Buckner James S, Jones Walker A
Insect Genetics and Biochemistry Unit, Biosciences Research Laboratory, Red River Valley Agricultural Research Center, USDA-ARS, 1605 Albrecht Blvd., Fargo, ND 58105, USA.
Comp Biochem Physiol A Mol Integr Physiol. 2005 Jan;140(1):59-65. doi: 10.1016/j.cbpb.2004.11.001.
The parasitic wasp Eretmocerus mundus (Hymenoptera: Aphelinidae), a natural enemy of the silverleaf whitefly Bemisia argentifolii (Homoptera: Aleyrodidae), deposits eggs beneath nymphs and not within them. Experiments were designed to establish whether ovipositing E. mundus females leave marking chemicals on nymphs to enable searching females to discriminate parasitized from unparasitized hosts. Cuticular lipids from three experimental treatment groups were characterized: parasitoid-exposed nymphs that had a parasitoid egg between the nymph and leaf; control nymphs not exposed to E. mundus; and a third treatment condition of parasitized nymphs, held for 10 days after wasp exposure. Lipids were solvent-extracted from the nymphal cuticles of the various treatment groups and the lipid components were characterized and quantified by gas chromatography and mass spectrometry. Results indicated the presence of quantities of C31 and C33 dimethylalkanes only from parasitoid-exposed groups of nymphs and not in the extracts from control nymphs or the parasitized nymphs after 10-day exposure. Furthermore, the C31 and C33 dimethylalkanes were shown to be major lipid components of the hexane extracts from E. mundus females. Since the lipids were removed from parasitoid-exposed nymphs before interaction with hatched parasitoid larvae, the findings indicated that the dimethylalkanes were transferred onto nymphal cuticles by ovipositing E. mundus females.
寄生蜂芒氏桨角蚜小蜂（膜翅目：蚜小蜂科）是银叶粉虱（半翅目：粉虱科）的一种天敌，它将卵产在若虫下方而非体内。本实验旨在确定正在产卵的芒氏桨角蚜小蜂雌蜂是否会在若虫上留下标记化学物质，以便搜寻的雌蜂能够区分被寄生和未被寄生的宿主。对三个实验处理组的表皮脂类进行了表征：暴露于寄生蜂的若虫，其若虫与叶片之间有一枚寄生蜂卵；未暴露于芒氏桨角蚜小蜂的对照若虫；以及第三个处理条件，即寄生后的若虫，在暴露于黄蜂后饲养10天。从各个处理组的若虫表皮中溶剂提取脂类，并通过气相色谱和质谱对脂类成分进行表征和定量。结果表明，仅在暴露于寄生蜂的若虫组中存在大量的C31和C33二甲基烷烃，而在对照若虫或暴露10天后的寄生若虫提取物中未检测到。此外，C31和C33二甲基烷烃被证明是芒氏桨角蚜小蜂雌蜂己烷提取物中的主要脂类成分。由于在与孵化出的寄生蜂幼虫相互作用之前，脂类已从暴露于寄生蜂的若虫中去除，因此研究结果表明，二甲基烷烃是由正在产卵的芒氏桨角蚜小蜂雌蜂转移到若虫表皮上的。
