南美斑潜蝇寄主选择性与植物次生化合物及叶毛的关系

Relationship between host plant preference of Liriomyza huidobrensis (Blanchard) (Diptera:Agromyzidae) and secondary plant compounds and trichomes of host foliage

采用非自由选择法,以刺伤孔(包括取食孔和产卵孔)数为指标,在室内测定了南美斑潜蝇对6科、16种、22个蔬菜品种的寄主选择性。结果表明,南美斑潜蝇对供试蔬菜品种的选择性存在显著差异,选择性大小依次为豆科>菊科>葫芦科>茄科>伞形科>十字花科;菜豆和茼蒿是南美斑潜蝇最喜欢产卵和取食的寄主,而甘蓝和番茄是其选择性最差的寄主。化学分析和解剖镜观察表明,叶片单宁酸、黄酮含量及叶毛密度在供试品种间存在显著差异:苦瓜的单宁酸含量最高,其次为豌豆、番茄和青椒,含量最低的为金丝搅瓜、茼蒿、菜豆和美国西芹;黄酮含量最高的为甘蓝和番茄,其次为苦瓜,最低为茼蒿、菜豆和美国西芹;南瓜和小白菜的叶毛密度最高,其次为西葫芦、金丝搅瓜和甘蓝,最低为青椒、莴苣和苦瓜。相关分析表明,南美斑潜蝇寄主选择性与叶片单宁酸和黄酮含量呈显著的负相关关系,相关系数分别为-0.4425(P=0.0392)和-0.5728(P=0.0053) ,而与叶毛密度相关关系不显著(R=-0.1807 ,P=0.4211)。说明黄酮和单宁酸对南美斑潜蝇产卵和取食具有明显的抑制作用。

With no-free choice means, the host plant preference of Liriomyza huidobrensis （Blanchard） was examined according to the number of stipples （oviposition and/or feeding punctures） as a preference index on 22 vegetable varieties of 16 species of 6 families in the laboratory. The results showed that the host preference for feeding and oviposition was significantly different among the hosts tested. The preference levels decreased from Leguminosae, Compositae, Cucurbitaceae, Solanaceae, Umbelliferae to Cruciferae. Kidney bean and garland chrysanthemum were the most preferred, and cabbage and tomato were the least. Chemical analysis and microscopical investigation showed that the content of tannin and flavorne in foliages and the density of leaf trichomes differed significantly among the vegetable varieties tested. The content of tannin was the highest in balsam pear, less in pea, tomato and green pepper, and the least in Cucurbita maschata var. medullosa, garland chrysanthemum, kidney bean and American celery. The content of flavone was the highest in cabbage and tomato, less in balsam pear, and the least in garland chrysanthemum, kidney bean and American celery. The density of leaf trichomes was the highest in C. maschata and Chinese cabbage, less in C. pepo, C. maschata var. medullosa and cabbage, and the lowest in green pepper, lettuce and balsam pear. The correlative analysis indicated that the host preference of L. huidobrensis was significantly negatively correlated with the content of tannin and flavone in foliages, and correlation coefficients were -0.4425 （P = 0.0392） and -0.5728 （P =0.0053）, respectively, but it was not significantly correlated with the density of leaf trichomes （R = -0. 1807, P = 0.4211）. These results indicated that tannin and flavorne might play an important role in restraining feeding and oviposition of the pea leaf miner.