van Tol R W H M, Helsen H H M, Griepink F C, de Kogel W J
Plant Research International, Wageningen-UR, PO Box 69, 6700 AB Wageningen, The Netherlands.
Bull Entomol Res. 2009 Dec;99(6):593-602. doi: 10.1017/S0007485309006634. Epub 2009 Feb 19.
All aphid species studied so far share the same sex pheromone components, nepetalactol and nepetalactone. Variation by different enantiomers and blends of the two components released by different aphid species are limited and can only partially explain species-specific attraction of males to females. While some host-plant odours are known to enhance specific attraction of aphid species, herbivore-induced plant volatiles that synergise attractiveness to the sex pheromone are unknown. Here, we demonstrate that for the host-alternating rosy apple aphid (Dysaphis plantaginea (Passerini)) specificity of attraction of males to females is triggered by female-induced tree odours in combination with a 1:8 ratio of (4aS,7S,7aR)-nepetalactone and (1R,4aS,7S,7aR)-nepetalactol. Female aphid infestation induces increased release of four esters (hexyl butyrate, (E)-2-hexenyl butyrate, (Z)-3-hexenyl 3-methylbutyrate and hexyl 2-methylbutyrate) from apple leaves. Two different combinations of three esters applied in a 1:1:1 ratio increase the number of male D. plantaginea and decrease the number of other aphid species caught in water traps in the presence of the pheromone components. The ester blend alone was not attractive. Combination of the pheromone blend with each single ester was not increasing attraction of male D. plantaginea. The demonstration that sexual aphid species use herbivore-induced plant volatiles as a species-specific attractant for mate finding adds a new dimension to our understanding of insect species using or manipulating chemical cues of host plants for orientation.
到目前为止，所有已研究的蚜虫物种都共享相同的性信息素成分，即荆芥醇和荆芥内酯。不同蚜虫物种释放的这两种成分的不同对映体和混合物的变化有限，只能部分解释雄性对雌性的物种特异性吸引。虽然已知一些寄主植物气味会增强蚜虫物种的特异性吸引力，但协同增强对性信息素吸引力的植食性昆虫诱导植物挥发物尚不清楚。在这里，我们证明，对于寄主交替的蔷薇长管蚜（Dysaphis plantaginea (Passerini)），雄性对雌性的吸引特异性是由雌性诱导的树木气味与(4aS,7S,7aR)-荆芥内酯和(1R,4aS,7S,7aR)-荆芥醇1:8的比例共同触发的。雌性蚜虫侵染会导致苹果叶片中四种酯（丁酸己酯、(E)-2-己烯基丁酸酯、(Z)-3-己烯基3-甲基丁酸酯和2-甲基丁酸己酯）的释放增加。以1:1:1的比例施用的三种酯的两种不同组合，在存在性信息素成分的情况下，会增加蔷薇长管蚜雄性的数量，并减少诱捕在水陷阱中的其他蚜虫物种的数量。单独的酯混合物没有吸引力。性信息素混合物与每种单一酯的组合并没有增加蔷薇长管蚜雄性的吸引力。蚜虫物种利用植食性昆虫诱导植物挥发物作为寻找配偶的物种特异性引诱剂，这一证明为我们对利用或操纵寄主植物化学线索进行定向的昆虫物种的理解增添了新的维度。
