Relationship between temperature and development of Ooencyrtus kuwanae(Hymenoptera:Encyrtidae),the egg parasitoid of Lymantria dispar(Lepidoptera: Lymantriidae),with an evaluation of its offspring quality reared from eggs of the substitute host Antheraea pernyi(Lepidoptera:Saturniidae)

舞毒蛾Lymantr dispar(L.)是国际性检疫害虫.大蛾卵跳小蜂Ooencyrtus kuwanae (Howard)是舞毒蛾卵的重要寄生蜂,对舞毒蛾有一定的控制作用.为了在规模化繁育大蛾卵跳小蜂时控制小蜂的发育进度,设置不同的温度梯度研究了该蜂发育与温度的关系;同时,为了对替代寄主繁育出的天敌质量进行评价,对利用其自然寄主舞毒蛾卵和替代寄主柞蚕Antheraea pernyi卵繁育出的子代成蜂的寿命、胸宽、雌雄性比进行了比较.结果显示:大蛾卵跳小蜂的发育起点温度和有效积温分别为10.50±1.41℃和260.74±25.09日·度,温度与发育速率的关系为T=10.50+ 260.74V.当采用30％的蜂蜜水饲喂成蜂时,柞蚕卵繁育出的大蛾卵跳小蜂雌、雄蜂的平均寿命分别为15.01和10.38 d,采用原寄主舞毒蛾卵繁育出的雌、雄蜂平均寿命分别为20.94和15.95 d,两者差异显著;采用柞蚕卵繁育出的雌蜂个体显著大于用舞毒蛾卵繁育出的雌蜂个体;柞蚕卵和舞毒蛾卵繁育出的大蛾卵跳小蜂雌雄性比没有显著差异,分别为2.42∶1和2.57:1.结果表明,在野外开展舞毒蛾的生物防治时,释放利用柞蚕卵繁育出的大蛾卵跳小蜂具有可行性.     

舞毒蛾卵平腹小蜂野外寄生柞蚕卵规律的观察

2005年5～9月,在长春市吉林农业大学校园内的杨树林和李树林内进行人工挂放柞蚕Antheraea pernyi Guerin-Meneville卵卡诱集本地平腹小蜂Anastatus spp.寄生试验.结果表明杨树林中的舞毒蛾卵平腹小蜂Anastatus japonicus Ashmead的寄生率最高可达23.1%,李树林中的舞毒蛾卵平腹小蜂的寄生率最高可达33.5%,李树林中舞毒蛾卵平腹小蜂的寄生率明显高于杨树林.全年中,舞毒蛾卵平腹小蜂分别在6月下旬和8月上旬出现2次寄生高峰.     

柞蚕卵为繁育寄主的黏虫赤眼蜂发育起点温度和有效积温研究

为了明确黏虫赤眼蜂的发育起点温度和有效积温,本研究以柞蚕卵为中间繁育寄主,测定了黏虫赤眼蜂在17℃、20℃、23℃、26℃、29℃下各虫态的发育历期,并运用有效积温法则计算出黏虫赤眼蜂的发育起点温度和有效积温。结果表明:黏虫赤眼蜂各虫态在17℃～29℃均能正常发育,并且各温度下的发育历期明显不同,世代发育历期也明显不同,均随着温度的升高而逐渐变短。柞蚕卵繁育黏虫赤眼蜂的卵期、幼虫前期、幼虫中期、幼虫后期、预蛹期、蛹期的发育起点温度分别为8.01℃、15.41℃、13.51℃、13.32℃、15.39℃、9.04℃,有效积温分别为22.01、7.66、8.98、9.19、37.23、115.22℃·d。本研究为指导利用柞蚕卵大量繁育黏虫赤眼蜂以及探索诱导滞育温度提供了理论依据。     

Incidence of superparasitism in the egg parasitoid,Ooencyrtus kuvanae Howard (Hymenoptera: Encyrtidae)

The encyrtid Ooencyrtus kuvanae is a solitary parasitoid of the gypsy moth, Lymantria dispar L. (Lepidoptera-Lymantridae) that is used in biological control programmes and whose mass rearing is influenced by superparasitism. The purpose of this study was to investigate the effect of the self-superparasitism of O. kuvanae at different host densities (5, 10, 15 and 20), female ages (3 and 5 days) and durations of exposure (1 and 5 days) under various laboratory conditions (25°C?±?1°C, RH 60?±?5% and a 16:8?h light:dark photoperiod) as well as in a new laboratory host, Philosamia ricini (Danovan) (Lepidoptera: Saturniidae) of O. kuvanae. In this study, we determined the rate of egg superparasitism and adult emergence and recorded development time, longevity and body weight. Superparasitism increased with female age and the duration of exposure to parasitoids when females had access to five host eggs. Superparasitism increased the number of parasitoid offspring, but it resulted in male-biased (56.90%) progeny. Furthermore, superparasitism caused deleterious effects to the fitness of the progeny by prolonging the developmental process, and decreasing longevity. For example, we found that when four adults can emerge from one superparasitised host egg, the body size of the parasitoid offspring decreases significantly. Hence, superparasitism should be avoided when mass rearing O. kuvanae.