Strand Jackson R, Perez Moya Oscar G, Peterson Robert K D, Sterling Tracy M, Weaver David K
Department of Land Resources and Environmental Sciences, Montana State University, Bozeman, MT, USA.
Private Consultant, La Ribera de Belen, Heredia, Costa Rica.
J Insect Sci. 2025 Mar 14;25(2). doi: 10.1093/jisesa/ieaf016.
The wheat stem sawfly, Cephus cinctus Norton, is a major pest of cultivated wheat (Triticum aestivum L.) and other cereals in North America. The native congeneric parasitoids Bracon cephi (Gahan) and B. lissogaster Muesebeck are important biocontrol agents and play a crucial role in managing wheat stem sawfly outbreaks and damage. Smooth brome grass (Bromus inermis Leyss) has been found to be an effective wheat stem sawfly sink and parasitoid source when grown in areas neighboring wheat fields in Montana. To better understand the ecology of the system, we investigated both the wheat stem sawfly-induced volatile organic compounds produced by smooth brome and winter wheat, and the electrophysiological and behavioral response of B. cephi and B. lissogaster to the collected volatiles via coupled electroantennography and gas chromatography-flame ionization detection. Volatile concentration analysis indicated significantly increased production of (Z)-3-hexenyl acetate, 6-methyl-5-hepten-2-one, and (E)-2-hexenal in wheat stem sawfly-infested smooth brome, and elevated production of 6-methyl-5-hepten-2-one in infested smooth brome and winter wheat when compared to their uninfested counterparts. Both B. cephi and B. lissogaster exhibited significant electrophysiological and behavioral response to (Z)-3-hexenyl acetate, 6-methyl-5-hepten-2-one, and hexahydrofarnesyl acetone. Our results provide important evidence supporting habitat management recommendations that will enhance the effectiveness of biological control, contributing to more sustainable agricultural practices and the preservation of vital ecological functions.
小麦茎蜂（Cephus cinctus Norton）是北美种植小麦（Triticum aestivum L.）和其他谷物的主要害虫。本地同属的寄生蜂Bracon cephi（Gahan）和B. lissogaster Muesebeck是重要的生物防治剂，在控制小麦茎蜂的爆发和损害方面发挥着关键作用。已发现无芒雀麦（Bromus inermis Leyss）在蒙大拿州麦田附近种植时，是一种有效的小麦茎蜂诱捕源和寄生蜂来源。为了更好地理解该系统的生态学，我们研究了无芒雀麦和冬小麦产生的小麦茎蜂诱导的挥发性有机化合物，以及通过耦合电触角图和气相色谱 - 火焰离子化检测，Bracon cephi和B. lissogaster对收集到的挥发物的电生理和行为反应。挥发性浓度分析表明，受小麦茎蜂侵害的无芒雀麦中，（Z）-3-己烯基乙酸酯、6-甲基-5-庚烯-2-酮和（E）-2-己烯醛的产量显著增加，与未受侵害的对照相比，受侵害的无芒雀麦和冬小麦中6-甲基-5-庚烯-2-酮的产量有所提高。Bracon cephi和B. lissogaster对（Z）-3-己烯基乙酸酯、6-甲基-5-庚烯-2-酮和六氢法呢基丙酮均表现出显著的电生理和行为反应。我们的结果提供了重要证据，支持栖息地管理建议，这将提高生物防治的有效性，有助于实现更可持续的农业实践和保护重要的生态功能。
