Thermosensitivity of germ lines of Trichogramma brassicae Bezdenko (Hymenoptera). Implications for efficacy of the parasitoid
Thermosensitivity of germ lines of Trichogramma brassicae Bezdenko (Hymenoptera). Implications for efficacy of the parasitoid
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DOI：
10.1139/z97-059
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发表时间：
1997-03-01
期刊：
影响因子：
--
通讯作者：
Lauge, G
中科院分区：
文献类型：
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作者：
Chihrane, J;Lauge, G
甘蓝赤眼蜂是一种用于生物防治欧洲玉米螟的寄生蜂，如果在释放时存在某些热条件，则其效果会降低。一项实验室研究表明，在田间释放的一代繁殖力降低，下一代雌性比例降低。这些结果促使我们研究拟寄生蜂的生殖系。在白色若虫阶段暴露于35 ℃的温度不会影响卵巢功能，但暴露于44 ℃会影响卵巢功能：出现时成熟卵母细胞的数量低于对照组;某些卵巢异常或保持幼年。在出现时，雄性对照的精囊含有大量的典型精子和少量的非典型精子，后者在暴露于35 ℃的雄性中变得更多。在暴露于44摄氏度后，囊泡只含有少量精子或完全空了。自从T.甘蓝是一种孤雌生殖的物种（未受精的卵变成雄性），这些观察结果解释了第二代雌性数量减少的原因。
Trichogramma brassicae, a parasitoid used in the biological control of the European corn borer, Ostrinia nubilalis, becomes less effective if certain thermal conditions prevail at the time of its release. A laboratory study demonstrated that the generation liberated in the field had reduced fecundity and that the proportion of females was lower in the following generation. These results prompted us to examine the germ lines of the parasitoid. Exposure to a temperature of 35 degrees C at the white nymph stage does not affect ovarian function, but exposure to 44 degrees C does: the number of mature ovocytes at emergence is lower than that observed in controls; certain ovaries are abnormal or remain juvenile. At the time of emergence, the seminal vesicles of male controls contain large numbers of typical sperm and a few atypical sperm, the latter becoming more numerous in males exposed to 35 degrees C. After exposure to 44 degrees C, vesicles contain only a few sperm or are completely empty. Since T. brassicae is an arrhenotokous parthenogenetic species (unfertilized eggs become males), these observations explain the reduced number of females in the second generation.