稻虱缨小蜂对褐飞虱和白背飞虱卵的识别机制

研究了室内条件下信息化合物及稻飞虱卵的形态特征在稻虱缨小蜂识别2种卵寄主褐飞虱和白背飞虱中的作用。结果表明，褐飞虱和白背飞虱雌成虫诱导的水稻挥发物对稻虱缨小蜂的引诱作用无显著差异，各自的引诱比例(头数)分别为57.50%(23头)和42.50%(17头)。稻虱缨小蜂对2种飞虱4组材料，完整卵、磨碎卵、带卵叶鞘和若虫为害叶鞘的行为反应，除了在褐飞虱完整卵上的搜索时间极显著地长于在白背飞虱完整卵上的以外，其余的均不存在差异。挥发物捕集结果表明，褐飞虱和白背飞虱雌成虫诱导的水稻挥发物组成相非常一致。上述结果表明水稻挥发物、稻飞虱利它素及飞虱卵的形态特征在稻虱缨小蜂识别褐飞虱和白背飞虱卵中的作用不明显。文中就稻虱缨小蜂识别2种寄主的机制进行了讨论。

Discrimination by the egg parasitoid Anagrus nilaparvatae between two hosts, Nilaparvata lugens and Sogatella furcifera

Laboratory experiments were conducted to study the role of infochemicals from rice volatiles and rice planthoppers, and morphological characters of rice planthopper eggs, in host discrimination by the egg parasitoid, Anagrus nilaparvatae, between the brown rice planthopper (BPH), Nilaparvata lugens (Stal), and the white backed rice planthopper (WBPH), Sogatella furcifera (Horváth). The results indicated that there was no significant difference in attractiveness between BPH female induced rice volatiles and WBPH female-induced rice volatiles, each of which attracted 57.50% (23) and 42.50% (17) of parasitoids tested, respectively. In a comparison of 4 types of BPH and WBPH materials, i.e., intact eggs, mashed eggs, plants with eggs and nymph-damaged plants, parasitoids showed no preference for any material except intact eggs, spending longer time on BPH eggs than on WBPH eggs. The headspace composition of BPH-infected rice plants was similar to that of WBPH-infected rice plants. The results suggest that infochemicals, kairomone from hosts and synomone from host-infected rice volatiles, and the morphological characters of eggs, do not mediate discrimination by the parasitoid between BPH and WBPH. The mechanism of host discrimination by the parasitoid between BPH and WBPH is discussed.