:超临界CO2萃取物中检测到的21种组分中以倍半萜烯及其氧化物为主,没有检测到单萜类物质;索氏提取法检测到23种组分,韧皮部中检测到的组分以高沸点的树脂酸和二萜等为主,单萜烯和倍半萜及其氧化物含量较低;木质部中以倍半萜烯及其氧化物为主。将不同提取样品进行双条杉天牛Semanotus bifasciatus(Motschulsky)的触角电位反应,结果表明:2种方法的萃取物均能引起天牛的EAG反应,但以超临界萃取物引起的EAG反应较强,且与索氏提取物的反应值差异显著。罗汉柏烯和雪松醇可能是侧柏植物中引诱双条杉天牛的重要活性组分。     

川硬皮肿腿蜂的复壮技术研究

为了得到大量用作实验室繁殖的川硬皮肿腿蜂种蜂,并提高双条杉天牛的生物防治效果,在室内进行双条杉天牛人工养殖的基础上,开展了川硬皮肿腿蜂复壮技术的研究,并进行室内放蜂试验检验复壮前后川硬皮肿腿蜂的搜索寄生能力差异。结果发现,在双条杉天牛的实验室饲养过程中,发现该天牛各虫态出现的时间均比野外环境下早10天左右。通过对川蜂进行连续三代复壮并进行室内放蜂防治试验,结果表明野外收集的川硬皮肿腿蜂对双条杉天牛的平均搜索率为39.33%,寄生率为37.33%,复壮后的川蜂平均搜索率为38.11%,寄生率为34.4%,两者在对双条杉天牛的搜索寄生能力上没有显著的差异。而黄粉虫繁殖的川蜂平均搜索率为30%,寄生率为24.4%,搜索寄生能力存在明显的退化现象。